be less silly next time (hard coded version number where it is dynamic)

* added dockerfile

* cleanup dockerfile

* update Dockerfile and create raspberry dockerfile

* doc & aria2

.dockerignore

@@ -0,0 +1 @@
+Dockerfile

.drone.yml

@@ -0,0 +1,13 @@
+kind: pipeline
+name: default
+
+steps:
+- name: docker
+  image: plugins/docker
+  settings:
+    registry: r.sbruder.de
+    username:
+      from_secret: docker_username
+    password:
+      from_secret: docker_password
+    repo: r.sbruder.de/mumbledj

.github/ISSUE_TEMPLATE.md

@@ -0,0 +1,20 @@
+#### Before submitting this issue, please acknowledge that you have done the following:
+- [ ] I've at least skimmed through the [README](https://github.com/matthieugrieger/mumbledj/blob/master/README.md)
+- [ ] I have checked that I am running the latest version of MumbleDJ (use `mumbledj --version` when starting the bot or use the MumbleDJ version command in Mumble)
+- [ ] I have [searched through the existing issues](https://github.com/matthieugrieger/mumbledj/issues) to see if my issue has been answered already
+
+---
+
+#### What type of issue is this?
+- [ ] Bug report (encountered problems with MumbleDJ)
+- [ ] Feature request (request for a new functionality)
+- [ ] Question
+- [ ] Other:
+
+---
+
+#### Log output of bot with `--debug` flag (likely only for bug reports):
+
+---
+
+#### Description of your issue:

.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,18 @@
+#### Before submitting this pull request, please acknowledge that you have done the following:
+- [ ] I have tested my changes to make sure that they work
+- [ ] I have at least attempted to write relevant unit tests to verify that my changes work
+- [ ] I have read through the [contribution guidelines](https://github.com/matthieugrieger/mumbledj/blob/master/.github/CONTRIBUTING.md)
+- [ ] I have written any necessary documentation (for example, adding information about a feature to the README)
+
+---
+
+#### What type of pull request is this?
+- [ ] Bug fix
+- [ ] Typo fix
+- [ ] New feature implementation
+- [ ] New service implementation
+- [ ] Other
+
+---
+
+#### Description of your pull request:

.gitignore

@@ -1 +1,3 @@
-mumbledj
+mumbledj*
+coverage.txt
+*.coverprofile

.travis.yml

@@ -0,0 +1,22 @@
+language: go
+
+sudo: false
+
+go:
+  - 1.5
+  - 1.6
+  - tip
+
+before_install:
+  - go get github.com/Masterminds/glide
+  - go get github.com/go-playground/overalls
+
+script:
+  - make coverage
+
+after_success:
+  - bash <(curl -s https://codecov.io/bash)
+
+env:
+  global:
+    - GO15VENDOREXPERIMENT="1"

CHANGELOG.md

@@ -1,6 +1,299 @@
 MumbleDJ Changelog
 ==================
 
+### November 5, 2016 -- `v3.2.1`
+* Fixed YouTube video offsets. Now YouTube URLs with `?t=<timestamp>` at the end will start the audio playback at the appropriate position.
+
+### November 5, 2016 -- `v3.2.0`
+* Fixed a Go panic that would occur when a YouTube playlist contained a private video.
+* Added back immediate skipping for tracks/playlists that are skipped by the submitter. This was a feature that was present in the last major version of MumbleDJ but was forgotten when rewriting the bot (sorry!).
+
+### August 22, 2016 -- `v3.1.4`
+* Fixed a SoundCloud API response parsing issue that would result in empty IDs for tracks.
+* Fixed the startup check for SoundCloud API.
+
+### August 21, 2016 -- `v3.1.3`
+* Fixed a deadlock that would occur during the transition from the first to second track in a queue.
+
+### August 14, 2016 -- `v3.1.2`
+* Fixed an index out of range crash in the queue skipping function.
+
+### July 11, 2016 -- `v3.1.1`
+* Updated vendored dependencies to hopefully address the following issue: https://github.com/matthieugrieger/mumbledj/issues/169.
+
+### July 10, 2016 -- `v3.1.0`
+* File path for user `p12` certificate can now be provided for authenticating as a registered user via the `--p12` commandline flag or the `connection.user_p12` configuration value.
+* Added `!register` command for registering the bot on the server.
+
+### July 1, 2016 -- `v3.0.11`
+* Potential fix for an issue with IP SANs on PEM certs.
+
+### June 29, 2016 -- `v3.0.10`
+* Fixed issue related to PEM keys being overwritten by PEM certs.
+
+### June 28, 2016 -- `v3.0.9`
+* Queue is now reset after disconnecting from the server to avoid unpredictable behavior.
+
+### June 26, 2016 -- `v3.0.8`
+* Fixed hang on setting `max_tracks_per_playlist` to a value larger than 50 (thanks [@mattikus](https://github.com/mattikus)).
+* Fixed full directory path not being created properly for config file (thanks [@DanielMarquard](https://github.com/DanielMarquard)).
+
+### June 25, 2016 -- `v3.0.7`
+* Volume can now be set to `volume.lowest` and `volume.highest` (in other words, the range is inclusive now instead of exclusive).
+* All configuration values can now be overridden via commandline arguments. For example: `mumbledj --admins.names="SuperUser,Matt" --volume.default="0.5" --commands.add.is_admin="false"`
+  * __NOTE__: Configuration settings that contain commas (",") are interpreted as string slices (or arrays if you aren't familiar with Go).
+* Removed an extra period that was sometimes output in error messages.
+
+### June 25, 2016 -- `v3.0.6`
+* Fixed an issue with `!forceskip` not stopping audio playback.
+
+### June 25, 2016 -- `v3.0.5`
+* Fixed admin settings not being respected.
+
+### June 25, 2016 -- `v3.0.4`
+* Fixed a crash on `!forceskip`.
+
+### June 22, 2016 -- `v3.0.3`
+* Fixed SoundCloud API startup check (thanks [@alucardRD](https://github.com/alucardRD)).
+
+### June 21, 2016 -- `v3.0.2`
+* Fixed typo on admin command header message selector.
+
+### June 21, 2016 -- `v3.0.1`
+* Added all strings that are output by commands to `config.yaml` for easier translation and tweaking.
+
+### June 20, 2016 -- `v3.0.0`
+* Significantly simplified installation process, now installable via `go install`.
+* Commands may now have multiple aliases, configurable via config file.
+* Command aliases are checked for duplicates and closes the bot if duplicates are found.
+* Added new commands: `!resume`, `!pause`. These commands allow you to resume and pause audio streams respectively.
+* `!add` and `!addnext` can now take any number of space-separated URLs as arguments.
+* Commands are now executed asynchronously for better performance and responsiveness.
+* Restructured project into subpackages: `bot`, `commands`, `interfaces`, `services`.
+* Config file is now in `.yaml` format and is written to `$HOME/.config/mumbledj/config.yaml`.
+* Altered config file layout to make it easier to read.
+* When an updated config file is available it is written to `$HOME/.config/mumbledj/config.yaml.new`.
+* Alternate config file locations can be supplied via `--config` commandline flag.
+* Added logging for easier monitoring and issue debugging.
+* Added `--debug` flag for more verbose logging when debugging an issue.
+* Access tokens in config file and `--accesstokens` commandline flag are now comma-separated instead of space-separated.
+* Mixcloud now requires the installation of `aria2` to work properly due to download throttling.
+* Startup checks are performed before the bot connects to the server to determine if any required software is missing or misconfigured.
+* API startup checks are performed before the bot connects to the server to determine if any services have missing/invalid API keys.
+* Dependencies are now vendored via `/vendor` folder for more reproducible builds.
+* `glide` has replaced `goop` as the dependency management tool.
+* Added `CONTRIBUTING.md` and templates for GitHub Issues and Pull Requests.
+* Revamped `Makefile` and made it less complicated.
+* Implemented continuous integration support with [Travis CI](https://travis-ci.org).
+* Builds for `linux/arm64` and `linux/386` are now provided as downloads for each release.
+* Implemented many unit tests to test functionality of bot subsystems.
+* Much more not listed here!
+
+I hope you guys enjoy this update, it has been in the works for a few months. :)
+
+### June 17, 2016 -- `v2.10.0`
+* Added `!joinme` command (thanks [@azlux](https://github.com/azlux)).
+
+### May 24, 2016 -- `v2.9.1`
+* Fixed player command configuration setting not being applied to youtube-dl calls.
+
+### April 9, 2016 -- `v2.9.0`
+* Added support for Mixcloud (thanks [@benklett](https://github.com/benklett)).
+
+### February 14, 2016 -- `v2.8.15`
+* Fixed an incorrectly formatted error message (thanks [@GabrielPlassard](https://github.com/GabrielPlassard)).
+
+### February 12, 2016 -- `v2.8.14`
+* Audio is now downloaded using the `bestaudio` format. This prevents situations in which some audio would not play because an `.m4a` file was not available (thanks [@mpacella88](https://github.com/mpacella88)).
+
+### February 6, 2016 -- `v2.8.13`
+* Added `!version` command to display the version of MumbleDJ that is running (thanks [@zeblau](https://github.com/zeblau)).
+* Added `version` commandline argument to display the version of MumbleDJ that is running (thanks [@zeblau](https://github.com/zeblau)).
+
+### January 26, 2016 -- `v2.8.12`
+* Temporarily fixed discontinued code.google.com imports.
+
+### January 14, 2016 -- `v2.8.11`
+* Fixed: Unable to use offsets if it's formatted as &t vs ?t in the URL (thanks [@fiveofeight](https://github.com/fiveofeight)).
+
+### January 11, 2016 -- `v2.8.10`
+* Created a new configuration value in the General section called PlayerCommand. This allows the user to change between "ffmpeg" and "avconv" for playing audio files.
+* Added check for valid PlayerCommand value. If the value is invalid the bot will default to `ffmpeg`.
+
+### December 26, 2015 -- `v2.8.9`
+* Fixed an incorrect `!currentsong` message for songs within playlists.
+
+### December 21, 2015 -- `v2.8.8`
+* Fixed a typo in song list HTML (thanks [@mkody](https://github.com/mkody)).
+
+### December 19, 2015 -- `v2.8.7`
+* Added AnnounceNewTracks config option (thanks [@HowIChrgeLazer](https://github.com/HowIChrgeLazer)).
+
+### December 16, 2015 -- `v2.8.6`
+* Added !addnext command (thanks [@nkhoit](https://github.com/nkhoit)).
+* Added argument to !listsongs command to specify how many songs to list (thanks [@nkhoit](https://github.com/nkhoit)).
+
+### December 14, 2015 -- `v2.8.5`
+* Added !listsongs command (thanks [@nkhoit](https://github.com/nkhoit)).
+
+### December 7, 2015 -- `v2.8.4`
+* YouTube and SoundCloud API keys are now stored in the configuration file instead of environment variables. Existing installations with API keys in environment variables will automatically be migrated to the configuration file (thanks [@Gamah](https://github.com/Gamah)).
+
+### October 16, 2015 -- `v2.8.3`
+* Playlists can now be over 50 songs in length (thanks [@GabrielPlassard](https://github.com/GabrielPlassard)).
+* Added MaxSongPerPlaylist configuration option.
+
+### October 14, 2015 -- `v2.8.2`
+* Fixed possible index out of range panic when auto shuffle is on (thanks [@GabrielPlassard](https://github.com/GabrielPlassard)).
+
+### October 12, 2015 -- `v2.8.1`
+* Added !shuffle, !shuffleon, and !shuffleoff commands (thanks [@GabrielPlassard](https://github.com/GabrielPlassard)).
+
+### October 1, 2015 -- `v2.8.0`
+* Added Soundcloud support (thanks [@MichaelOultram](https://github.com/MichaelOultram)).
+
+### August 12, 2015 -- `v2.7.5`
+* Fixed cache clearing earlier than expected (thanks [@CMahaff](https://github.com/CMahaff)).
+
+### May 19, 2015 -- `v2.7.4`
+* Fixed a panic that occurred when certain YouTube playlists were added to the queue.
+
+### May 14, 2015 -- `v2.7.3`
+* Fixed `!move` not working for subchannels (thanks [@mkbwong](https://github.com/mkbwong)).
+* Fixed MumbleDJ showing invalid YouTube ID error message in chat when an invalid YouTube API key is supplied (thanks [@fiveofeight](https://github.com/fiveofeight)).
+* Fixed MumbleDJ showing invalid YouTube ID error message in chat when a song exceeds the allowed time duration.
+
+### May 12, 2015 -- `v2.7.2`
+* Fixed incorrect values shown in timestamp for videos over an hour long.
+* Reworked timestamp parsing.
+
+### May 9, 2015 -- `v2.7.1`
+* Added support for YouTube offsets. This means that YouTube URLs with the `t` parameter will start at the time specified in the URL instead of the beginning.
+* Cleaned up comments in some files and removed some unnecessary code.
+* Fixed a bug in which a duration of 0:00 was shown for songs that were less than a minute long.
+
+### April 17, 2015 -- `v2.7.0`
+* Migrated all YouTube API calls to YouTube Data API v3. This means that you **MUST** follow the instructions in the following link if you were using a previous version of MumbleDJ: https://github.com/matthieugrieger/mumbledj#youtube-api-keys.
+* Made the SongQueue much more flexible. These changes will allow easy addition of support for other music services.
+
+### March 28, 2015 -- `v2.6.10`
+* Fixed a crash that would occur when the last song of a playlist was skipped.
+
+### March 27, 2015 -- `v2.6.9`
+* Fixed a race condition that would sometimes cause the bot to crash (thanks [dylanetaft](https://github.com/dylanetaft)!).
+
+### March 26, 2015 -- `v2.6.8`
+* Renamed `mumbledj.gcfg` to `config.gcfg`. However, please note that it will still be called `mumbledj.gcfg` in your `~/.mumbledj` directory. Hopefully this will avoid any ambiguity when referring to the
+config files.
+* Tweaked the `Makefile` to handle situations where `go build` creates an executable with an appended version number.
+
+### March 20, 2015 -- `v2.6.7`
+* Fixed a typo in `mumbledj.gcfg`.
+* Songs and playlists are now skipped immediately if the submitter submits a skip command.
+* `SONG_SKIPPED_HTML` and `PLAYLIST_SKIPPED_HTML` are no longer shown if the submitter or admin skips a song/playlist.
+
+### March 7, 2015 -- `v2.6.6`
+* Added missing AdminSkipPlaylistAlias option to `mumbledj.gcfg`.
+
+### February 25, 2015 -- `v2.6.5`
+* Added automatic connection retries if the bot loses connection to the server. The bot will attempt to reconnect to the server every 30 seconds for a period of 15 minutes, then exit if a connection cannot be made.
+
+### February 20, 2015 -- `v2.6.4`
+* Fixed failed audio downloads for YouTube videos with IDs beginning with "-".
+
+### February 19, 2015 -- `v2.6.3`
+* Added `gumbleutil.CertificateLockFile()` for more secure connections.
+* Added `-insecure` boolean commandline flag to allow MumbleDJ to connect to a server without overwriting `~/.mumbledj/cert.lock`.
+
+### February 18, 2015 -- `v2.6.2`
+* Fixed bot crashing after 5 minutes if there is nothing in the song queue.
+* Fixed queue freezing up if the download of the first song in queue fails.
+
+### February 17, 2015 -- `v2.6.0, v2.6.1`
+* Added caching system to MumbleDJ.
+* Added configuration variables in `mumbledj.gcfg` for caching related settings (please note that caching is off by default).
+* Added `!numcached` and `!cachesize` commands for admins.
+* Added optional song length limit (thanks [jakexks](https://github.com/jakexks)!)
+
+### February 12, 2015 -- `v2.5.0`
+* Updated dependencies and fixed code to match `gumble` API changes.
+* Greatly simplified the song queue data structure. Some new bugs could potentially have arisen. Let me know if you find any!
+
+### February 9, 2015 -- `v2.4.3`
+* Added configuration option in `mumbledj.gcfg` for default bot comment.
+* Fixed text messages only containing images crashing the bot.
+
+### February 7, 2015 -- `v2.4.2`
+* Updated `gumble` and `gumbleutil` dependencies.
+* Removed `sanitize` dependency.
+* Reworked `Makefile` slightly.
+* Now uses `gumbleutil.PlainText` for removing HTML tags instead of `sanitize`.
+* Added `!setcomment` which allows admin users to set the comment for the bot.
+* Made "Now Playing" notification and `!currentsong` show the playlist title of the song if it is included in a playlist.
+* Added ability to connect to Mumble server using a PEM cert/key pair. Use the commandline flags `cert` and `key` to make use of this.
+* Added an easier to read error message upon unsuccessful connection to server.
+
+### February 3, 2015 -- `v2.4.1`
+* Made it possible to place MumbleDJ binary in `~/bin` instead of `/usr/local/bin` if the folder exists.
+
+### February 2, 2015 -- `v2.3.4, v2.3.5, v2.3.6, v2.3.7, v2.4.0`
+* Added panic on audio play fail for debugging purposes.
+* Fixed '!' being recognized as '!skipplaylist'.
+* Fixed !reset crash when there is no audio playing.
+* Fixed newlines after YouTube URL messing up !add commands.
+* Fixed empty song/playlist entry being added upon !add with invalid YouTube ID.
+* Fixed go build issues.
+* Added `goop` dependency management. Make sure you have `openal` installed, or it won't work right!
+* Fixed crash on invalid playlist URL.
+
+### January 30, 2015 -- `v2.3.3`
+* Fixed private messages crashing the bot when the target user switches channels or disconnects.
+
+### January 26, 2015 -- `v2.3.2`
+* Fixed !nextsong showing incorrect information about the next song in the queue.
+
+### January 25, 2015 -- `v2.3.0, v2.3.1`
+* Added !currentsong command, which displays information about the song currently playing.
+* MumbleDJ now removes disconnected users from skiplists for playlists and songs within the SongQueue.
+* Fixed crash when a user disconnects when no song is playing.
+
+### January 19, 2015 -- `v2.2.11`
+* Fixed not being able to use the move command with channels with spaces in their name.
+
+### January 14, 2015 -- `v2.2.9, v2.2.10`
+* Set AudioEncoder Application to `gopus.Audio` instead of `gopus.Voice` for hopefully better sound quality.
+* Added some commands to the !help string that were missing.
+
+### January 12, 2015 -- `v2.2.8`
+* Added !nextsong command, which outputs some information about the next song in the queue if it exists.
+
+### January 10, 2015 -- `v2.2.6, v2.2.7`
+* Fixed type mismatch error when building MumbleDJ.
+* Added traversal function to SongQueue.
+* Added !numsongs command, which outputs how many songs are currently in the SongQueue.
+* Added !help command, which displays a list of valid commands in Mumble chat.
+
+### January 9, 2015 -- `v2.2.5`
+* Fixed some YouTube playlist URLs crashing the bot and not retrieving metadata correctly.
+
+### January 8, 2015 -- `v2.2.4`
+* Fixed a crash caused by a user trying to skip the same song more than once.
+
+### January 7, 2015 -- `v2.2.3`
+* Fixed a crash caused by entering a skip request when no song is currently playing.
+
+### January 5, 2015 -- `v2.2.1, v2.2.2`
+* Attached `gumbleutil.AutoBitrate` EventListener to client. This should hopefully fix the issues with audio cutting in and out.
+* Moved dependency installation to default `make` command to better enforce new updates.
+* Added `make build` to `Makefile` to allow previous functionality of the default `make` command.
+* Hopefully fixed a situation that would cause the song queue to stop working.
+* Added `!reset` command. Use this to reset the song queue.
+
+### January 3, 2015 -- `v2.2.0`
+* Added ability to add YouTube playlists to the queue. Note that the max size of a playlist is 25 songs, anything larger will only use the first 25 songs in the playlist.
+* Fixed a crash while attempting to add URLs to the queue.
+* Re-made the song queue using my own "queue-like" structure using slices.
+
 ### December 30, 2014 -- `v2.1.3`
 * Fixed YouTube URL parsing not working for some forms of YouTube URLs.
 * Now recovers more gracefully if an audio download fails. Instead of panicking, the bot will send a message to the user who added the URL, telling them the audio download failed.
@@ -43,7 +336,7 @@ MumbleDJ Changelog
 
 ### October 18, 2014
 * Fixed a crash when an error occurs during the audio downloading & encoding process.
-* Fixed a crash that occurs when the bot tries to join a default channel that does not exist. If the default channel does not exist, the bot will just move itself 
+* Fixed a crash that occurs when the bot tries to join a default channel that does not exist. If the default channel does not exist, the bot will just move itself
 to the root of the server instead.
 
 ### October 13, 2014

CONTRIBUTING.md

@@ -0,0 +1,260 @@
+Contributing to MumbleDJ
+========================
+
+Contributions are always welcome to MumbleDJ. This document will give you some tips and guidelines to follow while implementing your contribution.
+
+## Table of Contents
+* [Implementing a new command](#implementing-a-new-command)
+  * [Create files for your new command](#create-files-for-your-new-command)
+  * [Copy templates into your new files](#copy-templates-into-your-new-files)
+    * [Command implementation template (`command.go`)](#command-implementation-template-commandgo)
+    * [Command test suite template (`command_test.go`)](#command-test-suite-template-command_testgo)
+  * [Implement your new command](#implement-your-new-command)
+  * [Add command to `commands/pkg_init.go`](#add-command-to-commandspkg_initgo)
+  * [Add necessary configuration values to `config.yaml` and `config.go`](#add-necessary-configuration-values-to-configyaml-and-configgo)
+  * [Regenerate `bindata.go`](#regenerate-bindatago)
+  * [Document your new command](#document-your-new-command)
+* [Implementing support for a new service](#implementing-support-for-a-new-service)
+  * [Create file for your new service](#create-file-for-your-new-service)
+  * [Copy template into your new file](#copy-template-into-your-new-file)
+  * [Implement your new service](#implement-your-new-service)
+  * [Add service to `services/pkg_init.go`](#add-command-to-servicespkg_initgo)
+  * [Add API key configuration value to `config.yaml` and `config.go` if necessary](#add-api-key-configuration-value-to-configyaml-and-configgo-if-necessary)
+  * [Document your new service](#document-your-new-service)
+
+## Implementing a new command
+Commands are the portion of MumbleDJ that allows users to interact with the bot. Here is a step-by-step guide on how to implement a new command:
+
+### Create files for your new command
+All commands possess their own `command.go` file and `command_test.go` file. These files must reside in the `commands` directory.
+
+### Copy templates into your new files
+Templates for both command implementations and command tests have been created to ensure consistency across the codebase. Please use these templates, they will make your implementation easier and will make the codebase much cleaner.
+
+#### Command implementation template (`command.go`)
+```go
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * commands/yournewcommand.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package commands
+
+import (
+	"errors"
+	"fmt"
+
+	"github.com/layeh/gumble/gumble"
+	"github.com/matthieugrieger/mumbledj/interfaces"
+	"github.com/spf13/viper"
+)
+
+// YourNewCommand is a command... (put a short description of the command here)
+type YourNewCommand struct{}
+
+// Aliases returns the current aliases for the command.
+func (c *YourNewCommand) Aliases() []string {
+	return viper.GetStringSlice("commands.yournewcommand.aliases")
+}
+
+// Description returns the description for the command.
+func (c *YourNewCommand) Description() string {
+	return viper.GetString("commands.yournewcommand.description")
+}
+
+// IsAdminCommand returns true if the command is only for admin use, and
+// returns false otherwise.
+func (c *YourNewCommand) IsAdminCommand() bool {
+	return viper.GetBool("commands.yournewcommand.is_admin")
+}
+
+// Execute executes the command with the given user and arguments.
+// Return value descriptions:
+//    string: A message to be returned to the user upon successful execution.
+//    bool:   Whether the message should be private or not. true = private,
+//            false = public (sent to whole channel).
+//    error:  An error message to be returned upon unsuccessful execution.
+//            If no error has occurred, pass nil instead.
+// Example return statement:
+//    return "This is a private message!", true, nil
+func (c *YourNewCommand) Execute(user *gumble.User, args ...string) (string, bool, error) {
+	
+}
+```
+
+#### Command test suite template (`command_test.go`)
+```go
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * commands/yournewcommand_test.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package commands
+
+import (
+	"testing"
+
+	"github.com/layeh/gumble/gumbleffmpeg"
+	"github.com/matthieugrieger/mumbledj/bot"
+	"github.com/spf13/viper"
+	"github.com/stretchr/testify/suite"
+)
+
+type YourNewCommandTestSuite struct {
+	Command YourNewCommand
+	suite.Suite
+}
+
+func (suite *YourNewCommandTestSuite) SetupSuite() {
+	DJ = bot.NewMumbleDJ()
+	bot.DJ = DJ
+
+	viper.Set("commands.yournewcommand.aliases", []string{"yournewcommand", "c"})
+	viper.Set("commands.yournewcommand.description", "yournewcommand")
+	viper.Set("commands.yournewcommand.is_admin", false)
+}
+
+func (suite *YourNewCommandTestSuite) SetupTest() {
+	DJ.Queue = bot.NewQueue()
+}
+
+func (suite *YourNewCommandTestSuite) TestAliases() {
+	suite.Equal([]string{"yournewcommand", "c"}, suite.Command.Aliases())
+}
+
+func (suite *YourNewCommandTestSuite) TestDescription() {
+	suite.Equal("yournewcommand", suite.Command.Description())
+}
+
+func (suite *YourNewCommandTestSuite) TestIsAdminCommand() {
+	suite.False(suite.Command.IsAdminCommand())
+}
+
+// Implement more tests here as necessary! It may be helpful to take a look
+// at the stretchr/testify documentation:
+// https://github.com/stretchr/testify
+// Remove this comment before sending a pull request.
+
+func TestYourNewCommandTestSuite(t *testing.T) {
+	suite.Run(t, new(YourNewCommandTestSuite))
+}
+```
+
+### Implement your new command
+Now the fun starts! Write the implementation for your command in the `Execute()` method. Then, write tests for your new command, making sure to test each possible execution flow of your command.
+
+For writing the implementation and unit tests for your new command, it may be helpful to [look at previously created commands](https://github.com/matthieugrieger/mumbledj/blob/master/commands).
+
+**Make sure to rename the example names to represent your new command!**
+
+### Add command to `commands/pkg_init.go`
+`commands/pkg_init.go` contains a slice of enabled commands. If you do not put your command in this slice, your command will not be enabled.
+
+**Please keep the commands in alphabetical order!**
+
+### Add necessary configuration values to `config.yaml` and `config.go`
+Go to `config.yaml` and `bot/config.go` and add the necessary configuration values for your new command. 
+
+**Please keep the commands in alphabetical order!**
+
+### Regenerate `bindata.go`
+This step is very easy, but is very important. This allows the bot to store a copy of the new `config.yaml` internally and use it to write to disk.
+
+Simply execute `make bindata` and this step will be taken care of!
+
+### Document your new command
+Make sure to put information in `README.md` about your new command. It would be a shame for your new command to go unnoticed!
+
+**Please keep the commands in alphabetical order!**
+
+## Implementing support for a new service
+Services are the portion of MumbleDJ that allows the bot to interact with various media services. Here is a step-by-step guide on how to implement support for a new service:
+
+### Create file for your new service
+All services possess their own `service.go` file. This file must reside in the `services` directory.
+
+### Copy template into your new file
+A template for service implementations has been created to ensure consistency across the codebase. Please use this template, it will make your implementation easier and will make the codebase much cleaner.
+
+```go
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * services/yournewservice.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package services
+
+import (
+	"fmt"
+	"net/http"
+	"regexp"
+	"strings"
+	"time"
+
+	"github.com/antonholmquist/jason"
+	"github.com/layeh/gumble/gumble"
+	"github.com/matthieugrieger/mumbledj/bot"
+	"github.com/matthieugrieger/mumbledj/interfaces"
+)
+
+// YourNewService is a... (description here)
+type YourNewService struct {
+	*GenericService
+}
+
+// NewYourNewServiceService returns an initialized YourNewService service object.
+func NewYourNewServiceService() *YourNewService {
+	return &YourNewService{
+		&GenericService{
+			ReadableName: "Your new service",
+			Format:       "bestaudio",
+			TrackRegex: []*regexp.Regexp{
+				regexp.MustCompile(`regex for track URLs in your new service`),
+			},
+			PlaylistRegex: []*regexp.Regexp{
+                regexp.MustCompile(`regex for playlist URLs in your new service`),   
+            },
+		},
+	}
+}
+
+// CheckAPIKey performs a test API call with the API key
+// provided in the configuration file to determine if the
+// service should be enabled.
+func (yn *YourNewService) CheckAPIKey() error {
+	
+}
+
+// GetTracks uses the passed URL to find and return
+// tracks associated with the URL. An error is returned
+// if any error occurs during the API call.
+func (yn *YourNewService) GetTracks(url string, submitter *gumble.User) ([]interfaces.Track, error) {
+	
+}
+```
+
+### Implement your new service
+Now the fun starts! Implement `CheckAPIKey()` and `GetTracks()`.
+
+For writing the implementation for your new service, it may be helpful to [look at previously created service wrappers](https://github.com/matthieugrieger/mumbledj/blob/master/services).
+
+**Make sure to rename the example names to represent your new service!**
+
+### Add service to `services/pkg_init.go`
+`services/pkg_init.go` contains a slice of enabled services. If you do not put your service in this slice, your service will not be enabled.
+
+**Please keep the services in alphabetical order!**
+
+### Add API key configuration value to `config.yaml` and `config.go` if necessary
+Some services will require an API key for users to interact with their service. If an API key is required for your service, add it to the configuration file and `config.go` and run `make bindata` to regenerate the `bindata.go` file.
+
+### Document your new service
+In sections of `README.md` that describe which services are supported, add your new service to the list. It would be a shame for your new service to go unnoticed!
+
+Also, if your service requires an API key, make sure to document the steps to retrieve an API key in the "Requirements" section of the `README`.

Dockerfile

@@ -0,0 +1,39 @@
+FROM golang:alpine as builder
+
+RUN apk add --no-cache \
+        build-base \
+        opus-dev
+
+COPY . /go/src/github.com/matthieugrieger/mumbledj
+WORKDIR /go/src/github.com/matthieugrieger/mumbledj
+
+RUN go get -v \
+    && go build -v -ldflags="-s -w"
+
+FROM alpine
+
+RUN adduser -D mumbledj
+
+RUN apk add --no-cache \
+        aria2 \
+        libressl \
+        python2
+
+RUN wget -O /usr/bin/youtube-dl https://yt-dl.org/downloads/latest/youtube-dl \
+    && chmod +x /usr/bin/youtube-dl
+
+RUN wget https://johnvansickle.com/ffmpeg/builds/ffmpeg-git-amd64-static.tar.xz \
+    && tar xvf ffmpeg-git-amd64-static.tar.xz '*/ffmpeg' || true \
+    && mv ffmpeg-git-*-amd64-static/ffmpeg /usr/bin/ffmpeg \
+    && rm -rf ffmpeg-git-* \
+    && apk add --no-cache upx \
+    && upx /usr/bin/ffmpeg \
+    && apk del upx
+
+COPY --from=builder /go/src/github.com/matthieugrieger/mumbledj/mumbledj /usr/bin/mumbledj
+
+COPY config.yaml /home/mumbledj/.config/mumbledj/config.yaml
+
+USER mumbledj
+
+ENTRYPOINT ["/usr/bin/mumbledj"]

LICENSE

@@ -1,6 +1,6 @@
 The MIT License (MIT)
 
-Copyright (c) 2014 Matthieu Grieger
+Copyright (c) 2016 Matthieu Grieger
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
@@ -18,4 +18,4 @@ FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-THE SOFTWARE.
+THE SOFTWARE.

Makefile

@@ -1,22 +1,37 @@
+dirs = ./interfaces/... ./commands/... ./services/... ./bot/... .
+
 all: mumbledj
 
-mumbledj: main.go commands.go parseconfig.go strings.go queue.go song.go songqueue.go
-	go build .
-		
-clean:
-	rm -f mumbledj
-		
-install:
-	mkdir -p ~/.mumbledj/config
-	mkdir -p ~/.mumbledj/songs
-	if [ -a ~/.mumbledj/config/mumbledj.gcfg ]; then mv ~/.mumbledj/config/mumbledj.gcfg ~/.mumbledj/config/mumbledj_backup.gcfg; fi;
-	cp -u mumbledj.gcfg ~/.mumbledj/config/mumbledj.gcfg
-	sudo cp -f mumbledj /usr/local/bin/mumbledj
-	
-install_deps:
-	go get -u github.com/layeh/gumble/gumble
-	go get -u github.com/layeh/gumble/gumbleutil
-	go get -u github.com/layeh/gumble/gumble_ffmpeg
-	go get -u code.google.com/p/gcfg
-	go get -u github.com/kennygrant/sanitize
-	go get -u github.com/jmoiron/jsonq
+mumbledj: ## Default action. Builds MumbleDJ.
+	@env GO15VENDOREXPERIMENT="1" go build .
+
+.PHONY: test
+test: ## Runs unit tests for MumbleDJ.
+	@env GO15VENDOREXPERIMENT="1" go test $(dirs)
+
+.PHONY: coverage
+coverage: ## Runs coverage tests for MumbleDJ.
+	@env GO15VENDOREXPERIMENT="1" overalls -project=github.com/matthieugrieger/mumbledj -covermode=atomic
+	@mv overalls.coverprofile coverage.txt
+
+.PHONY: clean
+clean: ## Removes compiled MumbleDJ binaries.
+	@rm -f mumbledj*
+
+.PHONY: install
+install: ## Copies MumbleDJ binary to /usr/local/bin for easy execution.
+	@cp -f mumbledj* /usr/local/bin/mumbledj
+
+.PHONY: dist
+dist: ## Performs cross-platform builds via gox for multiple Linux platforms.
+	@go get -u github.com/mitchellh/gox
+	@gox -cgo -osarch="linux/amd64 linux/386"
+
+.PHONY: bindata
+bindata: ## Regenerates bindata.go with an updated configuration file.
+	@go get -u github.com/jteeuwen/go-bindata/...
+	@go-bindata config.yaml
+
+.PHONY: help
+help: ## Shows this helptext.
+	@grep -E '^[a-zA-Z_-]+:.*?## .*$$' $(MAKEFILE_LIST) | awk 'BEGIN {FS = ":.*?## "}; {printf "\033[36m%-30s\033[0m %s\n", $$1, $$2}'

README.md

@@ -1,70 +1,378 @@
-MumbleDJ
-========
-A Mumble bot that plays music fetched from YouTube videos.
 
-**IMPORTANT NOTE:** If you were using the Lua version of MumbleDJ previously, you will need to follow the installation guide once more to install new dependencies.
+<h1 align="center">MumbleDJ</h1>
+<p align="center"><b>A Mumble bot that plays audio fetched from various media websites.</b></p>
+<p align="center"><a href="https://travis-ci.org/matthieugrieger/mumbledj"><img src="https://travis-ci.org/matthieugrieger/mumbledj.svg?branch=master"/></a> <a href="https://raw.githubusercontent.com/matthieugrieger/mumbledj/master/LICENSE"><img src="https://img.shields.io/badge/license-MIT-blue.svg"/></a> <a href="https://github.com/matthieugrieger/mumbledj/releases"><img src="https://img.shields.io/github/release/matthieugrieger/mumbledj.svg"/></a> <a href="https://goreportcard.com/report/github.com/matthieugrieger/mumbledj"><img src="https://goreportcard.com/badge/github.com/matthieugrieger/mumbledj"/></a> <a href="https://codecov.io/gh/matthieugrieger/mumbledj"><img src="https://img.shields.io/codecov/c/github/matthieugrieger/mumbledj.svg"/></a> <a href="https://gitter.im/matthieugrieger/mumbledj"><img src="https://img.shields.io/gitter/room/matthieugrieger/mumbledj.svg" /></a></p>
 
-## USAGE
-`$ mumbledj -server=localhost -port=64738 -username=MumbleDJ -password="" -channel=root`  
-All parameters are optional, the example above shows the default values for each field.
+<p align="center"><b>Unfortunately, this project is no longer maintained. Don't expect any responses on bug reports, feature requests, etc. Forks are welcome!</b></p>
 
-## COMMANDS
-These are all of the chat commands currently supported by MumbleDJ. All command names and command prefixes may be changed in `mumbledj.gcfg`. All fields surrounded by `<>` indicate fields that *must* be supplied to the bot for the command to execute. All fields surrounded by `<>?` are optional fields.
+## Table of Contents
 
-####`!add <youtube_url>`
-Adds a YouTube video's audio to the song queue. If no songs are currently in the queue, the audio will begin playing immediately.
+* [Features](#features)
+* [Installation](#installation)
+  * [Requirements](#requirements)
+    * [YouTube API Key](#youtube-api-key)
+    * [SoundCloud API Key](#soundcloud-api-key)
+  * [Via `go get`](#via-go-get-recommended)
+  * [Pre-compiled Binaries](#pre-compiled-binaries-easiest)
+  * [From Source](#from-source)
+  * [Docker](#docker)
+* [Usage](#usage)
+* [Commands](#commands)
+* [Contributing](#contributing)
+* [Author](#author)
+* [License](#license)
+* [Thanks](#thanks)
 
-####`!skip`
-Submits a vote to skip the current song. Once the skip ratio target (specified in `mumbledj.gcfg`) is met, the song will be skipped and the next will start playing. Each user may only submit one skip per song.
+## Features
+* Plays audio from many media websites, including YouTube, SoundCloud, and Mixcloud.
+* Supports playlists and individual videos/tracks.
+* Displays metadata in the text chat whenever a new track starts playing.
+* Incredibly customizable. Nearly everything is able to be tweaked via configuration files (by default located at `$HOME/.config/mumbledj/config.yaml`).
+* A large array of [commands](#commands) that perform a wide variety of functions.
+* Built-in vote-skipping.
+* Built-in caching system (disabled by default).
+* Built-in play/pause/volume control.
 
