Separate the audio player app from Files.app

ui/file_manager/file_manager/audio_player/js/audio_player.js

-// Copyright (c) 2012 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-'use strict';
-
-/**
- * @param {HTMLElement} container Container element.
- * @constructor
- */
-function AudioPlayer(container) {
-  this.container_ = container;
-  this.volumeManager_ = new VolumeManagerWrapper(
-      VolumeManagerWrapper.DriveEnabledStatus.DRIVE_ENABLED);
-  this.metadataCache_ = MetadataCache.createFull(this.volumeManager_);
-  this.selectedEntry_ = null;
-
-  this.model_ = new AudioPlayerModel();
-  var observer = new PathObserver(this.model_, 'expanded');
-  observer.open(function(newValue, oldValue) {
-    // Inverse arguments intentionally to match the Polymer way.
-    this.onModelExpandedChanged(oldValue, newValue);
-  }.bind(this));
-
-  this.entries_ = [];
-  this.currentTrackIndex_ = -1;
-  this.playlistGeneration_ = 0;
-
-  /**
-   * Whether if the playlist is expanded or not. This value is changed by
-   * this.syncExpanded().
-   * True: expanded, false: collapsed, null: unset.
-   *
-   * @type {?boolean}
-   * @private
-   */
-  this.isExpanded_ = null;  // Initial value is null. It'll be set in load().
-
-  this.player_ = document.querySelector('audio-player');
-  // TODO(yoshiki): Move tracks into the model.
-  this.player_.tracks = [];
-  this.player_.model = this.model_;
-  Platform.performMicrotaskCheckpoint();
-
-  this.errorString_ = '';
-  this.offlineString_ = '';
-  chrome.fileManagerPrivate.getStrings(function(strings) {
-    container.ownerDocument.title = strings['AUDIO_PLAYER_TITLE'];
-    this.errorString_ = strings['AUDIO_ERROR'];
-    this.offlineString_ = strings['AUDIO_OFFLINE'];
-    AudioPlayer.TrackInfo.DEFAULT_ARTIST =
-        strings['AUDIO_PLAYER_DEFAULT_ARTIST'];
-  }.bind(this));
-
-  this.volumeManager_.addEventListener('externally-unmounted',
-      this.onExternallyUnmounted_.bind(this));
-
-  window.addEventListener('resize', this.onResize_.bind(this));
-
-  // Show the window after DOM is processed.
-  var currentWindow = chrome.app.window.current();
-  if (currentWindow)
-    setTimeout(currentWindow.show.bind(currentWindow), 0);
-}
-
-/**
- * Initial load method (static).
- */
-AudioPlayer.load = function() {
-  document.ondragstart = function(e) { e.preventDefault() };
-
-  AudioPlayer.instance =
-      new AudioPlayer(document.querySelector('.audio-player'));
-
-  reload();
-};
-
-/**
- * Unloads the player.
- */
-function unload() {
-  if (AudioPlayer.instance)
-    AudioPlayer.instance.onUnload();
-}
-
-/**
- * Reloads the player.
- */
-function reload() {
-  AudioPlayer.instance.load(window.appState);
-}
-
-/**
- * Loads a new playlist.
- * @param {Playlist} playlist Playlist object passed via mediaPlayerPrivate.
- */
-AudioPlayer.prototype.load = function(playlist) {
-  this.playlistGeneration_++;
-  this.currentTrackIndex_ = -1;
-
-  // Save the app state, in case of restart. Make a copy of the object, so the
-  // playlist member is not changed after entries are resolved.
-  window.appState = JSON.parse(JSON.stringify(playlist));  // cloning
-  util.saveAppState();
-
-  this.isExpanded_ = this.model_.expanded;
-
-  // Resolving entries has to be done after the volume manager is initialized.
-  this.volumeManager_.ensureInitialized(function() {
-    util.URLsToEntries(playlist.items, function(entries) {
-      this.entries_ = entries;
-
-      var position = playlist.position || 0;
-      var time = playlist.time || 0;
-
-      if (this.entries_.length == 0)
-        return;
-
-      var newTracks = [];
-      var currentTracks = this.player_.tracks;
-      var unchanged = (currentTracks.length === this.entries_.length);
-
-      for (var i = 0; i != this.entries_.length; i++) {
-        var entry = this.entries_[i];
-        var onClick = this.select_.bind(this, i);
-        newTracks.push(new AudioPlayer.TrackInfo(entry, onClick));
-
-        if (unchanged && entry.toURL() !== currentTracks[i].url)
-          unchanged = false;
-      }
-
-      if (!unchanged) {
-        this.player_.tracks = newTracks;
-
-        // Makes it sure that the handler of the track list is called, before
-        // the handler of the track index.
