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/lib/cast.js

@@ -96,7 +96,7 @@ function chromecastPlayer () {
 
   function open () {
     var torrentSummary = state.saved.torrents.find((x) => x.infoHash === state.playing.infoHash)
-    ret.device.play(state.server.networkURL, {
+    ret.device.play(state.server.networkURL + '/' + state.playing.fileIndex, {
       type: 'video/mp4',
       title: config.APP_NAME + ' - ' + torrentSummary.name
     }, function (err) {
@@ -183,7 +183,7 @@ function airplayPlayer () {
   }
 
   function open () {
-    ret.device.play(state.server.networkURL, function (err, res) {
+    ret.device.play(state.server.networkURL + '/' + state.playing.fileIndex, function (err, res) {
       if (err) {
         state.playing.location = 'local'
         state.errors.push({
@@ -275,7 +275,7 @@ function dlnaPlayer (player) {
 
   function open () {
     var torrentSummary = state.saved.torrents.find((x) => x.infoHash === state.playing.infoHash)
-    ret.device.play(state.server.networkURL, {
+    ret.device.play(state.server.networkURL + '/' + state.playing.fileIndex, {
       type: 'video/mp4',
       title: config.APP_NAME + ' - ' + torrentSummary.name,
       seek: state.playing.currentTime > 10 ? state.playing.currentTime : 0

src/renderer/lib/errors.js

@@ -1,8 +1,15 @@
 module.exports = {
-  UnplayableError
+  UnplayableTorrentError,
+  UnplayableFileError
 }
 
-function UnplayableError () {
+function UnplayableTorrentError () {
   this.message = 'Can\'t play any files in torrent'
 }
-UnplayableError.prototype = Error
+
+function UnplayableFileError () {
+  this.message = 'Can\'t play that file'
+}
+
+UnplayableTorrentError.prototype = Error
+UnplayableFileError.prototype = Error

src/renderer/lib/playlist.js

@@ -0,0 +1,85 @@
+module.exports = {
+  hasNext,
+  getNextIndex,
+  hasPrevious,
+  getPreviousIndex,
+  getCurrentLocalURL
+}
+
+const TorrentSummary = require('./torrent-summary')
+const TorrentPlayer = require('./torrent-player')
+
+var cache = {
+  infoHash: null,
+  previousIndex: null,
+  currentIndex: null,
+  nextIndex: null
+}
+
+function hasNext (state) {
+  updateCache(state)
+  return cache.nextIndex !== null
+}
+
+function getNextIndex (state) {
+  updateCache(state)
+  return cache.nextIndex
+}
+
+function hasPrevious (state) {
+  updateCache(state)
+  return cache.previousIndex !== null
+}
+
+function getPreviousIndex (state) {
+  updateCache(state)
+  return cache.previousIndex
+}
+
+function getCurrentLocalURL (state) {
+  return state.server.localURL + '/' + state.playing.fileIndex
+}
+
+function updateCache (state) {
+  var infoHash = state.playing.infoHash
+  var fileIndex = state.playing.fileIndex
+
+  if (infoHash === cache.infoHash) {
+    switch (fileIndex) {
+      case cache.currentIndex:
+        return
+      case cache.nextIndex:
+        cache.previousIndex = cache.currentIndex
+        cache.currentIndex = fileIndex
+        cache.nextIndex = findNextIndex(state)
+        return
+      case cache.previousIndex:
+        cache.previousIndex = findPreviousIndex(state)
+        cache.nextIndex = cache.currentIndex
+        cache.currentIndex = fileIndex
+        return
+    }
+  } else {
+    cache.infoHash = infoHash
+  }
+
+  cache.previousIndex = findPreviousIndex(state)
+  cache.currentIndex = fileIndex
+  cache.nextIndex = findNextIndex(state)
+}
+
+function findPreviousIndex (state) {
+  var files = TorrentSummary.getByKey(state, state.playing.infoHash).files
+  for (var i = state.playing.fileIndex - 1; i >= 0; i--) {
+    if (TorrentPlayer.isPlayable(files[i])) return i
+  }
+  return null
+}
+
+function findNextIndex (state) {
+  var files = TorrentSummary.getByKey(state, state.playing.infoHash).files
+  for (var i = state.playing.fileIndex + 1; i < files.length; i++) {
+    if (TorrentPlayer.isPlayable(files[i])) return i
+  }
+  return null
+}

src/renderer/lib/torrent-player.js

@@ -3,8 +3,7 @@ module.exports = {
   isVideo,
   isAudio,
   isTorrent,
-  isPlayableTorrentSummary,
-  pickFileToPlay
+  isPlayableTorrentSummary
 }
 
 var path = require('path')
@@ -60,25 +59,3 @@ function getFileExtension (file) {
 function isPlayableTorrentSummary (torrentSummary) {
   return torrentSummary.files && torrentSummary.files.some(isPlayable)
 }
-
-// Picks the default file to play from a list of torrent or torrentSummary files
-// Returns an index or undefined, if no files are playable
-function pickFileToPlay (files) {
-  // first, try to find the biggest video file
-  var videoFiles = files.filter(isVideo)
-  if (videoFiles.length > 0) {
-    var largestVideoFile = videoFiles.reduce(function (a, b) {
-      return a.length > b.length ? a : b
-    })
-    return files.indexOf(largestVideoFile)
-  }
-
-  // if there are no videos, play the first audio file
-  var audioFiles = files.filter(isAudio)
-  if (audioFiles.length > 0) {
-    return files.indexOf(audioFiles[0])
-  }
-
-  // no video or audio means nothing is playable
-  return undefined
-}