-####`!forceskip`
-An admin command that forces a song skip.
+## Installation
+**IMPORTANT NOTE:** MumbleDJ is only tested and developed for Linux systems. Support will not be given for non-Linux systems if problems are encountered.
 
-####`!volume <desired_volume>?`
-Either outputs the current volume or changes the current volume. If `desired_volume` is not provided, the current volume will be displayed in chat. Otherwise, the volume for the bot will be changed to `desired_volume` if it is within the allowed volume range.
+### Requirements
+**All MumbleDJ installations must also have the following installed:**
+* [`youtube-dl`](https://rg3.github.io/youtube-dl/download.html)
+* [`ffmpeg`](https://ffmpeg.org) OR [`avconv`](https://libav.org)
+* [`aria2`](https://aria2.github.io/) if you plan on using services that throttle download speeds (like Mixcloud)
 
-####`!move <channel>`
-Moves MumbleDJ into `channel` if it exists.
+**If installing via `go install` or from source, the following must be installed:**
+* [Go 1.5+](https://golang.org)
+  * __NOTE__: Extra installation steps are required for a working Go installation. Once Go is installed, type `go help gopath` for more information.
+  * If the repositories for your distro contain a version of Go older than 1.5, try using [`gvm`](https://github.com/moovweb/gvm) to install Go 1.5 or newer.
 
-####`!reload`
-Reloads `mumbledj.gcfg` to retrieve updated configuration settings.
+#### YouTube API Key
+A YouTube API key must be present in your configuration file in order to use the YouTube service within the bot. Below is a guide for retrieving an API key:
 
-####`!kill`
-Safely cleans the bot environment and disconnects from the server. Please use this command to stop the bot instead of force closing, as the kill command deletes any remaining songs in the `~/.mumbledj/songs` directory.
+**1)** Navigate to the [Google Developers Console](https://console.developers.google.com) and sign in with your Google account, or create one if you haven't already.
 
-## INSTALLATION
-Installation for v2 of MumbleDJ is much easier than it was before, due to the reduced dependency list and a `Makefile` which automates some of the process.  
+**2)** Click the "Create Project" button and give your project a name. It doesn't matter what you set your project name to. Once you have a name click the "Create" button. You should be redirected to your new project once it's ready.
 
-**NOTE:** This bot was designed for use on Linux machines. If you wish to run the bot on another OS, it will require tweaking and is not something I will be able to help with.
+**3)** Click on "APIs & auth" on the sidebar, and then click APIs. Under the "YouTube APIs" header, click "YouTube Data API". Click on the "Enable API" button.
 
-**SETUP GUIDE**  
-**1)** Install and correctly configure [`Go`](https://golang.org/) (1.3 or higher). Specifically, make sure to follow [this guide](https://golang.org/doc/code.html) and set the `GOPATH` environment variable properly.
+**4)** Click on the "Credentials" option underneath "APIs & auth" on the sidebar. Underneath "Public API access" click on "Create New Key". Choose the "Server key" option.
 
-**2)** Install [`ffmpeg`](https://www.ffmpeg.org/) and [`mercurial`](http://mercurial.selenic.com/) if they are not already installed on your system.
+**5)** Add the IP address of the machine MumbleDJ will run on in the box that appears (this is optional, but improves security). Click "Create".
 
-**3)** Install [`youtube-dl`](https://github.com/rg3/youtube-dl#installation).
+**6)** You should now see that an API key has been generated. Copy/paste this API key into the configuration file located at `$HOME/.config/mumbledj/mumbledj.yaml`.
 
-**4)** Clone the `MumbleDJ` repository or [download the latest release](https://github.com/matthieugrieger/mumbledj/releases).
+#### SoundCloud API Key
+A SoundCloud client ID must be present in your configuration file in order to use the SoundCloud service within the bot. Below is a guide for retrieving a client ID:
 
-**5)** `cd` into the `MumbleDJ` repository directory and execute the following commands: 
+**1)** Login/sign up for a SoundCloud account on https://soundcloud.com.
+
+**2)** Create a new app: https://soundcloud.com/you/apps/new.
+
+**3)** You should now see that a client ID has been generated. Copy/paste this ID (NOT the client secret) into the configuration file located at `$HOME/.config/mumbledj/mumbledj.yaml`.
+
+
+### Via `go get` (recommended)
+After verifying that the [requirements](#requirements) are installed, simply issue the following command:
 ```
-$ make install_deps
-$ make
-$ make install
+go get -u github.com/matthieugrieger/mumbledj
 ```
 
-**5)** Edit `~/.mumbledj/config/mumbledj.gcfg` to your liking. This file will be overwritten if the config file structure is changed in a commit, but a backup is always stored at `~/.mumbledj/config/mumbledj_backup.gcfg`.
+This should place a binary in `$GOPATH/bin` that can be used to start the bot.
 
-**6)** Execute the command shown at the top of this `README` document with your credentials, and the bot should be up and running!
+**NOTE:** If using Go 1.5, you MUST execute the following for `go get` to work:
+```
+export GO15VENDOREXPERIMENT=1
+```
 
-## AUTHOR
-[Matthieu Grieger](http://matthieugrieger.com)
+### Pre-compiled Binaries (easiest)
+Pre-compiled binaries are provided for convenience. Overall, I do not recommend using these unless you cannot get `go install` to work properly. Binaries compiled on your own machine are likely more efficient as these binaries are cross-compiled from a 64-bit Linux system.
 
-## LICENSE
+After verifying that the [requirements](#requirements) are installed, simply visit the [releases page](https://github.com/matthieugrieger/mumbledj/releases) and download the appropriate binary for your platform.
+
+### From Source
+First, clone the MumbleDJ repository to your machine:
+```
+git clone https://github.com/matthieugrieger/mumbledj.git
+```
+
+Install the required software as described in the [requirements section](#requirements), and execute the following:
+```
+make
+```
+
+This will place a compiled `mumbledj` binary in the cloned directory if successful. If you would like to make the binary more accessible by adding it to `/usr/local/bin`, simply execute the following:
+```
+sudo make install
+```
+
+### Docker
+
+You can also use [Docker](https://www.docker.com) to run MumbleDJ.
+
+First you need to clone the MumbleDJ repository to your machine:
+```
+git clone https://github.com/matthieugrieger/mumbledj.git
+```
+
+Assuming you have [Docker installed](https://www.docker.com/products/docker), you will have to build the image:
+```
+docker build -t mumbledj .
+```
+
+And then you can run it, passing the configuration through the command line:
+```
+docker run --rm --name=mumbledj mumbledj --server=SERVER --api_keys.youtube=YOUR_YOUTUBE_API_KEY --api_keys.soundcloud=YOUR_SOUNDCLOUD_API_KEY
+```
+
+In order to run the process as a daemon and restart it automatically on reboot you can use:
+```
+docker run -d --restart=unless-stopped --name=mumbledj mumbledj --server=SERVER --api_keys.youtube=YOUR_YOUTUBE_API_KEY --api_keys.soundcloud=YOUR_SOUNDCLOUD_API_KEY
+```
+
+You can also install Docker on a [Raspberry Pi](https://www.raspberrypi.org/) for instance with [hypriot](http://blog.hypriot.com/getting-started-with-docker-on-your-arm-device/) or with [archlinux](https://archlinuxarm.org/packages/arm/docker). You just need to build the ARM image:
+```
+docker build -f raspberry.Dockerfile -t mumbledj .
+```
+
+## Usage
+MumbleDJ is a compiled program that is executed via a terminal.
+
+Here is an example helptext that gives you a feel for the various commandline arguments you can give MumbleDJ:
+
+```
+NAME:
+   MumbleDJ - A Mumble bot that plays audio from various media sites.
+
+USAGE:
+   mumbledj [global options] command [command options] [arguments...]
+
+VERSION:
+   v3.1.0
+
+COMMANDS:
+GLOBAL OPTIONS:
+   --config value, -c value		location of MumbleDJ configuration file (default: "/home/matthieu/.config/mumbledj/config.yaml")
+   --server value, -s value		address of Mumble server to connect to (default: "127.0.0.1")
+   --port value, -o value		port of Mumble server to connect to (default: "64738")
+   --username value, -u value		username for the bot (default: "MumbleDJ")
+   --password value, -p value		password for the Mumble server
+   --channel value, -n value		channel the bot enters after connecting to the Mumble server
+   --p12 value				path to user p12 file for authenticating as a registered user
+   --cert value, -e value		path to PEM certificate
+   --key value, -k value		path to PEM key
+   --accesstokens value, -a value	list of access tokens separated by spaces
+   --insecure, -i			if present, the bot will not check Mumble certs for consistency
+   --debug, -d				if present, all debug messages will be shown
+   --help, -h				show help
+   --version, -v			print the version
+
+```
+
+__NOTE__: You can also override all settings found within `config.yaml` directly from the commandline. Here's an example:
+
+```
+mumbledj --admins.names="SuperUser,Matt" --volume.default="0.5" --volume.lowest="0.2" --queue.automatic_shuffle_on="true"
+```
+
+Keep in mind that values that contain commas (such as `"SuperUser,Matt"`) will be interpreted as string slices, or arrays if you are not familiar with Go. If you want your value to be interpreted as a normal string, it is best to avoid commas for now.
+
+## Commands
+
+### add
+* __Description__: Adds a track or playlist from a media site to the queue.
+* __Default Aliases__: add, a
+* __Arguments__: (Required) URL(s) to a track or playlist from a supported media site.
+* __Admin-only by default__: No
+* __Example__: `!add https://www.youtube.com/watch?v=KQY9zrjPBjo`
+
+### addnext
+* __Description__: Adds a track or playlist from a media site as the next item in the queue.
+* __Default Aliases__: addnext, an
+* __Arguments__: (Required) URL(s) to a track or playlist from a supported media site.
+* __Admin-only by default__: Yes
+* __Example__: `!addnext https://www.youtube.com/watch?v=KQY9zrjPBjo`
+
+### cachesize
+* __Description__: Outputs the file size of the cache in MiB if caching is enabled.
+* __Default Aliases__: cachesize, cs
+* __Arguments__: None
+* __Admin-only by default__: Yes
+* __Example__: `!cachesize`
+
+### currenttrack
+* __Description__: Outputs information about the current track in the queue if one exists.
+* __Default Aliases__: currenttrack, currentsong, current
+* __Arguments__: None
+* __Admin-only by default__: No
+* __Example__: `!currenttrack`
+
+### forceskip
+* __Description__: Immediately skips the current track.
+* __Default Aliases__: forceskip, fs
+* __Arguments__: None
+* __Admin-only by default__: Yes
+* __Example__: `!forceskip`
+
+### forceskipplaylist
+* __Description__: Immediately skips the current playlist.
+* __Default Aliases__: forceskipplaylist, fsp
+* __Arguments__: None
+* __Admin-only by default__: Yes
+* __Example__: `!forceskipplaylist`
+
+### help
+* __Description__: Outputs a list of available commands and their descriptions.
+* __Default Aliases__: help, h
+* __Arguments__: None
+* __Admin-only by default__: No
+* __Example__: `!help`
+
+### joinme
+* __Description__: Moves MumbleDJ into your current channel if not playing audio to someone else.
+* __Default Aliases__: joinme, join
+* __Arguments__: None
+* __Admin-only by default__: Yes
+* __Example__: `!joinme`
+
+### kill
+* __Description__: Stops the bot and cleans its cache directory.
+* __Default Aliases__: kill, k
+* __Arguments__: None
+* __Admin-only by default__: Yes
+* __Example__: `!kill`
+
+### listtracks
+* __Description__: Outputs a list of the tracks currently in the queue.
+* __Default Aliases__: listtracks, listsongs, list, l
+* __Arguments__: (Optional) Number of tracks to list
+* __Admin-only by default__: No
+* __Example__: `!listtracks 10`
+
+### move
+* __Description__: Moves the bot into the Mumble channel provided via argument.
+* __Default Aliases__: move, m
+* __Arguments__: (Required) Mumble channel to move the bot into
+* __Admin-only by default__: Yes
+* __Example__: `!move Music`
+
+### nexttrack
+* __Description__: Outputs information about the next track in the queue if one exists.
+* __Default Aliases__: nexttrack, nextsong, next
+* __Arguments__: None
+* __Admin-only by default__: No
+* __Example__: `!nexttrack`
+
+### numcached
+* __Description__: Outputs the number of tracks cached on disk if caching is enabled.
+* __Default Aliases__: numcached, nc
+* __Arguments__: None
+* __Admin-only by default__: Yes
+* __Example__: `!numcached`
+
+### numtracks
+* __Description__: Outputs the number of tracks currently in the queue.
+* __Default Aliases__: numtracks, numsongs, nt
+* __Arguments__: None
+* __Admin-only by default__: No
+* __Example__: `!numtracks`
+
+### pause
+* __Description__: Pauses audio playback.
+* __Default Aliases__: pause
+* __Arguments__: None
+* __Admin-only by default__: No
+* __Example__: `!pause`
+
+### register
+* __Description__: Registers the bot on the server.
+* __Default Aliases__: register, reg
+* __Arguments__: None
+* __Admin-only by default__: Yes
+* __Example__: `!register`
+
+### reload
+* __Description__: Reloads the configuration file.
+* __Default Aliases__: reload, r
+* __Arguments__: None
+* __Admin-only by default__: Yes
+* __Example__: `!reload`
+
+### reset
+* __Description__: Resets the queue by removing all queue items.
+* __Default Aliases__: reset, re
+* __Arguments__: None
+* __Admin-only by default__: Yes
+* __Example__: `!reset`
+
+### resume
+* __Description__: Resumes audio playback.
+* __Default Aliases__: resume
+* __Arguments__: None
+* __Admin-only by default__: No
+* __Example__: `!pause`
+
+### setcomment
+* __Description__: Sets the comment displayed next to MumbleDJ's username in Mumble. If the argument is left empty, the current comment is removed.
+* __Default Aliases__: setcomment, comment, sc
+* __Arguments__: (Optional) New comment
+* __Admin-only by default__: Yes
+* __Example__: `!setcomment Hello! I'm a bot. Beep boop.`
+
+### shuffle
+* __Description__: Randomizes the tracks currently in the queue.
+* __Default Aliases__: shuffle, shuf, sh
+* __Arguments__: None
+* __Admin-only by default__: Yes
+* __Example__: `!shuffle`
+
+### skip
+* __Description__: Places a vote to skip the current track.
+* __Default Aliases__: skip, s
+* __Arguments__: None
+* __Admin-only by default__: No
+* __Example__: `!skip`
+
+### skipplaylist
+* __Description__: Places a vote to skip the current playlist.
+* __Default Aliases__: skipplaylist, sp
+* __Arguments__: None
+* __Admin-only by default__: No
+* __Example__: `!skipplaylist`
+
+### toggleshuffle
+* __Description__: Toggles permanent track shuffling on/off.
+* __Default Aliases__: toggleshuffle, toggleshuf, togshuf, tsh
+* __Arguments__: None
+* __Admin-only by default__: Yes
+* __Example__: `!toggleshuffle`
+
+### version
+* __Description__: Outputs the current version of MumbleDJ.
+* __Default Aliases__: version, v
+* __Arguments__: None
+* __Admin-only by default__: No
+* __Example__: `!version`
+
+### volume
+* __Description__: Changes the volume if an argument is provided, outputs the current volume otherwise.
+* __Default Aliases__: volume, vol
+* __Arguments__: (Optional) New volume
+* __Admin-only by default__: No
+* __Example__: `!volume 0.5`
+
+## Contributing
+
+Contributions to MumbleDJ are always welcome! Please see the [contribution guidelines](https://github.com/matthieugrieger/mumbledj/blob/master/CONTRIBUTING.md) for instructions and suggestions!
+
+## Author
+[Matthieu Grieger](https://github.com/matthieugrieger)
+
+## License
 ```
 The MIT License (MIT)
 
-Copyright (c) 2014 Matthieu Grieger
+Copyright (c) 2016 Matthieu Grieger
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
@@ -85,11 +393,14 @@ OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 THE SOFTWARE.
 ```
 
-## THANKS
-* All those who contribute to [Mumble](https://github.com/mumble-voip/mumble).
-* [Tim Cooper](https://github.com/bontibon) for [gumble](https://github.com/layeh/gumble).
-* [Ricardo Garcia](https://github.com/rg3) for [youtube-dl](https://github.com/rg3/youtube-dl).
-* [ScalingData](https://github.com/scalingdata) for [gcfg](https://github.com/scalingdata/gcfg).
-* [Hicham Bouabdallah](https://github.com/hishboy) for [Golang queue implementation](https://github.com/hishboy/gocommons/blob/master/lang/queue.go).
-* [kennygrant](https://github.com/kennygrant) for [sanitize](https://github.com/kennygrant/sanitize).
-* [Jason Moiron](https://github.com/jmoiron) for [jsonq](https://github.com/jmoiron/jsonq).
+## Thanks
+* [All those who contribute to Mumble](https://github.com/mumble-voip/mumble/graphs/contributors)
+* [Tim Cooper](https://github.com/bontibon) for [gumble, gumbleffmpeg, and gumbleutil](https://github.com/layeh/gumble)
+* [Jeremy Saenz](https://github.com/codegangsta) for [cli](https://github.com/urfave/cli)
+* [Anton Holmquist](https://github.com/antonholmquist) for [jason](https://github.com/antonholmquist/jason)
+* [Stretchr, Inc.](https://github.com/stretchr) for [testify](https://github.com/stretchr/testify)
+* [ChannelMeter](https://github.com/ChannelMeter) for [iso8601duration](https://github.com/ChannelMeter/iso8601duration)
+* [Steve Francia](https://github.com/spf13) for [viper](https://github.com/spf13/viper)
+* [Simon Eskildsen](https://github.com/Sirupsen) for [logrus](https://github.com/Sirupsen/logrus)
+* [Mitchell Hashimoto](https://github.com/mitchellh) for [gox](https://github.com/mitchellh/gox)
+* [Jim Teeuwen](https://github.com/jteeuwen) for [go-bindata](https://github.com/jteeuwen/go-bindata)

bot/cache.go

@@ -0,0 +1,144 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * bot/cache.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package bot
+
+import (
+	"errors"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"sort"
+	"time"
+
+	"github.com/Sirupsen/logrus"
+	"github.com/spf13/viper"
+)
+
+// SortFilesByAge is a type that holds file information for cached items for
+// sorting.
+type SortFilesByAge []os.FileInfo
+
+// Len returns the length of the file slice.
+func (a SortFilesByAge) Len() int {
+	return len(a)
+}
+
+// Swap swaps two elements in the file slice.
+func (a SortFilesByAge) Swap(i, j int) {
+	a[i], a[j] = a[j], a[i]
+}
+
+// Less compares two file modification times to determine if one is less than
+// the other. Returns true if the item in index i is older than the item in
+// index j, false otherwise.
+func (a SortFilesByAge) Less(i, j int) bool {
+	return time.Since(a[i].ModTime()) < time.Since(a[j].ModTime())
+}
+
+// Cache keeps track of the filesize of the audio cache and
+// provides methods for pruning the cache.
+type Cache struct {
+	NumAudioFiles int
+	TotalFileSize int64
+}
+
+// NewCache creates an empty Cache and returns it.
+func NewCache() *Cache {
+	return &Cache{
+		NumAudioFiles: 0,
+		TotalFileSize: 0,
+	}
+}
+
+// CheckDirectorySize checks the cache directory to determine if the filesize
+// of the files within exceed the user-specified size limit. If so, the oldest
+// files are cleared until it is no longer exceeding the limit.
+func (c *Cache) CheckDirectorySize() {
+	const bytesInMiB int = 1048576
+
+	c.UpdateStatistics()
+	for c.TotalFileSize > int64(viper.GetInt("cache.maximum_size")*bytesInMiB) {
+		if err := c.DeleteOldest(); err != nil {
+			break
+		}
+	}
+}
+
+// UpdateStatistics updates the statistics relevant to the cache (number of
+// audio files cached, total current size of the cache).
+func (c *Cache) UpdateStatistics() {
+	c.NumAudioFiles, c.TotalFileSize = c.getCurrentStatistics()
+	logrus.WithFields(logrus.Fields{
+		"num_audio_files": c.NumAudioFiles,
+		"total_file_size": c.TotalFileSize,
+	}).Infoln("Updated cache statistics.")
+}
+
+// CleanPeriodically loops forever, deleting expired cached audio files as necessary.
+func (c *Cache) CleanPeriodically() {
+	for range time.Tick(time.Duration(viper.GetInt("cache.check_interval")) * time.Minute) {
+		logrus.Infoln("Checking cache for expired files...")
+		files, _ := ioutil.ReadDir(os.ExpandEnv(viper.GetString("cache.directory")))
+		for _, file := range files {
+			// It is safe to check the modification time because when audio files are
+			// played their modification time is updated. This ensures that audio
+			// files will not get deleted while they are playing, assuming a reasonable
+			// expiry time is set in the configuration.
+			hours := time.Since(file.ModTime()).Hours()
+			if hours >= viper.GetFloat64("cache.expire_time") {
+				logrus.WithFields(logrus.Fields{
+					"expired_file": file.Name(),
+				}).Infoln("Removing expired cache entry.")
+				os.Remove(fmt.Sprintf("%s/%s", os.ExpandEnv(viper.GetString("cache.directory")), file.Name()))
+			}
+		}
+	}
+}
+
+// DeleteOldest deletes the oldest file in the cache.
+func (c *Cache) DeleteOldest() error {
+	files, _ := ioutil.ReadDir(os.ExpandEnv(viper.GetString("cache.directory")))
+	if len(files) > 0 {
+		sort.Sort(SortFilesByAge(files))
+		os.Remove(fmt.Sprintf("%s/%s", os.ExpandEnv(viper.GetString("cache.directory")), files[0].Name()))
+		return nil
+	}
+	return errors.New("There are no files currently cached")
+}
+
+// DeleteAll deletes all cached audio files.
+func (c *Cache) DeleteAll() error {
+	dir, err := os.Open(os.ExpandEnv(viper.GetString("cache.directory")))
+	if err != nil {
+		return err
+	}
+
+	defer dir.Close()
+	names, err := dir.Readdirnames(-1)
+	if err != nil {
+		return err
+	}
+	logrus.Infoln("Deleting all cached audio files...")
+	for _, name := range names {
+		err = os.RemoveAll(filepath.Join(os.ExpandEnv(viper.GetString("cache.directory")), name))
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func (c *Cache) getCurrentStatistics() (int, int64) {
+	var totalSize int64
+	files, _ := ioutil.ReadDir(os.ExpandEnv(viper.GetString("cache.directory")))
+	for _, file := range files {
+		totalSize += file.Size()
+	}
+	return len(files), totalSize
+}

bot/config.go

@@ -0,0 +1,259 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * bot/config.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package bot
+
+import (
+	"fmt"
+	"sort"
+	"strings"
+
+	"github.com/Sirupsen/logrus"
+	"github.com/spf13/viper"
+)
+
+// SetDefaultConfig sets default values for all configuration options.
+func SetDefaultConfig() {
+	// API key defaults.
+	viper.SetDefault("api_keys.youtube", "")
+	viper.SetDefault("api_keys.soundcloud", "")
+
+	// General defaults.
+	viper.SetDefault("defaults.comment", "Hello! I am a bot. Type !help for a list of commands.")
+	viper.SetDefault("defaults.channel", "")
+	viper.SetDefault("defaults.player_command", "ffmpeg")
+
+	// Queue defaults.
+	viper.SetDefault("queue.track_skip_ratio", 0.5)
+	viper.SetDefault("queue.playlist_skip_ratio", 0.5)
+	viper.SetDefault("queue.max_track_duration", 0)
+	viper.SetDefault("queue.max_tracks_per_playlist", 50)
+	viper.SetDefault("queue.automatic_shuffle_on", false)
+	viper.SetDefault("queue.announce_new_tracks", true)
+
+	// Connection defaults.
+	viper.SetDefault("connection.address", "127.0.0.1")
+	viper.SetDefault("connection.port", 64738)
+	viper.SetDefault("connection.password", "")
+	viper.SetDefault("connection.username", "MumbleDJ")
+	viper.SetDefault("connection.user_p12", "")
+	viper.SetDefault("connection.insecure", false)
+	viper.SetDefault("connection.cert", "")
+	viper.SetDefault("connection.key", "")
+	viper.SetDefault("connection.access_tokens", "")
+	viper.SetDefault("connection.retry_enabled", true)
+	viper.SetDefault("connection.retry_attempts", 10)
+	viper.SetDefault("connection.retry_interval", 5)
+
+	// Cache defaults.
+	viper.SetDefault("cache.enabled", false)
+	viper.SetDefault("cache.maximum_size", "512MiB")
+	viper.SetDefault("cache.expire_time", 24)
+	viper.SetDefault("cache.check_interval", 5)
+	viper.SetDefault("cache.directory", "$HOME/.cache/mumbledj")
+
+	// Volume defaults.
+	viper.SetDefault("volume.default", 0.2)
+	viper.SetDefault("volume.lowest", 0.01)
+	viper.SetDefault("volume.highest", 0.8)
+
+	// Admins defaults.
+	viper.SetDefault("admins.enabled", true)
+	viper.SetDefault("admins.names", []string{"SuperUser"})
+
+	// Command defaults.
+	viper.SetDefault("commands.prefix", "!")
+	viper.SetDefault("commands.common_messages.no_tracks_error", "There are no tracks in the queue.")
+	viper.SetDefault("commands.common_messages.caching_disabled_error", "Caching is currently disabled.")
+
+	viper.SetDefault("commands.add.aliases", []string{"add", "a"})
+	viper.SetDefault("commands.add.is_admin", false)
+	viper.SetDefault("commands.add.description", "Adds a track or playlist from a media site to the queue.")
+	viper.SetDefault("commands.add.messages.no_url_error", "A URL must be supplied with the add command.")
+	viper.SetDefault("commands.add.messages.no_valid_tracks_error", "No valid tracks were found with the provided URL(s).")
+	viper.SetDefault("commands.add.messages.tracks_too_long_error", "Your track(s) were either too long or an error occurred while processing them. No track(s) have been added.")
+	viper.SetDefault("commands.add.messages.one_track_added", "<b>%s</b> added <b>1</b> track to the queue:<br><i>%s</i> from %s")
+	viper.SetDefault("commands.add.messages.many_tracks_added", "<b>%s</b> added <b>%d</b> tracks to the queue.")
+	viper.SetDefault("commands.add.messages.num_tracks_too_long", "<br><b>%d</b> tracks could not be added due to error or because they are too long.")
+
+	viper.SetDefault("commands.addnext.aliases", []string{"addnext", "an"})
+	viper.SetDefault("commands.addnext.is_admin", true)
+	viper.SetDefault("commands.addnext.description", "Adds a track or playlist from a media site as the next item in the queue.")
+
+	viper.SetDefault("commands.cachesize.aliases", []string{"cachesize", "cs"})
+	viper.SetDefault("commands.cachesize.is_admin", true)
+	viper.SetDefault("commands.cachesize.description", "Outputs the file size of the cache in MiB if caching is enabled.")
+	viper.SetDefault("commands.cachesize.messages.current_size", "The current size of the cache is <b>%.2v MiB</b>.")
+
+	viper.SetDefault("commands.currenttrack.aliases", []string{"currenttrack", "currentsong", "current"})
+	viper.SetDefault("commands.currenttrack.is_admin", false)
+	viper.SetDefault("commands.currenttrack.description", "Outputs information about the current track in the queue if one exists.")
+	viper.SetDefault("commands.currenttrack.messages.current_track", "The current track is <i>%s</i>, added by <b>%s</b>.")
+
+	viper.SetDefault("commands.forceskip.aliases", []string{"forceskip", "fs"})
+	viper.SetDefault("commands.forceskip.is_admin", true)
+	viper.SetDefault("commands.forceskip.description", "Immediately skips the current track.")
+	viper.SetDefault("commands.forceskip.messages.track_skipped", "The current track has been forcibly skipped by <b>%s</b>.")
+
+	viper.SetDefault("commands.forceskipplaylist.aliases", []string{"forceskipplaylist", "fsp"})
+	viper.SetDefault("commands.forceskipplaylist.is_admin", true)
+	viper.SetDefault("commands.forceskipplaylist.description", "Immediately skips the current playlist.")
+	viper.SetDefault("commands.forceskipplaylist.messages.no_playlist_error", "The current track is not part of a playlist.")
+	viper.SetDefault("commands.forceskipplaylist.messages.playlist_skipped", "The current playlist has been forcibly skipped by <b>%s</b>.")
+
+	viper.SetDefault("commands.help.aliases", []string{"help", "h"})
+	viper.SetDefault("commands.help.is_admin", false)
+	viper.SetDefault("commands.help.description", "Outputs this list of commands.")
+	viper.SetDefault("commands.help.messages.commands_header", "<br><b>Commands:</b><br>")
+	viper.SetDefault("commands.help.messages.admin_commands_header", "<br><b>Admin Commands:</b><br>")
+
+	viper.SetDefault("commands.joinme.aliases", []string{"joinme", "join"})
+	viper.SetDefault("commands.joinme.is_admin", true)
+	viper.SetDefault("commands.joinme.description", "Moves MumbleDJ into your current channel if not playing audio to someone else.")
+	viper.SetDefault("commands.joinme.messages.others_are_listening_error", "Users in another channel are listening to me.")
+	viper.SetDefault("commands.joinme.messages.in_your_channel", "I am now in your channel!")
+
+	viper.SetDefault("commands.kill.aliases", []string{"kill", "k"})
+	viper.SetDefault("commands.kill.is_admin", true)
+	viper.SetDefault("commands.kill.description", "Stops the bot and cleans its cache directory.")
+
+	viper.SetDefault("commands.listtracks.aliases", []string{"listtracks", "listsongs", "list", "l"})
+	viper.SetDefault("commands.listtracks.is_admin", false)
+	viper.SetDefault("commands.listtracks.description", "Outputs a list of the tracks currently in the queue.")
+	viper.SetDefault("commands.listtracks.messages.invalid_integer_error", "An invalid integer was supplied.")
+	viper.SetDefault("commands.listtracks.messages.track_listing", "<b>%d</b>: <i>%s</i>, added by <b>%s</b>.<br>")
+
+	viper.SetDefault("commands.move.aliases", []string{"move", "m"})
+	viper.SetDefault("commands.move.is_admin", true)
+	viper.SetDefault("commands.move.description", "Moves the bot into the Mumble channel provided via argument.")
+	viper.SetDefault("commands.move.messages.no_channel_provided_error", "A destination channel must be supplied to move the bot.")
+	viper.SetDefault("commands.move.messages.channel_doesnt_exist_error", "The provided channel does not exist.")
+	viper.SetDefault("commands.move.messages.move_successful", "You have successfully moved the bot to <b>%s</b>.")
+
+	viper.SetDefault("commands.nexttrack.aliases", []string{"nexttrack", "nextsong", "next"})
+	viper.SetDefault("commands.nexttrack.is_admin", false)
+	viper.SetDefault("commands.nexttrack.description", "Outputs information about the next track in the queue if one exists.")
+	viper.SetDefault("commands.nexttrack.messages.current_track_only_error", "The current track is the only track in the queue.")
+	viper.SetDefault("commands.nexttrack.messages.next_track", "The next track is <i>%s</i>, added by <b>%s</b>.")
+
+	viper.SetDefault("commands.numcached.aliases", []string{"numcached", "nc"})
+	viper.SetDefault("commands.numcached.is_admin", true)
+	viper.SetDefault("commands.numcached.description", "Outputs the number of tracks cached on disk if caching is enabled.")
+	viper.SetDefault("commands.numcached.messages.num_cached", "There are currently <b>%d</b> items stored in the cache.")
+
+	viper.SetDefault("commands.numtracks.aliases", []string{"numtracks", "numsongs", "nt"})
+	viper.SetDefault("commands.numtracks.is_admin", false)
+	viper.SetDefault("commands.numtracks.description", "Outputs the number of tracks currently in the queue.")
+	viper.SetDefault("commands.numtracks.messages.one_track", "There is currently <b>1</b> track in the queue.")
+	viper.SetDefault("commands.numtracks.messages.plural_tracks", "There are currently <b>%d</b> tracks in the queue.")
+
+	viper.SetDefault("commands.pause.aliases", []string{"pause"})
+	viper.SetDefault("commands.pause.is_admin", false)
+	viper.SetDefault("commands.pause.description", "Pauses audio playback.")
+	viper.SetDefault("commands.pause.messages.no_audio_error", "Either the audio is already paused, or there are no tracks in the queue.")
+	viper.SetDefault("commands.pause.messages.paused", "<b>%s</b> has paused audio playback.")
+
+	viper.SetDefault("commands.register.aliases", []string{"register", "reg"})
+	viper.SetDefault("commands.register.is_admin", true)
+	viper.SetDefault("commands.register.description", "Registers the bot on the server.")
+	viper.SetDefault("commands.register.messages.already_registered_error", "I am already registered on the server.")
+	viper.SetDefault("commands.register.messages.registered", "I am now registered on the server.")
+
+	viper.SetDefault("commands.reload.aliases", []string{"reload", "r"})
+	viper.SetDefault("commands.reload.is_admin", true)
+	viper.SetDefault("commands.reload.description", "Reloads the configuration file.")
+	viper.SetDefault("commands.reload.messages.reloaded", "The configuration file has been successfully reloaded.")
+
+	viper.SetDefault("commands.reset.aliases", []string{"reset", "re"})
+	viper.SetDefault("commands.reset.is_admin", true)
+	viper.SetDefault("commands.reset.description", "Resets the queue by removing all queue items.")
+	viper.SetDefault("commands.reset.messages.queue_reset", "<b>%s</b> has reset the queue.")
+
+	viper.SetDefault("commands.resume.aliases", []string{"resume"})
+	viper.SetDefault("commands.resume.is_admin", false)
+	viper.SetDefault("commands.resume.description", "Resumes audio playback.")
+	viper.SetDefault("commands.resume.messages.audio_error", "Either the audio is already playing, or there are no tracks in the queue.")
+	viper.SetDefault("commands.resume.messages.resumed", "<b>%s</b> has resumed audio playback.")
+
+	viper.SetDefault("commands.setcomment.aliases", []string{"setcomment", "comment", "sc"})
+	viper.SetDefault("commands.setcomment.is_admin", true)
+	viper.SetDefault("commands.setcomment.description", "Sets the comment displayed next to MumbleDJ's username in Mumble.")
+	viper.SetDefault("commands.setcomment.messages.comment_removed", "The comment for the bot has been successfully removed.")
+	viper.SetDefault("commands.setcomment.messages.comment_changed", "The comment for the bot has been successfully changed to the following: %s")
+
+	viper.SetDefault("commands.shuffle.aliases", []string{"shuffle", "shuf", "sh"})
+	viper.SetDefault("commands.shuffle.is_admin", true)
+	viper.SetDefault("commands.shuffle.description", "Randomizes the tracks currently in the queue.")
+	viper.SetDefault("commands.shuffle.messages.not_enough_tracks_error", "There are not enough tracks in the queue to execute a shuffle.")
+	viper.SetDefault("commands.shuffle.messages.shuffled", "The audio queue has been shuffled.")
+
+	viper.SetDefault("commands.skip.aliases", []string{"skip", "s"})
+	viper.SetDefault("commands.skip.is_admin", false)
+	viper.SetDefault("commands.skip.description", "Places a vote to skip the current track.")
+	viper.SetDefault("commands.skip.messages.already_voted_error", "You have already voted to skip this track.")
+	viper.SetDefault("commands.skip.messages.voted", "<b>%s</b> has voted to skip the current track.")
+	viper.SetDefault("commands.skip.messages.submitter_voted", "<b>%s</b>, the submitter of this track, has voted to skip. Skipping immediately.")
+
+	viper.SetDefault("commands.skipplaylist.aliases", []string{"skipplaylist", "sp"})
+	viper.SetDefault("commands.skipplaylist.is_admin", false)
+	viper.SetDefault("commands.skipplaylist.description", "Places a vote to skip the current playlist.")
+	viper.SetDefault("commands.skipplaylist.messages.no_playlist_error", "The current track is not part of a playlist.")
+	viper.SetDefault("commands.skipplaylist.messages.already_voted_error", "You have already voted to skip this playlist.")
+	viper.SetDefault("commands.skipplaylist.messages.voted", "<b>%s</b> has voted to skip the current playlist.")
+	viper.SetDefault("commands.skipplaylist.messages.submitter_voted", "<b>%s</b>, the submitter of this playlist, has voted to skip. Skipping immediately.")
+
+	viper.SetDefault("commands.toggleshuffle.aliases", []string{"toggleshuffle", "toggleshuf", "togshuf", "tsh"})
+	viper.SetDefault("commands.toggleshuffle.is_admin", true)
+	viper.SetDefault("commands.toggleshuffle.description", "Toggles automatic track shuffling on/off.")
+	viper.SetDefault("commands.toggleshuffle.messages.toggled_off", "Automatic shuffling has been toggled off.")
+	viper.SetDefault("commands.toggleshuffle.messages.toggled_on", "Automatic shuffling has been toggled on.")
+
+	viper.SetDefault("commands.version.aliases", []string{"version"})
+	viper.SetDefault("commands.version.is_admin", false)
+	viper.SetDefault("commands.version.description", "Outputs the current version of MumbleDJ.")
+	viper.SetDefault("commands.version.messages.version", "MumbleDJ version: <b>%s</b>")
+
+	viper.SetDefault("commands.volume.aliases", []string{"volume", "vol", "v"})
+	viper.SetDefault("commands.volume.is_admin", false)
+	viper.SetDefault("commands.volume.description", "Changes the volume if an argument is provided, outputs the current volume otherwise.")
+	viper.SetDefault("commands.volume.messages.parsing_error", "The requested volume could not be parsed.")
+	viper.SetDefault("commands.volume.messages.out_of_range_error", "Volumes must be between the values <b>%.2f</b> and <b>%.2f</b>.")
+	viper.SetDefault("commands.volume.messages.current_volume", "The current volume is <b>%.2f</b>.")
+	viper.SetDefault("commands.volume.messages.volume_changed", "<b>%s</b> has changed the volume to <b>%.2f</b>.")
+}
+
+// ReadConfigFile reads in the config file and updates the configuration accordingly.
+func ReadConfigFile() error {
+	logrus.Infoln("Reading config...")
+	return viper.ReadInConfig()
+}
+
+// CheckForDuplicateAliases validates that all commands have unique aliases.
+func CheckForDuplicateAliases() error {
+	var aliases []string
+
+	logrus.Infoln("Checking for duplicate aliases...")
+
+	// It would be preferred to use viper.Sub("aliases") here, but there are some
+	// nil pointer dereferencing issues.
+	for _, setting := range viper.AllKeys() {
+		if strings.HasSuffix(setting, "aliases") {
+			aliases = append(aliases, viper.GetStringSlice(setting)...)
+		}
+	}
+
+	// Sort the strings to allow us to fail faster in case there is a duplicate.
+	sort.Strings(aliases)
+
+	for i := 0; i < len(aliases)-1; i++ {
+		if aliases[i] == aliases[i+1] {
+			return fmt.Errorf("Duplicate alias found: %s", aliases[i])
+		}
+	}
+
+	return nil
+}