-        Platform.performMicrotaskCheckpoint();
-      }
-
-      this.select_(position, !!time);
-
-      // Load the selected track metadata first, then load the rest.
-      this.loadMetadata_(position);
-      for (i = 0; i != this.entries_.length; i++) {
-        if (i != position)
-          this.loadMetadata_(i);
-      }
-    }.bind(this));
-  }.bind(this));
-};
-
-/**
- * Loads metadata for a track.
- * @param {number} track Track number.
- * @private
- */
-AudioPlayer.prototype.loadMetadata_ = function(track) {
-  this.fetchMetadata_(
-      this.entries_[track], this.displayMetadata_.bind(this, track));
-};
-
-/**
- * Displays track's metadata.
- * @param {number} track Track number.
- * @param {Object} metadata Metadata object.
- * @param {string=} opt_error Error message.
- * @private
- */
-AudioPlayer.prototype.displayMetadata_ = function(track, metadata, opt_error) {
-  this.player_.tracks[track].setMetadata(metadata, opt_error);
-};
-
-/**
- * Closes audio player when a volume containing the selected item is unmounted.
- * @param {Event} event The unmount event.
- * @private
- */
-AudioPlayer.prototype.onExternallyUnmounted_ = function(event) {
-  if (!this.selectedEntry_)
-    return;
-
-  if (this.volumeManager_.getVolumeInfo(this.selectedEntry_) ===
-      event.volumeInfo)
-    window.close();
-};
-
-/**
- * Called on window is being unloaded.
- */
-AudioPlayer.prototype.onUnload = function() {
-  if (this.player_)
-    this.player_.onPageUnload();
-
-  if (this.volumeManager_)
-    this.volumeManager_.dispose();
-};
-
-/**
- * Selects a new track to play.
- * @param {number} newTrack New track number.
- * @param {number} time New playback position (in second).
- * @private
- */
-AudioPlayer.prototype.select_ = function(newTrack, time) {
-  if (this.currentTrackIndex_ == newTrack) return;
-
-  this.currentTrackIndex_ = newTrack;
-  this.player_.currentTrackIndex = this.currentTrackIndex_;
-  this.player_.audioController.time = time;
-  Platform.performMicrotaskCheckpoint();
-
-  if (!window.appReopen)
-    this.player_.audioElement.play();
-
-  window.appState.position = this.currentTrackIndex_;
-  window.appState.time = 0;
-  util.saveAppState();
-
-  var entry = this.entries_[this.currentTrackIndex_];
-
-  this.fetchMetadata_(entry, function(metadata) {
-    if (this.currentTrackIndex_ != newTrack)
-      return;
-
-    this.selectedEntry_ = entry;
-  }.bind(this));
-};
-
-/**
- * @param {FileEntry} entry Track file entry.
- * @param {function(object)} callback Callback.
- * @private
- */
-AudioPlayer.prototype.fetchMetadata_ = function(entry, callback) {
-  this.metadataCache_.getOne(entry, 'thumbnail|media|external',
-      function(generation, metadata) {
-        // Do nothing if another load happened since the metadata request.
-        if (this.playlistGeneration_ == generation)
-          callback(metadata);
-      }.bind(this, this.playlistGeneration_));
-};
-
-/**
- * Media error handler.
- * @private
- */
-AudioPlayer.prototype.onError_ = function() {
-  var track = this.currentTrackIndex_;
-
-  this.invalidTracks_[track] = true;
-
-  this.fetchMetadata_(
-      this.entries_[track],
-      function(metadata) {
-        var error = (!navigator.onLine && !metadata.external.present) ?
-            this.offlineString_ : this.errorString_;
-        this.displayMetadata_(track, metadata, error);
-        this.scheduleAutoAdvance_();
-      }.bind(this));
-};
-
-/**
- * Toggles the expanded mode when resizing.
- *
- * @param {Event} event Resize event.
- * @private
- */
-AudioPlayer.prototype.onResize_ = function(event) {
-  if (!this.isExpanded_ &&
-      window.innerHeight >= AudioPlayer.EXPANDED_MODE_MIN_HEIGHT) {
-    this.isExpanded_ = true;
-    this.model_.expanded = true;
-  } else if (this.isExpanded_ &&
-             window.innerHeight < AudioPlayer.EXPANDED_MODE_MIN_HEIGHT) {
-    this.isExpanded_ = false;
-    this.model_.expanded = false;
-  }
-};
-
-/* Keep the below constants in sync with the CSS. */
-
-/**
- * Window header size in pixels.
- * @type {number}
- * @const
- */
-AudioPlayer.HEADER_HEIGHT = 33;  // 32px + border 1px
-
-/**
- * Track height in pixels.
