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mumbledj/songqueue.go

155 lines
3.9 KiB
Go

/*
* MumbleDJ
* By Matthieu Grieger
* songqueue.go
* Copyright (c) 2014, 2015 Matthieu Grieger (MIT License)
*/
package main
import (
"errors"
)
// QueueItem type declaration. QueueItem is an interface that groups together Song and Playlist
// types in a queue.
type QueueItem interface {
AddSkip(string) error
RemoveSkip(string) error
SkipReached(int) bool
ItemType() string
}
// SongQueue type declaration. Serves as a wrapper around the queue structure defined in queue.go.
type SongQueue struct {
queue []QueueItem
}
// Initializes a new queue and returns the new SongQueue.
func NewSongQueue() *SongQueue {
return &SongQueue{
queue: make([]QueueItem, 0),
}
}
// Adds an item to the SongQueue.
func (q *SongQueue) AddItem(i QueueItem) error {
beforeLen := q.Len()
q.queue = append(q.queue, i)
if len(q.queue) == beforeLen+1 {
return nil
} else {
return errors.New("Could not add QueueItem to the SongQueue.")
}
}
// Returns the current QueueItem.
func (q *SongQueue) CurrentItem() QueueItem {
return q.queue[0]
}
// Moves to the next item in SongQueue. NextItem() removes the first value in the queue.
func (q *SongQueue) NextItem() {
q.queue = q.queue[1:]
}
// Peeks at the next Song and returns it.
func (q *SongQueue) PeekNext() (*Song, error) {
if q.Len() != 0 {
if q.CurrentItem().ItemType() == "playlist" {
return q.CurrentItem().(*Playlist).songs.queue[1].(*Song), nil
} else if q.Len() > 1 {
if q.queue[1].ItemType() == "playlist" {
return q.queue[1].(*Playlist).songs.queue[0].(*Song), nil
} else {
return q.queue[1].(*Song), nil
}
} else {
return nil, errors.New("There is no song coming up next.")
}
} else {
return nil, errors.New("There are no items in the queue.")
}
}
// Returns the length of the SongQueue.
func (q *SongQueue) Len() int {
return len(q.queue)
}
// A traversal function for SongQueue. Allows a visit function to be passed in which performs
// the specified action on each queue item. Traverses all individual songs, and all songs
// within playlists.
func (q *SongQueue) Traverse(visit func(i int, item QueueItem)) {
for iQueue, queueItem := range q.queue {
if queueItem.ItemType() == "playlist" {
for iPlaylist, playlistItem := range q.queue[iQueue].(*Playlist).songs.queue {
visit(iPlaylist, playlistItem)
}
} else {
visit(iQueue, queueItem)
}
}
}
// OnItemFinished event. Deletes item that just finished playing, then queues the next item.
func (q *SongQueue) OnItemFinished() {
if q.Len() != 0 {
if q.CurrentItem().ItemType() == "playlist" {
if err := q.CurrentItem().(*Playlist).songs.CurrentItem().(*Song).Delete(); err == nil {
if q.CurrentItem().(*Playlist).skipped == true {
if q.Len() > 1 {
q.NextItem()
q.PrepareAndPlayNextItem()
} else {
q.queue = q.queue[:0]
}
} else if q.CurrentItem().(*Playlist).songs.Len() > 1 {
q.CurrentItem().(*Playlist).songs.NextItem()
q.PrepareAndPlayNextItem()
} else {
if q.Len() > 1 {
q.NextItem()
q.PrepareAndPlayNextItem()
} else {
q.queue = q.queue[:0]
}
}
} else {
panic(err)
}
} else {
if err := q.CurrentItem().(*Song).Delete(); err == nil {
if q.Len() > 1 {
q.NextItem()
q.PrepareAndPlayNextItem()
} else {
q.queue = q.queue[:0]
}
} else {
panic(err)
}
}
}
}
func (q *SongQueue) PrepareAndPlayNextItem() {
if q.Len() != 0 {
if q.CurrentItem().ItemType() == "playlist" {
if err := q.CurrentItem().(*Playlist).songs.CurrentItem().(*Song).Download(); err == nil {
q.CurrentItem().(*Playlist).songs.CurrentItem().(*Song).Play()
} else {
dj.client.Self.Channel.Send(AUDIO_FAIL_MSG, false)
q.OnItemFinished()
}
} else {
if err := q.CurrentItem().(*Song).Download(); err == nil {
q.CurrentItem().(*Song).Play()
} else {
dj.client.Self.Channel.Send(AUDIO_FAIL_MSG, false)
q.OnItemFinished()
}
}
}
}