/*
 * MumbleDJ
 * By Matthieu Grieger
 * commands.go
 * Copyright (c) 2014, 2015 Matthieu Grieger (MIT License)
 */

package main

import (
	"errors"
	"fmt"
	"os"
	"regexp"
	"strconv"
	"strings"

	"github.com/layeh/gumble/gumble"
)

// 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
	split := strings.Split(command, "\n")
	splitString := split[0]
	if strings.Contains(splitString, " ") {
		index := strings.Index(splitString, " ")
		com, argument = splitString[0:index], splitString[(index+1):]
	} else {
		com = command
		argument = ""
	}

	switch com {
	// Add command
	case dj.conf.Aliases.AddAlias:
		if dj.HasPermission(username, dj.conf.Permissions.AdminAdd) {
			add(user, username, argument)
		} else {
			dj.SendPrivateMessage(user, NO_PERMISSION_MSG)
		}
	// Skip command
	case dj.conf.Aliases.SkipAlias:
		if dj.HasPermission(username, dj.conf.Permissions.AdminSkip) {
			skip(user, username, false, false)
		} else {
			dj.SendPrivateMessage(user, NO_PERMISSION_MSG)
		}
	// Skip playlist command
	case dj.conf.Aliases.SkipPlaylistAlias:
		if dj.HasPermission(username, dj.conf.Permissions.AdminAddPlaylists) {
			skip(user, username, false, true)
		} else {
			dj.SendPrivateMessage(user, NO_PERMISSION_MSG)
		}
	// Forceskip command
	case dj.conf.Aliases.AdminSkipAlias:
		if dj.HasPermission(username, true) {
			skip(user, username, true, false)
		} else {
			dj.SendPrivateMessage(user, NO_PERMISSION_MSG)
		}
	// Playlist forceskip command
	case dj.conf.Aliases.AdminSkipPlaylistAlias:
		if dj.HasPermission(username, true) {
			skip(user, username, true, true)
		} else {
			dj.SendPrivateMessage(user, NO_PERMISSION_MSG)
		}
	// Help command
	case dj.conf.Aliases.HelpAlias:
		if dj.HasPermission(username, dj.conf.Permissions.AdminHelp) {
			help(user)
		} else {
			dj.SendPrivateMessage(user, NO_PERMISSION_MSG)
		}
	// Volume command
	case dj.conf.Aliases.VolumeAlias:
		if dj.HasPermission(username, dj.conf.Permissions.AdminVolume) {
			volume(user, username, argument)
		} else {
			dj.SendPrivateMessage(user, NO_PERMISSION_MSG)
		}
	// Move command
	case dj.conf.Aliases.MoveAlias:
		if dj.HasPermission(username, dj.conf.Permissions.AdminMove) {
			move(user, argument)
		} else {
			dj.SendPrivateMessage(user, NO_PERMISSION_MSG)
		}
	// Reload command
	case dj.conf.Aliases.ReloadAlias:
		if dj.HasPermission(username, dj.conf.Permissions.AdminReload) {
			reload(user)
		} else {
			dj.SendPrivateMessage(user, NO_PERMISSION_MSG)
		}
	// Reset command
	case dj.conf.Aliases.ResetAlias:
		if dj.HasPermission(username, dj.conf.Permissions.AdminReset) {
			reset(username)
		} else {
			dj.SendPrivateMessage(user, NO_PERMISSION_MSG)
		}
	// Numsongs command
	case dj.conf.Aliases.NumSongsAlias:
		if dj.HasPermission(username, dj.conf.Permissions.AdminNumSongs) {
			numSongs()
		} else {
			dj.SendPrivateMessage(user, NO_PERMISSION_MSG)
		}
	// Nextsong command
	case dj.conf.Aliases.NextSongAlias:
		if dj.HasPermission(username, dj.conf.Permissions.AdminNextSong) {
			nextSong(user)
		} else {
			dj.SendPrivateMessage(user, NO_PERMISSION_MSG)
		}
	// Currentsong command
	case dj.conf.Aliases.CurrentSongAlias:
		if dj.HasPermission(username, dj.conf.Permissions.AdminCurrentSong) {
			currentSong(user)
		} else {
			dj.SendPrivateMessage(user, NO_PERMISSION_MSG)
		}
	// Setcomment command
	case dj.conf.Aliases.SetCommentAlias:
		if dj.HasPermission(username, dj.conf.Permissions.AdminSetComment) {
			setComment(user, argument)
		} else {
			dj.SendPrivateMessage(user, NO_PERMISSION_MSG)
		}
	// Numcached command
	case dj.conf.Aliases.NumCachedAlias:
		if dj.HasPermission(username, dj.conf.Permissions.AdminNumCached) {
			numCached(user)
		} else {
			dj.SendPrivateMessage(user, NO_PERMISSION_MSG)
		}
	// Cachesize command
	case dj.conf.Aliases.CacheSizeAlias:
		if dj.HasPermission(username, dj.conf.Permissions.AdminCacheSize) {
			cacheSize(user)
		} else {
			dj.SendPrivateMessage(user, NO_PERMISSION_MSG)
		}
	// Kill command
	case dj.conf.Aliases.KillAlias:
		if dj.HasPermission(username, dj.conf.Permissions.AdminKill) {
			kill()
		} else {
			dj.SendPrivateMessage(user, NO_PERMISSION_MSG)
		}
	default:
		dj.SendPrivateMessage(user, 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 *gumble.User, username, url string) {
	if url == "" {
		dj.SendPrivateMessage(user, NO_ARGUMENT_MSG)
	} else {
		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 {
			if newSong, err := NewYouTubeSong(username, shortUrl, nil); err == nil {
				dj.client.Self.Channel.Send(fmt.Sprintf(SONG_ADDED_HTML, username, newSong.title), false)
				if dj.queue.Len() == 1 && !dj.audioStream.IsPlaying() {
					if err := dj.queue.CurrentSong().Download(); err == nil {
						dj.queue.CurrentSong().Play()
					} else {
						dj.SendPrivateMessage(user, AUDIO_FAIL_MSG)
						dj.queue.CurrentSong().Delete()
						dj.queue.OnSongFinished()
					}
				}
			} else if fmt.Sprint(err) == "video exceeds the maximum allowed duration." {
				dj.SendPrivateMessage(user, VIDEO_TOO_LONG_MSG)
			} else {
				dj.SendPrivateMessage(user, INVALID_YOUTUBE_ID_MSG)
			}
		} else {
			// Check to see if we have a playlist URL instead.
			youtubePlaylistPattern := `https?:\/\/www\.youtube\.com\/playlist\?list=([\w-]+)`
			if re, err := regexp.Compile(youtubePlaylistPattern); err == nil {
				if re.MatchString(url) {
					if dj.HasPermission(username, dj.conf.Permissions.AdminAddPlaylists) {
						shortUrl = re.FindStringSubmatch(url)[1]
						oldLength := dj.queue.Len()
						if newPlaylist, err := NewYouTubePlaylist(username, shortUrl); err == nil {
							dj.client.Self.Channel.Send(fmt.Sprintf(PLAYLIST_ADDED_HTML, username, newPlaylist.title), false)
							if oldLength == 0 && dj.queue.Len() != 0 && !dj.audioStream.IsPlaying() {
								if err := dj.queue.CurrentSong().Download(); err == nil {
									dj.queue.CurrentSong().Play()
								} else {
									dj.SendPrivateMessage(user, AUDIO_FAIL_MSG)
									dj.queue.CurrentSong().Delete()
									dj.queue.OnSongFinished()
								}
							}
						} else {
							dj.SendPrivateMessage(user, INVALID_YOUTUBE_ID_MSG)
						}
					} else {
						dj.SendPrivateMessage(user, NO_PLAYLIST_PERMISSION_MSG)
					}
				} else {
					dj.SendPrivateMessage(user, INVALID_URL_MSG)
				}
			}
		}
	}
}