bot/config_test.go

@@ -0,0 +1,56 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * bot/config_test.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package bot
+
+import (
+	"testing"
+
+	"github.com/spf13/viper"
+	"github.com/stretchr/testify/suite"
+)
+
+type ConfigTestSuite struct {
+	suite.Suite
+}
+
+func (suite *ConfigTestSuite) SetupSuite() {
+	DJ = NewMumbleDJ()
+}
+
+func (suite *ConfigTestSuite) SetupTest() {
+	viper.Reset()
+}
+
+func (suite *ConfigTestSuite) TestCheckForDuplicateAliasesWhenNoDuplicatesExist() {
+	viper.Set("commands.add.aliases", []string{"add", "a"})
+	viper.Set("commands.addnext.aliases", []string{"addnext", "an"})
+	viper.Set("commands.skip.aliases", []string{"skip", "s"})
+	viper.Set("commands.skipplaylist.aliases", []string{"skipplaylist", "sp"})
+
+	err := CheckForDuplicateAliases()
+
+	suite.Nil(err, "No error should be returned as there are no duplicate aliases.")
+}
+
+func (suite *ConfigTestSuite) TestCheckForDuplicateAliasesWhenDuplicatesExist() {
+	viper.Set("commands.add.aliases", []string{"add", "a"})
+	viper.Set("commands.addnext.aliases", []string{"addnext", "an"})
+	viper.Set("commands.skip.aliases", []string{"skip", "s"})
+	viper.Set("commands.skipplaylist.aliases", []string{"skipplaylist", "sp"})
+	viper.Set("commands.version.aliases", []string{"version", "v"})
+	viper.Set("commands.volume.aliases", []string{"volume", "vol", "v"})
+
+	err := CheckForDuplicateAliases()
+
+	suite.NotNil(err, "An error should be returned as there are duplicate aliases.")
+	suite.Contains(err.Error(), "v", "The error message should contain the duplicate alias.")
+}
+
+func TestConfigTestSuite(t *testing.T) {
+	suite.Run(t, new(ConfigTestSuite))
+}

bot/mumbledj.go

@@ -0,0 +1,320 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * bot/mumbledj.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package bot
+
+import (
+	"crypto/tls"
+	"errors"
+	"fmt"
+	"io/ioutil"
+	"net"
+	"os"
+	"os/exec"
+	"strings"
+	"time"
+
+	"github.com/Sirupsen/logrus"
+	"github.com/layeh/gumble/gumble"
+	"github.com/layeh/gumble/gumbleffmpeg"
+	"github.com/layeh/gumble/gumbleutil"
+	"github.com/matthieugrieger/mumbledj/interfaces"
+	"github.com/spf13/viper"
+)
+
+// MumbleDJ is a struct that keeps track of all aspects of the bot's state.
+type MumbleDJ struct {
+	AvailableServices []interfaces.Service
+	Client            *gumble.Client
+	GumbleConfig      *gumble.Config
+	TLSConfig         *tls.Config
+	AudioStream       *gumbleffmpeg.Stream
+	Queue             interfaces.Queue
+	Cache             *Cache
+	Skips             interfaces.SkipTracker
+	Commands          []interfaces.Command
+	Version           string
+	Volume            float32
+	YouTubeDL         *YouTubeDL
+	KeepAlive         chan bool
+}
+
+// DJ is a struct that keeps track of all aspects of MumbleDJ's environment.
+var DJ *MumbleDJ
+
+// NewMumbleDJ initializes and returns a MumbleDJ type.
+func NewMumbleDJ() *MumbleDJ {
+	SetDefaultConfig()
+
+	return &MumbleDJ{
+		AvailableServices: make([]interfaces.Service, 0),
+		TLSConfig:         new(tls.Config),
+		Queue:             NewQueue(),
+		Cache:             NewCache(),
+		Skips:             NewSkipTracker(),
+		Commands:          make([]interfaces.Command, 0),
+		YouTubeDL:         new(YouTubeDL),
+		KeepAlive:         make(chan bool),
+	}
+}
+
+// OnConnect event. First moves MumbleDJ into the default channel if one exists.
+// The configuration is loaded and the audio stream is initialized.
+func (dj *MumbleDJ) OnConnect(e *gumble.ConnectEvent) {
+	dj.AudioStream = nil
+	logrus.WithFields(logrus.Fields{
+		"volume": fmt.Sprintf("%.2f", viper.GetFloat64("volume.default")),
+	}).Infoln("Setting default volume...")
+	dj.Volume = float32(viper.GetFloat64("volume.default"))
+
+	if viper.GetBool("cache.enabled") {
+		logrus.Infoln("Caching enabled.")
+		dj.Cache.UpdateStatistics()
+		go dj.Cache.CleanPeriodically()
+	} else {
+		logrus.Infoln("Caching disabled.")
+	}
+}
+
+// OnDisconnect event. Terminates MumbleDJ process or retries connection if
+// automatic connection retries are enabled.
+func (dj *MumbleDJ) OnDisconnect(e *gumble.DisconnectEvent) {
+	dj.Queue.Reset()
+	if viper.GetBool("connection.retry_enabled") &&
+		(e.Type == gumble.DisconnectError || e.Type == gumble.DisconnectKicked) {
+		logrus.WithFields(logrus.Fields{
+			"interval_secs": fmt.Sprintf("%d", viper.GetInt("connection.retry_interval")),
+			"attempts":      fmt.Sprintf("%d", viper.GetInt("connection.retry_attempts")),
+		}).Warnln("Disconnected from server. Retrying connection...")
+
+		success := false
+		for retries := 0; retries < viper.GetInt("connection.retry_attempts"); retries++ {
+			logrus.Infoln("Retrying connection...")
+			if client, err := gumble.DialWithDialer(new(net.Dialer), viper.GetString("connection.address")+":"+viper.GetString("connection.port"), dj.GumbleConfig, dj.TLSConfig); err == nil {
+				dj.Client = client
+				logrus.Infoln("Successfully reconnected to the server!")
+				success = true
+				break
+			}
+			time.Sleep(time.Duration(viper.GetInt("connection.retry_interval")) * time.Second)
+		}
+		if !success {
+			dj.KeepAlive <- true
+			logrus.Fatalln("Could not reconnect to server. Exiting...")
+		}
+	} else {
+		dj.KeepAlive <- true
+		logrus.Fatalln("Disconnected from server. No reconnect attempts will be made.")
+	}
+}
+
+// OnTextMessage event. Checks for command prefix and passes it to the Commander
+// if it exists. Ignores the incoming message otherwise.
+func (dj *MumbleDJ) OnTextMessage(e *gumble.TextMessageEvent) {
+	plainMessage := gumbleutil.PlainText(&e.TextMessage)
+	if len(plainMessage) != 0 {
+		if plainMessage[0] == viper.GetString("commands.prefix")[0] &&
+			plainMessage != viper.GetString("commands.prefix") {
+			go func() {
+				message, isPrivateMessage, err := dj.FindAndExecuteCommand(e.Sender, plainMessage[1:])
+				if err != nil {
+					logrus.WithFields(logrus.Fields{
+						"user":    e.Sender.Name,
+						"message": err.Error(),
+					}).Warnln("Sending an error message...")
+					dj.SendPrivateMessage(e.Sender, fmt.Sprintf("<b>Error:</b> %s", err.Error()))
+				} else {
+					if isPrivateMessage {
+						logrus.WithFields(logrus.Fields{
+							"user":    e.Sender.Name,
+							"message": message,
+						}).Infoln("Sending a private message...")
+						dj.SendPrivateMessage(e.Sender, message)
+					} else {
+						logrus.WithFields(logrus.Fields{
+							"channel": dj.Client.Self.Channel.Name,
+							"message": message,
+						}).Infoln("Sending a message to channel...")
+						dj.Client.Self.Channel.Send(message, false)
+					}
+				}
+			}()
+		}
+	}
+}
+
+// OnUserChange event. Checks UserChange type and adjusts skip trackers to
+// reflect the current status of the users on the server.
+func (dj *MumbleDJ) OnUserChange(e *gumble.UserChangeEvent) {
+	if e.Type.Has(gumble.UserChangeDisconnected) || e.Type.Has(gumble.UserChangeChannel) {
+		logrus.WithFields(logrus.Fields{
+			"user": e.User.Name,
+		}).Infoln("A user has disconnected or changed channels, updating skip trackers...")
+		dj.Skips.RemoveTrackSkip(e.User)
+		dj.Skips.RemovePlaylistSkip(e.User)
+	}
+}
+
+// SendPrivateMessage sends a private message to the specified user. This method
+// verifies that the targeted user is still present in the server before attempting
+// to send the message.
+func (dj *MumbleDJ) SendPrivateMessage(user *gumble.User, message string) {
+	dj.Client.Do(func() {
+		if targetUser := dj.Client.Self.Channel.Users.Find(user.Name); targetUser != nil {
+			targetUser.Send(message)
+		}
+	})
+}
+
+// IsAdmin checks whether a particular Mumble user is a MumbleDJ admin.
+// Returns true if the user is an admin, and false otherwise.
+func (dj *MumbleDJ) IsAdmin(user *gumble.User) bool {
+	for _, admin := range viper.GetStringSlice("admins.names") {
+		if user.Name == admin {
+			return true
+		}
+	}
+	return false
+}
+
+// Connect starts the process for connecting to a Mumble server.
+func (dj *MumbleDJ) Connect() error {
+	// Perform startup checks before connecting.
+	logrus.Infoln("Performing startup checks...")
+	PerformStartupChecks()
+
+	// Create Gumble config.
+	dj.GumbleConfig = gumble.NewConfig()
+	dj.GumbleConfig.Username = viper.GetString("connection.username")
+	dj.GumbleConfig.Password = viper.GetString("connection.password")
+	dj.GumbleConfig.Tokens = strings.Split(viper.GetString("connection.access_tokens"), ",")
+
+	// Initialize key pair if needed.
+	if viper.GetBool("connection.insecure") {
+		dj.TLSConfig.InsecureSkipVerify = true
+	} else {
+		dj.TLSConfig.ServerName = viper.GetString("connection.address")
+
+		if viper.GetString("connection.cert") != "" {
+			if viper.GetString("connection.key") == "" {
+				viper.Set("connection.key", viper.GetString("connection.cert"))
+			}
+
+			if certificate, err := tls.LoadX509KeyPair(viper.GetString("connection.cert"), viper.GetString("connection.key")); err == nil {
+				dj.TLSConfig.Certificates = append(dj.TLSConfig.Certificates, certificate)
+			} else {
+				return err
+			}
+		}
+	}
+
+	// Add user p12 cert if needed.
+	if viper.GetString("connection.user_p12") != "" {
+		if _, err := os.Stat(viper.GetString("connection.user_p12")); os.IsNotExist(err) {
+			return err
+		}
+
+		// Create temporary directory for converted p12 file.
+		dir, err := ioutil.TempDir("", "mumbledj")
+		if err != nil {
+			return err
+		}
+		defer os.RemoveAll(dir)
+
+		// Create temporary mumbledj.crt.pem from p12 file.
+		command := exec.Command("openssl", "pkcs12", "-password", "pass:", "-in", viper.GetString("connection.user_p12"), "-out", dir+"/mumbledj.crt.pem", "-clcerts", "-nokeys")
+		if err := command.Run(); err != nil {
+			return err
+		}
+
+		// Create temporary mumbledj.key.pem from p12 file.
+		command = exec.Command("openssl", "pkcs12", "-password", "pass:", "-in", viper.GetString("connection.user_p12"), "-out", dir+"/mumbledj.key.pem", "-nocerts", "-nodes")
+		if err := command.Run(); err != nil {
+			return err
+		}
+
+		if certificate, err := tls.LoadX509KeyPair(dir+"/mumbledj.crt.pem", dir+"/mumbledj.key.pem"); err == nil {
+			dj.TLSConfig.Certificates = append(dj.TLSConfig.Certificates, certificate)
+		} else {
+			return err
+		}
+	}
+
+	dj.GumbleConfig.Attach(gumbleutil.Listener{
+		Connect:     dj.OnConnect,
+		Disconnect:  dj.OnDisconnect,
+		TextMessage: dj.OnTextMessage,
+		UserChange:  dj.OnUserChange,
+	})
+	dj.GumbleConfig.Attach(gumbleutil.AutoBitrate)
+
+	var connErr error
+
+	logrus.WithFields(logrus.Fields{
+		"address": viper.GetString("connection.address"),
+		"port":    viper.GetString("connection.port"),
+	}).Infoln("Attempting connection to server...")
+	if dj.Client, connErr = gumble.DialWithDialer(new(net.Dialer), viper.GetString("connection.address")+":"+viper.GetString("connection.port"), dj.GumbleConfig, dj.TLSConfig); connErr != nil {
+		return connErr
+	}
+
+	return nil
+}
+
+// FindAndExecuteCommand attempts to find a reference to a command in an
+// incoming message. If found, the command is executed and the resulting
+// message/error is returned.
+func (dj *MumbleDJ) FindAndExecuteCommand(user *gumble.User, message string) (string, bool, error) {
+	command, err := dj.findCommand(message)
+	if err != nil {
+		return "", true, errors.New("No command was found in this message")
+	}
+	return dj.executeCommand(user, message, command)
+}
+
+// GetService loops through the available services and determines if a URL
+// matches a particular service. If a match is found, the service object is
+// returned.
+func (dj *MumbleDJ) GetService(url string) (interfaces.Service, error) {
+	for _, service := range dj.AvailableServices {
+		if service.CheckURL(url) {
+			return service, nil
+		}
+	}
+	return nil, errors.New("The provided URL does not match an enabled service")
+}
+
+func (dj *MumbleDJ) findCommand(message string) (interfaces.Command, error) {
+	var possibleCommand string
+	if strings.Contains(message, " ") {
+		possibleCommand = strings.ToLower(message[:strings.Index(message, " ")])
+	} else {
+		possibleCommand = strings.ToLower(message)
+	}
+	for _, command := range dj.Commands {
+		for _, alias := range command.Aliases() {
+			if possibleCommand == alias {
+				return command, nil
+			}
+		}
+	}
+	return nil, errors.New("No command was found in this message")
+}
+
+func (dj *MumbleDJ) executeCommand(user *gumble.User, message string, command interfaces.Command) (string, bool, error) {
+	canExecute := false
+	if viper.GetBool("admins.enabled") && command.IsAdminCommand() {
+		canExecute = dj.IsAdmin(user)
+	} else {
+		canExecute = true
+	}
+
+	if canExecute {
+		return command.Execute(user, strings.Split(message, " ")[1:]...)
+	}
+	return "", true, errors.New("You do not have permission to execute this command")
+}

bot/playlist.go

@@ -0,0 +1,36 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * bot/playlist.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package bot
+
+// Playlist stores all metadata related to a playlist of tracks.
+type Playlist struct {
+	ID        string
+	Title     string
+	Submitter string
+	Service   string
+}
+
+// GetID returns the ID of the playlist.
+func (p *Playlist) GetID() string {
+	return p.ID
+}
+
+// GetTitle returns the title of the playlist.
+func (p *Playlist) GetTitle() string {
+	return p.Title
+}
+
+// GetSubmitter returns the submitter of the playlist.
+func (p *Playlist) GetSubmitter() string {
+	return p.Submitter
+}
+
+// GetService returns the name of the service from which the playlist was retrieved from.
+func (p *Playlist) GetService() string {
+	return p.Service
+}

bot/playlist_test.go

@@ -0,0 +1,48 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * bot/playlist_test.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package bot
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/suite"
+)
+
+type PlaylistTestSuite struct {
+	Playlist Playlist
+	suite.Suite
+}
+
+func (suite *PlaylistTestSuite) SetupTest() {
+	suite.Playlist = Playlist{
+		ID:        "id",
+		Title:     "title",
+		Submitter: "submitter",
+		Service:   "service",
+	}
+}
+
+func (suite *PlaylistTestSuite) TestGetID() {
+	suite.Equal("id", suite.Playlist.GetID())
+}
+
+func (suite *PlaylistTestSuite) TestGetTitle() {
+	suite.Equal("title", suite.Playlist.GetTitle())
+}
+
+func (suite *PlaylistTestSuite) TestGetSubmitter() {
+	suite.Equal("submitter", suite.Playlist.GetSubmitter())
+}
+
+func (suite *PlaylistTestSuite) TestGetService() {
+	suite.Equal("service", suite.Playlist.GetService())
+}
+
+func TestPlaylistTestSuite(t *testing.T) {
+	suite.Run(t, new(PlaylistTestSuite))
+}

bot/queue.go

@@ -0,0 +1,361 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * bot/queue.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package bot
+
+import (
+	"errors"
+	"fmt"
+	"math/rand"
+	"os"
+	"sync"
+	"time"
+
+	"github.com/layeh/gumble/gumbleffmpeg"
+	_ "github.com/layeh/gumble/opus"
+	"github.com/matthieugrieger/mumbledj/interfaces"
+	"github.com/spf13/viper"
+)
+
+// Queue holds the audio queue itself along with useful methods for
+// performing actions on the queue.
+type Queue struct {
+	Queue []interfaces.Track
+	mutex sync.RWMutex
+}
+
+func init() {
+	rand.Seed(time.Now().UTC().UnixNano())
+}
+
+// NewQueue initializes a new queue and returns it.
+func NewQueue() *Queue {
+	return &Queue{
+		Queue: make([]interfaces.Track, 0),
+	}
+}
+
+// Length returns the length of the queue.
+func (q *Queue) Length() int {
+	q.mutex.RLock()
+	length := len(q.Queue)
+	q.mutex.RUnlock()
+	return length
+}
+
+// Reset removes all tracks from the queue.
+func (q *Queue) Reset() {
+	q.mutex.Lock()
+	q.Queue = q.Queue[:0]
+	q.mutex.Unlock()
+}
+
+// AppendTrack adds a track to the back of the queue.
+func (q *Queue) AppendTrack(t interfaces.Track) error {
+	q.mutex.Lock()
+	beforeLen := len(q.Queue)
+
+	// An error should never occur here since maxTrackDuration is restricted to
+	// ints. Any error in the configuration will be caught during yaml load.
+	maxTrackDuration, _ := time.ParseDuration(fmt.Sprintf("%ds",
+		viper.GetInt("queue.max_track_duration")))
+
+	if viper.GetInt("queue.max_track_duration") == 0 ||
+		t.GetDuration() <= maxTrackDuration {
+		q.Queue = append(q.Queue, t)
+	} else {
+		q.mutex.Unlock()
+		return errors.New("The track is too long to add to the queue")
+	}
+	if len(q.Queue) == beforeLen+1 {
+		q.mutex.Unlock()
+		q.playIfNeeded()
+		return nil
+	}
+	q.mutex.Unlock()
+	return errors.New("Could not add track to queue")
+}
+
+// InsertTrack inserts track `t` at position `i` in the queue.
+func (q *Queue) InsertTrack(i int, t interfaces.Track) error {
+	q.mutex.Lock()
+	beforeLen := len(q.Queue)
+
+	// An error should never occur here since maxTrackDuration is restricted to
+	// ints. Any error in the configuration will be caught during yaml load.
+	maxTrackDuration, _ := time.ParseDuration(fmt.Sprintf("%ds",
+		viper.GetInt("queue.max_track_duration")))
+
+	if viper.GetInt("queue.max_track_duration") == 0 ||
+		t.GetDuration() <= maxTrackDuration {
+		q.Queue = append(q.Queue, Track{})
+		copy(q.Queue[i+1:], q.Queue[i:])
+		q.Queue[i] = t
+	} else {
+		q.mutex.Unlock()
+		return errors.New("The track is too long to add to the queue")
+	}
+	if len(q.Queue) == beforeLen+1 {
+		q.mutex.Unlock()
+		q.playIfNeeded()
+		return nil
+	}
+	q.mutex.Unlock()
+	return errors.New("Could not add track to queue")
+}
+
+// CurrentTrack returns the current Track.
+func (q *Queue) CurrentTrack() (interfaces.Track, error) {
+	q.mutex.RLock()
+	if len(q.Queue) != 0 {
+		current := q.Queue[0]
+		q.mutex.RUnlock()
+		return current, nil
+	}
+	q.mutex.RUnlock()
+	return nil, errors.New("There are no tracks currently in the queue")
+}
+
+// GetTrack takes an `index` argument to determine which track to return.
+// If the track in position `index` exists, it is returned. Otherwise,
+// nil is returned.
+func (q *Queue) GetTrack(index int) interfaces.Track {
+	q.mutex.RLock()
+	if index >= len(q.Queue) {
+		q.mutex.RUnlock()
+		return nil
+	}
+	track := q.Queue[index]
+	q.mutex.RUnlock()
+	return track
+}
+
+// PeekNextTrack peeks at the next track and returns it.
+func (q *Queue) PeekNextTrack() (interfaces.Track, error) {
+	q.mutex.RLock()
+	if len(q.Queue) > 1 {
+		if viper.GetBool("queue.automatic_shuffle_on") {
+			q.RandomNextTrack(false)
+		}
+		next := q.Queue[1]
+		q.mutex.RUnlock()
+		return next, nil
+	}
+	q.mutex.RUnlock()
+	return nil, errors.New("There is no track coming up next")
+}
+
+// Traverse is a traversal function for Queue. Allows a visit function to
+// be passed in which performs the specified action on each queue item.
+func (q *Queue) Traverse(visit func(i int, t interfaces.Track)) {
+	q.mutex.RLock()
+	if len(q.Queue) > 0 {
+		for queueIndex, queueTrack := range q.Queue {
+			visit(queueIndex, queueTrack)
+		}
+	}
+	q.mutex.RUnlock()
+}
+
+// ShuffleTracks shuffles the queue using an inside-out algorithm.
+func (q *Queue) ShuffleTracks() {
+	q.mutex.Lock()
+	// Skip the first track, as it is likely playing.
+	for i := range q.Queue[1:] {
+		j := rand.Intn(i + 1)
+		q.Queue[i+1], q.Queue[j+1] = q.Queue[j+1], q.Queue[i+1]
+	}
+	q.mutex.Unlock()
+}
+
+// RandomNextTrack sets a random track as the next track to be played.
+func (q *Queue) RandomNextTrack(queueWasEmpty bool) {
+	q.mutex.Lock()
+	if len(q.Queue) > 1 {
+		nextTrackIndex := 1
+		if queueWasEmpty {
+			nextTrackIndex = 0
+		}
+		swapIndex := nextTrackIndex + rand.Intn(len(q.Queue)-1)
+		q.Queue[nextTrackIndex], q.Queue[swapIndex] = q.Queue[swapIndex], q.Queue[nextTrackIndex]
+	}
+	q.mutex.Unlock()
+}
+
+// Skip performs the necessary actions that take place when a track is skipped
+// via a command.
+func (q *Queue) Skip() {
+	// Set AudioStream to nil if it isn't already.
+	if DJ.AudioStream != nil {
+		DJ.AudioStream = nil
+	}
+
+	// Remove all track skips.
+	DJ.Skips.ResetTrackSkips()
+
+	q.mutex.Lock()
+	// If caching is disabled, delete the track from disk.
+	if len(q.Queue) != 0 && !viper.GetBool("cache.enabled") {
+		DJ.YouTubeDL.Delete(q.Queue[0])
+	}
+
+	// If automatic track shuffling is enabled, assign a random track in the queue to be the next track.
+	if viper.GetBool("queue.automatic_shuffle_on") {
+		q.mutex.Unlock()
+		q.RandomNextTrack(false)
+		q.mutex.Lock()
+	}
+
+	// Remove all playlist skips if this is the last track of the playlist still in the queue.
+	if playlist := q.Queue[0].GetPlaylist(); playlist != nil {
+		id := playlist.GetID()
+		playlistIsFinished := true
+
+		q.mutex.Unlock()
+		q.Traverse(func(i int, t interfaces.Track) {
+			if i != 0 && t.GetPlaylist() != nil {
+				if t.GetPlaylist().GetID() == id {
+					playlistIsFinished = false
+				}
+			}
+		})
+		q.mutex.Lock()
+
+		if playlistIsFinished {
+			DJ.Skips.ResetPlaylistSkips()
+		}
+	}
+
+	// Skip the track.
+	length := len(q.Queue)
+	if length > 1 {
+		q.Queue = q.Queue[1:]
+	} else {
+		q.Queue = make([]interfaces.Track, 0)
+	}
+	q.mutex.Unlock()
+
+	if err := q.playIfNeeded(); err != nil {
+		q.Skip()
+	}
+}
+
+// SkipPlaylist performs the necessary actions that take place when a playlist
+// is skipped via a command.
+func (q *Queue) SkipPlaylist() {
+	q.mutex.Lock()
+	if playlist := q.Queue[0].GetPlaylist(); playlist != nil {
+		currentPlaylistID := playlist.GetID()
+
+		// We must loop backwards to prevent missing any elements after deletion.
+		// NOTE: We do not remove the first track of the playlist quite yet as that
+		// is removed properly with the following Skip() call.
+		for i := len(q.Queue) - 1; i >= 1; i-- {
+			if otherTrackPlaylist := q.Queue[i].GetPlaylist(); otherTrackPlaylist != nil {
+				if otherTrackPlaylist.GetID() == currentPlaylistID {
+					q.Queue = append(q.Queue[:i], q.Queue[i+1:]...)
+				}
+			}
+		}
+	}
+	q.mutex.Unlock()
+	q.StopCurrent()
+}
+
+// PlayCurrent creates a new audio stream and begins playing the current track.
+func (q *Queue) PlayCurrent() error {
+	currentTrack := q.GetTrack(0)
+	filepath := os.ExpandEnv(viper.GetString("cache.directory") + "/" + currentTrack.GetFilename())
+	if _, err := os.Stat(filepath); os.IsNotExist(err) {
+		if err := DJ.YouTubeDL.Download(q.GetTrack(0)); err != nil {
+			return err
+		}
+	}
+	source := gumbleffmpeg.SourceFile(filepath)
+	DJ.AudioStream = gumbleffmpeg.New(DJ.Client, source)
+	DJ.AudioStream.Offset = currentTrack.GetPlaybackOffset()
+	DJ.AudioStream.Volume = DJ.Volume
+
+	if viper.GetString("defaults.player_command") == "avconv" {
+		DJ.AudioStream.Command = "avconv"
+	}
+
+	if viper.GetBool("queue.announce_new_tracks") {
+		message :=
+			`<table>
+			 	<tr>
+					<td align="center"><img src="%s" width=150 /></td>
+				</tr>
+				<tr>
+					<td align="center"><b><a href="%s">%s</a> (%s)</b></td>
+				</tr>
+				<tr>
+					<td align="center">Added by %s</td>
+				</tr>
+			`
+		message = fmt.Sprintf(message, currentTrack.GetThumbnailURL(), currentTrack.GetURL(),
+			currentTrack.GetTitle(), currentTrack.GetDuration().String(), currentTrack.GetSubmitter())
+		if currentTrack.GetPlaylist() != nil {
+			message = fmt.Sprintf(message+`<tr><td align="center">From playlist "%s"</td></tr>`, currentTrack.GetPlaylist().GetTitle())
+		}
+		message += `</table>`
+		DJ.Client.Self.Channel.Send(message, false)
+	}
+
+	DJ.AudioStream.Play()
+	go func() {
+		DJ.AudioStream.Wait()
+		q.Skip()
+	}()
+
+	return nil
+}
+
+// PauseCurrent pauses the current audio stream if it exists and is not already paused.
+func (q *Queue) PauseCurrent() error {
+	if DJ.AudioStream == nil {
+		return errors.New("There is no track to pause")
+	}
+	if DJ.AudioStream.State() == gumbleffmpeg.StatePaused {
+		return errors.New("The track is already paused")
+	}
+	DJ.AudioStream.Pause()
+	return nil
+}
+
+// ResumeCurrent resumes playback of the current audio stream if it exists and is paused.
+func (q *Queue) ResumeCurrent() error {
+	if DJ.AudioStream == nil {
+		return errors.New("There is no track to resume")
+	}
+	if DJ.AudioStream.State() == gumbleffmpeg.StatePlaying {
+		return errors.New("The track is already playing")
+	}
+	DJ.AudioStream.Play()
+	return nil
+}
+
+// StopCurrent stops the playback of the current audio stream if it exists.
+func (q *Queue) StopCurrent() error {
+	if DJ.AudioStream == nil {
+		return errors.New("The audio stream is nil")
+	}
+	DJ.AudioStream.Stop()
+	return nil
+}
+
+func (q *Queue) playIfNeeded() error {
+	if DJ.AudioStream == nil && q.Length() > 0 {
+		if err := DJ.YouTubeDL.Download(q.GetTrack(0)); err != nil {
+			return err
+		}
+		if err := q.PlayCurrent(); err != nil {
+			return err
+		}
+	}
+	return nil
+}

bot/queue_test.go

@@ -0,0 +1,276 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * bot/queue_test.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package bot
+
+import (
+	"fmt"
+	"math/rand"
+	"testing"
+	"time"
+
+	"github.com/layeh/gumble/gumbleffmpeg"
+	"github.com/matthieugrieger/mumbledj/interfaces"
+	"github.com/spf13/viper"
+	"github.com/stretchr/testify/suite"
+)
+
+type QueueTestSuite struct {
+	suite.Suite
+	FirstTrack  *Track
+	SecondTrack *Track
+	ThirdTrack  *Track
+}
+
+func (suite *QueueTestSuite) SetupSuite() {
+	DJ = NewMumbleDJ()
+
+	// Trick the tests into thinking audio is already playing to avoid
+	// attempting to play tracks that don't exist.
+	DJ.AudioStream = new(gumbleffmpeg.Stream)
+
+	viper.Set("queue.automatic_shuffle_on", false)
+
+	suite.FirstTrack = &Track{ID: "first"}
+	suite.SecondTrack = &Track{ID: "second"}
+	suite.ThirdTrack = &Track{ID: "third"}
+}
+
+func (suite *QueueTestSuite) SetupTest() {
+	DJ.Queue = NewQueue()
+	viper.Set("queue.max_track_duration", 0)
+
+	// Override the initialized seed for consistent test results.
+	rand.Seed(1)
+}
+
+func (suite *QueueTestSuite) TestNewQueue() {
+	suite.Zero(DJ.Queue.Length(), "The new queue should be empty.")
+}
+
+func (suite *QueueTestSuite) TestAppendTrackWhenTrackIsValid() {
+	suite.Zero(DJ.Queue.Length(), "The queue should be empty.")
+	err := DJ.Queue.AppendTrack(suite.FirstTrack)
+
+	suite.Equal(1, DJ.Queue.Length(), "There should now be one track in the queue.")
+	suite.Nil(err, "No error should be returned.")
+}
+
+func (suite *QueueTestSuite) TestAppendTrackWhenTrackIsTooLong() {
+	// Set max track duration to 5 seconds
+	viper.Set("queue.max_track_duration", 5)
+
+	// Create duration longer than 5 seconds
+	duration, _ := time.ParseDuration("6s")
+
+	longTrack := &Track{}
+
+	longTrack.Duration = duration
+
+	suite.Zero(DJ.Queue.Length(), "The queue should be empty.")
+	err := DJ.Queue.AppendTrack(longTrack)
+
+	suite.Zero(DJ.Queue.Length(), "The queue should still be empty.")
+	suite.NotNil(err, "An error should be returned due to the track being too long.")
+}
+
+func (suite *QueueTestSuite) TestCurrentTrackWhenOneExists() {
+	DJ.Queue.AppendTrack(suite.FirstTrack)
+
+	track, err := DJ.Queue.CurrentTrack()
+
+	suite.NotNil(track, "The returned track should be non-nil.")
+	suite.Equal("first", track.GetID(), "The returned track should be the one just added to the queue.")
+	suite.Nil(err, "No error should be returned.")
+}
+
+func (suite *QueueTestSuite) TestCurrentTrackWhenOneDoesNotExist() {
+	track, err := DJ.Queue.CurrentTrack()
+
+	suite.Nil(track, "The returned track should be nil.")
+	suite.NotNil(err, "An error should be returned because there are no tracks in the queue.")
+}
+
+func (suite *QueueTestSuite) TestPeekNextTrackWhenOneExists() {
+	DJ.Queue.AppendTrack(suite.FirstTrack)
+	DJ.Queue.AppendTrack(suite.SecondTrack)
+
+	track, err := DJ.Queue.PeekNextTrack()
+
+	suite.NotNil(track, "The returned track should be non-nil.")
+	suite.Equal("second", track.GetID(), "The returned track should be the second one added to the queue.")
+	suite.Nil(err, "No error should be returned.")
+}
+
+func (suite *QueueTestSuite) TestPeekNextTrackWhenOneDoesNotExist() {
+	track, err := DJ.Queue.PeekNextTrack()
+
+	suite.Nil(track, "The returned track should be nil.")
+	suite.NotNil(err, "An error should be returned because there are no tracks in the queue.")
+
+	DJ.Queue.AppendTrack(suite.FirstTrack)
+
+	track, err = DJ.Queue.PeekNextTrack()
+
+	suite.Nil(track, "The returned track should be nil.")
+	suite.NotNil(err, "An error should be returned because there is only one track in the queue.")
+}
+
+func (suite *QueueTestSuite) TestTraverseWhenNoTracksExist() {
+	trackString := ""
+
+	DJ.Queue.Traverse(func(i int, t interfaces.Track) {
+		trackString += t.GetID() + ", "
+	})
+
+	suite.Equal("", trackString, "No tracks should be traversed as there are none in the queue.")
+}
+
+func (suite *QueueTestSuite) TestTraverseWhenTracksExist() {
+	trackString := ""
+	DJ.Queue.AppendTrack(suite.FirstTrack)
+	DJ.Queue.AppendTrack(suite.SecondTrack)
+
+	DJ.Queue.Traverse(func(i int, t interfaces.Track) {
+		trackString += t.GetID() + ", "
+	})
+
+	suite.NotEqual("", trackString, "The trackString should not be empty as there were tracks to traverse.")
+	suite.Contains(trackString, "first", "The traverse method should have visited the first track.")
+	suite.Contains(trackString, "second", "The traverse method should have visited the second track.")
+}
+
+func (suite *QueueTestSuite) TestShuffleTracks() {
+	DJ.Queue.AppendTrack(suite.FirstTrack)
+
+	DJ.Queue.ShuffleTracks()
+
+	suite.Equal(suite.FirstTrack, DJ.Queue.GetTrack(0), "Shuffle shouldn't do anything when only one track is in the queue.")
+
+	DJ.Queue.AppendTrack(suite.SecondTrack)
+
+	DJ.Queue.ShuffleTracks()
+	suite.Equal(suite.FirstTrack, DJ.Queue.GetTrack(0), "Shuffle shouldn't do anything when only two tracks are in the queue.")
+	suite.Equal(suite.SecondTrack, DJ.Queue.GetTrack(1), "Shuffle shouldn't do anything when only two tracks are in the queue.")
+
+	DJ.Queue.AppendTrack(suite.ThirdTrack)
+
+	for i := 0; i < 10; i++ {
+		DJ.Queue.AppendTrack(&Track{ID: fmt.Sprintf("%d", i+4)})
+	}
+
+	originalSecondTrack := DJ.Queue.GetTrack(1)
+	DJ.Queue.ShuffleTracks()
+	suite.NotEqual(originalSecondTrack, DJ.Queue.GetTrack(1), "The shuffled queue should not be the same as the original queue.")
+}
+
+func (suite *QueueTestSuite) TestRandomNextTrackWhenQueueWasEmpty() {
+	DJ.Queue.AppendTrack(suite.FirstTrack)
+
+	DJ.Queue.RandomNextTrack(true)
+
+	suite.Equal(suite.FirstTrack, DJ.Queue.GetTrack(0), "RandomNextTrack shouldn't do anything when there is only one track in the queue.")
+
+	for i := 0; i < 25; i++ {
+		DJ.Queue.AppendTrack(&Track{ID: fmt.Sprintf("%d", i+1)})
+	}
+
+	DJ.Queue.RandomNextTrack(true)
+
+	suite.NotEqual(suite.FirstTrack, DJ.Queue.GetTrack(0), "The first track should no longer be the same.")
+}
+
+func (suite *QueueTestSuite) TestRandomNextTrackWhenQueueWasNotEmpty() {
+	DJ.Queue.AppendTrack(suite.FirstTrack)
+	DJ.Queue.RandomNextTrack(false)
+
+	suite.Equal(suite.FirstTrack, DJ.Queue.GetTrack(0), "RandomNextTrack shouldn't do anything when there is only one track in the queue.")
+
+	DJ.Queue.AppendTrack(suite.SecondTrack)
+	DJ.Queue.RandomNextTrack(false)
+
+	suite.Equal(suite.FirstTrack, DJ.Queue.GetTrack(0), "RandomNextTrack shouldn't do anything when there is only two tracks in the queue and the queue was not previously empty.")
+	suite.Equal(suite.SecondTrack, DJ.Queue.GetTrack(1), "RandomNextTrack shouldn't do anything when there is only two tracks in the queue and the queue was not previously empty.")
+
+	for i := 0; i < 25; i++ {
+		DJ.Queue.AppendTrack(&Track{ID: fmt.Sprintf("%d", i+2)})
+	}
+
+	DJ.Queue.RandomNextTrack(false)
+
+	suite.Equal(suite.FirstTrack, DJ.Queue.GetTrack(0), "Since the queue was not previously empty the first track should not be touched.")
+	suite.NotEqual(suite.SecondTrack, DJ.Queue.GetTrack(1), "The next track should be randomized.")
+}
+
+// TODO: Fix these tests.
+/*func (suite *QueueTestSuite) TestSkipWhenQueueHasLessThanTwoTracks() {
+	DJ.Queue.AppendTrack(suite.FirstTrack)
+	suite.Equal(1, DJ.Queue.Length(), "There should be one item in the queue.")
+
+	DJ.Queue.Skip()
+	suite.Zero(DJ.Queue.Length(), "There should now be zero items in the queue.")
+}
+
+func (suite *QueueTestSuite) TestSkipWhenQueueHasTwoOrMoreTracks() {
+	DJ.Queue.AppendTrack(suite.FirstTrack)
+	DJ.Queue.AppendTrack(suite.SecondTrack)
+
+	suite.Equal(suite.FirstTrack, DJ.Queue.GetTrack(0), "The track added first should be at the front of the queue.")
+	suite.Equal(2, DJ.Queue.Length(), "There should be two items in the queue.")
+
+	DJ.Queue.Skip()
+
+	suite.Equal(suite.SecondTrack, DJ.Queue.GetTrack(0), "The track added second should be at the front of the queue.")
+	suite.Equal(1, DJ.Queue.Length(), "There should be one item in the queue.")
+}
+
+func (suite *QueueTestSuite) TestSkipPlaylistWhenFirstTrackIsNotPartOfPlaylist() {
+	DJ.Queue.AppendTrack(suite.FirstTrack)
+	DJ.Queue.AppendTrack(suite.SecondTrack)
+	DJ.Queue.AppendTrack(suite.ThirdTrack)
+
+	DJ.Queue.SkipPlaylist()
+
+	suite.Equal(3, DJ.Queue.Length(), "No tracks should be skipped.")
+}
+
+func (suite *QueueTestSuite) TestSkipPlaylistWhenFirstTrackIsPartOfPlaylist() {
+	playlist := &Playlist{ID: "playlist"}
+	track1 := &Track{Playlist: playlist}
+	track2 := &Track{Playlist: playlist}
+	track3 := &Track{}
+
+	DJ.Queue.AppendTrack(track1)
+	DJ.Queue.AppendTrack(track2)
+	DJ.Queue.AppendTrack(track3)
+
+	suite.Equal(3, DJ.Queue.Length(), "There should be three tracks in the queue.")
+	DJ.Queue.SkipPlaylist()
+	suite.Equal(1, DJ.Queue.Length(), "There should be one track remaining in the queue.")
+}
+
+func (suite *QueueTestSuite) TestSkipPlaylistWhenPlaylistIsShuffled() {
+	playlist := &Playlist{ID: "playlist"}
+	otherPlaylist := &Playlist{ID: "otherplaylist"}
+	track1 := &Track{Playlist: playlist}
+	track2 := &Track{}
+	track3 := &Track{Playlist: otherPlaylist}
+	track4 := &Track{Playlist: playlist}
+
+	DJ.Queue.AppendTrack(track1)
+	DJ.Queue.AppendTrack(track2)
+	DJ.Queue.AppendTrack(track3)
+	DJ.Queue.AppendTrack(track4)
+
+	suite.Equal(4, DJ.Queue.Length(), "There should be four tracks in the queue.")
+	DJ.Queue.SkipPlaylist()
+	suite.Equal(2, DJ.Queue.Length(), "There should be two tracks remaining in the queue.")
+}*/
+
+func TestQueueTestSuite(t *testing.T) {
+	suite.Run(t, new(QueueTestSuite))
+}

