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/pages/PlayerPage.js

@@ -5,6 +5,7 @@ const zeroFill = require('zero-fill')
 const path = require('path')
 
 const TorrentSummary = require('../lib/torrent-summary')
+const Playlist = require('../lib/playlist')
 const {dispatch, dispatcher} = require('../lib/dispatcher')
 
 // Shows a streaming video player. Standard features + Chromecast + Airplay
@@ -109,7 +110,7 @@ function renderMedia (state) {
   var MediaTagName = state.playing.type
   var mediaTag = (
     <MediaTagName
-      src={state.server.localURL}
+      src={Playlist.getCurrentLocalURL(state)}
       onDoubleClick={dispatcher('toggleFullScreen')}
       onLoadedMetadata={onLoadedMetadata}
       onEnded={onEnded}
@@ -144,9 +145,13 @@ function renderMedia (state) {
     dispatch('setDimensions', dimensions)
   }
 
-  // When the video completes, pause the video instead of looping
   function onEnded (e) {
-    state.playing.isPaused = true
+    if (Playlist.hasNext(state)) {
+      dispatch('nextTrack')
+    } else {
+      // When the last video completes, pause the video instead of looping
+      state.playing.isPaused = true
+    }
   }
 
   function onCanPlay (e) {
@@ -378,6 +383,8 @@ function renderPlayerControls (state) {
     : state.playing.subtitles.selectedIndex >= 0
       ? 'active'
       : ''
+  var prevClass = Playlist.hasPrevious(state) ? '' : 'disabled'
+  var nextClass = Playlist.hasNext(state) ? '' : 'disabled'
 
   var elements = [
     <div key='playback-bar' className='playback-bar'>
@@ -397,6 +404,13 @@ function renderPlayerControls (state) {
       />
     </div>,
 
+    <i
+      key='skip-previous'
+      className={'icon skip-previous float-left ' + prevClass}
+      onClick={dispatcher('previousTrack')}>
+      skip_previous
+    </i>,
+
     <i
       key='play'
       className='icon play-pause float-left'
@@ -404,6 +418,13 @@ function renderPlayerControls (state) {
       {state.playing.isPaused ? 'play_arrow' : 'pause'}
     </i>,
 
+    <i
+      key='skip-next'
+      className={'icon skip-next float-left ' + nextClass}
+      onClick={dispatcher('nextTrack')}>
+      skip_next
+    </i>,
+
     <i
       key='fullscreen'
       className='icon fullscreen float-right'

src/renderer/pages/TorrentListPage.js

@@ -207,10 +207,10 @@ module.exports = class TorrentList extends React.Component {
       // Do we have a saved position? Show it using a radial progress bar on top
       // of the play button, unless already showing a spinner there:
       var willShowSpinner = torrentSummary.playStatus === 'requested'
-      var defaultFile = torrentSummary.files &&
-        torrentSummary.files[torrentSummary.defaultPlayFileIndex]
-      if (defaultFile && defaultFile.currentTime && !willShowSpinner) {
-        var fraction = defaultFile.currentTime / defaultFile.duration
+      var mostRecentFile = torrentSummary.files &&
+        torrentSummary.files[torrentSummary.mostRecentFileIndex]
+      if (mostRecentFile && mostRecentFile.currentTime && !willShowSpinner) {
+        var fraction = mostRecentFile.currentTime / mostRecentFile.duration
         positionElem = this.renderRadialProgressBar(fraction, 'radial-progress-large')
         playClass = 'resume-position'
       }
@@ -273,11 +273,6 @@ module.exports = class TorrentList extends React.Component {
       var fileRows = torrentSummary.files
         .filter((file) => !file.path.includes('/.____padding_file/'))
         .map((file, index) => ({ file, index }))
-        .sort(function (a, b) {
-          if (a.file.name < b.file.name) return -1
-          if (b.file.name < a.file.name) return 1
-          return 0
-        })
         .map((object) => this.renderFileRow(torrentSummary, object.file, object.index))
 
       filesElement = (