// 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 *gumble.User, username string, admin, playlistSkip bool) {
	if dj.audioStream.IsPlaying() {
		if playlistSkip {
			if dj.queue.CurrentSong().Playlist() != nil {
				if err := dj.queue.CurrentSong().Playlist().AddSkip(username); err == nil {
					submitterSkipped := false
					if admin {
						dj.client.Self.Channel.Send(ADMIN_PLAYLIST_SKIP_MSG, false)
					} else if dj.queue.CurrentSong().Submitter() == username {
						dj.client.Self.Channel.Send(fmt.Sprintf(PLAYLIST_SUBMITTER_SKIP_HTML, username), false)
						submitterSkipped = true
					} else {
						dj.client.Self.Channel.Send(fmt.Sprintf(PLAYLIST_SKIP_ADDED_HTML, username), false)
					}
					if submitterSkipped || dj.queue.CurrentSong().Playlist().SkipReached(len(dj.client.Self.Channel.Users)) || admin {
						id := dj.queue.CurrentSong().Playlist().ID()
						dj.queue.CurrentSong().Playlist().DeleteSkippers()
						for i := 0; i < len(dj.queue.queue); i++ {
							if dj.queue.queue[i].Playlist() != nil {
								if dj.queue.queue[i].Playlist().ID() == id {
									dj.queue.queue = append(dj.queue.queue[:i], dj.queue.queue[i+1:]...)
									i--
								}
							}
						}
						if dj.queue.Len() != 0 {
							// Set dontSkip to true to avoid audioStream.Stop() callback skipping the new first song.
							dj.queue.CurrentSong().SetDontSkip(true)
						}
						if !(submitterSkipped || admin) {
							dj.client.Self.Channel.Send(PLAYLIST_SKIPPED_HTML, false)
						}
						if err := dj.audioStream.Stop(); err != nil {
							panic(errors.New("An error occurred while stopping the current song."))
						}
					}
				}
			} else {
				dj.SendPrivateMessage(user, NO_PLAYLIST_PLAYING_MSG)
			}
		} else {
			if err := dj.queue.CurrentSong().AddSkip(username); err == nil {
				submitterSkipped := false
				if admin {
					dj.client.Self.Channel.Send(ADMIN_SONG_SKIP_MSG, false)
				} else if dj.queue.CurrentSong().Submitter() == username {
					dj.client.Self.Channel.Send(fmt.Sprintf(SUBMITTER_SKIP_HTML, username), false)
					submitterSkipped = true
				} else {
					dj.client.Self.Channel.Send(fmt.Sprintf(SKIP_ADDED_HTML, username), false)
				}
				if submitterSkipped || dj.queue.CurrentSong().SkipReached(len(dj.client.Self.Channel.Users)) || admin {
					if !(submitterSkipped || admin) {
						dj.client.Self.Channel.Send(SONG_SKIPPED_HTML, false)
					}
					if err := dj.audioStream.Stop(); err != nil {
						panic(errors.New("An error occurred while stopping the current song."))
					}
				}
			}
		}
	} else {
		dj.SendPrivateMessage(user, NO_MUSIC_PLAYING_MSG)
	}
}

// Performs help functionality. Displays a list of valid commands.
func help(user *gumble.User) {
	dj.SendPrivateMessage(user, HELP_HTML)
}

// 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 *gumble.User, username, value string) {
	if value == "" {
		dj.client.Self.Channel.Send(fmt.Sprintf(CUR_VOLUME_HTML, dj.audioStream.Volume), false)
	} else {
		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.Volume = newVolume
				dj.client.Self.Channel.Send(fmt.Sprintf(VOLUME_SUCCESS_HTML, username, dj.audioStream.Volume), false)
			} else {
				dj.SendPrivateMessage(user, fmt.Sprintf(NOT_IN_VOLUME_RANGE_MSG, dj.conf.Volume.LowestVolume, dj.conf.Volume.HighestVolume))
			}
		} else {
			dj.SendPrivateMessage(user, fmt.Sprintf(NOT_IN_VOLUME_RANGE_MSG, dj.conf.Volume.LowestVolume, dj.conf.Volume.HighestVolume))
		}
	}
}

// Performs move functionality. Determines if the supplied channel is valid and moves the bot
// to the channel if it is.
func move(user *gumble.User, channel string) {
	if channel == "" {
		dj.SendPrivateMessage(user, NO_ARGUMENT_MSG)
	} else {
		if dj.client.Channels.Find(channel) != nil {
			dj.client.Self.Move(dj.client.Channels.Find(channel))
		} else {
			dj.SendPrivateMessage(user, CHANNEL_DOES_NOT_EXIST_MSG)
		}
	}
}