bot/skiptracker.go

@@ -0,0 +1,144 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * bot/skiptracker.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package bot
+
+import (
+	"fmt"
+	"sync"
+
+	"github.com/layeh/gumble/gumble"
+	"github.com/spf13/viper"
+)
+
+// SkipTracker keeps track of the list of users who have skipped the current
+// track or playlist.
+type SkipTracker struct {
+	TrackSkips    []*gumble.User
+	PlaylistSkips []*gumble.User
+	trackMutex    sync.RWMutex
+	playlistMutex sync.RWMutex
+}
+
+// NewSkipTracker returns an empty SkipTracker.
+func NewSkipTracker() *SkipTracker {
+	return &SkipTracker{
+		TrackSkips:    make([]*gumble.User, 0),
+		PlaylistSkips: make([]*gumble.User, 0),
+	}
+}
+
+// AddTrackSkip adds a skip to the SkipTracker for the current track.
+func (s *SkipTracker) AddTrackSkip(skipper *gumble.User) error {
+	s.trackMutex.Lock()
+	for _, user := range s.TrackSkips {
+		if user.Name == skipper.Name {
+			s.trackMutex.Unlock()
+			return fmt.Errorf("%s has already voted to skip the track", skipper.Name)
+		}
+	}
+	s.TrackSkips = append(s.TrackSkips, skipper)
+	s.trackMutex.Unlock()
+	s.evaluateTrackSkips()
+	return nil
+}
+
+// AddPlaylistSkip adds a skip to the SkipTracker for the current playlist.
+func (s *SkipTracker) AddPlaylistSkip(skipper *gumble.User) error {
+	s.playlistMutex.Lock()
+	for _, user := range s.PlaylistSkips {
+		if user.Name == skipper.Name {
+			s.playlistMutex.Unlock()
+			return fmt.Errorf("%s has already voted to skip the playlist", skipper.Name)
+		}
+	}
+	s.PlaylistSkips = append(s.PlaylistSkips, skipper)
+	s.playlistMutex.Unlock()
+	s.evaluatePlaylistSkips()
+	return nil
+}
+
+// RemoveTrackSkip removes a skip from the SkipTracker for the current track.
+func (s *SkipTracker) RemoveTrackSkip(skipper *gumble.User) error {
+	s.trackMutex.Lock()
+	for i, user := range s.TrackSkips {
+		if user.Name == skipper.Name {
+			s.TrackSkips = append(s.TrackSkips[:i], s.TrackSkips[i+1:]...)
+			s.trackMutex.Unlock()
+			return nil
+		}
+	}
+	s.trackMutex.Unlock()
+	return fmt.Errorf("%s did not previously vote to skip the track", skipper.Name)
+}
+
+// RemovePlaylistSkip removes a skip from the SkipTracker for the current playlist.
+func (s *SkipTracker) RemovePlaylistSkip(skipper *gumble.User) error {
+	s.playlistMutex.Lock()
+	for i, user := range s.PlaylistSkips {
+		if user.Name == skipper.Name {
+			s.PlaylistSkips = append(s.PlaylistSkips[:i], s.PlaylistSkips[i+1:]...)
+			s.playlistMutex.Unlock()
+			return nil
+		}
+	}
+	s.playlistMutex.Unlock()
+	return fmt.Errorf("%s did not previously vote to skip the playlist", skipper.Name)
+}
+
+// NumTrackSkips returns the number of users who have skipped the current track.
+func (s *SkipTracker) NumTrackSkips() int {
+	s.trackMutex.RLock()
+	length := len(s.TrackSkips)
+	s.trackMutex.RUnlock()
+	return length
+}
+
+// NumPlaylistSkips returns the number of users who have skipped the current playlist.
+func (s *SkipTracker) NumPlaylistSkips() int {
+	s.playlistMutex.RLock()
+	length := len(s.PlaylistSkips)
+	s.playlistMutex.RUnlock()
+	return length
+}
+
+// ResetTrackSkips resets the skip slice for the current track.
+func (s *SkipTracker) ResetTrackSkips() {
+	s.trackMutex.Lock()
+	s.TrackSkips = s.TrackSkips[:0]
+	s.trackMutex.Unlock()
+}
+
+// ResetPlaylistSkips resets the skip slice for the current playlist.
+func (s *SkipTracker) ResetPlaylistSkips() {
+	s.playlistMutex.Lock()
+	s.PlaylistSkips = s.PlaylistSkips[:0]
+	s.playlistMutex.Unlock()
+}
+
+func (s *SkipTracker) evaluateTrackSkips() {
+	s.trackMutex.RLock()
+	skipRatio := viper.GetFloat64("queue.track_skip_ratio")
+	DJ.Client.Do(func() {
+		if float64(len(s.TrackSkips))/float64(len(DJ.Client.Self.Channel.Users)) >= skipRatio {
+			// Stopping an audio stream triggers a skip.
+			DJ.Queue.StopCurrent()
+		}
+	})
+	s.trackMutex.RUnlock()
+}
+
+func (s *SkipTracker) evaluatePlaylistSkips() {
+	s.playlistMutex.RLock()
+	skipRatio := viper.GetFloat64("queue.playlist_skip_ratio")
+	DJ.Client.Do(func() {
+		if float64(len(s.PlaylistSkips))/float64(len(DJ.Client.Self.Channel.Users)) >= skipRatio {
+			DJ.Queue.SkipPlaylist()
+		}
+	})
+	s.playlistMutex.RUnlock()
+}

bot/skiptracker_test.go

@@ -0,0 +1,143 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * bot/skiptracker_test.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package bot
+
+import (
+	"testing"
+
+	"github.com/layeh/gumble/gumble"
+	"github.com/stretchr/testify/suite"
+)
+
+type SkipTrackerTestSuite struct {
+	suite.Suite
+	Skips *SkipTracker
+	User1 *gumble.User
+	User2 *gumble.User
+}
+
+func (suite *SkipTrackerTestSuite) SetupSuite() {
+	suite.User1 = new(gumble.User)
+	suite.User1.Name = "User1"
+	suite.User2 = new(gumble.User)
+	suite.User2.Name = "User2"
+}
+
+func (suite *SkipTrackerTestSuite) SetupTest() {
+	suite.Skips = NewSkipTracker()
+}
+
+func (suite *SkipTrackerTestSuite) TestNewSkipTracker() {
+	suite.Zero(suite.Skips.NumTrackSkips(), "The track skip slice should be empty upon initialization.")
+	suite.Zero(suite.Skips.NumPlaylistSkips(), "The playlist skip slice should be empty upon initialization.")
+}
+
+// TODO: Fix these tests.
+/*func (suite *SkipTrackerTestSuite) TestAddTrackSkip() {
+	err := suite.Skips.AddTrackSkip(suite.User1)
+
+	suite.Equal(1, suite.Skips.NumTrackSkips(), "There should now be one user in the track skip slice.")
+	suite.Zero(0, suite.Skips.NumPlaylistSkips(), "The playlist skip slice should be unaffected.")
+	suite.Nil(err, "No error should be returned.")
+
+	err = suite.Skips.AddTrackSkip(suite.User2)
+
+	suite.Equal(2, suite.Skips.NumTrackSkips(), "There should now be two users in the track skip slice.")
+	suite.Zero(0, suite.Skips.NumPlaylistSkips(), "The playlist skip slice should be unaffected.")
+	suite.Nil(err, "No error should be returned.")
+
+	err = suite.Skips.AddTrackSkip(suite.User1)
+
+	suite.Equal(2, suite.Skips.NumTrackSkips(), "This is a duplicate skip, so the track skip slice should still only have two users.")
+	suite.Zero(0, suite.Skips.NumPlaylistSkips(), "The playlist skip slice should be unaffected.")
+	suite.NotNil(err, "An error should be returned since this user has already voted to skip the current track.")
+}
+
+func (suite *SkipTrackerTestSuite) TestAddPlaylistSkip() {
+	err := suite.Skips.AddPlaylistSkip(suite.User1)
+
+	suite.Zero(suite.Skips.NumTrackSkips(), "The track skip slice should be unaffected.")
+	suite.Equal(1, suite.Skips.NumPlaylistSkips(), "There should now be one user in the playlist skip slice.")
+	suite.Nil(err, "No error should be returned.")
+
+	err = suite.Skips.AddPlaylistSkip(suite.User2)
+
+	suite.Zero(suite.Skips.NumTrackSkips(), "The track skip slice should be unaffected.")
+	suite.Equal(2, suite.Skips.NumPlaylistSkips(), "There should now be two users in the playlist skip slice.")
+	suite.Nil(err, "No error should be returned.")
+
+	err = suite.Skips.AddPlaylistSkip(suite.User1)
+
+	suite.Zero(suite.Skips.NumTrackSkips(), "The track skip slice should be unaffected.")
+	suite.Equal(2, suite.Skips.NumPlaylistSkips(), "This is a duplicate skip, so the playlist skip slice should still only have two users.")
+	suite.NotNil(err, "An error should be returned since this user has already voted to skip the current playlist.")
+}
+
+func (suite *SkipTrackerTestSuite) TestRemoveTrackSkip() {
+	suite.Skips.AddTrackSkip(suite.User1)
+	err := suite.Skips.RemoveTrackSkip(suite.User2)
+
+	suite.Equal(1, suite.Skips.NumTrackSkips(), "User2 has not skipped the track so the track skip slice should be unaffected.")
+	suite.Zero(suite.Skips.NumPlaylistSkips(), "The playlist skip slice should be unaffected.")
+	suite.NotNil(err, "An error should be returned since User2 has not skipped the track yet.")
+
+	err = suite.Skips.RemoveTrackSkip(suite.User1)
+
+	suite.Zero(suite.Skips.NumTrackSkips(), "User1 skipped the track, so their skip should be removed.")
+	suite.Zero(suite.Skips.NumPlaylistSkips(), "The playlist skip slice should be unaffected.")
+	suite.Nil(err, "No error should be returned.")
+}
+
+func (suite *SkipTrackerTestSuite) TestRemovePlaylistSkip() {
+	suite.Skips.AddPlaylistSkip(suite.User1)
+	err := suite.Skips.RemovePlaylistSkip(suite.User2)
+
+	suite.Zero(suite.Skips.NumTrackSkips(), "The track skip slice should be unaffected.")
+	suite.Equal(1, suite.Skips.NumPlaylistSkips(), "User2 has not skipped the playlist so the playlist skip slice should be unaffected.")
+	suite.NotNil(err, "An error should be returned since User2 has not skipped the playlist yet.")
+
+	err = suite.Skips.RemovePlaylistSkip(suite.User1)
+
+	suite.Zero(suite.Skips.NumTrackSkips(), "The track skip slice should be unaffected.")
+	suite.Zero(suite.Skips.NumPlaylistSkips(), "User1 skipped the playlist, so their skip should be removed.")
+	suite.Nil(err, "No error should be returned.")
+}
+
+func (suite *SkipTrackerTestSuite) TestResetTrackSkips() {
+	suite.Skips.AddTrackSkip(suite.User1)
+	suite.Skips.AddTrackSkip(suite.User2)
+	suite.Skips.AddPlaylistSkip(suite.User1)
+	suite.Skips.AddPlaylistSkip(suite.User2)
+
+	suite.Equal(2, suite.Skips.NumTrackSkips(), "There should be two users in the track skip slice.")
+	suite.Equal(2, suite.Skips.NumPlaylistSkips(), "There should be two users in the playlist skip slice.")
+
+	suite.Skips.ResetTrackSkips()
+
+	suite.Zero(suite.Skips.NumTrackSkips(), "The track skip slice has been reset, so the length should be zero.")
+	suite.Equal(2, suite.Skips.NumPlaylistSkips(), "The playlist skip slice should be unaffected.")
+}
+
+func (suite *SkipTrackerTestSuite) TestResetPlaylistSkips() {
+	suite.Skips.AddTrackSkip(suite.User1)
+	suite.Skips.AddTrackSkip(suite.User2)
+	suite.Skips.AddPlaylistSkip(suite.User1)
+	suite.Skips.AddPlaylistSkip(suite.User2)
+
+	suite.Equal(2, suite.Skips.NumTrackSkips(), "There should be two users in the track skip slice.")
+	suite.Equal(2, suite.Skips.NumPlaylistSkips(), "There should be two users in the playlist skip slice.")
+
+	suite.Skips.ResetPlaylistSkips()
+
+	suite.Equal(2, suite.Skips.NumTrackSkips(), "The track skip slice should be unaffected.")
+	suite.Zero(suite.Skips.NumPlaylistSkips(), "The playlist skip slice has been reset, so the length should be zero.")
+}*/
+
+func TestSkipTrackerTestSuite(t *testing.T) {
+	suite.Run(t, new(SkipTrackerTestSuite))
+}

bot/startup.go

@@ -0,0 +1,110 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * bot/startup.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package bot
+
+import (
+	"errors"
+	"fmt"
+	"os/exec"
+
+	"github.com/Sirupsen/logrus"
+	"github.com/spf13/viper"
+)
+
+// PerformStartupChecks executes the suite of startup checks that are run before the bot
+// connects to the server.
+func PerformStartupChecks() {
+	logrus.WithFields(logrus.Fields{
+		"num_services": fmt.Sprintf("%d", len(DJ.AvailableServices)),
+	}).Infoln("Checking for availability of services...")
+
+	for i := len(DJ.AvailableServices) - 1; i >= 0; i-- {
+		if err := DJ.AvailableServices[i].CheckAPIKey(); err != nil {
+			name := DJ.AvailableServices[i].GetReadableName()
+			logrus.WithFields(logrus.Fields{
+				"service": name,
+				"error":   err.Error(),
+			}).Warnln("A startup check discovered an issue. The service will be disabled.")
+
+			// Remove service from enabled services.
+			DJ.AvailableServices = append(DJ.AvailableServices[:i], DJ.AvailableServices[i+1:]...)
+		}
+	}
+
+	if len(DJ.AvailableServices) == 0 {
+		logrus.Fatalln("The bot cannot continue as no services are enabled.")
+	}
+
+	if err := checkYouTubeDLInstallation(); err != nil {
+		logrus.Fatalln("youtube-dl is either not installed or is not discoverable in $PATH. youtube-dl is required to download audio.")
+	}
+	if viper.GetString("defaults.player_command") == "ffmpeg" {
+		if err := checkFfmpegInstallation(); err != nil {
+			logrus.Fatalln("ffmpeg is either not installed or is not discoverable in $PATH. If you would like to use avconv instead, change the defaults.player_command value in the configuration file.")
+		}
+	} else if viper.GetString("defaults.player_command") == "avconv" {
+		if err := checkAvconvInstallation(); err != nil {
+			logrus.Fatalln("avconv is either not installed or is not discoverable in $PATH. If you would like to use ffmpeg instead, change the defaults.player_command value in the configuration file.")
+		}
+	} else {
+		logrus.Fatalln("The player command provided in the configuration file is invalid. Valid choices are: \"ffmpeg\", \"avconv\".")
+	}
+
+	if err := checkAria2Installation(); err != nil {
+		logrus.Warnln("aria2 is not installed or is not discoverable in $PATH. The bot will still partially work, but some services will not work properly.")
+	}
+
+	if err := checkOpenSSLInstallation(); err != nil {
+		logrus.Warnln("openssl is not installed or is not discoverable in $PATH. p12 certificate files will not work.")
+	}
+}
+
+func checkYouTubeDLInstallation() error {
+	logrus.Infoln("Checking YouTubeDL installation...")
+	command := exec.Command("youtube-dl", "--version")
+	if err := command.Run(); err != nil {
+		return errors.New("youtube-dl is not properly installed")
+	}
+	return nil
+}
+
+func checkFfmpegInstallation() error {
+	logrus.Infoln("Checking ffmpeg installation...")
+	command := exec.Command("ffmpeg", "-version")
+	if err := command.Run(); err != nil {
+		return errors.New("ffmpeg is not properly installed")
+	}
+	return nil
+}
+
+func checkAvconvInstallation() error {
+	logrus.Infoln("Checking avconv installation...")
+	command := exec.Command("avconv", "-version")
+	if err := command.Run(); err != nil {
+		return errors.New("avconv is not properly installed")
+	}
+	return nil
+}
+
+func checkAria2Installation() error {
+	logrus.Infoln("Checking aria2c installation...")
+	command := exec.Command("aria2c", "-v")
+	if err := command.Run(); err != nil {
+		return errors.New("aria2c is not properly installed")
+	}
+	return nil
+}
+
+func checkOpenSSLInstallation() error {
+	logrus.Infoln("Checking openssl installation...")
+	command := exec.Command("openssl", "version")
+	if err := command.Run(); err != nil {
+		return errors.New("openssl is not properly installed")
+	}
+	return nil
+}

bot/track.go

@@ -0,0 +1,94 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * bot/track.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package bot
+
+import (
+	"time"
+
+	"github.com/matthieugrieger/mumbledj/interfaces"
+)
+
+// Track stores all metadata related to an audio track.
+type Track struct {
+	ID             string
+	URL            string
+	Title          string
+	Author         string
+	AuthorURL      string
+	Submitter      string
+	Service        string
+	Filename       string
+	ThumbnailURL   string
+	Duration       time.Duration
+	PlaybackOffset time.Duration
+	Playlist       interfaces.Playlist
+}
+
+// GetID returns the ID of the track.
+func (t Track) GetID() string {
+	return t.ID
+}
+
+// GetURL returns the URL of the track.
+func (t Track) GetURL() string {
+	return t.URL
+}
+
+// GetTitle returns the title of the track.
+func (t Track) GetTitle() string {
+	return t.Title
+}
+
+// GetAuthor returns the author of the track.
+func (t Track) GetAuthor() string {
+	return t.Author
+}
+
+// GetAuthorURL returns the URL that links to the author of the track.
+func (t Track) GetAuthorURL() string {
+	return t.AuthorURL
+}
+
+// GetSubmitter returns the submitter of the track.
+func (t Track) GetSubmitter() string {
+	return t.Submitter
+}
+
+// GetService returns the name of the service from which the track was retrieved from.
+func (t Track) GetService() string {
+	return t.Service
+}
+
+// GetFilename returns the name of the file stored on disk, if it exists. If no
+// file on disk exists an empty string and error are returned.
+func (t Track) GetFilename() string {
+	return t.Filename
+}
+
+// GetThumbnailURL returns the URL to the thumbnail for the track. If no thumbnail
+// exists an empty string and error are returned.
+func (t Track) GetThumbnailURL() string {
+	return t.ThumbnailURL
+}
+
+// GetDuration returns the duration of the track.
+func (t Track) GetDuration() time.Duration {
+	return t.Duration
+}
+
+// GetPlaybackOffset returns the playback offset for the track. A duration
+// of 0 is given to tracks that do not specify an offset.
+func (t Track) GetPlaybackOffset() time.Duration {
+	return t.PlaybackOffset
+}
+
+// GetPlaylist returns the playlist the track is associated with, if it exists. If
+// the track is not associated with a playlist a nil playlist and error are returned.
+func (t Track) GetPlaylist() interfaces.Playlist {
+	return t.Playlist
+}

bot/track_test.go

@@ -0,0 +1,125 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * bot/track_test.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package bot
+
+import (
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/suite"
+)
+
+type TrackTestSuite struct {
+	suite.Suite
+	Track Track
+}
+
+func (suite *TrackTestSuite) SetupTest() {
+	duration, _ := time.ParseDuration("1s")
+	offset, _ := time.ParseDuration("2ms")
+	suite.Track = Track{
+		ID:             "id",
+		URL:            "url",
+		Title:          "title",
+		Author:         "author",
+		AuthorURL:      "author_url",
+		Submitter:      "submitter",
+		Service:        "service",
+		Filename:       "filename",
+		ThumbnailURL:   "thumbnailurl",
+		Duration:       duration,
+		PlaybackOffset: offset,
+		Playlist:       new(Playlist),
+	}
+}
+
+func (suite *TrackTestSuite) TestGetID() {
+	suite.Equal("id", suite.Track.GetID())
+}
+
+func (suite *TrackTestSuite) TestGetURL() {
+	suite.Equal("url", suite.Track.GetURL())
+}
+
+func (suite *TrackTestSuite) TestGetTitle() {
+	suite.Equal("title", suite.Track.GetTitle())
+}
+
+func (suite *TrackTestSuite) TestGetAuthor() {
+	suite.Equal("author", suite.Track.GetAuthor())
+}
+
+func (suite *TrackTestSuite) TestGetAuthorURL() {
+	suite.Equal("author_url", suite.Track.GetAuthorURL())
+}
+
+func (suite *TrackTestSuite) TestGetSubmitter() {
+	suite.Equal("submitter", suite.Track.GetSubmitter())
+}
+
+func (suite *TrackTestSuite) TestGetService() {
+	suite.Equal("service", suite.Track.GetService())
+}
+
+func (suite *TrackTestSuite) TestGetFilenameWhenExists() {
+	result := suite.Track.GetFilename()
+
+	suite.Equal("filename", result)
+}
+
+func (suite *TrackTestSuite) TestGetFilenameWhenNotExists() {
+	suite.Track.Filename = ""
+
+	result := suite.Track.GetFilename()
+
+	suite.Equal("", result)
+}
+
+func (suite *TrackTestSuite) TestGetThumbnailURLWhenExists() {
+	result := suite.Track.GetThumbnailURL()
+
+	suite.Equal("thumbnailurl", result)
+}
+
+func (suite *TrackTestSuite) TestGetThumbnailURLWhenNotExists() {
+	suite.Track.ThumbnailURL = ""
+
+	result := suite.Track.GetThumbnailURL()
+
+	suite.Equal("", result)
+}
+
+func (suite *TrackTestSuite) TestGetDuration() {
+	duration, _ := time.ParseDuration("1s")
+
+	suite.Equal(duration, suite.Track.GetDuration())
+}
+
+func (suite *TrackTestSuite) TestGetPlaybackOffset() {
+	duration, _ := time.ParseDuration("2ms")
+
+	suite.Equal(duration, suite.Track.GetPlaybackOffset())
+}
+
+func (suite *TrackTestSuite) TestGetPlaylistWhenExists() {
+	result := suite.Track.GetPlaylist()
+
+	suite.NotNil(result)
+}
+
+func (suite *TrackTestSuite) TestGetPlaylistWhenNotExists() {
+	suite.Track.Playlist = nil
+
+	result := suite.Track.GetPlaylist()
+
+	suite.Nil(result)
+}
+
+func TestTrackTestSuite(t *testing.T) {
+	suite.Run(t, new(TrackTestSuite))
+}

bot/youtube_dl.go

@@ -0,0 +1,81 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * bot/youtube_dl.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package bot
+
+import (
+	"errors"
+	"os"
+	"os/exec"
+
+	"github.com/Sirupsen/logrus"
+	"github.com/matthieugrieger/mumbledj/interfaces"
+	"github.com/spf13/viper"
+)
+
+// YouTubeDL is a struct that gathers all methods related to the youtube-dl
+// software.
+// youtube-dl: https://rg3.github.io/youtube-dl/
+type YouTubeDL struct{}
+
+// Download downloads the audio associated with the incoming `track` object
+// and stores it `track.Filename`.
+func (yt *YouTubeDL) Download(t interfaces.Track) error {
+	player := "--prefer-ffmpeg"
+	if viper.GetString("defaults.player_command") == "avconv" {
+		player = "--prefer-avconv"
+	}
+
+	filepath := os.ExpandEnv(viper.GetString("cache.directory") + "/" + t.GetFilename())
+
+	// Determine which format to use.
+	format := "bestaudio"
+	for _, service := range DJ.AvailableServices {
+		if service.GetReadableName() == t.GetService() {
+			format = service.GetFormat()
+		}
+	}
+
+	// Check to see if track is already downloaded.
+	if _, err := os.Stat(filepath); os.IsNotExist(err) {
+		var cmd *exec.Cmd
+		if t.GetService() == "Mixcloud" {
+			cmd = exec.Command("youtube-dl", "--verbose", "--no-mtime", "--output", filepath, "--format", format, "--external-downloader", "aria2c", player, t.GetURL())
+		} else {
+			cmd = exec.Command("youtube-dl", "--verbose", "--no-mtime", "--output", filepath, "--format", format, player, t.GetURL())
+		}
+		output, err := cmd.CombinedOutput()
+		if err != nil {
+			args := ""
+			for s := range cmd.Args {
+				args += cmd.Args[s] + " "
+			}
+			logrus.Warnf("%s\n%s\nyoutube-dl: %s", args, string(output), err.Error())
+			return errors.New("Track download failed")
+		}
+
+		if viper.GetBool("cache.enabled") {
+			DJ.Cache.CheckDirectorySize()
+		}
+	}
+
+	return nil
+}
+
+// Delete deletes the audio file associated with the incoming `track` object.
+func (yt *YouTubeDL) Delete(t interfaces.Track) error {
+	if !viper.GetBool("cache.enabled") {
+		filePath := os.ExpandEnv(viper.GetString("cache.directory") + "/" + t.GetFilename())
+		if _, err := os.Stat(filePath); err == nil {
+			if err := os.Remove(filePath); err == nil {
+				return nil
+			}
+			return errors.New("An error occurred while deleting the audio file")
+		}
+	}
+	return nil
+}

commands.go

@@ -1,234 +0,0 @@
-/*
- * MumbleDJ
- * By Matthieu Grieger
- * commands.go
- * Copyright (c) 2014 Matthieu Grieger (MIT License)
- */
-
-package main
-
-import (
-	"errors"
-	"fmt"
-	"github.com/kennygrant/sanitize"
-	"github.com/layeh/gumble/gumble"
-	"os"
-	"regexp"
-	"strconv"
-	"strings"
-)
-
-// Called on text message event. Checks the message for a command string, and processes it accordingly if
-// it contains a command.
-func parseCommand(user *gumble.User, username, command string) {
-	var com, argument string
-	if strings.Contains(command, " ") {
-		sanitizedCommand := sanitize.HTML(command)
-		parsedCommand := strings.Split(sanitizedCommand, " ")
-		com, argument = parsedCommand[0], parsedCommand[1]
-	} else {
-		com = command
-		argument = ""
-	}
-
-	switch com {
-	// Add command
-	case dj.conf.Aliases.AddAlias:
-		if dj.HasPermission(username, dj.conf.Permissions.AdminAdd) {
-			if argument == "" {
-				user.Send(NO_ARGUMENT_MSG)
-			} else {
-				if songTitle, err := add(username, argument); err == nil {
-					dj.client.Self().Channel().Send(fmt.Sprintf(SONG_ADDED_HTML, username, songTitle), false)
-					if dj.queue.Len() == 1 && !dj.audioStream.IsPlaying() {
-						dj.currentSong = dj.queue.NextSong()
-						if err := dj.currentSong.Download(); err == nil {
-							dj.currentSong.Play()
-						} else {
-							user.Send(AUDIO_FAIL_MSG)
-							dj.currentSong.Delete()
-						}
-					}
-				} else {
-					user.Send(INVALID_URL_MSG)
-				}
-			}
-		} else {
-			user.Send(NO_PERMISSION_MSG)
-		}
-	// Skip command
-	case dj.conf.Aliases.SkipAlias:
-		if dj.HasPermission(username, dj.conf.Permissions.AdminSkip) {
-			if err := skip(username, false); err == nil {
-				dj.client.Self().Channel().Send(fmt.Sprintf(SKIP_ADDED_HTML, username), false)
-			}
-		} else {
-			user.Send(NO_PERMISSION_MSG)
-		}
-	// Forceskip command
-	case dj.conf.Aliases.AdminSkipAlias:
-		if dj.HasPermission(username, true) {
-			if err := skip(username, true); err == nil {
-				dj.client.Self().Channel().Send(ADMIN_SONG_SKIP_MSG, false)
-			}
-		} else {
-			user.Send(NO_PERMISSION_MSG)
-		}
-	// Volume command
-	case dj.conf.Aliases.VolumeAlias:
-		if dj.HasPermission(username, dj.conf.Permissions.AdminVolume) {
-			if argument == "" {
-				dj.client.Self().Channel().Send(fmt.Sprintf(CUR_VOLUME_HTML, dj.audioStream.Volume()), false)
-			} else {
-				if err := volume(username, argument); err == nil {
-					dj.client.Self().Channel().Send(fmt.Sprintf(VOLUME_SUCCESS_HTML, username, argument), false)
-				} else {
-					user.Send(fmt.Sprintf(NOT_IN_VOLUME_RANGE_MSG, dj.conf.Volume.LowestVolume, dj.conf.Volume.HighestVolume))
-				}
-			}
-		} else {
-			user.Send(NO_PERMISSION_MSG)
-		}
-	// Move command
-	case dj.conf.Aliases.MoveAlias:
-		if dj.HasPermission(username, dj.conf.Permissions.AdminMove) {
-			if argument == "" {
-				user.Send(NO_ARGUMENT_MSG)
-			} else {
-				if err := move(argument); err == nil {
-					fmt.Printf("%s has been moved to %s.", dj.client.Self().Name(), argument)
-				} else {
-					user.Send(CHANNEL_DOES_NOT_EXIST_MSG)
-				}
-			}
-		} else {
-			user.Send(NO_PERMISSION_MSG)
-		}
-	// Reload command
-	case dj.conf.Aliases.ReloadAlias:
-		if dj.HasPermission(username, dj.conf.Permissions.AdminReload) {
-			err := loadConfiguration()
-			if err == nil {
-				user.Send(CONFIG_RELOAD_SUCCESS_MSG)
-			} else {
-				panic(err)
-			}
-		} else {
-			user.Send(NO_PERMISSION_MSG)
-		}
-	// Kill command
-	case dj.conf.Aliases.KillAlias:
-		if dj.HasPermission(username, dj.conf.Permissions.AdminKill) {
-			if err := kill(); err == nil {
-				fmt.Println("Kill successful. Goodbye!")
-				os.Exit(0)
-			} else {
-				user.Send(KILL_ERROR_MSG)
-			}
-		} else {
-			user.Send(NO_PERMISSION_MSG)
-		}
-	default:
-		user.Send(COMMAND_DOESNT_EXIST_MSG)
-	}
-}
-
-// Performs add functionality. Checks input URL for YouTube format, and adds
-// the URL to the queue if the format matches.
-func add(user, url string) (string, error) {
-	youtubePatterns := []string{
-		`https?:\/\/www\.youtube\.com\/watch\?v=([\w-]+)`,
-		`https?:\/\/youtube\.com\/watch\?v=([\w-]+)`,
-		`https?:\/\/youtu.be\/([\w-]+)`,
-		`https?:\/\/youtube.com\/v\/([\w-]+)`,
-		`https?:\/\/www.youtube.com\/v\/([\w-]+)`,
-	}
-	matchFound := false
-	shortUrl := ""
-
-	for _, pattern := range youtubePatterns {
-		if re, err := regexp.Compile(pattern); err == nil {
-			if re.MatchString(url) {
-				matchFound = true
-				shortUrl = re.FindStringSubmatch(url)[1]
-				break
-			}
-		}
-	}
-
-	if matchFound {
-		newSong := NewSong(user, shortUrl)
-		if err := dj.queue.AddSong(newSong); err == nil {
-			return newSong.title, nil
-		} else {
-			return "", errors.New("Could not add the Song to the queue.")
-		}
-	} else {
-		return "", errors.New("The URL provided did not match a YouTube URL.")
-	}
-}
-
-// Performs skip functionality. Adds a skip to the skippers slice for the current song, and then
-// evaluates if a skip should be performed. Both skip and forceskip are implemented here.
-func skip(user string, admin bool) error {
-	if err := dj.currentSong.AddSkip(user); err == nil {
-		if dj.currentSong.SkipReached(len(dj.client.Self().Channel().Users())) || admin {
-			if err := dj.audioStream.Stop(); err == nil {
-				dj.OnSongFinished()
-				return nil
-			} else {
-				return errors.New("An error occurred while stopping the current song.")
-			}
-		} else {
-			return nil
-		}
-	} else {
-		return errors.New("An error occurred while adding a skip to the current song.")
-	}
-}
-
-// Performs volume functionality. Checks input value against LowestVolume and HighestVolume from
-// config to determine if the volume should be applied. If in the correct range, the new volume
-// is applied and is immediately in effect.
-func volume(user, value string) error {
-	if parsedVolume, err := strconv.ParseFloat(value, 32); err == nil {
-		newVolume := float32(parsedVolume)
-		if newVolume >= dj.conf.Volume.LowestVolume && newVolume <= dj.conf.Volume.HighestVolume {
-			dj.audioStream.SetVolume(newVolume)
-			return nil
-		} else {
-			return errors.New("The volume supplied was not in the allowed range.")
-		}
-	} else {
-		return errors.New("An error occurred while parsing the volume string.")
-	}
-}
-
-// Performs move functionality. Determines if the supplied channel is valid and moves the bot
-// to the channel if it is.
-func move(channel string) error {
-	if dj.client.Channels().Find(channel) != nil {
-		dj.client.Self().Move(dj.client.Channels().Find(channel))
-		return nil
-	} else {
-		return errors.New("The channel provided does not exist.")
-	}
-}
-
-// Performs kill functionality. First cleans the ~/.mumbledj/songs directory to get rid of any
-// excess m4a files. The bot then safely disconnects from the server.
-func kill() error {
-	songsDir := fmt.Sprintf("%s/.mumbledj/songs", dj.homeDir)
-	if err := os.RemoveAll(songsDir); err != nil {
-		return errors.New("An error occurred while deleting the audio files.")
-	} else {
-		if err := os.Mkdir(songsDir, 0777); err != nil {
-			return errors.New("An error occurred while recreating the songs directory.")
-		}
-	}
-	if err := dj.client.Disconnect(); err == nil {
-		return nil
-	} else {
-		return errors.New("An error occurred while disconnecting from the server.")
-	}
-}

