Add playlists feature (#871)

* Open multi-file torrents as playlists

* Add `repeat` and `shuffle` options to the player

* Autoplay first file in torrent

* replaces `pickFileToPlay` feature
* when reopening player, restores the most recently viewed file

* Add playlist navigation buttons to Windows thumbar

* Remove `repeat` and `shuffle` options

This reverts commit 9284122461.

* Play files in order they appear in torrent

* Clean up playlists code

src/renderer/controllers/playback-controller.js

@@ -8,6 +8,7 @@ const errors = require('../lib/errors')
 const sound = require('../lib/sound')
 const TorrentPlayer = require('../lib/torrent-player')
 const TorrentSummary = require('../lib/torrent-summary')
+const Playlist = require('../lib/playlist')
 const State = require('../lib/state')
 
 const ipcRenderer = electron.ipcRenderer
@@ -24,18 +25,29 @@ module.exports = class PlaybackController {
   // Play a file in a torrent.
   // * Start torrenting, if necessary
   // * Stream, if not already fully downloaded
-  // * If no file index is provided, pick the default file to play
+  // * If no file index is provided, restore the most recently viewed file or autoplay the first
   playFile (infoHash, index /* optional */) {
-    this.state.location.go({
-      url: 'player',
-      setup: (cb) => {
-        this.play()
-        this.openPlayer(infoHash, index, cb)
-      },
-      destroy: () => this.closePlayer()
-    }, (err) => {
-      if (err) dispatch('error', err)
-    })
+    var state = this.state
+    if (state.location.url() === 'player') {
+      this.updatePlayer(infoHash, index, false, (err) => {
+        if (err) dispatch('error', err)
+        else this.play()
+      })
+    } else {
+      state.location.go({
+        url: 'player',
+        setup: (cb) => {
+          this.play()
+          this.openPlayer(infoHash, index, (err) => {
+            if (!err) this.play
+            cb(err)
+          })
+        },
+        destroy: () => this.closePlayer()
+      }, (err) => {
+        if (err) dispatch('error', err)
+      })
+    }
   }
 
   // Open a file in OS default app.
@@ -64,6 +76,30 @@ module.exports = class PlaybackController {
     else this.pause()
   }
 
+  // Play next file in list (if any)
+  nextTrack () {
+    var state = this.state
+    if (Playlist.hasNext(state)) {
+      this.updatePlayer(
+          state.playing.infoHash, Playlist.getNextIndex(state), false, (err) => {
+            if (err) dispatch('error', err)
+            else this.play()
+          })
+    }
+  }
+
+  // Play previous track in list (if any)
+  previousTrack () {
+    var state = this.state
+    if (Playlist.hasPrevious(state)) {
+      this.updatePlayer(
+        state.playing.infoHash, Playlist.getPreviousIndex(state), false, (err) => {
+          if (err) dispatch('error', err)
+          else this.play()
+        })
+    }
+  }
+
   // Play (unpause) the current media
   play () {
     var state = this.state
@@ -169,13 +205,16 @@ module.exports = class PlaybackController {
 
   // Opens the video player to a specific torrent
   openPlayer (infoHash, index, cb) {
-    var torrentSummary = TorrentSummary.getByKey(this.state, infoHash)
+    var state = this.state
 
-    // automatically choose which file in the torrent to play, if necessary
-    if (index === undefined) index = torrentSummary.defaultPlayFileIndex
-    if (index === undefined) index = TorrentPlayer.pickFileToPlay(torrentSummary.files)
+    var torrentSummary = TorrentSummary.getByKey(state, infoHash)
+
+    if (index === undefined) index = torrentSummary.mostRecentFileIndex
+    if (index === undefined) index = torrentSummary.files.findIndex(TorrentPlayer.isPlayable)
     if (index === undefined) return cb(new errors.UnplayableError())
 
+    state.playing.infoHash = torrentSummary.infoHash
+
     // update UI to show pending playback
     if (torrentSummary.progress !== 1) sound.play('PLAY')
     // TODO: remove torrentSummary.playStatus
@@ -191,34 +230,68 @@ module.exports = class PlaybackController {
       this.update()
     }, 10000) /* give it a few seconds */
 