// Performs reload functionality. Tells command submitter if the reload completed successfully.
func reload(user *gumble.User) {
	if err := loadConfiguration(); err == nil {
		dj.SendPrivateMessage(user, CONFIG_RELOAD_SUCCESS_MSG)
	}
}

// Performs reset functionality. Clears the song queue, stops playing audio, and deletes all
// remaining songs in the ~/.mumbledj/songs directory.
func reset(username string) {
	dj.queue.queue = dj.queue.queue[:0]
	if dj.audioStream.IsPlaying() {
		if err := dj.audioStream.Stop(); err != nil {
			panic(err)
		}
	}
	if err := deleteSongs(); err == nil {
		dj.client.Self.Channel.Send(fmt.Sprintf(QUEUE_RESET_HTML, username), false)
	} else {
		panic(err)
	}
}

// Performs numsongs functionality. Uses the SongQueue traversal function to traverse the
// queue with a function call that increments a counter. Once finished, the bot outputs
// the number of songs in the queue to chat.
func numSongs() {
	songCount := 0
	dj.queue.Traverse(func(i int, song Song) {
		songCount++
	})
	dj.client.Self.Channel.Send(fmt.Sprintf(NUM_SONGS_HTML, songCount), false)
}

// Performs nextsong functionality. Uses the SongQueue PeekNext function to peek at the next
// item if it exists. The user will then be sent a message containing the title and submitter
// of the next item if it exists.
func nextSong(user *gumble.User) {
	if song, err := dj.queue.PeekNext(); err != nil {
		dj.SendPrivateMessage(user, NO_SONG_NEXT_MSG)
	} else {
		dj.SendPrivateMessage(user, fmt.Sprintf(NEXT_SONG_HTML, song.Title(), song.Submitter()))
	}
}

// Performs currentsong functionality. Sends the user who submitted the currentsong command
// information about the song currently playing.
func currentSong(user *gumble.User) {
	if dj.audioStream.IsPlaying() {
		if dj.queue.CurrentSong().Playlist() == nil {
			dj.SendPrivateMessage(user, fmt.Sprintf(CURRENT_SONG_HTML, dj.queue.CurrentSong().Title(), dj.queue.CurrentSong().Submitter()))
		} else {
			dj.SendPrivateMessage(user, fmt.Sprintf(CURRENT_SONG_PLAYLIST_HTML, dj.queue.CurrentSong().Title(),
				dj.queue.CurrentSong().Submitter(), dj.queue.CurrentSong().Playlist().Title()))
		}
	} else {
		dj.SendPrivateMessage(user, NO_MUSIC_PLAYING_MSG)
	}
}

// Performs setcomment functionality. Sets the bot's comment to whatever text is supplied in the argument.
func setComment(user *gumble.User, comment string) {
	dj.client.Self.SetComment(comment)
	dj.SendPrivateMessage(user, COMMENT_UPDATED_MSG)
}

// Performs numcached functionality. Displays the number of songs currently cached on disk at ~/.mumbledj/songs.
func numCached(user *gumble.User) {
	if dj.conf.Cache.Enabled {
		dj.cache.Update()
		dj.SendPrivateMessage(user, fmt.Sprintf(NUM_CACHED_MSG, dj.cache.NumSongs))
	} else {
		dj.SendPrivateMessage(user, CACHE_NOT_ENABLED_MSG)
	}
}

// Performs cachesize functionality. Displays the total file size of the cached audio files.
func cacheSize(user *gumble.User) {
	if dj.conf.Cache.Enabled {
		dj.cache.Update()
		dj.SendPrivateMessage(user, fmt.Sprintf(CACHE_SIZE_MSG, float64(dj.cache.TotalFileSize/1048576)))
	} else {
		dj.SendPrivateMessage(user, CACHE_NOT_ENABLED_MSG)
	}
}

// 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() {
	if err := deleteSongs(); err != nil {
		panic(err)
	}
	if err := dj.client.Disconnect(); err == nil {
		fmt.Println("Kill successful. Goodbye!")
		os.Exit(0)
	} else {
		panic(errors.New("An error occurred while disconnecting from the server."))
	}
}

// Deletes songs from ~/.mumbledj/songs.
func deleteSongs() 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.")
		}
		return nil
	}
}