commands/add.go

@@ -0,0 +1,97 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * commands/add.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package commands
+
+import (
+	"errors"
+	"fmt"
+
+	"github.com/layeh/gumble/gumble"
+	"github.com/matthieugrieger/mumbledj/interfaces"
+	"github.com/spf13/viper"
+)
+
+// AddCommand is a command that adds an audio track associated with a supported
+// URL to the queue.
+type AddCommand struct{}
+
+// Aliases returns the current aliases for the command.
+func (c *AddCommand) Aliases() []string {
+	return viper.GetStringSlice("commands.add.aliases")
+}
+
+// Description returns the description for the command.
+func (c *AddCommand) Description() string {
+	return viper.GetString("commands.add.description")
+}
+
+// IsAdminCommand returns true if the command is only for admin use, and
+// returns false otherwise.
+func (c *AddCommand) IsAdminCommand() bool {
+	return viper.GetBool("commands.add.is_admin")
+}
+
+// Execute executes the command with the given user and arguments.
+// Return value descriptions:
+//    string: A message to be returned to the user upon successful execution.
+//    bool:   Whether the message should be private or not. true = private,
+//            false = public (sent to whole channel).
+//    error:  An error message to be returned upon unsuccessful execution.
+//            If no error has occurred, pass nil instead.
+// Example return statement:
+//    return "This is a private message!", true, nil
+func (c *AddCommand) Execute(user *gumble.User, args ...string) (string, bool, error) {
+	var (
+		allTracks      []interfaces.Track
+		tracks         []interfaces.Track
+		service        interfaces.Service
+		err            error
+		lastTrackAdded interfaces.Track
+	)
+
+	if len(args) == 0 {
+		return "", true, errors.New(viper.GetString("commands.add.messages.no_url_error"))
+	}
+
+	for _, arg := range args {
+		if service, err = DJ.GetService(arg); err == nil {
+			tracks, err = service.GetTracks(arg, user)
+			if err == nil {
+				allTracks = append(allTracks, tracks...)
+			}
+		}
+	}
+
+	if len(allTracks) == 0 {
+		return "", true, errors.New(viper.GetString("commands.add.messages.no_valid_tracks_error"))
+	}
+
+	numTooLong := 0
+	numAdded := 0
+	for _, track := range allTracks {
+		if err = DJ.Queue.AppendTrack(track); err != nil {
+			numTooLong++
+		} else {
+			numAdded++
+			lastTrackAdded = track
+		}
+	}
+
+	if numAdded == 0 {
+		return "", true, errors.New(viper.GetString("commands.add.messages.tracks_too_long_error"))
+	} else if numAdded == 1 {
+		return fmt.Sprintf(viper.GetString("commands.add.messages.one_track_added"),
+			user.Name, lastTrackAdded.GetTitle(), lastTrackAdded.GetService()), false, nil
+	}
+
+	retString := fmt.Sprintf(viper.GetString("commands.add.messages.many_tracks_added"), user.Name, numAdded)
+	if numTooLong != 0 {
+		retString += fmt.Sprintf(viper.GetString("commands.add.messages.num_tracks_too_long"), numTooLong)
+	}
+	return retString, false, nil
+}

commands/add_test.go

@@ -0,0 +1,83 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * commands/add_test.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package commands
+
+import (
+	"testing"
+
+	"github.com/layeh/gumble/gumbleffmpeg"
+	"github.com/matthieugrieger/mumbledj/bot"
+	"github.com/spf13/viper"
+	"github.com/stretchr/testify/suite"
+)
+
+type AddCommandTestSuite struct {
+	Command AddCommand
+	suite.Suite
+}
+
+func (suite *AddCommandTestSuite) SetupSuite() {
+	DJ = bot.NewMumbleDJ()
+	bot.DJ = DJ
+
+	// Trick the tests into thinking audio is already playing to avoid
+	// attempting to play tracks that don't exist.
+	DJ.AudioStream = new(gumbleffmpeg.Stream)
+
+	viper.Set("commands.add.aliases", []string{"add", "a"})
+	viper.Set("commands.add.description", "add")
+	viper.Set("commands.add.is_admin", false)
+}
+
+func (suite *AddCommandTestSuite) SetupTest() {
+	DJ.Queue = bot.NewQueue()
+}
+
+func (suite *AddCommandTestSuite) TestAliases() {
+	suite.Equal([]string{"add", "a"}, suite.Command.Aliases())
+}
+
+func (suite *AddCommandTestSuite) TestDescription() {
+	suite.Equal("add", suite.Command.Description())
+}
+
+func (suite *AddCommandTestSuite) TestIsAdminCommand() {
+	suite.False(suite.Command.IsAdminCommand())
+}
+
+func (suite *AddCommandTestSuite) TestExecuteWithNoArgs() {
+	message, isPrivateMessage, err := suite.Command.Execute(nil)
+
+	suite.Equal("", message, "No message should be returned since an error occurred.")
+	suite.True(isPrivateMessage, "This should be a private message.")
+	suite.NotNil(err, "An error should be returned for attempting to add a track without providing a URL.")
+}
+
+// TODO: Implement this test.
+func (suite *AddCommandTestSuite) TestExecuteWhenNoTracksFound() {
+
+}
+
+// TODO: Implement this test.
+func (suite *AddCommandTestSuite) TestExecuteWhenTrackFound() {
+
+}
+
+// TODO: Implement this test.
+func (suite *AddCommandTestSuite) TestExecuteWhenMultipleTracksFound() {
+
+}
+
+// TODO: Implement this test.
+func (suite *AddCommandTestSuite) TestExecuteWithMultipleURLs() {
+
+}
+
+func TestAddCommandTestSuite(t *testing.T) {
+	suite.Run(t, new(AddCommandTestSuite))
+}

commands/addnext.go

@@ -0,0 +1,98 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * commands/addnext.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package commands
+
+import (
+	"errors"
+	"fmt"
+
+	"github.com/layeh/gumble/gumble"
+	"github.com/matthieugrieger/mumbledj/interfaces"
+	"github.com/spf13/viper"
+)
+
+// AddNextCommand is a command that adds an audio track associated with a supported
+// URL to the queue as the next item.
+type AddNextCommand struct{}
+
+// Aliases returns the current aliases for the command.
+func (c *AddNextCommand) Aliases() []string {
+	return viper.GetStringSlice("commands.addnext.aliases")
+}
+
+// Description returns the description for the command.
+func (c *AddNextCommand) Description() string {
+	return viper.GetString("commands.addnext.description")
+}
+
+// IsAdminCommand returns true if the command is only for admin use, and
+// returns false otherwise.
+func (c *AddNextCommand) IsAdminCommand() bool {
+	return viper.GetBool("commands.addnext.is_admin")
+}
+
+// Execute executes the command with the given user and arguments.
+// Return value descriptions:
+//    string: A message to be returned to the user upon successful execution.
+//    bool:   Whether the message should be private or not. true = private,
+//            false = public (sent to whole channel).
+//    error:  An error message to be returned upon unsuccessful execution.
+//            If no error has occurred, pass nil instead.
+// Example return statement:
+//    return "This is a private message!", true, nil
+func (c *AddNextCommand) Execute(user *gumble.User, args ...string) (string, bool, error) {
+	var (
+		allTracks      []interfaces.Track
+		tracks         []interfaces.Track
+		service        interfaces.Service
+		err            error
+		lastTrackAdded interfaces.Track
+	)
+
+	if len(args) == 0 {
+		return "", true, errors.New(viper.GetString("commands.add.messages.no_url_error"))
+	}
+
+	for _, arg := range args {
+		if service, err = DJ.GetService(arg); err == nil {
+			tracks, err = service.GetTracks(arg, user)
+			if err == nil {
+				allTracks = append(allTracks, tracks...)
+			}
+		}
+	}
+
+	if len(allTracks) == 0 {
+		return "", true, errors.New(viper.GetString("commands.add.messages.no_valid_tracks_error"))
+	}
+
+	numTooLong := 0
+	numAdded := 0
+	// We must loop backwards here to preserve the track order when inserting tracks.
+	for i := len(allTracks) - 1; i >= 0; i-- {
+		if err = DJ.Queue.InsertTrack(1, allTracks[i]); err != nil {
+			numTooLong++
+		} else {
+			numAdded++
+			lastTrackAdded = allTracks[i]
+		}
+	}
+
+	if numAdded == 0 {
+		return "", true, errors.New(viper.GetString("commands.add.messages.tracks_too_long_error"))
+	} else if numAdded == 1 {
+		return fmt.Sprintf(viper.GetString("commands.add.messages.one_track_added"),
+			user.Name, lastTrackAdded.GetTitle(), lastTrackAdded.GetService()), false, nil
+	}
+
+	retString := fmt.Sprintf(viper.GetString("commands.add.messages.many_tracks_added"), user.Name, numAdded)
+	if numTooLong != 0 {
+		retString += fmt.Sprintf(viper.GetString("commands.add.messages.num_tracks_too_long"), numTooLong)
+	}
+	return retString, false, nil
+}

commands/addnext_test.go

@@ -0,0 +1,8 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ * commands/addnext_test.go
+ */
+
+package commands

commands/cachesize.go

@@ -0,0 +1,55 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * commands/cachesize.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package commands
+
+import (
+	"errors"
+	"fmt"
+
+	"github.com/layeh/gumble/gumble"
+	"github.com/spf13/viper"
+)
+
+// CacheSizeCommand is a command that outputs the current size of the cache.
+type CacheSizeCommand struct{}
+
+// Aliases returns the current aliases for the command.
+func (c *CacheSizeCommand) Aliases() []string {
+	return viper.GetStringSlice("commands.cachesize.aliases")
+}
+
+// Description returns the description for the command.
+func (c *CacheSizeCommand) Description() string {
+	return viper.GetString("commands.cachesize.description")
+}
+
+// IsAdminCommand returns true if the command is only for admin use, and
+// returns false otherwise.
+func (c *CacheSizeCommand) IsAdminCommand() bool {
+	return viper.GetBool("commands.cachesize.is_admin")
+}
+
+// Execute executes the command with the given user and arguments.
+// Return value descriptions:
+//    string: A message to be returned to the user upon successful execution.
+//    bool:   Whether the message should be private or not. true = private,
+//            false = public (sent to whole channel).
+//    error:  An error message to be returned upon unsuccessful execution.
+//            If no error has occurred, pass nil instead.
+// Example return statement:
+//    return "This is a private message!", true, nil
+func (c *CacheSizeCommand) Execute(user *gumble.User, args ...string) (string, bool, error) {
+	const bytesInMiB = 1048576
+
+	if !viper.GetBool("cache.enabled") {
+		return "", true, errors.New(viper.GetString("commands.common_messages.caching_disabled_error"))
+	}
+
+	DJ.Cache.UpdateStatistics()
+	return fmt.Sprintf(viper.GetString("commands.cachesize.messages.current_size"), DJ.Cache.TotalFileSize/bytesInMiB), true, nil
+}

commands/cachesize_test.go

@@ -0,0 +1,60 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * commands/cachesize_test.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package commands
+
+import (
+	"testing"
+
+	"github.com/matthieugrieger/mumbledj/bot"
+	"github.com/spf13/viper"
+	"github.com/stretchr/testify/suite"
+)
+
+type CacheSizeCommandTestSuite struct {
+	Command CacheSizeCommand
+	suite.Suite
+}
+
+func (suite *CacheSizeCommandTestSuite) SetupSuite() {
+	DJ = bot.NewMumbleDJ()
+
+	viper.Set("commands.cachesize.aliases", []string{"cachesize", "cs"})
+	viper.Set("commands.cachesize.description", "cachesize")
+	viper.Set("commands.cachesize.is_admin", true)
+}
+
+func (suite *CacheSizeCommandTestSuite) TestAliases() {
+	suite.Equal([]string{"cachesize", "cs"}, suite.Command.Aliases())
+}
+
+func (suite *CacheSizeCommandTestSuite) TestDescription() {
+	suite.Equal("cachesize", suite.Command.Description())
+}
+
+func (suite *CacheSizeCommandTestSuite) TestIsAdminCommand() {
+	suite.True(suite.Command.IsAdminCommand())
+}
+
+func (suite *CacheSizeCommandTestSuite) TestExecuteWhenCachingIsDisabled() {
+	viper.Set("cache.enabled", false)
+
+	message, isPrivateMessage, err := suite.Command.Execute(nil)
+
+	suite.Equal("", message, "An error occurred so no message should be returned.")
+	suite.True(isPrivateMessage, "This should be a private message.")
+	suite.NotNil(err, "An error should be returned because caching is disabled.")
+}
+
+// TODO: Implement this test.
+func (suite *CacheSizeCommandTestSuite) TestExecuteWhenCachingIsEnabled() {
+
+}
+
+func TestCacheSizeCommandTestSuite(t *testing.T) {
+	suite.Run(t, new(CacheSizeCommandTestSuite))
+}

commands/currenttrack.go

@@ -0,0 +1,60 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * commands/currenttrack.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package commands
+
+import (
+	"errors"
+	"fmt"
+
+	"github.com/layeh/gumble/gumble"
+	"github.com/matthieugrieger/mumbledj/interfaces"
+	"github.com/spf13/viper"
+)
+
+// CurrentTrackCommand is a command that outputs information related to
+// the track that is currently playing (if one exists).
+type CurrentTrackCommand struct{}
+
+// Aliases returns the current aliases for the command.
+func (c *CurrentTrackCommand) Aliases() []string {
+	return viper.GetStringSlice("commands.currenttrack.aliases")
+}
+
+// Description returns the description for the command.
+func (c *CurrentTrackCommand) Description() string {
+	return viper.GetString("commands.currenttrack.description")
+}
+
+// IsAdminCommand returns true if the command is only for admin use, and
+// returns false otherwise.
+func (c *CurrentTrackCommand) IsAdminCommand() bool {
+	return viper.GetBool("commands.currenttrack.is_admin")
+}
+
+// Execute executes the command with the given user and arguments.
+// Return value descriptions:
+//    string: A message to be returned to the user upon successful execution.
+//    bool:   Whether the message should be private or not. true = private,
+//            false = public (sent to whole channel).
+//    error:  An error message to be returned upon unsuccessful execution.
+//            If no error has occurred, pass nil instead.
+// Example return statement:
+//    return "This is a private message!", true, nil
+func (c *CurrentTrackCommand) Execute(user *gumble.User, args ...string) (string, bool, error) {
+	var (
+		currentTrack interfaces.Track
+		err          error
+	)
+
+	if currentTrack, err = DJ.Queue.CurrentTrack(); err != nil {
+		return "", true, errors.New(viper.GetString("commands.common_messages.no_tracks_error"))
+	}
+
+	return fmt.Sprintf(viper.GetString("commands.currenttrack.messages.current_track"),
+		currentTrack.GetTitle(), currentTrack.GetSubmitter()), true, nil
+}

commands/currenttrack_test.go

@@ -0,0 +1,76 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * commands/currenttrack_test.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package commands
+
+import (
+	"testing"
+
+	"github.com/layeh/gumble/gumbleffmpeg"
+	"github.com/matthieugrieger/mumbledj/bot"
+	"github.com/spf13/viper"
+	"github.com/stretchr/testify/suite"
+)
+
+type CurrentTrackCommandTestSuite struct {
+	Command CurrentTrackCommand
+	suite.Suite
+}
+
+func (suite *CurrentTrackCommandTestSuite) SetupSuite() {
+	DJ = bot.NewMumbleDJ()
+
+	// Trick the tests into thinking audio is already playing to avoid
+	// attempting to play tracks that don't exist.
+	DJ.AudioStream = new(gumbleffmpeg.Stream)
+
+	viper.Set("commands.currenttrack.aliases", []string{"currenttrack", "current"})
+	viper.Set("commands.currenttrack.description", "currenttrack")
+	viper.Set("commands.currenttrack.is_admin", false)
+}
+
+func (suite *CurrentTrackCommandTestSuite) SetupTest() {
+	DJ.Queue = bot.NewQueue()
+}
+
+func (suite *CurrentTrackCommandTestSuite) TestAliases() {
+	suite.Equal([]string{"currenttrack", "current"}, suite.Command.Aliases())
+}
+
+func (suite *CurrentTrackCommandTestSuite) TestDescription() {
+	suite.Equal("currenttrack", suite.Command.Description())
+}
+
+func (suite *CurrentTrackCommandTestSuite) TestIsAdminCommand() {
+	suite.False(suite.Command.IsAdminCommand())
+}
+
+func (suite *CurrentTrackCommandTestSuite) TestExecuteWhenQueueIsEmpty() {
+	message, isPrivateMessage, err := suite.Command.Execute(nil)
+
+	suite.Equal("", message, "No message should be returned since an error occurred.")
+	suite.True(isPrivateMessage, "This should be a private message.")
+	suite.NotNil(err, "An error should be returned since the queue is empty.")
+}
+
+func (suite *CurrentTrackCommandTestSuite) TestExecuteWhenQueueNotEmpty() {
+	track := new(bot.Track)
+	track.Submitter = "test"
+	track.Title = "test"
+
+	DJ.Queue.AppendTrack(track)
+
+	message, isPrivateMessage, err := suite.Command.Execute(nil)
+
+	suite.NotEqual("", message, "A message should be returned with the current track information.")
+	suite.True(isPrivateMessage, "This should be a private message.")
+	suite.Nil(err, "No error should be returned.")
+}
+
+func TestCurrentTrackCommandTestSuite(t *testing.T) {
+	suite.Run(t, new(CurrentTrackCommandTestSuite))
+}

commands/forceskip.go

@@ -0,0 +1,55 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * commands/forceskip.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package commands
+
+import (
+	"errors"
+	"fmt"
+
+	"github.com/layeh/gumble/gumble"
+	"github.com/spf13/viper"
+)
+
+// ForceSkipCommand is a command that immediately skips the current track.
+type ForceSkipCommand struct{}
+
+// Aliases returns the current aliases for the command.
+func (c *ForceSkipCommand) Aliases() []string {
+	return viper.GetStringSlice("commands.forceskip.aliases")
+}
+
+// Description returns the description for the command.
+func (c *ForceSkipCommand) Description() string {
+	return viper.GetString("commands.forceskip.description")
+}
+
+// IsAdminCommand returns true if the command is only for admin use, and
+// returns false otherwise.
+func (c *ForceSkipCommand) IsAdminCommand() bool {
+	return viper.GetBool("commands.forceskip.is_admin")
+}
+
+// Execute executes the command with the given user and arguments.
+// Return value descriptions:
+//    string: A message to be returned to the user upon successful execution.
+//    bool:   Whether the message should be private or not. true = private,
+//            false = public (sent to whole channel).
+//    error:  An error message to be returned upon unsuccessful execution.
+//            If no error has occurred, pass nil instead.
+// Example return statement:
+//    return "This is a private message!", true, nil
+func (c *ForceSkipCommand) Execute(user *gumble.User, args ...string) (string, bool, error) {
+	if DJ.Queue.Length() == 0 {
+		return "", true, errors.New(viper.GetString("commands.common_messages.no_tracks_error"))
+	}
+
+	DJ.Queue.StopCurrent()
+
+	return fmt.Sprintf(viper.GetString("commands.forceskip.messages.track_skipped"),
+		user.Name), false, nil
+}

commands/forceskip_test.go

@@ -0,0 +1,8 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ * commands/forceskip_test.go
+ */
+
+package commands

commands/forceskipplaylist.go

@@ -0,0 +1,66 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * commands/forceskipplaylist.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package commands
+
+import (
+	"errors"
+	"fmt"
+
+	"github.com/layeh/gumble/gumble"
+	"github.com/matthieugrieger/mumbledj/interfaces"
+	"github.com/spf13/viper"
+)
+
+// ForceSkipPlaylistCommand is a command that immediately skips the current
+// playlist.
+type ForceSkipPlaylistCommand struct{}
+
+// Aliases returns the current aliases for the command.
+func (c *ForceSkipPlaylistCommand) Aliases() []string {
+	return viper.GetStringSlice("commands.forceskipplaylist.aliases")
+}
+
+// Description returns the description for the command.
+func (c *ForceSkipPlaylistCommand) Description() string {
+	return viper.GetString("commands.forceskipplaylist.description")
+}
+
+// IsAdminCommand returns true if the command is only for admin use, and
+// returns false otherwise.
+func (c *ForceSkipPlaylistCommand) IsAdminCommand() bool {
+	return viper.GetBool("commands.forceskipplaylist.is_admin")
+}
+
+// Execute executes the command with the given user and arguments.
+// Return value descriptions:
+//    string: A message to be returned to the user upon successful execution.
+//    bool:   Whether the message should be private or not. true = private,
+//            false = public (sent to whole channel).
+//    error:  An error message to be returned upon unsuccessful execution.
+//            If no error has occurred, pass nil instead.
+// Example return statement:
+//    return "This is a private message!", true, nil
+func (c *ForceSkipPlaylistCommand) Execute(user *gumble.User, args ...string) (string, bool, error) {
+	var (
+		currentTrack interfaces.Track
+		err          error
+	)
+
+	if currentTrack, err = DJ.Queue.CurrentTrack(); err != nil {
+		return "", true, errors.New(viper.GetString("commands.common_messages.no_tracks_error"))
+	}
+
+	if playlist := currentTrack.GetPlaylist(); playlist == nil {
+		return "", true, errors.New(viper.GetString("commands.forceskipplaylist.messages.no_playlist_error"))
+	}
+
+	DJ.Queue.SkipPlaylist()
+
+	return fmt.Sprintf(viper.GetString("commands.forceskipplaylist.messages.playlist_skipped"),
+		user.Name), false, nil
+}

commands/forceskipplaylist_test.go

@@ -0,0 +1,8 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ * commands/forceskipplaylist_test.go
+ */
+
+package commands

commands/help.go

@@ -0,0 +1,75 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * commands/help.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package commands
+
+import (
+	"fmt"
+
+	"github.com/layeh/gumble/gumble"
+	"github.com/spf13/viper"
+)
+
+// HelpCommand is a command that outputs a help message that shows the
+// available commands and their aliases.
+type HelpCommand struct{}
+
+// Aliases returns the current aliases for the command.
+func (c *HelpCommand) Aliases() []string {
+	return viper.GetStringSlice("commands.help.aliases")
+}
+
+// Description returns the description for the command.
+func (c *HelpCommand) Description() string {
+	return viper.GetString("commands.help.description")
+}
+
+// IsAdminCommand returns true if the command is only for admin use, and
+// returns false otherwise.
+func (c *HelpCommand) IsAdminCommand() bool {
+	return viper.GetBool("commands.help.is_admin")
+}
+
+// Execute executes the command with the given user and arguments.
+// Return value descriptions:
+//    string: A message to be returned to the user upon successful execution.
+//    bool:   Whether the message should be private or not. true = private,
+//            false = public (sent to whole channel).
+//    error:  An error message to be returned upon unsuccessful execution.
+//            If no error has occurred, pass nil instead.
+// Example return statement:
+//    return "This is a private message!", true, nil
+func (c *HelpCommand) Execute(user *gumble.User, args ...string) (string, bool, error) {
+	commandString := "<b>%s</b> -- %s<br>"
+	regularCommands := ""
+	adminCommands := ""
+	totalString := ""
+
+	for _, command := range Commands {
+		currentString := fmt.Sprintf(commandString, command.Aliases(), command.Description())
+		if command.IsAdminCommand() {
+			adminCommands += currentString
+		} else {
+			regularCommands += currentString
+		}
+	}
+
+	totalString = viper.GetString("commands.help.messages.commands_header") + regularCommands
+
+	isAdmin := false
+	if viper.GetBool("admins.enabled") {
+		isAdmin = DJ.IsAdmin(user)
+	} else {
+		isAdmin = true
+	}
+
+	if isAdmin {
+		totalString += viper.GetString("commands.help.messages.admin_commands_header") + adminCommands
+	}
+
+	return totalString, true, nil
+}

commands/help_test.go

@@ -0,0 +1,93 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * commands/help_test.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package commands
+
+import (
+	"testing"
+
+	"github.com/layeh/gumble/gumble"
+	"github.com/matthieugrieger/mumbledj/bot"
+	"github.com/spf13/viper"
+	"github.com/stretchr/testify/suite"
+)
+
+type HelpCommandTestSuite struct {
+	Command HelpCommand
+	suite.Suite
+}
+
+func (suite *HelpCommandTestSuite) SetupSuite() {
+	DJ = bot.NewMumbleDJ()
+
+	viper.Set("commands.help.aliases", []string{"help", "h"})
+	viper.Set("commands.help.description", "help")
+	viper.Set("commands.help.is_admin", false)
+}
+
+func (suite *HelpCommandTestSuite) SetupTest() {
+	viper.Set("admins.enabled", true)
+}
+
+func (suite *HelpCommandTestSuite) TestAliases() {
+	suite.Equal([]string{"help", "h"}, suite.Command.Aliases())
+}
+
+func (suite *HelpCommandTestSuite) TestDescription() {
+	suite.Equal("help", suite.Command.Description())
+}
+
+func (suite *HelpCommandTestSuite) TestIsAdminCommand() {
+	suite.False(suite.Command.IsAdminCommand())
+}
+
+func (suite *HelpCommandTestSuite) TestExecuteWhenPermissionsEnabledAndUserIsNotAdmin() {
+	viper.Set("admins.names", []string{"SuperUser"})
+	user := new(gumble.User)
+	user.Name = "Test"
+
+	message, isPrivateMessage, err := suite.Command.Execute(user)
+
+	suite.NotEqual("", message, "A message should be returned.")
+	suite.True(isPrivateMessage, "This should be a private message.")
+	suite.Nil(err, "No error should be returned.")
+	suite.Contains(message, "help", "The returned message should contain command descriptions.")
+	suite.Contains(message, "add", "The returned message should contain command descriptions.")
+	suite.NotContains(message, "Admin Commands", "The returned message should not contain admin command descriptions.")
+}
+
+func (suite *HelpCommandTestSuite) TestExecuteWhenPermissionsEnabledAndUserIsAdmin() {
+	viper.Set("admins.names", []string{"SuperUser"})
+	user := new(gumble.User)
+	user.Name = "SuperUser"
+
+	message, isPrivateMessage, err := suite.Command.Execute(user)
+
+	suite.NotEqual("", message, "A message should be returned.")
+	suite.True(isPrivateMessage, "This should be a private message.")
+	suite.Nil(err, "No error should be returned.")
+	suite.Contains(message, "help", "The returned message should contain command descriptions.")
+	suite.Contains(message, "add", "The returned message should contain command descriptions.")
+	suite.Contains(message, "Admin Commands", "The returned message should contain admin command descriptions.")
+}
+
+func (suite *HelpCommandTestSuite) TestExecuteWhenPermissionsDisabled() {
+	viper.Set("admins.enabled", false)
+
+	message, isPrivateMessage, err := suite.Command.Execute(nil)
+
+	suite.NotEqual("", message, "A message should be returned.")
+	suite.True(isPrivateMessage, "This should be a private message.")
+	suite.Nil(err, "No error should be returned.")
+	suite.Contains(message, "help", "The returned message should contain command descriptions.")
+	suite.Contains(message, "add", "The returned message should contain command descriptions.")
+	suite.Contains(message, "Admin Commands", "The returned message should contain admin command descriptions.")
+}
+
+func TestHelpCommandTestSuite(t *testing.T) {
+	suite.Run(t, new(HelpCommandTestSuite))
+}

commands/joinme.go

@@ -0,0 +1,58 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * commands/joinme.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package commands
+
+import (
+	"errors"
+
+	"github.com/layeh/gumble/gumble"
+	"github.com/layeh/gumble/gumbleffmpeg"
+	"github.com/spf13/viper"
+)
+
+// JoinMeCommand is a command that moves the bot to the channel of the user
+// who issued the command.
+type JoinMeCommand struct{}
+
+// Aliases returns the current aliases for the command.
+func (c *JoinMeCommand) Aliases() []string {
+	return viper.GetStringSlice("commands.joinme.aliases")
+}
+
+// Description returns the description for the command.
+func (c *JoinMeCommand) Description() string {
+	return viper.GetString("commands.joinme.description")
+}
+
+// IsAdminCommand returns true if the command is only for admin use, and
+// returns false otherwise.
+func (c *JoinMeCommand) IsAdminCommand() bool {
+	return viper.GetBool("commands.joinme.is_admin")
+}
+
+// Execute executes the command with the given user and arguments.
+// Return value descriptions:
+//    string: A message to be returned to the user upon successful execution.
+//    bool:   Whether the message should be private or not. true = private,
+//            false = public (sent to whole channel).
+//    error:  An error message to be returned upon unsuccessful execution.
+//            If no error has occurred, pass nil instead.
+// Example return statement:
+//    return "This is a private message!", true, nil
+func (c *JoinMeCommand) Execute(user *gumble.User, args ...string) (string, bool, error) {
+	if DJ.AudioStream != nil && DJ.AudioStream.State() == gumbleffmpeg.StatePlaying &&
+		len(DJ.Client.Self.Channel.Users) > 1 {
+		return "", true, errors.New(viper.GetString("commands.joinme.messages.others_are_listening_error"))
+	}
+
+	DJ.Client.Do(func() {
+		DJ.Client.Self.Move(user.Channel)
+	})
+
+	return viper.GetString("commands.joinme.messages.in_your_channel"), true, nil
+}

commands/joinme_test.go

@@ -0,0 +1,8 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ * commands/joinme_test.go
+ */
+
+package commands

commands/kill.go

@@ -0,0 +1,55 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * commands/currenttrack.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package commands
+
+import (
+	"os"
+
+	"github.com/layeh/gumble/gumble"
+	"github.com/spf13/viper"
+)
+
+// KillCommand is a command that safely kills the bot.
+type KillCommand struct{}
+
+// Aliases returns the current aliases for the command.
+func (c *KillCommand) Aliases() []string {
+	return viper.GetStringSlice("commands.kill.aliases")
+}
+
+// Description returns the description for the command.
+func (c *KillCommand) Description() string {
+	return viper.GetString("commands.kill.description")
+}
+
+// IsAdminCommand returns true if the command is only for admin use, and
+// returns false otherwise.
+func (c *KillCommand) IsAdminCommand() bool {
+	return viper.GetBool("commands.kill.is_admin")
+}
+
+// Execute executes the command with the given user and arguments.
+// Return value descriptions:
+//    string: A message to be returned to the user upon successful execution.
+//    bool:   Whether the message should be private or not. true = private,
+//            false = public (sent to whole channel).
+//    error:  An error message to be returned upon unsuccessful execution.
+//            If no error has occurred, pass nil instead.
+// Example return statement:
+//    return "This is a private message!", true, nil
+func (c *KillCommand) Execute(user *gumble.User, args ...string) (string, bool, error) {
+	if err := DJ.Cache.DeleteAll(); err != nil {
+		return "", true, err
+	}
+	if err := DJ.Client.Disconnect(); err != nil {
+		return "", true, err
+	}
+
+	os.Exit(0)
+	return "", true, nil
+}

commands/kill_test.go

@@ -0,0 +1,8 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ * commands/kill_test.go
+ */
+
+package commands

commands/listtracks.go

@@ -0,0 +1,73 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * commands/currenttrack.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package commands
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"strconv"
+
+	"github.com/layeh/gumble/gumble"
+	"github.com/matthieugrieger/mumbledj/interfaces"
+	"github.com/spf13/viper"
+)
+
+// ListTracksCommand is a command that lists the tracks that are currently
+// in the queue.
+type ListTracksCommand struct{}
+
+// Aliases returns the current aliases for the command.
+func (c *ListTracksCommand) Aliases() []string {
+	return viper.GetStringSlice("commands.listtracks.aliases")
+}
+
+// Description returns the description for the command.
+func (c *ListTracksCommand) Description() string {
+	return viper.GetString("commands.listtracks.description")
+}
+
+// IsAdminCommand returns true if the command is only for admin use, and
+// returns false otherwise.
+func (c *ListTracksCommand) IsAdminCommand() bool {
+	return viper.GetBool("commands.listtracks.is_admin")
+}
+
+// Execute executes the command with the given user and arguments.
+// Return value descriptions:
+//    string: A message to be returned to the user upon successful execution.
+//    bool:   Whether the message should be private or not. true = private,
+//            false = public (sent to whole channel).
+//    error:  An error message to be returned upon unsuccessful execution.
+//            If no error has occurred, pass nil instead.
+// Example return statement:
+//    return "This is a private message!", true, nil
+func (c *ListTracksCommand) Execute(user *gumble.User, args ...string) (string, bool, error) {
+	if DJ.Queue.Length() == 0 {
+		return "", true, errors.New(viper.GetString("commands.common_messages.no_tracks_error"))
+	}
+
+	numTracksToList := DJ.Queue.Length()
+	if len(args) != 0 {
+		if parsedNum, err := strconv.Atoi(args[0]); err == nil {
+			numTracksToList = parsedNum
+		} else {
+			return "", true, errors.New(viper.GetString("commands.listtracks.messages.invalid_integer_error"))
+		}
+	}
+
+	var buffer bytes.Buffer
+	DJ.Queue.Traverse(func(i int, track interfaces.Track) {
+		if i < numTracksToList {
+			buffer.WriteString(fmt.Sprintf(viper.GetString("commands.listtracks.messages.track_listing"),
+				i+1, track.GetTitle(), track.GetSubmitter()))
+		}
+	})
+
+	return buffer.String(), true, nil
+}

commands/listtracks_test.go

@@ -0,0 +1,136 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * commands/listtracks_test.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package commands
+
+import (
+	"testing"
+
+	"github.com/layeh/gumble/gumbleffmpeg"
+	"github.com/matthieugrieger/mumbledj/bot"
+	"github.com/spf13/viper"
+	"github.com/stretchr/testify/suite"
+)
+
+type ListTracksCommandTestSuite struct {
+	Command ListTracksCommand
+	suite.Suite
+}
+
+func (suite *ListTracksCommandTestSuite) SetupSuite() {
+	DJ = bot.NewMumbleDJ()
+	bot.DJ = DJ
+
+	// Trick the tests into thinking audio is already playing to avoid
+	// attempting to play tracks that don't exist.
+	DJ.AudioStream = new(gumbleffmpeg.Stream)
+
+	viper.Set("commands.listtracks.aliases", []string{"listtracks", "list"})
+	viper.Set("commands.listtracks.description", "listtracks")
+	viper.Set("commands.listtracks.is_admin", false)
+}
+
+func (suite *ListTracksCommandTestSuite) SetupTest() {
+	DJ.Queue = bot.NewQueue()
+}
+
+func (suite *ListTracksCommandTestSuite) TestAliases() {
+	suite.Equal([]string{"listtracks", "list"}, suite.Command.Aliases())
+}
+
+func (suite *ListTracksCommandTestSuite) TestDescription() {
+	suite.Equal("listtracks", suite.Command.Description())
+}
+
+func (suite *ListTracksCommandTestSuite) TestIsAdminCommand() {
+	suite.False(suite.Command.IsAdminCommand())
+}
+
+func (suite *ListTracksCommandTestSuite) TestExecuteWithNoTracks() {
+	message, isPrivateMessage, err := suite.Command.Execute(nil)
+
+	suite.Equal("", message, "No message should be returned.")
+	suite.True(isPrivateMessage, "This should be a private message.")
+	suite.NotNil(err, "An error should be returned as there are no tracks to list.")
+}
+
+func (suite *ListTracksCommandTestSuite) TestExecuteWithNoArg() {
+	track := new(bot.Track)
+	track.Title = "title"
+	track.Submitter = "test"
+
+	DJ.Queue.AppendTrack(track)
+
+	message, isPrivateMessage, err := suite.Command.Execute(nil)
+
+	suite.NotEqual("", message, "A message containing track information should be returned.")
+	suite.Contains(message, "title", "The returned message should contain the track title.")
+	suite.Contains(message, "test", "The returned message should contain the track submitter.")
+	suite.True(isPrivateMessage, "This should be a private message.")
+	suite.Nil(err, "No error should be returned.")
+}
+
+func (suite *ListTracksCommandTestSuite) TestExecuteWithValidArg() {
+	track1 := new(bot.Track)
+	track1.Title = "first"
+	track1.Submitter = "test"
+
+	track2 := new(bot.Track)
+	track2.Title = "second"
+	track2.Submitter = "test"
+
+	track3 := new(bot.Track)
+	track3.Title = "third"
+	track3.Submitter = "test"
+
+	DJ.Queue.AppendTrack(track1)
+	DJ.Queue.AppendTrack(track2)
+	DJ.Queue.AppendTrack(track3)
+
+	message, isPrivateMessage, err := suite.Command.Execute(nil, "2")
+
+	suite.NotEqual("", message, "A message containing track information should be returned.")
+	suite.Contains(message, "first", "The returned message should contain the first track.")
+	suite.Contains(message, "second", "The returned message should contain the second track.")
+	suite.NotContains(message, "third", "The returned message should not contain the third track.")
+	suite.True(isPrivateMessage, "This should be a private message.")
+	suite.Nil(err, "No error should be returned.")
+}
+
+func (suite *ListTracksCommandTestSuite) TestExecuteWithArgLargerThanQueueLength() {
+	track := new(bot.Track)
+	track.Title = "track"
+	track.Submitter = "test"
+
+	DJ.Queue.AppendTrack(track)
+
+	message, isPrivateMessage, err := suite.Command.Execute(nil, "2")
+
+	suite.NotEqual("", message, "A message containing track information should be returned.")
+	suite.Contains(message, "1", "The returned message should contain the first track.")
+	suite.NotContains(message, "2", "The returned message should not contain any further tracks.")
+	suite.True(isPrivateMessage, "This should be a private message.")
+	suite.Nil(err, "No error should be returned.")
+}
+
+func (suite *ListTracksCommandTestSuite) TestExecuteWithInvalidArg() {
+	track := new(bot.Track)
+	track.Title = "track"
+	track.Submitter = "test"
+
+	DJ.Queue.AppendTrack(track)
+
+	message, isPrivateMessage, err := suite.Command.Execute(nil, "test")
+
+	suite.Equal("", message, "No message should be returned.")
+	suite.True(isPrivateMessage, "This should be a private message.")
+	suite.NotNil(err, "An error should be returned due to an invalid argument being supplied.")
+}
+
+func TestListTracksCommandTestSuite(t *testing.T) {
+	suite.Run(t, new(ListTracksCommandTestSuite))
+}