- * @type {number}
- * @const
- */
-AudioPlayer.TRACK_HEIGHT = 44;
-
-/**
- * Controls bar height in pixels.
- * @type {number}
- * @const
- */
-AudioPlayer.CONTROLS_HEIGHT = 73;  // 72px + border 1px
-
-/**
- * Default number of items in the expanded mode.
- * @type {number}
- * @const
- */
-AudioPlayer.DEFAULT_EXPANDED_ITEMS = 5;
-
-/**
- * Minimum size of the window in the expanded mode in pixels.
- * @type {number}
- * @const
- */
-AudioPlayer.EXPANDED_MODE_MIN_HEIGHT = AudioPlayer.CONTROLS_HEIGHT +
-                                       AudioPlayer.TRACK_HEIGHT * 2;
-
-/**
- * Invoked when the 'expanded' property in the model is changed.
- * @param {boolean} oldValue Old value.
- * @param {boolean} newValue New value.
- */
-AudioPlayer.prototype.onModelExpandedChanged = function(oldValue, newValue) {
-  if (this.isExpanded_ !== null &&
-      this.isExpanded_ === newValue)
-    return;
-
-  if (this.isExpanded_ && !newValue)
-    this.lastExpandedHeight_ = window.innerHeight;
-
-  if (this.isExpanded_ !== newValue) {
-    this.isExpanded_ = newValue;
-    this.syncHeight_();
-
-    // Saves new state.
-    window.appState.expanded = newValue;
-    util.saveAppState();
-  }
-};
-
-/**
- * @private
- */
-AudioPlayer.prototype.syncHeight_ = function() {
-  var targetHeight;
-
-  if (this.model_.expanded) {
-    // Expanded.
-    if (!this.lastExpandedHeight_ ||
-        this.lastExpandedHeight_ < AudioPlayer.EXPANDED_MODE_MIN_HEIGHT) {
-      var expandedListHeight =
-          Math.min(this.entries_.length, AudioPlayer.DEFAULT_EXPANDED_ITEMS) *
-              AudioPlayer.TRACK_HEIGHT;
-      targetHeight = AudioPlayer.CONTROLS_HEIGHT + expandedListHeight;
-      this.lastExpandedHeight_ = targetHeight;
-    } else {
-      targetHeight = this.lastExpandedHeight_;
-    }
-  } else {
-    // Not expanded.
-    targetHeight = AudioPlayer.CONTROLS_HEIGHT + AudioPlayer.TRACK_HEIGHT;
-  }
-
-  window.resizeTo(window.innerWidth, targetHeight + AudioPlayer.HEADER_HEIGHT);
-};
-
-/**
- * Create a TrackInfo object encapsulating the information about one track.
- *
- * @param {fileEntry} entry FileEntry to be retrieved the track info from.
- * @param {function} onClick Click handler.
- * @constructor
- */
-AudioPlayer.TrackInfo = function(entry, onClick) {
-  this.url = entry.toURL();
-  this.title = this.getDefaultTitle();
-  this.artist = this.getDefaultArtist();
-
-  // TODO(yoshiki): implement artwork.
-  this.artwork = null;
-  this.active = false;
-};
-
-/**
- * @return {HTMLDivElement} The wrapper element for the track.
- */
-AudioPlayer.TrackInfo.prototype.getBox = function() { return this.box_ };
-
-/**
- * @return {string} Default track title (file name extracted from the url).
- */
-AudioPlayer.TrackInfo.prototype.getDefaultTitle = function() {
-  var title = this.url.split('/').pop();
-  var dotIndex = title.lastIndexOf('.');
-  if (dotIndex >= 0) title = title.substr(0, dotIndex);
-  title = decodeURIComponent(title);
-  return title;
-};
-
-/**
- * TODO(kaznacheev): Localize.
- */
-AudioPlayer.TrackInfo.DEFAULT_ARTIST = 'Unknown Artist';
-
-/**
- * @return {string} 'Unknown artist' string.
- */
-AudioPlayer.TrackInfo.prototype.getDefaultArtist = function() {
-  return AudioPlayer.TrackInfo.DEFAULT_ARTIST;
-};
-
-/**
- * @param {Object} metadata The metadata object.
- * @param {string} error Error string.
- */
-AudioPlayer.TrackInfo.prototype.setMetadata = function(
-    metadata, error) {
-  // TODO(yoshiki): Handle error in better way.
-  // TODO(yoshiki): implement artwork (metadata.thumbnail)
-  this.title = (metadata.media && metadata.media.title) ||
-      this.getDefaultTitle();
-  this.artist = error ||
-      (metadata.media && metadata.media.artist) || this.getDefaultArtist();
-};
-
-// Starts loading the audio player.
-window.addEventListener('polymer-ready', function(e) {
-  AudioPlayer.load();
-});