+    this.startServer(torrentSummary, () => {
+      clearTimeout(timeout)
+
+      // if we timed out (user clicked play a long time ago), don't autoplay
+      var timedOut = torrentSummary.playStatus === 'timeout'
+      delete torrentSummary.playStatus
+      if (timedOut) {
+        ipcRenderer.send('wt-stop-server')
+        return this.update()
+      }
+
+      ipcRenderer.send('onPlayerOpen')
+      this.updatePlayer(infoHash, index, true, cb)
+    })
+  }
+
+  // Starts WebTorrent server for media streaming
+  startServer (torrentSummary, cb) {
     if (torrentSummary.status === 'paused') {
       dispatch('startTorrentingSummary', torrentSummary.torrentKey)
       ipcRenderer.once('wt-ready-' + torrentSummary.infoHash,
-        () => this.openPlayerFromActiveTorrent(torrentSummary, index, timeout, cb))
+        () => onTorrentReady())
     } else {
-      this.openPlayerFromActiveTorrent(torrentSummary, index, timeout, cb)
+      onTorrentReady()
+    }
+
+    function onTorrentReady () {
+      ipcRenderer.send('wt-start-server', torrentSummary.infoHash)
+      ipcRenderer.once('wt-server-' + torrentSummary.infoHash, () => cb())
     }
   }
 
-  openPlayerFromActiveTorrent (torrentSummary, index, timeout, cb) {
+  // Called each time the current file changes
+  updatePlayer (infoHash, index, resume, cb) {
+    var state = this.state
+
+    var torrentSummary = TorrentSummary.getByKey(state, infoHash)
     var fileSummary = torrentSummary.files[index]
 
+    if (!TorrentPlayer.isPlayable(fileSummary)) {
+      torrentSummary.mostRecentFileIndex = undefined
+      return cb(new Error('Can\'t play that file'))
+    }
+
+    torrentSummary.mostRecentFileIndex = index
+
     // update state
-    var state = this.state
-    state.playing.infoHash = torrentSummary.infoHash
     state.playing.fileIndex = index
     state.playing.type = TorrentPlayer.isVideo(fileSummary) ? 'video'
       : TorrentPlayer.isAudio(fileSummary) ? 'audio'
       : 'other'
 
     // pick up where we left off
-    if (fileSummary.currentTime) {
+    var jumpToTime = 0
+    if (resume && fileSummary.currentTime) {
       var fraction = fileSummary.currentTime / fileSummary.duration
       var secondsLeft = fileSummary.duration - fileSummary.currentTime
       if (fraction < 0.9 && secondsLeft > 10) {
-        state.playing.jumpToTime = fileSummary.currentTime
+        jumpToTime = fileSummary.currentTime
       }
     }
+    state.playing.jumpToTime = jumpToTime
 
     // if it's audio, parse out the metadata (artist, title, etc)
     if (state.playing.type === 'audio' && !fileSummary.audioInfo) {
@@ -233,34 +306,21 @@ module.exports = class PlaybackController {
       dispatch('addSubtitles', [fileSummary.selectedSubtitle], true)
     }
 
-    ipcRenderer.send('wt-start-server', torrentSummary.infoHash, index)
-    ipcRenderer.once('wt-server-' + torrentSummary.infoHash, (e, info) => {
-      clearTimeout(timeout)
+    state.window.title = fileSummary.name
 
-      // if we timed out (user clicked play a long time ago), don't autoplay
-      var timedOut = torrentSummary.playStatus === 'timeout'
-      delete torrentSummary.playStatus
-      if (timedOut) {
-        ipcRenderer.send('wt-stop-server')
-        return this.update()
-      }
-
-      state.window.title = torrentSummary.files[state.playing.fileIndex].name
-
-      // play in VLC if set as default player (Preferences / Playback / Play in VLC)
-      if (this.state.saved.prefs.openExternalPlayer) {
-        dispatch('openExternalPlayer')
-        this.update()
-        cb()
-        return
-      }
-
-      // otherwise, play the video
+    // play in VLC if set as default player (Preferences / Playback / Play in VLC)
+    if (this.state.saved.prefs.openExternalPlayer) {
+      dispatch('openExternalPlayer')
       this.update()
-
-      ipcRenderer.send('onPlayerOpen')
       cb()
-    })
+      return
+    }
+
+    // otherwise, play the video
+    this.update()
+
+    ipcRenderer.send('onPlayerUpdate', Playlist.hasNext(state), Playlist.hasPrevious(state))
+    cb()
   }
 
   closePlayer () {