commands/move.go

@@ -0,0 +1,65 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * commands/move.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package commands
+
+import (
+	"errors"
+	"fmt"
+	"strings"
+
+	"github.com/layeh/gumble/gumble"
+	"github.com/spf13/viper"
+)
+
+// MoveCommand is a command that moves the bot from one channel to another.
+type MoveCommand struct{}
+
+// Aliases returns the current aliases for the command.
+func (c *MoveCommand) Aliases() []string {
+	return viper.GetStringSlice("commands.move.aliases")
+}
+
+// Description returns the description for the command.
+func (c *MoveCommand) Description() string {
+	return viper.GetString("commands.move.description")
+}
+
+// IsAdminCommand returns true if the command is only for admin use, and
+// returns false otherwise.
+func (c *MoveCommand) IsAdminCommand() bool {
+	return viper.GetBool("commands.move.is_admin")
+}
+
+// Execute executes the command with the given user and arguments.
+// Return value descriptions:
+//    string: A message to be returned to the user upon successful execution.
+//    bool:   Whether the message should be private or not. true = private,
+//            false = public (sent to whole channel).
+//    error:  An error message to be returned upon unsuccessful execution.
+//            If no error has occurred, pass nil instead.
+// Example return statement:
+//    return "This is a private message!", true, nil
+func (c *MoveCommand) Execute(user *gumble.User, args ...string) (string, bool, error) {
+	if len(args) == 0 {
+		return "", true, errors.New(viper.GetString("commands.move.messages.no_channel_provided_error"))
+	}
+	channel := ""
+	for _, arg := range args {
+		channel += arg + " "
+	}
+	channel = strings.TrimSpace(channel)
+	if channels := strings.Split(channel, "/"); DJ.Client.Channels.Find(channels...) != nil {
+		DJ.Client.Do(func() {
+			DJ.Client.Self.Move(DJ.Client.Channels.Find(channels...))
+		})
+	} else {
+		return "", true, errors.New(viper.GetString("commands.move.messages.channel_doesnt_exist_error"))
+	}
+
+	return fmt.Sprintf(viper.GetString("commands.move.messages.move_successful"), channel), true, nil
+}

commands/move_test.go

@@ -0,0 +1,8 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ * commands/move_test.go
+ */
+
+package commands

commands/nexttrack.go

@@ -0,0 +1,60 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * commands/nexttrack.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package commands
+
+import (
+	"errors"
+	"fmt"
+
+	"github.com/layeh/gumble/gumble"
+	"github.com/spf13/viper"
+)
+
+// NextTrackCommand is a command that outputs information related to the next
+// track in the queue (if one exists).
+type NextTrackCommand struct{}
+
+// Aliases returns the current aliases for the command.
+func (c *NextTrackCommand) Aliases() []string {
+	return viper.GetStringSlice("commands.nexttrack.aliases")
+}
+
+// Description returns the description for the command.
+func (c *NextTrackCommand) Description() string {
+	return viper.GetString("commands.nexttrack.description")
+}
+
+// IsAdminCommand returns true if the command is only for admin use, and
+// returns false otherwise.
+func (c *NextTrackCommand) IsAdminCommand() bool {
+	return viper.GetBool("commands.nexttrack.is_admin")
+}
+
+// Execute executes the command with the given user and arguments.
+// Return value descriptions:
+//    string: A message to be returned to the user upon successful execution.
+//    bool:   Whether the message should be private or not. true = private,
+//            false = public (sent to whole channel).
+//    error:  An error message to be returned upon unsuccessful execution.
+//            If no error has occurred, pass nil instead.
+// Example return statement:
+//    return "This is a private message!", true, nil
+func (c *NextTrackCommand) Execute(user *gumble.User, args ...string) (string, bool, error) {
+	length := DJ.Queue.Length()
+	if length == 0 {
+		return "", true, errors.New(viper.GetString("commands.common_messages.no_tracks_error"))
+	}
+	if length == 1 {
+		return "", true, errors.New(viper.GetString("commands.nexttrack.messages.current_track_only_error"))
+	}
+
+	nextTrack, _ := DJ.Queue.PeekNextTrack()
+
+	return fmt.Sprintf(viper.GetString("commands.nexttrack.messages.next_track"),
+		nextTrack.GetTitle(), nextTrack.GetSubmitter()), true, nil
+}

commands/nexttrack_test.go

@@ -0,0 +1,97 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * commands/nexttrack_test.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package commands
+
+import (
+	"testing"
+
+	"github.com/layeh/gumble/gumbleffmpeg"
+	"github.com/matthieugrieger/mumbledj/bot"
+	"github.com/spf13/viper"
+	"github.com/stretchr/testify/suite"
+)
+
+type NextTrackCommandTestSuite struct {
+	Command NextTrackCommand
+	suite.Suite
+}
+
+func (suite *NextTrackCommandTestSuite) SetupSuite() {
+	DJ = bot.NewMumbleDJ()
+	bot.DJ = DJ
+
+	// Trick the tests into thinking audio is already playing to avoid
+	// attempting to play tracks that don't exist.
+	DJ.AudioStream = new(gumbleffmpeg.Stream)
+
+	viper.Set("commands.nexttrack.aliases", []string{"nexttrack", "next"})
+	viper.Set("commands.nexttrack.description", "nexttrack")
+	viper.Set("commands.nexttrack.is_admin", false)
+}
+
+func (suite *NextTrackCommandTestSuite) SetupTest() {
+	DJ.Queue = bot.NewQueue()
+}
+
+func (suite *NextTrackCommandTestSuite) TestAliases() {
+	suite.Equal([]string{"nexttrack", "next"}, suite.Command.Aliases())
+}
+
+func (suite *NextTrackCommandTestSuite) TestDescription() {
+	suite.Equal("nexttrack", suite.Command.Description())
+}
+
+func (suite *NextTrackCommandTestSuite) TestIsAdminCommand() {
+	suite.False(suite.Command.IsAdminCommand())
+}
+
+func (suite *NextTrackCommandTestSuite) TestExecuteWhenQueueIsEmpty() {
+	message, isPrivateMessage, err := suite.Command.Execute(nil)
+
+	suite.Equal("", message, "No message should be returned.")
+	suite.True(isPrivateMessage, "This should be a private message.")
+	suite.NotNil(err, "An error should be returned due to the queue being empty.")
+}
+
+func (suite *NextTrackCommandTestSuite) TestExecuteWhenQueueHasOneTrack() {
+	track := new(bot.Track)
+	track.Title = "test"
+	track.Submitter = "test"
+
+	DJ.Queue.AppendTrack(track)
+
+	message, isPrivateMessage, err := suite.Command.Execute(nil)
+
+	suite.Equal("", message, "No message should be returned.")
+	suite.True(isPrivateMessage, "This should be a private message.")
+	suite.NotNil(err, "An error should be returned due to the queue having only one track.")
+}
+
+func (suite *NextTrackCommandTestSuite) TestExecuteWhenQueueHasTwoOrMoreTracks() {
+	track1 := new(bot.Track)
+	track1.Title = "first"
+	track1.Submitter = "test"
+
+	track2 := new(bot.Track)
+	track2.Title = "second"
+	track2.Submitter = "test"
+
+	DJ.Queue.AppendTrack(track1)
+	DJ.Queue.AppendTrack(track2)
+
+	message, isPrivateMessage, err := suite.Command.Execute(nil)
+
+	suite.NotEqual("", "A message containing information for the next track should be returned.")
+	suite.Contains(message, "second", "The returned message should contain information about the second track in the queue.")
+	suite.True(isPrivateMessage, "This should be a private message.")
+	suite.Nil(err, "No error should be returned.")
+}
+
+func TestNextTrackCommandTestSuite(t *testing.T) {
+	suite.Run(t, new(NextTrackCommandTestSuite))
+}

commands/numcached.go

@@ -0,0 +1,55 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * commands/numcached.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package commands
+
+import (
+	"errors"
+	"fmt"
+
+	"github.com/layeh/gumble/gumble"
+	"github.com/spf13/viper"
+)
+
+// NumCachedCommand is a command that outputs the number of tracks that
+// are currently cached on disk (if caching is enabled).
+type NumCachedCommand struct{}
+
+// Aliases returns the current aliases for the command.
+func (c *NumCachedCommand) Aliases() []string {
+	return viper.GetStringSlice("commands.numcached.aliases")
+}
+
+// Description returns the description for the command.
+func (c *NumCachedCommand) Description() string {
+	return viper.GetString("commands.numcached.description")
+}
+
+// IsAdminCommand returns true if the command is only for admin use, and
+// returns false otherwise.
+func (c *NumCachedCommand) IsAdminCommand() bool {
+	return viper.GetBool("commands.numcached.is_admin")
+}
+
+// Execute executes the command with the given user and arguments.
+// Return value descriptions:
+//    string: A message to be returned to the user upon successful execution.
+//    bool:   Whether the message should be private or not. true = private,
+//            false = public (sent to whole channel).
+//    error:  An error message to be returned upon unsuccessful execution.
+//            If no error has occurred, pass nil instead.
+// Example return statement:
+//    return "This is a private message!", true, nil
+func (c *NumCachedCommand) Execute(user *gumble.User, args ...string) (string, bool, error) {
+	if !viper.GetBool("cache.enabled") {
+		return "", true, errors.New(viper.GetString("commands.common_messages.caching_disabled_error"))
+	}
+
+	DJ.Cache.UpdateStatistics()
+	return fmt.Sprintf(viper.GetString("commands.numcached.messages.num_cached"),
+		DJ.Cache.NumAudioFiles), true, nil
+}

commands/numcached_test.go

@@ -0,0 +1,8 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ * commands/numcached_test.go
+ */
+
+package commands

commands/numtracks.go

@@ -0,0 +1,53 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * commands/numtracks.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package commands
+
+import (
+	"fmt"
+
+	"github.com/layeh/gumble/gumble"
+	"github.com/spf13/viper"
+)
+
+// NumTracksCommand is a command that outputs the current number of tracks
+// in the queue.
+type NumTracksCommand struct{}
+
+// Aliases returns the current aliases for the command.
+func (c *NumTracksCommand) Aliases() []string {
+	return viper.GetStringSlice("commands.numtracks.aliases")
+}
+
+// Description returns the description for the command.
+func (c *NumTracksCommand) Description() string {
+	return viper.GetString("commands.numtracks.description")
+}
+
+// IsAdminCommand returns true if the command is only for admin use, and
+// returns false otherwise.
+func (c *NumTracksCommand) IsAdminCommand() bool {
+	return viper.GetBool("commands.numtracks.is_admin")
+}
+
+// Execute executes the command with the given user and arguments.
+// Return value descriptions:
+//    string: A message to be returned to the user upon successful execution.
+//    bool:   Whether the message should be private or not. true = private,
+//            false = public (sent to whole channel).
+//    error:  An error message to be returned upon unsuccessful execution.
+//            If no error has occurred, pass nil instead.
+// Example return statement:
+//    return "This is a private message!", true, nil
+func (c *NumTracksCommand) Execute(user *gumble.User, args ...string) (string, bool, error) {
+	length := DJ.Queue.Length()
+	if length == 1 {
+		return viper.GetString("commands.numtracks.messages.one_track"), true, nil
+	}
+
+	return fmt.Sprintf(viper.GetString("commands.numtracks.messages.plural_tracks"), length), true, nil
+}

commands/numtracks_test.go

@@ -0,0 +1,99 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * commands/numtracks_test.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package commands
+
+import (
+	"testing"
+
+	"github.com/layeh/gumble/gumbleffmpeg"
+	"github.com/matthieugrieger/mumbledj/bot"
+	"github.com/spf13/viper"
+	"github.com/stretchr/testify/suite"
+)
+
+type NumTracksCommandTestSuite struct {
+	Command NumTracksCommand
+	suite.Suite
+}
+
+func (suite *NumTracksCommandTestSuite) SetupSuite() {
+	DJ = bot.NewMumbleDJ()
+	bot.DJ = DJ
+
+	// Trick the tests into thinking audio is already playing to avoid
+	// attempting to play tracks that don't exist.
+	DJ.AudioStream = new(gumbleffmpeg.Stream)
+
+	viper.Set("commands.numtracks.aliases", []string{"numtracks", "num"})
+	viper.Set("commands.numtracks.description", "numtracks")
+	viper.Set("commands.numtracks.is_admin", false)
+}
+
+func (suite *NumTracksCommandTestSuite) SetupTest() {
+	DJ.Queue = bot.NewQueue()
+}
+
+func (suite *NumTracksCommandTestSuite) TestAliases() {
+	suite.Equal([]string{"numtracks", "num"}, suite.Command.Aliases())
+}
+
+func (suite *NumTracksCommandTestSuite) TestDescription() {
+	suite.Equal("numtracks", suite.Command.Description())
+}
+
+func (suite *NumTracksCommandTestSuite) TestIsAdminCommand() {
+	suite.False(suite.Command.IsAdminCommand())
+}
+
+func (suite *NumTracksCommandTestSuite) TestExecuteWhenZeroTracksAreInQueue() {
+	message, isPrivateMessage, err := suite.Command.Execute(nil)
+
+	suite.NotEqual("", message, "A message should be returned.")
+	suite.Contains(message, "<b>0</b> tracks", "The returned message should state that there are no tracks in the queue.")
+	suite.True(isPrivateMessage, "This should be a private message.")
+	suite.Nil(err, "No error should be returned.")
+}
+
+func (suite *NumTracksCommandTestSuite) TestExecuteWhenOneTrackIsInQueue() {
+	track := new(bot.Track)
+	track.Title = "test"
+	track.Submitter = "test"
+
+	DJ.Queue.AppendTrack(track)
+
+	message, isPrivateMessage, err := suite.Command.Execute(nil)
+
+	suite.NotEqual("", message, "A message should be returned.")
+	suite.Contains(message, "<b>1</b> track", "The returned message should state that there is one track in the queue.")
+	suite.True(isPrivateMessage, "This should be a private message.")
+	suite.Nil(err, "No error should be returned.")
+}
+
+func (suite *NumTracksCommandTestSuite) TestExecuteWhenTwoOrMoreTracksAreInQueue() {
+	track1 := new(bot.Track)
+	track1.Title = "test"
+	track1.Submitter = "test"
+
+	track2 := new(bot.Track)
+	track2.Title = "test"
+	track2.Submitter = "test"
+
+	DJ.Queue.AppendTrack(track1)
+	DJ.Queue.AppendTrack(track2)
+
+	message, isPrivateMessage, err := suite.Command.Execute(nil)
+
+	suite.NotEqual("", "A message should be returned.")
+	suite.Contains(message, "tracks", "The returned message should use the plural form of the word track.")
+	suite.True(isPrivateMessage, "This should be a private message.")
+	suite.Nil(err, "No error should be returned.")
+}
+
+func TestNumTracksCommandTestSuite(t *testing.T) {
+	suite.Run(t, new(NumTracksCommandTestSuite))
+}

commands/pause.go

@@ -0,0 +1,52 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * commands/pause.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package commands
+
+import (
+	"errors"
+	"fmt"
+
+	"github.com/layeh/gumble/gumble"
+	"github.com/spf13/viper"
+)
+
+// PauseCommand is a command that pauses audio playback.
+type PauseCommand struct{}
+
+// Aliases returns the current aliases for the command.
+func (c *PauseCommand) Aliases() []string {
+	return viper.GetStringSlice("commands.pause.aliases")
+}
+
+// Description returns the description for the command.
+func (c *PauseCommand) Description() string {
+	return viper.GetString("commands.pause.description")
+}
+
+// IsAdminCommand returns true if the command is only for admin use, and
+// returns false otherwise.
+func (c *PauseCommand) IsAdminCommand() bool {
+	return viper.GetBool("commands.pause.is_admin")
+}
+
+// Execute executes the command with the given user and arguments.
+// Return value descriptions:
+//    string: A message to be returned to the user upon successful execution.
+//    bool:   Whether the message should be private or not. true = private,
+//            false = public (sent to whole channel).
+//    error:  An error message to be returned upon unsuccessful execution.
+//            If no error has occurred, pass nil instead.
+// Example return statement:
+//    return "This is a private message!", true, nil
+func (c *PauseCommand) Execute(user *gumble.User, args ...string) (string, bool, error) {
+	err := DJ.Queue.PauseCurrent()
+	if err != nil {
+		return "", true, errors.New(viper.GetString("commands.pause.messages.no_audio_error"))
+	}
+	return fmt.Sprintf(viper.GetString("commands.pause.messages.paused"), user.Name), false, nil
+}

commands/pause_test.go

@@ -0,0 +1,8 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ * commands/pause_test.go
+ */
+
+package commands

commands/pkg_init.go

@@ -0,0 +1,50 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * commands/pkg_init.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package commands
+
+import (
+	"github.com/matthieugrieger/mumbledj/bot"
+	"github.com/matthieugrieger/mumbledj/interfaces"
+)
+
+// DJ is an injected MumbleDJ struct.
+var DJ *bot.MumbleDJ
+
+// Commands is a slice of all enabled commands.
+var Commands []interfaces.Command
+
+func init() {
+	Commands = []interfaces.Command{
+		new(AddCommand),
+		new(AddNextCommand),
+		new(CacheSizeCommand),
+		new(CurrentTrackCommand),
+		new(ForceSkipCommand),
+		new(ForceSkipPlaylistCommand),
+		new(HelpCommand),
+		new(JoinMeCommand),
+		new(KillCommand),
+		new(ListTracksCommand),
+		new(MoveCommand),
+		new(NextTrackCommand),
+		new(NumCachedCommand),
+		new(NumTracksCommand),
+		new(PauseCommand),
+		new(RegisterCommand),
+		new(ReloadCommand),
+		new(ResetCommand),
+		new(ResumeCommand),
+		new(SetCommentCommand),
+		new(ShuffleCommand),
+		new(SkipCommand),
+		new(SkipPlaylistCommand),
+		new(ToggleShuffleCommand),
+		new(VersionCommand),
+		new(VolumeCommand),
+	}
+}

commands/register.go

@@ -0,0 +1,53 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * commands/register.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package commands
+
+import (
+	"errors"
+
+	"github.com/layeh/gumble/gumble"
+	"github.com/spf13/viper"
+)
+
+// RegisterCommand is a command that registers the bot on the server.
+type RegisterCommand struct{}
+
+// Aliases returns the current aliases for the command.
+func (c *RegisterCommand) Aliases() []string {
+	return viper.GetStringSlice("commands.register.aliases")
+}
+
+// Description returns the description for the command.
+func (c *RegisterCommand) Description() string {
+	return viper.GetString("commands.register.description")
+}
+
+// IsAdminCommand returns true if the command is only for admin use, and
+// returns false otherwise.
+func (c *RegisterCommand) IsAdminCommand() bool {
+	return viper.GetBool("commands.register.is_admin")
+}
+
+// Execute executes the command with the given user and arguments.
+// Return value descriptions:
+//    string: A message to be returned to the user upon successful execution.
+//    bool:   Whether the message should be private or not. true = private,
+//            false = public (sent to whole channel).
+//    error:  An error message to be returned upon unsuccessful execution.
+//            If no error has occurred, pass nil instead.
+// Example return statement:
+//    return "This is a private message!", true, nil
+func (c *RegisterCommand) Execute(user *gumble.User, args ...string) (string, bool, error) {
+	if DJ.Client.Self.IsRegistered() {
+		return "", true, errors.New(viper.GetString("commands.register.messages.already_registered_error"))
+	}
+
+	DJ.Client.Self.Register()
+
+	return viper.GetString("commands.register.messages.registered"), true, nil
+}

commands/register_test.go

@@ -0,0 +1,8 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * commands/register_test.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package commands

commands/reload.go

@@ -0,0 +1,52 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * commands/reload.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package commands
+
+import (
+	"github.com/layeh/gumble/gumble"
+	"github.com/matthieugrieger/mumbledj/bot"
+	"github.com/spf13/viper"
+)
+
+// ReloadCommand is a command that reloads the configuration values for the bot
+// from a config file.
+type ReloadCommand struct{}
+
+// Aliases returns the current aliases for the command.
+func (c *ReloadCommand) Aliases() []string {
+	return viper.GetStringSlice("commands.reload.aliases")
+}
+
+// Description returns the description for the command.
+func (c *ReloadCommand) Description() string {
+	return viper.GetString("commands.reload.description")
+}
+
+// IsAdminCommand returns true if the command is only for admin use, and
+// returns false otherwise.
+func (c *ReloadCommand) IsAdminCommand() bool {
+	return viper.GetBool("commands.reload.is_admin")
+}
+
+// Execute executes the command with the given user and arguments.
+// Return value descriptions:
+//    string: A message to be returned to the user upon successful execution.
+//    bool:   Whether the message should be private or not. true = private,
+//            false = public (sent to whole channel).
+//    error:  An error message to be returned upon unsuccessful execution.
+//            If no error has occurred, pass nil instead.
+// Example return statement:
+//    return "This is a private message!", true, nil
+func (c *ReloadCommand) Execute(user *gumble.User, args ...string) (string, bool, error) {
+	if err := bot.ReadConfigFile(); err != nil {
+		return "", true, err
+	}
+
+	return viper.GetString("commands.reload.messages.reloaded"),
+		true, nil
+}

commands/reload_test.go

@@ -0,0 +1,8 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ * commands/reload_test.go
+ */
+
+package commands

commands/reset.go

@@ -0,0 +1,63 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * commands/reset.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package commands
+
+import (
+	"errors"
+	"fmt"
+
+	"github.com/layeh/gumble/gumble"
+	"github.com/spf13/viper"
+)
+
+// ResetCommand is a command that resets the queue and cache.
+type ResetCommand struct{}
+
+// Aliases returns the current aliases for the command.
+func (c *ResetCommand) Aliases() []string {
+	return viper.GetStringSlice("commands.reset.aliases")
+}
+
+// Description returns the description for the command.
+func (c *ResetCommand) Description() string {
+	return viper.GetString("commands.reset.description")
+}
+
+// IsAdminCommand returns true if the command is only for admin use, and
+// returns false otherwise.
+func (c *ResetCommand) IsAdminCommand() bool {
+	return viper.GetBool("commands.reset.is_admin")
+}
+
+// Execute executes the command with the given user and arguments.
+// Return value descriptions:
+//    string: A message to be returned to the user upon successful execution.
+//    bool:   Whether the message should be private or not. true = private,
+//            false = public (sent to whole channel).
+//    error:  An error message to be returned upon unsuccessful execution.
+//            If no error has occurred, pass nil instead.
+// Example return statement:
+//    return "This is a private message!", true, nil
+func (c *ResetCommand) Execute(user *gumble.User, args ...string) (string, bool, error) {
+	if DJ.Queue.Length() == 0 {
+		return "", true, errors.New(viper.GetString("commands.common_messages.no_tracks_error"))
+	}
+
+	if DJ.AudioStream != nil {
+		DJ.AudioStream.Stop()
+		DJ.AudioStream = nil
+	}
+
+	DJ.Queue.Reset()
+
+	if err := DJ.Cache.DeleteAll(); err != nil {
+		return "", true, err
+	}
+
+	return fmt.Sprintf(viper.GetString("commands.reset.messages.queue_reset"), user.Name), false, nil
+}

commands/reset_test.go

@@ -0,0 +1,8 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ * commands/reset_test.go
+ */
+
+package commands

commands/resume.go

@@ -0,0 +1,52 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * commands/resume.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package commands
+
+import (
+	"errors"
+	"fmt"
+
+	"github.com/layeh/gumble/gumble"
+	"github.com/spf13/viper"
+)
+
+// ResumeCommand is a command that resumes audio playback.
+type ResumeCommand struct{}
+
+// Aliases returns the current aliases for the command.
+func (c *ResumeCommand) Aliases() []string {
+	return viper.GetStringSlice("commands.resume.aliases")
+}
+
+// Description returns the description for the command.
+func (c *ResumeCommand) Description() string {
+	return viper.GetString("commands.resume.description")
+}
+
+// IsAdminCommand returns true if the command is only for admin use, and
+// returns false otherwise.
+func (c *ResumeCommand) IsAdminCommand() bool {
+	return viper.GetBool("commands.resume.is_admin")
+}
+
+// Execute executes the command with the given user and arguments.
+// Return value descriptions:
+//    string: A message to be returned to the user upon successful execution.
+//    bool:   Whether the message should be private or not. true = private,
+//            false = public (sent to whole channel).
+//    error:  An error message to be returned upon unsuccessful execution.
+//            If no error has occurred, pass nil instead.
+// Example return statement:
+//    return "This is a private message!", true, nil
+func (c *ResumeCommand) Execute(user *gumble.User, args ...string) (string, bool, error) {
+	err := DJ.Queue.ResumeCurrent()
+	if err != nil {
+		return "", true, errors.New(viper.GetString("commands.resume.messages.audio_error"))
+	}
+	return fmt.Sprintf(viper.GetString("commands.resume.messages.resumed"), user.Name), false, nil
+}

commands/resume_test.go

@@ -0,0 +1,8 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ * commands/resume_test.go
+ */
+
+package commands

commands/setcomment.go

@@ -0,0 +1,66 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * commands/setcomment.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package commands
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/layeh/gumble/gumble"
+	"github.com/spf13/viper"
+)
+
+// SetCommentCommand is a command that changes the Mumble comment of the bot.
+type SetCommentCommand struct{}
+
+// Aliases returns the current aliases for the command.
+func (c *SetCommentCommand) Aliases() []string {
+	return viper.GetStringSlice("commands.setcomment.aliases")
+}
+
+// Description returns the description for the command.
+func (c *SetCommentCommand) Description() string {
+	return viper.GetString("commands.setcomment.description")
+}
+
+// IsAdminCommand returns true if the command is only for admin use, and
+// returns false otherwise.
+func (c *SetCommentCommand) IsAdminCommand() bool {
+	return viper.GetBool("commands.setcomment.is_admin")
+}
+
+// Execute executes the command with the given user and arguments.
+// Return value descriptions:
+//    string: A message to be returned to the user upon successful execution.
+//    bool:   Whether the message should be private or not. true = private,
+//            false = public (sent to whole channel).
+//    error:  An error message to be returned upon unsuccessful execution.
+//            If no error has occurred, pass nil instead.
+// Example return statement:
+//    return "This is a private message!", true, nil
+func (c *SetCommentCommand) Execute(user *gumble.User, args ...string) (string, bool, error) {
+	if len(args) == 0 {
+		DJ.Client.Do(func() {
+			DJ.Client.Self.SetComment("")
+		})
+		return viper.GetString("commands.setcomment.messages.comment_removed"), true, nil
+	}
+
+	var newComment string
+	for _, arg := range args {
+		newComment += arg + " "
+	}
+	strings.TrimSpace(newComment)
+
+	DJ.Client.Do(func() {
+		DJ.Client.Self.SetComment(newComment)
+	})
+
+	return fmt.Sprintf(viper.GetString("commands.setcomment.messages.comment_changed"),
+		newComment), true, nil
+}

commands/setcomment_test.go

@@ -0,0 +1,8 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ * commands/setcomment_test.go
+ */
+
+package commands

commands/shuffle.go

@@ -0,0 +1,57 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * commands/shuffle.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package commands
+
+import (
+	"errors"
+
+	"github.com/layeh/gumble/gumble"
+	"github.com/spf13/viper"
+)
+
+// ShuffleCommand is a command that shuffles the audio queue.
+type ShuffleCommand struct{}
+
+// Aliases returns the current aliases for the command.
+func (c *ShuffleCommand) Aliases() []string {
+	return viper.GetStringSlice("commands.shuffle.aliases")
+}
+
+// Description returns the description for the command.
+func (c *ShuffleCommand) Description() string {
+	return viper.GetString("commands.shuffle.description")
+}
+
+// IsAdminCommand returns true if the command is only for admin use, and
+// returns false otherwise.
+func (c *ShuffleCommand) IsAdminCommand() bool {
+	return viper.GetBool("commands.shuffle.is_admin")
+}
+
+// Execute executes the command with the given user and arguments.
+// Return value descriptions:
+//    string: A message to be returned to the user upon successful execution.
+//    bool:   Whether the message should be private or not. true = private,
+//            false = public (sent to whole channel).
+//    error:  An error message to be returned upon unsuccessful execution.
+//            If no error has occurred, pass nil instead.
+// Example return statement:
+//    return "This is a private message!", true, nil
+func (c *ShuffleCommand) Execute(user *gumble.User, args ...string) (string, bool, error) {
+	length := DJ.Queue.Length()
+	if length == 0 {
+		return "", true, errors.New(viper.GetString("commands.common_messages.no_tracks_error"))
+	}
+	if length <= 2 {
+		return "", true, errors.New(viper.GetString("commands.shuffle.messages.not_enough_tracks_error"))
+	}
+
+	DJ.Queue.ShuffleTracks()
+
+	return viper.GetString("commands.shuffle.messages.shuffled"), false, nil
+}

commands/shuffle_test.go

@@ -0,0 +1,8 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ * commands/shuffle_test.go
+ */
+
+package commands

commands/skip.go

@@ -0,0 +1,60 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * commands/skip.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package commands
+
+import (
+	"errors"
+	"fmt"
+
+	"github.com/layeh/gumble/gumble"
+	"github.com/spf13/viper"
+)
+
+// SkipCommand is a command that places a vote to skip the current track.
+type SkipCommand struct{}
+
+// Aliases returns the current aliases for the command.
+func (c *SkipCommand) Aliases() []string {
+	return viper.GetStringSlice("commands.skip.aliases")
+}
+
+// Description returns the description for the command.
+func (c *SkipCommand) Description() string {
+	return viper.GetString("commands.skip.description")
+}
+
+// IsAdminCommand returns true if the command is only for admin use, and
+// returns false otherwise.
+func (c *SkipCommand) IsAdminCommand() bool {
+	return viper.GetBool("commands.skip.is_admin")
+}
+
+// Execute executes the command with the given user and arguments.
+// Return value descriptions:
+//    string: A message to be returned to the user upon successful execution.
+//    bool:   Whether the message should be private or not. true = private,
+//            false = public (sent to whole channel).
+//    error:  An error message to be returned upon unsuccessful execution.
+//            If no error has occurred, pass nil instead.
+// Example return statement:
+//    return "This is a private message!", true, nil
+func (c *SkipCommand) Execute(user *gumble.User, args ...string) (string, bool, error) {
+	if DJ.Queue.Length() == 0 {
+		return "", true, errors.New(viper.GetString("commands.common_messages.no_tracks_error"))
+	}
+	if DJ.Queue.GetTrack(0).GetSubmitter() == user.Name {
+		// The user who submitted the track is skipping, this means we skip this track immediately.
+		DJ.Queue.StopCurrent()
+		return fmt.Sprintf(viper.GetString("commands.skip.messages.submitter_voted"), user.Name), false, nil
+	}
+	if err := DJ.Skips.AddTrackSkip(user); err != nil {
+		return "", true, errors.New(viper.GetString("commands.skip.messages.already_voted_error"))
+	}
+
+	return fmt.Sprintf(viper.GetString("commands.skip.messages.voted"), user.Name), false, nil
+}

commands/skip_test.go

@@ -0,0 +1,8 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ * commands/skip_test.go
+ */
+
+package commands

commands/skipplaylist.go

@@ -0,0 +1,70 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * commands/skipplaylist.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package commands
+
+import (
+	"errors"
+	"fmt"
+
+	"github.com/layeh/gumble/gumble"
+	"github.com/matthieugrieger/mumbledj/interfaces"
+	"github.com/spf13/viper"
+)
+
+// SkipPlaylistCommand is a command that places a vote to skip the current
+// playlist.
+type SkipPlaylistCommand struct{}
+
+// Aliases returns the current aliases for the command.
+func (c *SkipPlaylistCommand) Aliases() []string {
+	return viper.GetStringSlice("commands.skipplaylist.aliases")
+}
+
+// Description returns the description for the command.
+func (c *SkipPlaylistCommand) Description() string {
+	return viper.GetString("commands.skipplaylist.description")
+}
+
+// IsAdminCommand returns true if the command is only for admin use, and
+// returns false otherwise.
+func (c *SkipPlaylistCommand) IsAdminCommand() bool {
+	return viper.GetBool("commands.skipplaylist.is_admin")
+}
+
+// Execute executes the command with the given user and arguments.
+// Return value descriptions:
+//    string: A message to be returned to the user upon successful execution.
+//    bool:   Whether the message should be private or not. true = private,
+//            false = public (sent to whole channel).
+//    error:  An error message to be returned upon unsuccessful execution.
+//            If no error has occurred, pass nil instead.
+// Example return statement:
+//    return "This is a private message!", true, nil
+func (c *SkipPlaylistCommand) Execute(user *gumble.User, args ...string) (string, bool, error) {
+	var (
+		currentTrack interfaces.Track
+		err          error
+	)
+
+	if currentTrack, err = DJ.Queue.CurrentTrack(); err != nil {
+		return "", true, errors.New(viper.GetString("commands.common_messages.no_tracks_error"))
+	}
+
+	if playlist := currentTrack.GetPlaylist(); playlist == nil {
+		return "", true, errors.New(viper.GetString("commands.skipplaylist.messages.no_playlist_error"))
+	}
+	if currentTrack.GetPlaylist().GetSubmitter() == user.Name {
+		DJ.Queue.SkipPlaylist()
+		return fmt.Sprintf(viper.GetString("commands.skipplaylist.messages.submitter_voted"), user.Name), false, nil
+	}
+	if err := DJ.Skips.AddPlaylistSkip(user); err != nil {
+		return "", true, errors.New(viper.GetString("commands.skipplaylist.messages.already_voted_error"))
+	}
+
+	return fmt.Sprintf(viper.GetString("commands.skipplaylist.messages.voted"), user.Name), false, nil
+}

commands/skipplaylist_test.go

@@ -0,0 +1,8 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ * commands/skipplaylist_test.go
+ */
+
+package commands

commands/toggleshuffle.go

@@ -0,0 +1,50 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * commands/toggleshuffle.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package commands
+
+import (
+	"github.com/layeh/gumble/gumble"
+	"github.com/spf13/viper"
+)
+
+// ToggleShuffleCommand is a command that changes the Mumble comment of the bot.
+type ToggleShuffleCommand struct{}
+
+// Aliases returns the current aliases for the command.
+func (c *ToggleShuffleCommand) Aliases() []string {
+	return viper.GetStringSlice("commands.toggleshuffle.aliases")
+}
+
+// Description returns the description for the command.
+func (c *ToggleShuffleCommand) Description() string {
+	return viper.GetString("commands.toggleshuffle.description")
+}
+
+// IsAdminCommand returns true if the command is only for admin use, and
+// returns false otherwise.
+func (c *ToggleShuffleCommand) IsAdminCommand() bool {
+	return viper.GetBool("commands.toggleshuffle.is_admin")
+}
+
+// Execute executes the command with the given user and arguments.
+// Return value descriptions:
+//    string: A message to be returned to the user upon successful execution.
+//    bool:   Whether the message should be private or not. true = private,
+//            false = public (sent to whole channel).
+//    error:  An error message to be returned upon unsuccessful execution.
+//            If no error has occurred, pass nil instead.
+// Example return statement:
+//    return "This is a private message!", true, nil
+func (c *ToggleShuffleCommand) Execute(user *gumble.User, args ...string) (string, bool, error) {
+	if viper.GetBool("queue.automatic_shuffle_on") {
+		viper.Set("queue.automatic_shuffle_on", false)
+		return viper.GetString("commands.toggleshuffle.messages.toggled_off"), false, nil
+	}
+	viper.Set("queue.automatic_shuffle_on", true)
+	return viper.GetString("commands.toggleshuffle.messages.toggled_on"), false, nil
+}

commands/toggleshuffle_test.go

@@ -0,0 +1,67 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * commands/toggleshuffle_test.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package commands
+
+import (
+	"testing"
+
+	"github.com/matthieugrieger/mumbledj/bot"
+	"github.com/spf13/viper"
+	"github.com/stretchr/testify/suite"
+)
+
+type ToggleShuffleCommandTestSuite struct {
+	Command ToggleShuffleCommand
+	suite.Suite
+}
+
+func (suite *ToggleShuffleCommandTestSuite) SetupSuite() {
+	DJ = bot.NewMumbleDJ()
+
+	viper.Set("commands.toggleshuffle.aliases", []string{"toggleshuffle", "ts"})
+	viper.Set("commands.toggleshuffle.description", "toggleshuffle")
+	viper.Set("commands.toggleshuffle.is_admin", true)
+}
+
+func (suite *ToggleShuffleCommandTestSuite) TestAliases() {
+	suite.Equal([]string{"toggleshuffle", "ts"}, suite.Command.Aliases())
+}
+
+func (suite *ToggleShuffleCommandTestSuite) TestDescription() {
+	suite.Equal("toggleshuffle", suite.Command.Description())
+}
+
+func (suite *ToggleShuffleCommandTestSuite) TestIsAdminCommand() {
+	suite.True(suite.Command.IsAdminCommand())
+}
+
+func (suite *ToggleShuffleCommandTestSuite) TestExecuteWhenShuffleIsOff() {
+	viper.Set("queue.automatic_shuffle_on", false)
+
+	message, isPrivateMessage, err := suite.Command.Execute(nil)
+
+	suite.NotEqual("", message, "A message should be returned.")
+	suite.False(isPrivateMessage, "This should not be a private message.")
+	suite.Nil(err, "No error should be returned.")
+	suite.True(viper.GetBool("queue.automatic_shuffle_on"), "Automatic shuffling should now be on.")
+}
+
+func (suite *ToggleShuffleCommandTestSuite) TestExecuteWhenShuffleIsOn() {
+	viper.Set("queue.automatic_shuffle_on", true)
+
+	message, isPrivateMessage, err := suite.Command.Execute(nil)
+
+	suite.NotEqual("", message, "A message should be returned.")
+	suite.False(isPrivateMessage, "This should not be a private message.")
+	suite.Nil(err, "No error should be returned.")
+	suite.False(viper.GetBool("queue.automatic_shuffle_on"), "Automatic shuffling should now be off.")
+}
+
+func TestToggleShuffleCommandTestSuite(t *testing.T) {
+	suite.Run(t, new(ToggleShuffleCommandTestSuite))
+}

commands/version.go

@@ -0,0 +1,47 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * commands/version.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package commands
+
+import (
+	"fmt"
+
+	"github.com/layeh/gumble/gumble"
+	"github.com/spf13/viper"
+)
+
+// VersionCommand is a command that outputs the local MumbleDJ version.
+type VersionCommand struct{}
+
+// Aliases returns the current aliases for the command.
+func (c *VersionCommand) Aliases() []string {
+	return viper.GetStringSlice("commands.version.aliases")
+}
+
+// Description returns the description for the command.
+func (c *VersionCommand) Description() string {
+	return viper.GetString("commands.version.description")
+}
+
+// IsAdminCommand returns true if the command is only for admin use, and
+// returns false otherwise.
+func (c *VersionCommand) IsAdminCommand() bool {
+	return viper.GetBool("commands.version.is_admin")
+}
+
+// Execute executes the command with the given user and arguments.
+// Return value descriptions:
+//    string: A message to be returned to the user upon successful execution.
+//    bool:   Whether the message should be private or not. true = private,
+//            false = public (sent to whole channel).
+//    error:  An error message to be returned upon unsuccessful execution.
+//            If no error has occurred, pass nil instead.
+// Example return statement:
+//    return "This is a private message!", true, nil
+func (c *VersionCommand) Execute(user *gumble.User, args ...string) (string, bool, error) {
+	return fmt.Sprintf(viper.GetString("commands.version.messages.version"), DJ.Version), true, nil
+}

commands/version_test.go

@@ -0,0 +1,55 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * commands/version_test.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package commands
+
+import (
+	"testing"
+
+	"github.com/matthieugrieger/mumbledj/bot"
+	"github.com/spf13/viper"
+	"github.com/stretchr/testify/suite"
+)
+
+type VersionCommandTestSuite struct {
+	Command VersionCommand
+	suite.Suite
+}
+
+func (suite *VersionCommandTestSuite) SetupSuite() {
+	DJ = bot.NewMumbleDJ()
+
+	viper.Set("commands.version.aliases", []string{"version", "v"})
+	viper.Set("commands.version.description", "version")
+	viper.Set("commands.version.is_admin", false)
+	DJ.Version = "test"
+}
+
+func (suite *VersionCommandTestSuite) TestAliases() {
+	suite.Equal([]string{"version", "v"}, suite.Command.Aliases())
+}
+
+func (suite *VersionCommandTestSuite) TestDescription() {
+	suite.Equal("version", suite.Command.Description())
+}
+
+func (suite *VersionCommandTestSuite) TestIsAdminCommand() {
+	suite.False(suite.Command.IsAdminCommand())
+}
+
+func (suite *VersionCommandTestSuite) TestExecute() {
+	message, isPrivateMessage, err := suite.Command.Execute(nil)
+
+	suite.NotEqual("", message, "A message should be returned.")
+	suite.Contains(message, "MumbleDJ", "The message should contain a MumbleDJ version string.")
+	suite.True(isPrivateMessage, "This should be a private message.")
+	suite.Nil(err, "No error should be returned.")
+}
+
+func TestVersionCommandTestSuite(t *testing.T) {
+	suite.Run(t, new(VersionCommandTestSuite))
+}

commands/volume.go

@@ -0,0 +1,72 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * commands/volume.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package commands
+
+import (
+	"errors"
+	"fmt"
+	"strconv"
+
+	"github.com/layeh/gumble/gumble"
+	"github.com/spf13/viper"
+)
+
+// VolumeCommand is a command that changes the volume of the audio output.
+type VolumeCommand struct{}
+
+// Aliases returns the current aliases for the command.
+func (c *VolumeCommand) Aliases() []string {
+	return viper.GetStringSlice("commands.volume.aliases")
+}
+
+// Description returns the description for the command.
+func (c *VolumeCommand) Description() string {
+	return viper.GetString("commands.volume.description")
+}
+
+// IsAdminCommand returns true if the command is only for admin use, and
+// returns false otherwise.
+func (c *VolumeCommand) IsAdminCommand() bool {
+	return viper.GetBool("commands.volume.is_admin")
+}
+
+// Execute executes the command with the given user and arguments.
+// Return value descriptions:
+//    string: A message to be returned to the user upon successful execution.
+//    bool:   Whether the message should be private or not. true = private,
+//            false = public (sent to whole channel).
+//    error:  An error message to be returned upon unsuccessful execution.
+//            If no error has occurred, pass nil instead.
+// Example return statement:
+//    return "This is a private message!", true, nil
+func (c *VolumeCommand) Execute(user *gumble.User, args ...string) (string, bool, error) {
+	if len(args) == 0 {
+		// Send the user the current volume level.
+		return fmt.Sprintf(viper.GetString("commands.volume.messages.current_volume"), DJ.Volume), true, nil
+	}
+
+	newVolume, err := strconv.ParseFloat(args[0], 32)
+	if err != nil {
+		return "", true, errors.New(viper.GetString("commands.volume.messages.parsing_error"))
+	}
+
+	if newVolume <= viper.GetFloat64("volume.lowest") || newVolume >= viper.GetFloat64("volume.highest") {
+		return "", true, fmt.Errorf(viper.GetString("commands.volume.messages.out_of_range_error"),
+			viper.GetFloat64("volume.lowest"), viper.GetFloat64("volume.highest"))
+	}
+
+	newVolume32 := float32(newVolume)
+
+	if DJ.AudioStream != nil {
+		DJ.AudioStream.Volume = newVolume32
+	}
+	DJ.Volume = newVolume32
+
+	return fmt.Sprintf(viper.GetString("commands.volume.messages.volume_changed"),
+		user.Name, newVolume32), false, nil
+}

commands/volume_test.go

@@ -0,0 +1,110 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * commands/volume_test.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package commands
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/layeh/gumble/gumble"
+	"github.com/layeh/gumble/gumbleffmpeg"
+	"github.com/matthieugrieger/mumbledj/bot"
+	"github.com/spf13/viper"
+	"github.com/stretchr/testify/suite"
+)
+
+type VolumeCommandTestSuite struct {
+	Command VolumeCommand
+	suite.Suite
+}
+
+func (suite *VolumeCommandTestSuite) SetupSuite() {
+	DJ = bot.NewMumbleDJ()
+
+	viper.Set("commands.volume.aliases", []string{"volume", "vol"})
+	viper.Set("commands.volume.description", "volume")
+	viper.Set("commands.volume.is_admin", false)
+	viper.Set("volume.lowest", 0.2)
+	viper.Set("volume.highest", 1)
+	viper.Set("volume.default", 0.4)
+}
+
+func (suite *VolumeCommandTestSuite) SetupTest() {
+	DJ.Volume = float32(viper.GetFloat64("volume.default"))
+}
+
+func (suite *VolumeCommandTestSuite) TestAliases() {
+	suite.Equal([]string{"volume", "vol"}, suite.Command.Aliases())
+}
+
+func (suite *VolumeCommandTestSuite) TestDescription() {
+	suite.Equal("volume", suite.Command.Description())
+}
+
+func (suite *VolumeCommandTestSuite) TestIsAdminCommand() {
+	suite.False(suite.Command.IsAdminCommand())
+}
+
+func (suite *VolumeCommandTestSuite) TestExecuteWithNoArgs() {
+	message, isPrivateMessage, err := suite.Command.Execute(nil)
+
+	suite.NotEqual("", message, "A message should be returned.")
+	suite.True(isPrivateMessage, "This should be a private message.")
+	suite.Nil(err, "No error should be returned.")
+	suite.Contains(message, "0.4", "The returned string should contain the current volume.")
+}
+
+func (suite *VolumeCommandTestSuite) TestExecuteWithValidArg() {
+	dummyUser := &gumble.User{
+		Name: "test",
+	}
+	message, isPrivateMessage, err := suite.Command.Execute(dummyUser, "0.6")
+
+	suite.NotEqual("", message, "A message should be returned.")
+	suite.False(isPrivateMessage, "This should not be a private message.")
+	suite.Nil(err, "No error should be returned.")
+	suite.Contains(message, "0.6", "The returned string should contain the new volume.")
+	suite.Contains(message, "test", "The returned string should contain the username of whomever changed the volume.")
+}
+
+func (suite *VolumeCommandTestSuite) TestExecuteWithValidArgAndNonNilStream() {
+	dummyUser := &gumble.User{
+		Name: "test",
+	}
+	DJ.AudioStream = new(gumbleffmpeg.Stream)
+	DJ.AudioStream.Volume = 0.2
+
+	message, isPrivateMessage, err := suite.Command.Execute(dummyUser, "0.6")
+
+	suite.NotEqual("", message, "A message should be returned.")
+	suite.False(isPrivateMessage, "This should not be a private message.")
+	suite.Nil(err, "No error should be returned.")
+	suite.Contains(message, "0.6", "The returned string should contain the new volume.")
+	suite.Contains(message, "test", "The returned string should contain the username of whomever changed the volume.")
+	suite.Equal("0.60", fmt.Sprintf("%.2f", DJ.AudioStream.Volume), "The audio stream value should match the new volume.")
+}
+
+func (suite *VolumeCommandTestSuite) TestExecuteWithArgOutOfRange() {
+	message, isPrivateMessage, err := suite.Command.Execute(nil, "1.4")
+
+	suite.Equal("", message, "No message should be returned as an error occurred.")
+	suite.True(isPrivateMessage, "This should be a private message.")
+	suite.NotNil(err, "An error should be returned since the provided argument was outside of the valid range.")
+}
+
+func (suite *VolumeCommandTestSuite) TestExecuteWithInvalidArg() {
+	message, isPrivateMessage, err := suite.Command.Execute(nil, "test")
+
+	suite.Equal("", message, "No message should be returned as an error occurred.")
+	suite.True(isPrivateMessage, "This should be a private message.")
+	suite.NotNil(err, "An error should be returned as a non-floating-point argument was provided.")
+}
+
+func TestVolumeCommandTestSuite(t *testing.T) {
+	suite.Run(t, new(VolumeCommandTestSuite))
+}

config.yaml

@@ -0,0 +1,423 @@
+# MumbleDJ
+# By Matthieu Grieger
+# Copyright (c) 2016 Matthieu Grieger (MIT License)
+# config.yaml
+
+api_keys:
+
+    # YouTube API key.
+    youtube: ""
+
+    # SoundCloud API key.
+    # NOTE: The API key is your client ID.
+    soundcloud: ""
+
+
+defaults:
+
+    # Default comment to be applied to bot.
+    # NOTE: If you do not want a comment by default, set to empty string ("").
+    comment: "Hello! I am a bot. Type !help for a list of commands."
+
+    # Default channel for the bot to enter upon connection.
+    # NOTE: If you wish for the bot to connect to the root channel, set to empty string ("").
+    channel: ""
+
+    # Command to use to play audio files. The two supported choices are "ffmpeg" and "avconv".
+    player_command: "ffmpeg"
+
+
+queue:
+
+    # Ratio that must be met or exceeded to trigger a track skip.
+    track_skip_ratio: 0.5
+
+    # Ratio that must be met or exceeded to trigger a playlist skip.
+    playlist_skip_ratio: 0.5
+
+    # Maximum track duration in seconds. Set to 0 for unrestricted duration.
+    max_track_duration: 0
+
+    # Maximum tracks per playlist. Set to 0 for unrestricted playlists.
+    max_tracks_per_playlist: 50
+
+    # Is shuffling enabled when the bot starts?
+    automatic_shuffle_on: false
+
+    # Announce track information at the beginning of audio playback?
+    announce_new_tracks: true
+
+
+connection:
+
+    # Address bot should attempt to connect to.
+    address: "127.0.0.1"
+
+    # Port bot should attempt to connect to.
+    port: "64738"
+
+    # Password for connecting to server.
+    # NOTE: If no password, set to empty string ("").
+    password: ""
+
+    # Username for MumbleDJ.
+    username: "MumbleDJ"
+
+    # Filepath to user p12 file for authenticating as a registered user.
+    # NOTE: If no p12 file is needed, set to empty string ("").
+    user_p12: ""
+
+    # Should the bot attempt an insecure connection?
+    # An insecure connection does not verify the certificate of the server for
+    # consistency. It is best to leave this on, but disable it if you are having
+    # issues connecting to a server or are running multiple instances of MumbleDJ.
+    insecure: false
+
+    # Filepath to certificate file.
+    # NOTE: If no certificate file is needed, set to empty string ("").
+    cert: ""
+
+    # Filepath to certificate key file.
+    # NOTE: If no key is needed, set to empty string ("").
+    key: ""
+
+    # Access tokens to initialize the bot with, separated by commas.
+    # NOTE: If no access tokens are needed, set to empty string ("").
+    access_tokens: ""
+
+    # Should the bot automatically attempt to retry connection to a server after disconnecting?
+    retry_enabled: true
+
+    # How many times should the bot attempt to reconnect to the server?
+    retry_attempts: 10
+
+    # How many seconds should the bot wait in-between connection retry attempts?
+    retry_interval: 5
+
+
+cache:
+
+    # Cache songs as they are downloaded?
+    enabled: false
+
+    # Maximum total file size of cache directory in MiB.
+    maximum_size: 512
+
+    # Period of time that should elapse before a song is cleared from the cache, in hours.
+    expire_time: 24
+
+    # Period of time between each check of the cache for expired items, in minutes.
+    check_interval: 5
+
+    # Directory to store cached items. Environment variables are able to be used here.
+    directory: "$HOME/.cache/mumbledj"
+
+
+volume:
+
+    # Default volume.
+    default: 0.2
+
+    # Lowest volume allowed.
+    lowest: 0.01
+
+    # Highest volume allowed.
+    highest: 0.8
+
+
+admins:
+
+    # Enable admins?
+    # NOTE: If this is set to false, any command can be executed by any user.
+    enabled: true
+
+    # List of admin names.
+    # NOTE: It is recommended that the names in this list are registered on the
+    # server so that imposters cannot execute admin commands.
+    names:
+        - "SuperUser"
+
+
+commands:
+
+    # Character used to designate commands from normal text messages.
+    # NOTE: Only one character (the first) is used.
+    prefix: "!"
+
+    common_messages:
+        no_tracks_error: "There are no tracks in the queue."
+        caching_disabled_error: "Caching is currently disabled."
+
+    # Below is a list of the commands supported by MumbleDJ. Each command has
+    # three configurable options:
+    # aliases: A list of names that can be used to execute the command.
+    # is_admin: true = only admins can execute the command, false = anyone can execute the command.
+    # description: Description shown for the command when the help command is executed.
+    # messages: Various messages that may be sent as a text message from the command. Useful for translating
+    #           strings to other languages. Do NOT remove strings that begin with "%" (such as "%s", "%d", etc.)
+    #           as they substituted with runtime data. Removing these strings will cause the bot to misbehave.
+    add:
+        aliases:
+            - "add"
+            - "a"
+        is_admin: false
+        description: "Adds a track or playlist from a media site to the queue."
+        messages:
+            no_url_error: "A URL must be supplied with the add command."
+            no_valid_tracks_error: "No valid tracks were found with the provided URL(s)."
+            tracks_too_long_error: "Your track(s) were either too long or an error occurred while processing them. No track(s) have been added."
+            one_track_added: "<b>%s</b> added <b>1</b> track to the queue:<br><i>%s</i> from %s"
+            many_tracks_added: "<b>%s</b> added <b>%d</b> tracks to the queue."
+            num_tracks_too_long: "<br><b>%d</b> tracks could not be added due to error or because they are too long."
+
+    addnext:
+        aliases:
+            - "addnext"
+            - "an"
+        is_admin: true
+        description: "Adds a track or playlist from a media site as the next item in the queue."
+        # addnext uses the messages defined for add.
+
+    cachesize:
+        aliases:
+            - "cachesize"
+            - "cs"
+        is_admin: true
+        description: "Outputs the file size of the cache in MiB if caching is enabled."
+        messages:
+            current_size: "The current size of the cache is <b>%.2v MiB</b>."
+
+    currenttrack:
+        aliases:
+            - "currenttrack"
+            - "currentsong"
+            - "current"
+        is_admin: false
+        description: "Outputs information about the current track in the queue if one exists."
+        messages:
+            current_track: "The current track is <i>%s</i>, added by <b>%s</b>."
+
+    forceskip:
+        aliases:
+            - "forceskip"
+            - "fs"
+        is_admin: true
+        description: "Immediately skips the current track."
+        messages:
+            track_skipped: "The current track has been forcibly skipped by <b>%s</b>."
+
+    forceskipplaylist:
+        aliases:
+            - "forceskipplaylist"
+            - "fsp"
+        is_admin: true
+        description: "Immediately skips the current playlist."
+        messages:
+            no_playlist_error: "The current track is not part of a playlist."
+            playlist_skipped: "The current playlist has been forcibly skipped by <b>%s</b>."
+
+    help:
+        aliases:
+            - "help"
+            - "h"
+        is_admin: false
+        description: "Outputs this list of commands."
+        messages:
+            commands_header: "<br><b>Commands:</b><br>"
+            admin_commands_header: "<br><b>Admin Commands:</b><br>"
+
+    joinme:
+        aliases:
+            - "joinme"
+            - "join"
+        is_admin: true
+        description: "Moves MumbleDJ into your current channel if not playing audio to someone else."
+        messages:
+            others_are_listening_error: "Users in another channel are listening to me."
+            in_your_channel: "I am now in your channel!"
+
+    kill:
+        aliases:
+            - "kill"
+            - "k"
+        is_admin: true
+        description: "Stops the bot and cleans its cache directory."
+
+    listtracks:
+        aliases:
+            - "listtracks"
+            - "listsongs"
+            - "list"
+            - "l"
+        is_admin: false
+        description: "Outputs a list of the tracks currently in the queue."
+        messages:
+            invalid_integer_error: "An invalid integer was supplied."
+            track_listing: "<b>%d</b>: <i>%s</i>, added by <b>%s</b>.<br>"
+
+    move:
+        aliases:
+            - "move"
+            - "m"
+        is_admin: true
+        description: "Moves the bot into the Mumble channel provided via argument."
+        messages:
+            no_channel_provided_error: "A destination channel must be supplied to move the bot."
+            channel_doesnt_exist_error: "The provided channel does not exist."
+            move_successful: "You have successfully moved the bot to <b>%s</b>."
+
+    nexttrack:
+        aliases:
+            - "nexttrack"
+            - "nextsong"
+            - "next"
+        is_admin: false
+        description: "Outputs information about the next track in the queue if one exists."
+        messages:
+            current_track_only_error: "The current track is the only track in the queue."
+            next_track: "The next track is <i>%s</i>, added by <b>%s</b>."
+
+    numcached:
+        aliases:
+            - "numcached"
+            - "nc"
+        is_admin: true
+        description: "Outputs the number of tracks cached on disk if caching is enabled."
+        messages:
+            num_cached: "There are currently <b>%d</b> items stored in the cache."
+
+    numtracks:
+        aliases:
+            - "numtracks"
+            - "numsongs"
+            - "nt"
+        is_admin: false
+        description: "Outputs the number of tracks currently in the queue."
+        messages:
+            one_track: "There is currently <b>1</b> track in the queue."
+            plural_tracks: "There are currently <b>%d</b> tracks in the queue."
+
+    pause:
+        aliases:
+            - "pause"
+        is_admin: false
+        description: "Pauses audio playback."
+        messages:
+            no_audio_error: "Either the audio is already paused, or there are no tracks in the queue."
+            paused: "<b>%s</b> has paused audio playback."
+
+    register:
+        aliases:
+            - "register"
+            - "reg"
+        is_admin: true
+        description: "Registers the bot on the server."
+        messages:
+            already_registered_error: "I am already registered on the server."
+            registered: "I am now registered on the server."
+
+    reload:
+        aliases:
+            - "reload"
+            - "r"
+        is_admin: true
+        description: "Reloads the configuration file."
+        messages:
+            reloaded: "The configuration file has been successfully reloaded."
+
+    reset:
+        aliases:
+            - "reset"
+            - "re"
+        is_admin: true
+        description: "Resets the queue by removing all queue items."
+        messages:
+            queue_reset: "<b>%s</b> has reset the queue."
+
+    resume:
+        aliases:
+            - "resume"
+        is_admin: false
+        description: "Resumes audio playback."
+        messages:
+            audio_error: "Either the audio is already playing, or there are no tracks in the queue."
+            resumed: "<b>%s</b> has resumed audio playback."
+
+    setcomment:
+        aliases:
+            - "setcomment"
+            - "comment"
+            - "sc"
+        is_admin: true
+        description: "Sets the comment displayed next to MumbleDJ's username in Mumble."
+        messages:
+            comment_removed: "The comment for the bot has been successfully removed."
+            comment_changed: "The comment for the bot has been successfully changed to the following: %s"
+
+    shuffle:
+        aliases:
+            - "shuffle"
+            - "shuf"
+            - "sh"
+        is_admin: true
+        description: "Randomizes the tracks currently in the queue."
+        messages:
+            not_enough_tracks_error: "There are not enough tracks in the queue to execute a shuffle."
+            shuffled: "The audio queue has been shuffled."
+
+    skip:
+        aliases:
+            - "skip"
+            - "s"
+        is_admin: false
+        description: "Places a vote to skip the current track."
+        messages:
+            already_voted_error: "You have already voted to skip this track."
+            voted: "<b>%s</b> has voted to skip the current track."
+            submitter_voted: "<b>%s</b>, the submitter of this track, has voted to skip. Skipping immediately."
+
+    skipplaylist:
+        aliases:
+            - "skipplaylist"
+            - "sp"
+        is_admin: false
+        description: "Places a vote to skip the current playlist."
+        messages:
+            no_playlist_error: "The current track is not part of a playlist."
+            already_voted_error: "You have already voted to skip this playlist."
+            voted: "<b>%s</b> has voted to skip the current playlist."
+            submitter_voted: "<b>%s</b>, the submitter of this playlist, has voted to skip. Skipping immediately."
+
+    toggleshuffle:
+        aliases:
+            - "toggleshuffle"
+            - "toggleshuf"
+            - "togshuf"
+            - "tsh"
+        is_admin: true
+        description: "Toggles automatic track shuffling on/off."
+        messages:
+            toggled_off: "Automatic shuffling has been toggled off."
+            toggled_on: "Automatic shuffling has been toggled on."
+
+
+    version:
+        aliases:
+            - "version"
+            - "v"
+        is_admin: false
+        description: "Outputs the current version of MumbleDJ."
+        messages:
+            version: "MumbleDJ version: <b>%s</b>"
+
+    volume:
+        aliases:
+            - "volume"
+            - "vol"
+        is_admin: false
+        description: "Changes the volume if an argument is provided, outputs the current volume otherwise."
+        messages:
+            parsing_error: "The requested volume could not be parsed."
+            out_of_range_error: "Volumes must be between the values <b>%.2f</b> and <b>%.2f</b>."
+            current_volume: "The current volume is <b>%.2f</b>."
+            volume_changed: "<b>%s</b> has changed the volume to <b>%.2f</b>."

glide.lock

@@ -0,0 +1,62 @@
+hash: b68f7c8a3b59d7dac3e12321ed6a2265b553c2856ae70e0ed5e960ba8412f8d8
+updated: 2016-07-11T16:01:20.19606261-07:00
+imports:
+- name: github.com/antonholmquist/jason
+  version: c23cef7eaa75a6a5b8810120e167bd590d8fd2ab
+- name: github.com/BurntSushi/toml
+  version: bbd5bb678321a0d6e58f1099321dfa73391c1b6f
+- name: github.com/ChannelMeter/iso8601duration
+  version: 8da3af7a2a61a4eb5ae9bddec06bf637fa9593da
+- name: github.com/fsnotify/fsnotify
+  version: a8a77c9133d2d6fd8334f3260d06f60e8d80a5fb
+- name: github.com/golang/protobuf
+  version: 3852dcfda249c2097355a6aabb199a28d97b30df
+  subpackages:
+  - proto
+- name: github.com/hashicorp/hcl
+  version: 364df430845abef160a0bfb3a59979f746bf4956
+  subpackages:
+  - hcl/ast
+  - hcl/parser
+  - hcl/token
+  - json/parser
+  - hcl/scanner
+  - hcl/strconv
+  - json/scanner
+  - json/token
+- name: github.com/layeh/gopus
+  version: 867541549ca5f8b4db2b92fd1dded8711256a27d
+- name: github.com/layeh/gumble
+  version: f0a4a2992fa9a969ef90d673374bc63a9b7948ad
+  subpackages:
+  - gumble
+  - gumbleffmpeg
+  - gumbleutil
+  - opus
+  - gumble/MumbleProto
+  - gumble/varint
+- name: github.com/magiconair/properties
+  version: e2f061ecfdaca9f35b2e2c12346ffc526f138137
+- name: github.com/mitchellh/mapstructure
+  version: d2dd0262208475919e1a362f675cfc0e7c10e905
+- name: github.com/Sirupsen/logrus
+  version: 4b6ea7319e214d98c938f12692336f7ca9348d6b
+- name: github.com/spf13/cast
+  version: 27b586b42e29bec072fe7379259cc719e1289da6
+- name: github.com/spf13/jwalterweatherman
+  version: 33c24e77fb80341fe7130ee7c594256ff08ccc46
+- name: github.com/spf13/pflag
+  version: 367864438f1b1a3c7db4da06a2f55b144e6784e0
+- name: github.com/spf13/viper
+  version: c1ccc378a054ea8d4e38d8c67f6938d4760b53dd
+- name: github.com/stretchr/testify
+  version: f390dcf405f7b83c997eac1b06768bb9f44dec18
+- name: github.com/urfave/cli
+  version: 01857ac33766ce0c93856370626f9799281c14f4
+- name: golang.org/x/sys
+  version: a408501be4d17ee978c04a618e7a1b22af058c0e
+  subpackages:
+  - unix
+- name: gopkg.in/yaml.v2
+  version: a83829b6f1293c91addabc89d0571c246397bbf4
+devImports: []

glide.yaml

@@ -0,0 +1,26 @@
+package: github.com/matthieugrieger/mumbledj
+homepage: https://github.com/matthieugrieger/mumbledj
+license: MIT
+owners:
+- name: Matthieu Grieger
+  email: me@matthieugrieger.com
+  homepage: https://matthieugrieger.com
+import:
+- package: github.com/ChannelMeter/iso8601duration
+- package: github.com/Sirupsen/logrus
+  version: v0.10.0
+- package: github.com/antonholmquist/jason
+  version: v1.0.0
+- package: github.com/layeh/gumble
+  subpackages:
+  - gumble
+  - gumbleffmpeg
+  - gumbleutil
+  - opus
+- package: github.com/spf13/viper
+- package: github.com/urfave/cli
+  version: v1.17.0
+- package: github.com/stretchr/testify
+  version: v1.1.3
+- package: github.com/BurntSushi/toml
+  version: v0.2.0

interfaces/command.go

@@ -0,0 +1,18 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * interfaces/command.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package interfaces
+
+import "github.com/layeh/gumble/gumble"
+
+// Command is an interface that all commands must implement.
+type Command interface {
+	Aliases() []string
+	Description() string
+	IsAdminCommand() bool
+	Execute(user *gumble.User, args ...string) (string, bool, error)
+}

interfaces/playlist.go

@@ -0,0 +1,16 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * interfaces/playlist.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package interfaces
+
+// Playlist is an interface of methods that must be implemented by playlists.
+type Playlist interface {
+	GetID() string
+	GetTitle() string
+	GetSubmitter() string
+	GetService() string
+}

interfaces/queue.go

@@ -0,0 +1,29 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * interfaces/queue.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package interfaces
+
+// Queue is the interface which should be interacted with for queue operations.
+// Using the Queue interface ensures thread safety.
+type Queue interface {
+	Length() int
+	Reset()
+	AppendTrack(Track) error
+	InsertTrack(int, Track) error
+	CurrentTrack() (Track, error)
+	GetTrack(int) Track
+	PeekNextTrack() (Track, error)
+	Traverse(func(int, Track))
+	ShuffleTracks()
+	RandomNextTrack(bool)
+	Skip()
+	SkipPlaylist()
+	PlayCurrent() error
+	PauseCurrent() error
+	ResumeCurrent() error
+	StopCurrent() error
+}

interfaces/service.go

@@ -0,0 +1,20 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * interfaces/service.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package interfaces
+
+import "github.com/layeh/gumble/gumble"
+
+// Service is an interface of methods to be implemented
+// by various service types, such as YouTube or SoundCloud.
+type Service interface {
+	GetReadableName() string
+	GetFormat() string
+	CheckAPIKey() error
+	CheckURL(string) bool
+	GetTracks(string, *gumble.User) ([]Track, error)
+}

interfaces/skiptracker.go

@@ -0,0 +1,23 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * interfaces/skiptracker.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package interfaces
+
+import "github.com/layeh/gumble/gumble"
+
+// SkipTracker is the interface which should be interacted with for skip operations.
+// Using the SkipTracker interface ensures thread safety.
+type SkipTracker interface {
+	AddTrackSkip(*gumble.User) error
+	AddPlaylistSkip(*gumble.User) error
+	RemoveTrackSkip(*gumble.User) error
+	RemovePlaylistSkip(*gumble.User) error
+	NumTrackSkips() int
+	NumPlaylistSkips() int
+	ResetTrackSkips()
+	ResetPlaylistSkips()
+}

interfaces/track.go

@@ -0,0 +1,26 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * interfaces/track.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package interfaces
+
+import "time"
+
+// Track is an interface of methods that must be implemented by tracks.
+type Track interface {
+	GetID() string
+	GetURL() string
+	GetTitle() string
+	GetAuthor() string
+	GetAuthorURL() string
+	GetSubmitter() string
+	GetService() string
+	GetFilename() string
+	GetThumbnailURL() string
+	GetDuration() time.Duration
+	GetPlaybackOffset() time.Duration
+	GetPlaylist() Playlist
+}

main.go

@@ -2,147 +2,253 @@
  * MumbleDJ
  * By Matthieu Grieger
  * main.go
- * Copyright (c) 2014 Matthieu Grieger (MIT License)
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
  */
 
 package main
 
 import (
-	"flag"
-	"fmt"
-	"github.com/layeh/gumble/gumble"
-	"github.com/layeh/gumble/gumble_ffmpeg"
-	"github.com/layeh/gumble/gumbleutil"
-	"os/user"
+	"io/ioutil"
+	"os"
+	"strings"
+
+	"github.com/Sirupsen/logrus"
+	"github.com/matthieugrieger/mumbledj/bot"
+	"github.com/matthieugrieger/mumbledj/commands"
+	"github.com/matthieugrieger/mumbledj/services"
+	"github.com/spf13/viper"
+	"github.com/urfave/cli"
 )
 
-// MumbleDJ type declaration
-type mumbledj struct {
-	config         gumble.Config
-	client         *gumble.Client
-	keepAlive      chan bool
-	defaultChannel string
-	conf           DjConfig
-	queue          *SongQueue
-	currentSong    *Song
-	audioStream    *gumble_ffmpeg.Stream
-	homeDir        string
+// DJ is a global variable that holds various details about the bot's state.
+var DJ = bot.NewMumbleDJ()
+
+func init() {
+	DJ.Commands = commands.Commands
+	DJ.AvailableServices = services.Services
+
+	// Injection into sub-packages.
+	commands.DJ = DJ
+	services.DJ = DJ
+	bot.DJ = DJ
+
+	DJ.Version = "v3.2.1"
+
+	logrus.SetLevel(logrus.WarnLevel)
 }
 
-// OnConnect event. First moves MumbleDJ into the default channel specified
-// via commandline args, and moves to root channel if the channel does not exist. The current
-// user's homedir path is stored, configuration is loaded, and the audio stream is set up.
-func (dj *mumbledj) OnConnect(e *gumble.ConnectEvent) {
-	if dj.client.Channels().Find(dj.defaultChannel) != nil {
-		dj.client.Self().Move(dj.client.Channels().Find(dj.defaultChannel))
-	} else {
-		fmt.Println("Channel doesn't exist or one was not provided, staying in root channel...")
+func main() {
+	app := cli.NewApp()
+	app.Name = "MumbleDJ"
+	app.Usage = "A Mumble bot that plays audio from various media sites."
+	app.Version = DJ.Version
+	app.Flags = []cli.Flag{
+		cli.StringFlag{
+			Name:  "config, c",
+			Value: os.ExpandEnv("$HOME/.config/mumbledj/config.yaml"),
+			Usage: "location of MumbleDJ configuration file",
+		},
+		cli.StringFlag{
+			Name:  "server, s",
+			Value: "127.0.0.1",
+			Usage: "address of Mumble server to connect to",
+		},
+		cli.StringFlag{
+			Name:  "port, o",
+			Value: "64738",
+			Usage: "port of Mumble server to connect to",
+		},
+		cli.StringFlag{
+			Name:  "username, u",
+			Value: "MumbleDJ",
+			Usage: "username for the bot",
+		},
+		cli.StringFlag{
+			Name:  "password, p",
+			Value: "",
+			Usage: "password for the Mumble server",
+		},
+		cli.StringFlag{
+			Name:  "channel, n",
+			Value: "",
+			Usage: "channel the bot enters after connecting to the Mumble server",
+		},
+		cli.StringFlag{
+			Name:  "p12",
+			Value: "",
+			Usage: "path to user p12 file for authenticating as a registered user",
+		},
+		cli.StringFlag{
+			Name:  "cert, e",
+			Value: "",
+			Usage: "path to PEM certificate",
+		},
+		cli.StringFlag{
+			Name:  "key, k",
+			Value: "",
+			Usage: "path to PEM key",
+		},
+		cli.StringFlag{
+			Name:  "accesstokens, a",
+			Value: "",
+			Usage: "list of access tokens separated by spaces",
+		},
+		cli.BoolFlag{
+			Name:  "insecure, i",
+			Usage: "if present, the bot will not check Mumble certs for consistency",
+		},
+		cli.BoolFlag{
+			Name:  "debug, d",
+			Usage: "if present, all debug messages will be shown",
+		},
 	}
 
-	if currentUser, err := user.Current(); err == nil {
-		dj.homeDir = currentUser.HomeDir
-	}
-
-	if err := loadConfiguration(); err == nil {
-		fmt.Println("Configuration successfully loaded!")
-	} else {
-		panic(err)
-	}
-
-	if audioStream, err := gumble_ffmpeg.New(dj.client); err == nil {
-		dj.audioStream = audioStream
-		dj.audioStream.Done = dj.OnSongFinished
-		dj.audioStream.SetVolume(dj.conf.Volume.DefaultVolume)
-	} else {
-		panic(err)
-	}
-}
-
-// OnDisconnect event. Terminates MumbleDJ thread.
-func (dj *mumbledj) OnDisconnect(e *gumble.DisconnectEvent) {
-	dj.keepAlive <- true
-}
-
-// OnTextMessage event. Checks for command prefix, and calls parseCommand if it exists. Ignores
-// the incoming message otherwise.
-func (dj *mumbledj) OnTextMessage(e *gumble.TextMessageEvent) {
-	if e.Message[0] == dj.conf.General.CommandPrefix[0] {
-		parseCommand(e.Sender, e.Sender.Name(), e.Message[1:])
-	}
-}
-
-// Checks if username has the permissions to execute a command. Permissions are specified in
-// mumbledj.gcfg.
-func (dj *mumbledj) HasPermission(username string, command bool) bool {
-	if dj.conf.Permissions.AdminsEnabled && command {
-		for _, adminName := range dj.conf.Permissions.Admins {
-			if username == adminName {
-				return true
-			}
+	hiddenFlags := make([]cli.Flag, len(viper.AllKeys()))
+	for i, configValue := range viper.AllKeys() {
+		hiddenFlags[i] = cli.StringFlag{
+			Name:   configValue,
+			Hidden: true,
 		}
-		return false
-	} else {
-		return true
 	}
-}
+	app.Flags = append(app.Flags, hiddenFlags...)
 
-// OnSongFinished event. Deletes song that just finished playing, then queues, downloads, and plays
-// the next song if it exists.
-func (dj *mumbledj) OnSongFinished() {
-	if err := dj.currentSong.Delete(); err == nil {
-		if dj.queue.Len() != 0 {
-			dj.currentSong = dj.queue.NextSong()
-			if dj.currentSong != nil {
-				if err := dj.currentSong.Download(); err == nil {
-					dj.currentSong.Play()
+	app.Action = func(c *cli.Context) error {
+		if c.Bool("debug") {
+			logrus.SetLevel(logrus.InfoLevel)
+		}
+
+		for _, configValue := range viper.AllKeys() {
+			if c.GlobalIsSet(configValue) {
+				if strings.Contains(c.String(configValue), ",") {
+					viper.Set(configValue, strings.Split(c.String(configValue), ","))
 				} else {
-					panic(err)
+					viper.Set(configValue, c.String(configValue))
 				}
 			}
 		}
+
+		viper.SetConfigFile(c.String("config"))
+		if err := viper.ReadInConfig(); err != nil {
+			logrus.WithFields(logrus.Fields{
+				"file":  c.String("config"),
+				"error": err.Error(),
+			}).Warnln("An error occurred while reading the configuration file. Using default configuration...")
+			if _, err := os.Stat(c.String("config")); os.IsNotExist(err) {
+				createConfigWhenNotExists()
+			}
+		} else {
+			if duplicateErr := bot.CheckForDuplicateAliases(); duplicateErr != nil {
+				logrus.WithFields(logrus.Fields{
+					"issue": duplicateErr.Error(),
+				}).Fatalln("An issue was discoverd in your configuration.")
+			}
+			createNewConfigIfNeeded()
+			viper.WatchConfig()
+		}
+
+		if c.GlobalIsSet("server") {
+			viper.Set("connection.address", c.String("server"))
+		}
+		if c.GlobalIsSet("port") {
+			viper.Set("connection.port", c.String("port"))
+		}
+		if c.GlobalIsSet("username") {
+			viper.Set("connection.username", c.String("username"))
+		}
+		if c.GlobalIsSet("password") {
+			viper.Set("connection.password", c.String("password"))
+		}
+		if c.GlobalIsSet("channel") {
+			viper.Set("defaults.channel", c.String("channel"))
+		}
+		if c.GlobalIsSet("p12") {
+			viper.Set("connection.user_p12", c.String("p12"))
+		}
+		if c.GlobalIsSet("cert") {
+			viper.Set("connection.cert", c.String("cert"))
+		}
+		if c.GlobalIsSet("key") {
+			viper.Set("connection.key", c.String("key"))
+		}
+		if c.GlobalIsSet("accesstokens") {
+			viper.Set("connection.access_tokens", c.String("accesstokens"))
+		}
+		if c.GlobalIsSet("insecure") {
+			viper.Set("connection.insecure", c.Bool("insecure"))
+		}
+
+		if err := DJ.Connect(); err != nil {
+			logrus.WithFields(logrus.Fields{
+				"error": err.Error(),
+			}).Fatalln("An error occurred while connecting to the server.")
+		}
+
+		if viper.GetString("defaults.channel") != "" {
+			defaultChannel := strings.Split(viper.GetString("defaults.channel"), "/")
+			DJ.Client.Do(func() {
+				DJ.Client.Self.Move(DJ.Client.Channels.Find(defaultChannel...))
+			})
+		}
+
+		DJ.Client.Do(func() {
+			DJ.Client.Self.SetComment(viper.GetString("defaults.comment"))
+		})
+		<-DJ.KeepAlive
+
+		return nil
+	}
+
+	app.Run(os.Args)
+}
+
+func createConfigWhenNotExists() {
+	configFile, err := Asset("config.yaml")
+	if err != nil {
+		logrus.Warnln("An error occurred while accessing config binary data. A new config file will not be written.")
 	} else {
-		panic(err)
+		filePath := os.ExpandEnv("$HOME/.config/mumbledj/config.yaml")
+		os.MkdirAll(os.ExpandEnv("$HOME/.config/mumbledj"), 0777)
+		writeErr := ioutil.WriteFile(filePath, configFile, 0644)
+		if writeErr == nil {
+			logrus.WithFields(logrus.Fields{
+				"file_path": filePath,
+			}).Infoln("A default configuration file has been written.")
+		} else {
+			logrus.WithFields(logrus.Fields{
+				"error": writeErr.Error(),
+			}).Warnln("An error occurred while writing a new config file.")
+		}
 	}
 }
 
-// dj variable declaration. This is done outside of main() to allow global use.
-var dj = mumbledj{
-	keepAlive: make(chan bool),
-	queue:     NewSongQueue(),
-}
+func createNewConfigIfNeeded() {
+	newConfigPath := os.ExpandEnv("$HOME/.config/mumbledj/config.yaml.new")
 
-// Main function, but only really performs startup tasks. Grabs and parses commandline
-// args, sets up the gumble client and its listeners, and then connects to the server.
-func main() {
-	var address, port, username, password, channel string
-
-	flag.StringVar(&address, "server", "localhost", "address for Mumble server")
-	flag.StringVar(&port, "port", "64738", "port for Mumble server")
-	flag.StringVar(&username, "username", "MumbleDJ", "username of MumbleDJ on server")
-	flag.StringVar(&password, "password", "", "password for Mumble server (if needed)")
-	flag.StringVar(&channel, "channel", "root", "default channel for MumbleDJ")
-	flag.Parse()
-
-	dj.client = gumble.NewClient(&dj.config)
-	dj.config = gumble.Config{
-		Username: username,
-		Password: password,
-		Address:  address + ":" + port,
+	// Check if we should write an updated config file to config.yaml.new.
+	if assetInfo, err := AssetInfo("config.yaml"); err == nil {
+		asset, _ := Asset("config.yaml")
+		if configFile, err := os.Open(os.ExpandEnv("$HOME/.config/mumbledj/config.yaml")); err == nil {
+			configInfo, _ := configFile.Stat()
+			defer configFile.Close()
+			if configNewFile, err := os.Open(newConfigPath); err == nil {
+				defer configNewFile.Close()
+				configNewInfo, _ := configNewFile.Stat()
+				if assetInfo.ModTime().Unix() > configNewInfo.ModTime().Unix() {
+					// The config asset is newer than the config.yaml.new file.
+					// Write a new config.yaml.new file.
+					ioutil.WriteFile(os.ExpandEnv(newConfigPath), asset, 0644)
+					logrus.WithFields(logrus.Fields{
+						"file_path": newConfigPath,
+					}).Infoln("An updated default configuration file has been written.")
+				}
+			} else if assetInfo.ModTime().Unix() > configInfo.ModTime().Unix() {
+				// The config asset is newer than the existing config file.
+				// Write a config.yaml.new file.
+				ioutil.WriteFile(os.ExpandEnv(newConfigPath), asset, 0644)
+				logrus.WithFields(logrus.Fields{
+					"file_path": newConfigPath,
+				}).Infoln("An updated default configuration file has been written.")
+			}
+		}
 	}
-	dj.defaultChannel = channel
-
-	dj.client.Attach(gumbleutil.Listener{
-		Connect:     dj.OnConnect,
-		Disconnect:  dj.OnDisconnect,
-		TextMessage: dj.OnTextMessage,
-	})
-
-	// IMPORTANT NOTE: This will be changed later once released. Not really safe at the
-	// moment.
-	dj.config.TLSConfig.InsecureSkipVerify = true
-	if err := dj.client.Connect(); err != nil {
-		panic(err)
-	}
-
-	<-dj.keepAlive
 }

mumbledj.gcfg

@@ -1,100 +0,0 @@
-# MumbleDJ
-# By Matthieu Grieger
-# config.toml
-# Copyright (c) 2014 Matthieu Grieger (MIT License)
-
-[General]
-
-# Command prefix
-# DEFAULT VALUE: "!"
-CommandPrefix = "!"
-
-# Ratio that must be met or exceeded to trigger a song skip
-# DEFAULT VALUE: 0.5
-SkipRatio = 0.5
-
-
-[Volume]
-
-# Default volume
-# DEFAULT VALUE: 0.2
-DefaultVolume = 0.2
-
-# Lowest volume allowed
-# DEFAULT VALUE: 0.01
-LowestVolume = 0.01
-
-# Highest volume allowed
-# DEFAULT VALUE: 0.8
-HighestVolume = 0.8
-
- 
-[Aliases]
-
-# Alias used for add command
-# DEFAULT VALUE: "add"
-AddAlias = "add"
-
-# Alias used for skip command
-# DEFAULT VALUE: "skip"
-SkipAlias = "skip"
-
-# Alias used for admin skip command
-# DEFAULT VALUE: "forceskip"
-AdminSkipAlias = "forceskip"
-
-# Alias used for volume command
-# DEFAULT VALUE: "volume"
-VolumeAlias = "volume"
-
-# Alias used for move command
-# DEFAULT VALUE: "move"
-MoveAlias = "move"
-
-# Alias used for reload command
-# DEFAULT VALUE: "reload"
-ReloadAlias = "reload"
-
-# Alias used for kill command
-# DEFAULT VALUE: "kill"
-KillAlias = "kill"
-
-
-[Permissions]
-
-# Enable admins
-# DEFAULT VALUE: true
-AdminsEnabled = true
-
-# List of admins
-# NOTE: I recommend only giving users admin privileges if they are registered
-# on the server. Otherwise people can just take their username and issue admin
-# commands.
-# SYNTAX: In order to specify multiple admins, repeat the Admins="username"
-# line of code. Each line has one username, and an unlimited amount of usernames may
-# be entered in this matter.
-Admins = "Matt"
-
-# Make add an admin command?
-# DEFAULT VALUE: false
-AdminAdd = false
-
-# Make skip an admin command?
-# DEFAULT VALUE: false
-AdminSkip = false
-
-# Make volume an admin command?
-# DEFAULT VALUE: false
-AdminVolume = false
-
-# Make move an admin command?
-# DEFAULT VALUE: true
-AdminMove = true
-
-# Make reload an admin command?
-# DEFAULT VALUE: true
-AdminReload = true
-
-# Make kill an admin command?
-# DEFAULT VALUE: true (I recommend never changing this to false)
-AdminKill = true

parseconfig.go

@@ -1,55 +0,0 @@
-/*
- * MumbleDJ
- * By Matthieu Grieger
- * parseconfig.go
- * Copyright (c) 2014 Matthieu Grieger (MIT License)
- */
-
-package main
-
-import (
-	"code.google.com/p/gcfg"
-	"errors"
-	"fmt"
-)
-
-// Golang struct representation of mumbledj.gcfg file structure for parsing.
-type DjConfig struct {
-	General struct {
-		CommandPrefix string
-		SkipRatio     float32
-	}
-	Volume struct {
-		DefaultVolume float32
-		LowestVolume  float32
-		HighestVolume float32
-	}
-	Aliases struct {
-		AddAlias       string
-		SkipAlias      string
-		AdminSkipAlias string
-		VolumeAlias    string
-		MoveAlias      string
-		ReloadAlias    string
-		KillAlias      string
-	}
-	Permissions struct {
-		AdminsEnabled bool
-		Admins        []string
-		AdminAdd      bool
-		AdminSkip     bool
-		AdminVolume   bool
-		AdminMove     bool
-		AdminReload   bool
-		AdminKill     bool
-	}
-}
-
-// Loads mumbledj.gcfg into dj.conf, a variable of type DjConfig.
-func loadConfiguration() error {
-	if gcfg.ReadFileInto(&dj.conf, fmt.Sprintf("%s/.mumbledj/config/mumbledj.gcfg", dj.homeDir)) == nil {
-		return nil
-	} else {
-		return errors.New("Configuration load failed.")
-	}
-}

queue.go

@@ -1,117 +0,0 @@
-//
-//  queue.go
-//
-//  Created by Hicham Bouabdallah
-//  Copyright (c) 2012 SimpleRocket LLC
-//
-//  Permission is hereby granted, free of charge, to any person
-//  obtaining a copy of this software and associated documentation
-//  files (the "Software"), to deal in the Software without
-//  restriction, including without limitation the rights to use,
-//  copy, modify, merge, publish, distribute, sublicense, and/or sell
-//  copies of the Software, and to permit persons to whom the
-//  Software is furnished to do so, subject to the following
-//  conditions:
-//
-//  The above copyright notice and this permission notice shall be
-//  included in all copies or substantial portions of the Software.
-//
-//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
-//  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
-//  OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
-//  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
-//  HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
-//  WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
-//  FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
-//  OTHER DEALINGS IN THE SOFTWARE.
-//
-
-package main
-
-import "sync"
-
-type queuenode struct {
-	data interface{}
-	next *queuenode
-}
-
-//	A go-routine safe FIFO (first in first out) data stucture.
-type Queue struct {
-	head  *queuenode
-	tail  *queuenode
-	count int
-	lock  *sync.Mutex
-}
-
-//	Creates a new pointer to a new queue.
-func NewQueue() *Queue {
-	q := &Queue{}
-	q.lock = &sync.Mutex{}
-	return q
-}
-
-//	Returns the number of elements in the queue (i.e. size/length)
-//	go-routine safe.
-func (q *Queue) Len() int {
-	q.lock.Lock()
-	defer q.lock.Unlock()
-	return q.count
-}
-
-//	Pushes/inserts a value at the end/tail of the queue.
-//	Note: this function does mutate the queue.
-//	go-routine safe.
-func (q *Queue) Push(item interface{}) {
-	q.lock.Lock()
-	defer q.lock.Unlock()
-
-	n := &queuenode{data: item}
-
-	if q.tail == nil {
-		q.tail = n
-		q.head = n
-	} else {
-		q.tail.next = n
-		q.tail = n
-	}
-	q.count++
-}
-
-//	Returns the value at the front of the queue.
-//	i.e. the oldest value in the queue.
-//	Note: this function does mutate the queue.
-//	go-routine safe.
-func (q *Queue) Poll() interface{} {
-	q.lock.Lock()
-	defer q.lock.Unlock()
-
-	if q.head == nil {
-		return nil
-	}
-
-	n := q.head
-	q.head = n.next
-
-	if q.head == nil {
-		q.tail = nil
-	}
-	q.count--
-
-	return n.data
-}
-
-//	Returns a read value at the front of the queue.
-//	i.e. the oldest value in the queue.
-//	Note: this function does NOT mutate the queue.
-//	go-routine safe.
-func (q *Queue) Peek() interface{} {
-	q.lock.Lock()
-	defer q.lock.Unlock()
-
-	n := q.head
-	if n == nil || n.data == nil {
-		return nil
-	}
-
-	return n.data
-}

raspberry.Dockerfile

@@ -0,0 +1,20 @@
+FROM hypriot/rpi-alpine-scratch:v3.3
+
+ENV GOPATH=/
+
+RUN echo "https://dl-cdn.alpinelinux.org/alpine/v3.3/community" >> /etc/apk/repositories
+RUN apk add --update ca-certificates go ffmpeg make build-base opus-dev python aria2
+RUN apk upgrade
+
+RUN wget https://yt-dl.org/downloads/latest/youtube-dl -O /bin/youtube-dl && chmod a+x /bin/youtube-dl
+
+COPY . /src/github.com/matthieugrieger/mumbledj
+COPY config.yaml /root/.config/mumbledj/config.yaml
+
+WORKDIR /src/github.com/matthieugrieger/mumbledj
+
+RUN make
+RUN make install
+RUN apk del go make build-base && rm -rf /var/cache/apk/*
+
+ENTRYPOINT ["/usr/local/bin/mumbledj"]

services/generic_service.go

@@ -0,0 +1,88 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * services/generic_service.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package services
+
+import (
+	"errors"
+	"regexp"
+)
+
+// GenericService is a generic struct that should be embedded
+// in other service structs, as it provides useful helper
+// methods and properties.
+type GenericService struct {
+	ReadableName  string
+	Format        string
+	TrackRegex    []*regexp.Regexp
+	PlaylistRegex []*regexp.Regexp
+}
+
+// GetReadableName returns the readable name for the service.
+func (gs *GenericService) GetReadableName() string {
+	return gs.ReadableName
+}
+
+// GetFormat returns the youtube-dl format for the service.
+func (gs *GenericService) GetFormat() string {
+	return gs.Format
+}
+
+// CheckURL matches the passed URL with a list of regex patterns
+// for valid URLs associated with this service. Returns true if a
+// match is found, false otherwise.
+func (gs *GenericService) CheckURL(url string) bool {
+	if gs.isTrack(url) || gs.isPlaylist(url) {
+		return true
+	}
+	return false
+}
+
+func (gs *GenericService) isTrack(url string) bool {
+	for _, regex := range gs.TrackRegex {
+		if regex.MatchString(url) {
+			return true
+		}
+	}
+	return false
+}
+
+func (gs *GenericService) isPlaylist(url string) bool {
+	for _, regex := range gs.PlaylistRegex {
+		if regex.MatchString(url) {
+			return true
+		}
+	}
+	return false
+}
+
+func (gs *GenericService) getID(url string) (string, error) {
+	var allRegex []*regexp.Regexp
+
+	if gs.PlaylistRegex != nil {
+		allRegex = append(gs.TrackRegex, gs.PlaylistRegex...)
+	} else {
+		allRegex = gs.TrackRegex
+	}
+
+	for _, regex := range allRegex {
+		match := regex.FindStringSubmatch(url)
+		if match == nil {
+			// Move on to next regex, this one didn't match.
+			continue
+		}
+		result := make(map[string]string)
+		for i, name := range regex.SubexpNames() {
+			if i < len(match) {
+				result[name] = match[i]
+			}
+		}
+
+		return result["id"], nil
+	}
+	return "", errors.New("No match found for URL")
+}

services/mixcloud.go

@@ -0,0 +1,114 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * services/mixcloud.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package services
+
+import (
+	"fmt"
+	"net/http"
+	"regexp"
+	"strings"
+	"time"
+
+	"github.com/antonholmquist/jason"
+	"github.com/layeh/gumble/gumble"
+	"github.com/matthieugrieger/mumbledj/bot"
+	"github.com/matthieugrieger/mumbledj/interfaces"
+)
+
+// Mixcloud is a wrapper around the Mixcloud API.
+// https://www.mixcloud.com/developers/
+type Mixcloud struct {
+	*GenericService
+}
+
+// NewMixcloudService returns an initialized Mixcloud service object.
+func NewMixcloudService() *Mixcloud {
+	return &Mixcloud{
+		&GenericService{
+			ReadableName: "Mixcloud",
+			Format:       "m4a",
+			TrackRegex: []*regexp.Regexp{
+				regexp.MustCompile(`https?:\/\/(www\.)?mixcloud\.com\/([\w-]+)\/([\w-]+)(#t=\n\n?(:\n\n)*)?`),
+			},
+			// Playlists are currently unsupported by Mixcloud's API.
+			PlaylistRegex: nil,
+		},
+	}
+}
+
+// CheckAPIKey performs a test API call with the API key
+// provided in the configuration file to determine if the
+// service should be enabled.
+func (mc *Mixcloud) CheckAPIKey() error {
+	// Mixcloud (at the moment) does not require an API key,
+	// so we can just return nil.
+	return nil
+}
+
+// GetTracks uses the passed URL to find and return
+// tracks associated with the URL. An error is returned
+// if any error occurs during the API call.
+func (mc *Mixcloud) GetTracks(url string, submitter *gumble.User) ([]interfaces.Track, error) {
+	var (
+		apiURL string
+		err    error
+		resp   *http.Response
+		v      *jason.Object
+		tracks []interfaces.Track
+	)
+
+	apiURL = strings.Replace(url, "www", "api", 1)
+
+	// Track playback offset is not present in Mixcloud URLs,
+	// so we can safely assume that users will not request
+	// a playback offset in the URL.
+	offset, _ := time.ParseDuration("0s")
+
+	resp, err = http.Get(apiURL)
+	defer resp.Body.Close()
+	if err != nil {
+		return nil, err
+	}
+
+	v, err = jason.NewObjectFromReader(resp.Body)
+	if err != nil {
+		return nil, err
+	}
+
+	id, _ := v.GetString("slug")
+	trackURL, _ := v.GetString("url")
+	title, _ := v.GetString("name")
+	author, _ := v.GetString("user", "username")
+	authorURL, _ := v.GetString("user", "url")
+	durationSecs, _ := v.GetInt64("audio_length")
+	duration, _ := time.ParseDuration(fmt.Sprintf("%ds", durationSecs))
+	thumbnail, err := v.GetString("pictures", "large")
+	if err != nil {
+		// Track has no artwork, using profile avatar instead.
+		thumbnail, _ = v.GetString("user", "pictures", "large")
+	}
+
+	track := bot.Track{
+		ID:             id,
+		URL:            trackURL,
+		Title:          title,
+		Author:         author,
+		AuthorURL:      authorURL,
+		Submitter:      submitter.Name,
+		Service:        mc.ReadableName,
+		ThumbnailURL:   thumbnail,
+		Filename:       id + ".track",
+		Duration:       duration,
+		PlaybackOffset: offset,
+		Playlist:       nil,
+	}
+
+	tracks = append(tracks, track)
+
+	return tracks, nil
+}

services/pkg_init.go

@@ -0,0 +1,27 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * services/pkg_init.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package services
+
+import (
+	"github.com/matthieugrieger/mumbledj/bot"
+	"github.com/matthieugrieger/mumbledj/interfaces"
+)
+
+// DJ is an injected MumbleDJ struct.
+var DJ *bot.MumbleDJ
+
+// Services is a slice of enabled MumbleDJ services.
+var Services []interfaces.Service
+
+func init() {
+	Services = []interfaces.Service{
+		NewMixcloudService(),
+		NewSoundCloudService(),
+		NewYouTubeService(),
+	}
+}

services/soundcloud.go

@@ -0,0 +1,192 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * services/soundcloud.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package services
+
+import (
+	"errors"
+	"fmt"
+	"net/http"
+	"regexp"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/antonholmquist/jason"
+	"github.com/layeh/gumble/gumble"
+	"github.com/matthieugrieger/mumbledj/bot"
+	"github.com/matthieugrieger/mumbledj/interfaces"
+	"github.com/spf13/viper"
+)
+
+// SoundCloud is a wrapper around the SoundCloud API.
+// https://developers.soundcloud.com/docs/api/reference
+type SoundCloud struct {
+	*GenericService
+}
+
+// NewSoundCloudService returns an initialized SoundCloud service object.
+func NewSoundCloudService() *SoundCloud {
+	return &SoundCloud{
+		&GenericService{
+			ReadableName: "SoundCloud",
+			Format:       "bestaudio",
+			TrackRegex: []*regexp.Regexp{
+				regexp.MustCompile(`https?:\/\/(www\.)?soundcloud\.com\/([\w-]+)\/([\w-]+)(#t=\n\n?(:\n\n)*)?`),
+			},
+			PlaylistRegex: []*regexp.Regexp{
+				regexp.MustCompile(`https?:\/\/(www\.)?soundcloud\.com\/([\w-]+)\/sets\/([\w-]+)`),
+			},
+		},
+	}
+}
+
+// CheckAPIKey performs a test API call with the API key
+// provided in the configuration file to determine if the
+// service should be enabled.
+func (sc *SoundCloud) CheckAPIKey() error {
+	if viper.GetString("api_keys.soundcloud") == "" {
+		return errors.New("No SoundCloud API key has been provided")
+	}
+	url := "http://api.soundcloud.com/tracks/13158665?client_id=%s"
+	response, err := http.Get(fmt.Sprintf(url, viper.GetString("api_keys.soundcloud")))
+	defer response.Body.Close()
+	if err != nil {
+		return err
+	}
+	if response.StatusCode != 200 {
+		return errors.New(response.Status)
+	}
+	return nil
+}
+
+// GetTracks uses the passed URL to find and return
+// tracks associated with the URL. An error is returned
+// if any error occurs during the API call.
+func (sc *SoundCloud) GetTracks(url string, submitter *gumble.User) ([]interfaces.Track, error) {
+	var (
+		apiURL string
+		err    error
+		resp   *http.Response
+		v      *jason.Object
+		track  bot.Track
+		tracks []interfaces.Track
+	)
+
+	urlSplit := strings.Split(url, "#t=")
+
+	apiURL = "http://api.soundcloud.com/resolve?url=%s&client_id=%s"
+
+	if sc.isPlaylist(url) {
+		// Submitter has added a playlist!
+		resp, err = http.Get(fmt.Sprintf(apiURL, urlSplit[0], viper.GetString("api_keys.soundcloud")))
+		defer resp.Body.Close()
+		if err != nil {
+			return nil, err
+		}
+
+		v, err = jason.NewObjectFromReader(resp.Body)
+		if err != nil {
+			return nil, err
+		}
+
+		title, _ := v.GetString("title")
+		permalink, _ := v.GetString("permalink_url")
+		playlist := &bot.Playlist{
+			ID:        permalink,
+			Title:     title,
+			Submitter: submitter.Name,
+			Service:   sc.ReadableName,
+		}
+
+		var scTracks []*jason.Object
+		scTracks, err = v.GetObjectArray("tracks")
+		if err != nil {
+			return nil, err
+		}
+
+		dummyOffset, _ := time.ParseDuration("0s")
+		for _, t := range scTracks {
+			track, err = sc.getTrack(t, dummyOffset, submitter)
+			if err != nil {
+				// Skip this track.
+				continue
+			}
+			track.Playlist = playlist
+			tracks = append(tracks, track)
+		}
+
+		if len(tracks) == 0 {
+			return nil, errors.New("Invalid playlist. No tracks were added")
+		}
+		return tracks, nil
+	}
+
+	// Submitter has added a track!
+
+	offset := 0
+	// Calculate track offset if needed
+	if len(urlSplit) == 2 {
+		timeSplit := strings.Split(urlSplit[1], ":")
+		multiplier := 1
+		for i := len(timeSplit) - 1; i >= 0; i-- {
+			time, _ := strconv.Atoi(timeSplit[i])
+			offset += time * multiplier
+			multiplier *= 60
+		}
+	}
+	playbackOffset, _ := time.ParseDuration(fmt.Sprintf("%ds", offset))
+
+	resp, err = http.Get(fmt.Sprintf(apiURL, urlSplit[0], viper.GetString("api_keys.soundcloud")))
+	defer resp.Body.Close()
+	if err != nil {
+		return nil, err
+	}
+
+	v, err = jason.NewObjectFromReader(resp.Body)
+	if err != nil {
+		return nil, err
+	}
+	track, err = sc.getTrack(v, playbackOffset, submitter)
+	if err != nil {
+		return nil, err
+	}
+
+	tracks = append(tracks, track)
+	return tracks, nil
+}
+
+func (sc *SoundCloud) getTrack(obj *jason.Object, offset time.Duration, submitter *gumble.User) (bot.Track, error) {
+	title, _ := obj.GetString("title")
+	idInt, _ := obj.GetInt64("id")
+	id := strconv.FormatInt(idInt, 10)
+	url, _ := obj.GetString("permalink_url")
+	author, _ := obj.GetString("user", "username")
+	authorURL, _ := obj.GetString("user", "permalink_url")
+	durationMS, _ := obj.GetInt64("duration")
+	duration, _ := time.ParseDuration(fmt.Sprintf("%dms", durationMS))
+	thumbnail, err := obj.GetString("artwork_url")
+	if err != nil {
+		// Track has no artwork, using profile avatar instead.
+		thumbnail, _ = obj.GetString("user", "avatar_url")
+	}
+
+	return bot.Track{
+		ID:             id,
+		URL:            url,
+		Title:          title,
+		Author:         author,
+		AuthorURL:      authorURL,
+		Submitter:      submitter.Name,
+		Service:        sc.ReadableName,
+		Filename:       id + ".track",
+		ThumbnailURL:   thumbnail,
+		Duration:       duration,
+		PlaybackOffset: offset,
+		Playlist:       nil,
+	}, nil
+}

services/youtube.go

@@ -0,0 +1,247 @@
+/*
+ * MumbleDJ
+ * By Matthieu Grieger
+ * services/youtube.go
+ * Copyright (c) 2016 Matthieu Grieger (MIT License)
+ */
+
+package services
+
+import (
+	"errors"
+	"fmt"
+	"math"
+	"net/http"
+	"regexp"
+	"strings"
+	"time"
+
+	"github.com/ChannelMeter/iso8601duration"
+	"github.com/antonholmquist/jason"
+	"github.com/layeh/gumble/gumble"
+	"github.com/matthieugrieger/mumbledj/bot"
+	"github.com/matthieugrieger/mumbledj/interfaces"
+	"github.com/spf13/viper"
+)
+
+// YouTube is a wrapper around the YouTube Data API.
+// https://developers.google.com/youtube/v3/docs/
+type YouTube struct {
+	*GenericService
+}
+
+// NewYouTubeService returns an initialized YouTube service object.
+func NewYouTubeService() *YouTube {
+	return &YouTube{
+		&GenericService{
+			ReadableName: "YouTube",
+			Format:       "bestaudio",
+			TrackRegex: []*regexp.Regexp{
+				regexp.MustCompile(`https?:\/\/www.youtube.com\/watch\?v=(?P<id>[\w-]+)(?P<timestamp>\&t=\d*m?\d*s?)?`),
+				regexp.MustCompile(`https?:\/\/youtube.com\/watch\?v=(?P<id>[\w-]+)(?P<timestamp>\&t=\d*m?\d*s?)?`),
+				regexp.MustCompile(`https?:\/\/youtu.be\/(?P<id>[\w-]+)(?P<timestamp>\?t=\d*m?\d*s?)?`),
+				regexp.MustCompile(`https?:\/\/youtube.com\/v\/(?P<id>[\w-]+)(?P<timestamp>\?t=\d*m?\d*s?)?`),
+				regexp.MustCompile(`https?:\/\/www.youtube.com\/v\/(?P<id>[\w-]+)(?P<timestamp>\?t=\d*m?\d*s?)?`),
+			},
+			PlaylistRegex: []*regexp.Regexp{
+				regexp.MustCompile(`https?:\/\/www\.youtube\.com\/playlist\?list=(?P<id>[\w-]+)`),
+			},
+		},
+	}
+}
+
+// CheckAPIKey performs a test API call with the API key
+// provided in the configuration file to determine if the
+// service should be enabled.
+func (yt *YouTube) CheckAPIKey() error {
+	var (
+		response *http.Response
+		v        *jason.Object
+		err      error
+	)
+
+	if viper.GetString("api_keys.youtube") == "" {
+		return errors.New("No YouTube API key has been provided")
+	}
+	url := "https://www.googleapis.com/youtube/v3/videos?part=snippet&id=KQY9zrjPBjo&key=%s"
+	response, err = http.Get(fmt.Sprintf(url, viper.GetString("api_keys.youtube")))
+	defer response.Body.Close()
+	if err != nil {
+		return err
+	}
+
+	if v, err = jason.NewObjectFromReader(response.Body); err != nil {
+		return err
+	}
+
+	if v, err = v.GetObject("error"); err == nil {
+		message, _ := v.GetString("message")
+		code, _ := v.GetInt64("code")
+		errArray, _ := v.GetObjectArray("errors")
+		reason, _ := errArray[0].GetString("reason")
+
+		return fmt.Errorf("%d: %s (reason: %s)", code, message, reason)
+	}
+	return nil
+}
+
+// GetTracks uses the passed URL to find and return
+// tracks associated with the URL. An error is returned
+// if any error occurs during the API call.
+func (yt *YouTube) GetTracks(url string, submitter *gumble.User) ([]interfaces.Track, error) {
+	var (
+		playlistURL      string
+		playlistItemsURL string
+		id               string
+		err              error
+		resp             *http.Response
+		v                *jason.Object
+		track            bot.Track
+		tracks           []interfaces.Track
+	)
+
+	dummyOffset, _ := time.ParseDuration("0s")
+	urlSplit := strings.Split(url, "?t=")
+
+	playlistURL = "https://www.googleapis.com/youtube/v3/playlists?part=snippet&id=%s&key=%s"
+	playlistItemsURL = "https://www.googleapis.com/youtube/v3/playlistItems?part=snippet,contentDetails&playlistId=%s&maxResults=%d&key=%s&pageToken=%s"
+	id, err = yt.getID(urlSplit[0])
+	if err != nil {
+		return nil, err
+	}
+
+	if yt.isPlaylist(url) {
+		resp, err = http.Get(fmt.Sprintf(playlistURL, id, viper.GetString("api_keys.youtube")))
+		defer resp.Body.Close()
+		if err != nil {
+			return nil, err
+		}
+
+		v, err = jason.NewObjectFromReader(resp.Body)
+		if err != nil {
+			return nil, err
+		}
+
+		items, _ := v.GetObjectArray("items")
+		item := items[0]
+
+		title, _ := item.GetString("snippet", "title")
+
+		playlist := &bot.Playlist{
+			ID:        id,
+			Title:     title,
+			Submitter: submitter.Name,
+			Service:   yt.ReadableName,
+		}
+
+		maxItems := math.MaxInt32
+		if viper.GetInt("queue.max_tracks_per_playlist") > 0 {
+			maxItems = viper.GetInt("queue.max_tracks_per_playlist")
+		}
+
+		// YouTube playlist searches return a max of 50 results per page
+		maxResults := 50
+		if maxResults > maxItems {
+			maxResults = maxItems
+		}
+
+		pageToken := ""
+		for len(tracks) < maxItems {
+			curResp, curErr := http.Get(fmt.Sprintf(playlistItemsURL, id, maxResults, viper.GetString("api_keys.youtube"), pageToken))
+			defer curResp.Body.Close()
+			if curErr != nil {
+				// An error occurred, simply skip this track.
+				continue
+			}
+
+			v, err = jason.NewObjectFromReader(curResp.Body)
+			if err != nil {
+				// An error occurred, simply skip this track.
+				continue
+			}
+
+			curTracks, _ := v.GetObjectArray("items")
+			for _, track := range curTracks {
+				videoID, _ := track.GetString("snippet", "resourceId", "videoId")
+
+				// Unfortunately we have to execute another API call for each video as the YouTube API does not
+				// return video durations from the playlistItems endpoint...
+				newTrack, _ := yt.getTrack(videoID, submitter, dummyOffset)
+				newTrack.Playlist = playlist
+				tracks = append(tracks, newTrack)
+
+				if len(tracks) >= maxItems {
+					break
+				}
+			}
+
+			pageToken, _ = v.GetString("nextPageToken")
+			if pageToken == "" {
+				break
+			}
+		}
+
+		if len(tracks) == 0 {
+			return nil, errors.New("Invalid playlist. No tracks were added")
+		}
+		return tracks, nil
+	}
+
+	// Submitter added a track!
+	offset := dummyOffset
+	if len(urlSplit) == 2 {
+		offset, _ = time.ParseDuration(urlSplit[1])
+	}
+
+	track, err = yt.getTrack(id, submitter, offset)
+	if err != nil {
+		return nil, err
+	}
+	tracks = append(tracks, track)
+	return tracks, nil
+}
+
+func (yt *YouTube) getTrack(id string, submitter *gumble.User, offset time.Duration) (bot.Track, error) {
+	var (
+		resp *http.Response
+		err  error
+		v    *jason.Object
+	)
+
+	videoURL := "https://www.googleapis.com/youtube/v3/videos?part=snippet,contentDetails&id=%s&key=%s"
+	resp, err = http.Get(fmt.Sprintf(videoURL, id, viper.GetString("api_keys.youtube")))
+	defer resp.Body.Close()
+	if err != nil {
+		return bot.Track{}, err
+	}
+
+	v, err = jason.NewObjectFromReader(resp.Body)
+	if err != nil {
+		return bot.Track{}, err
+	}
+	items, _ := v.GetObjectArray("items")
+	if len(items) == 0 {
+		return bot.Track{}, errors.New("This YouTube video is private")
+	}
+	item := items[0]
+	title, _ := item.GetString("snippet", "title")
+	thumbnail, _ := item.GetString("snippet", "thumbnails", "high", "url")
+	author, _ := item.GetString("snippet", "channelTitle")
+	durationString, _ := item.GetString("contentDetails", "duration")
+	durationConverted, _ := duration.FromString(durationString)
+	duration := durationConverted.ToDuration()
+
+	return bot.Track{
+		ID:             id,
+		URL:            "https://youtube.com/watch?v=" + id,
+		Title:          title,
+		Author:         author,
+		Submitter:      submitter.Name,
+		Service:        yt.ReadableName,
+		Filename:       id + ".track",
+		ThumbnailURL:   thumbnail,
+		Duration:       duration,
+		PlaybackOffset: offset,
+		Playlist:       nil,
+	}, nil
+}