1 // Copyright 2014 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
29 observer
: 'tracksChanged'
33 * Track index of the current track.
34 * If the tracks property is empty, it should be -1. Otherwise, be a valid
40 observer
: 'currentTrackIndexChanged',
45 * Whether shuffling play order is enabled or not.
50 observer
: 'shuffleChanged'
55 * Initializes an element. This method is called automatically when the
59 this.observeTrackList();
61 window
.addEventListener('resize', this.onWindowResize_
.bind(this));
64 observeTrackList: function() {
65 // Unobserve the previous track list.
66 if (this.unobserveTrackList_
)
67 this.unobserveTrackList_();
69 // Observe the new track list.
70 var observer
= this.tracksValueChanged_
.bind(this);
71 Array
.observe(this.tracks
, observer
);
73 // Set the function to unobserve it.
74 this.unobserveTrackList_ = function(tracks
, observer
) {
75 Array
.unobserve(tracks
, observer
);
76 }.bind(null, this.tracks
, observer
);
80 * Play order of the tracks. Each value is the index of 'this.tracks'.
81 * @type {Array<number>}
86 * Invoked when 'shuffle' property is changed.
87 * @param {boolean} newValue New value.
88 * @param {boolean} oldValue Old value.
90 shuffleChanged: function(newValue
, oldValue
) {
91 this.generatePlayOrder(true /* keep the current track */);
95 * Invoked when the current track index is changed.
96 * @param {number} newValue new value.
97 * @param {number} oldValue old value.
99 currentTrackIndexChanged: function(newValue
, oldValue
) {
100 if (oldValue
=== newValue
)
103 if (!isNaN(oldValue
) && 0 <= oldValue
&& oldValue
< this.tracks
.length
)
104 this.set('tracks.' + oldValue
+ '.active', false);
106 if (0 <= newValue
&& newValue
< this.tracks
.length
) {
107 var currentPlayOrder
= this.playOrder
.indexOf(newValue
);
108 if (currentPlayOrder
!== -1) {
110 this.set('tracks.' + newValue
+ '.active', true);
112 this.ensureTrackInViewport_(newValue
/* trackIndex */);
118 if (this.tracks
.length
=== 0)
119 this.currentTrackIndex
= -1;
121 this.generatePlayOrder(false /* no need to keep the current track */);
125 * Invoked when 'tracks' property is changed.
126 * @param {Array<!TrackInfo>} newValue New value.
127 * @param {Array<!TrackInfo>} oldValue Old value.
129 tracksChanged: function(newValue
, oldValue
) {
130 // Note: Sometimes both oldValue and newValue are null though the actual
131 // values are not null. Maybe it's a bug of Polymer.
133 // Re-register the observer of 'this.tracks'.
134 this.observeTrackList();
136 if (this.tracks
.length
!== 0) {
137 // Restore the active track.
138 if (this.currentTrackIndex
!== -1 &&
139 this.currentTrackIndex
< this.tracks
.length
) {
140 this.set('tracks.' + this.currentTrackIndex
+ '.active', true);
143 // Reset play order and current index.
144 this.generatePlayOrder(false /* no need to keep the current track */);
147 this.currentTrackIndex
= -1;
152 * Invoked when the value in the 'tracks' is changed.
153 * @param {Array<Object>} changes The detail of the change.
155 tracksValueChanged_: function(changes
) {
156 if (this.tracks
.length
=== 0)
157 this.currentTrackIndex
= -1;
159 this.set('tracks.' + this.currentTrackIndex
+ '.active', true);
163 * Invoked when the track element is clicked.
164 * @param {Event} event Click event.
166 trackClicked: function(event
) {
167 var index
= ~~event
.currentTarget
.getAttribute('index');
168 var track
= this.tracks
[index
];
170 this.selectTrack(track
);
174 * Invoked when the window is resized.
177 onWindowResize_: function() {
178 this.ensureTrackInViewport_(this.currentTrackIndex
);
182 * Scrolls the track list to ensure the given track in the viewport.
183 * @param {number} trackIndex The index of the track to be in the viewport.
186 ensureTrackInViewport_: function(trackIndex
) {
187 var trackSelector
= '::shadow .track[index="' + trackIndex
+ '"]';
188 var trackElement
= this.querySelector(trackSelector
);
190 var viewTop
= this.scrollTop
;
191 var viewHeight
= this.clientHeight
;
192 var elementTop
= trackElement
.offsetTop
;
193 var elementHeight
= trackElement
.offsetHeight
;
195 if (elementTop
< viewTop
) {
197 this.scrollTop
= elementTop
;
198 } else if (elementTop
+ elementHeight
<= viewTop
+ viewHeight
) {
199 // The entire element is in the viewport. Do nothing.
201 // Adjust the bottoms.
202 this.scrollTop
= Math
.max(0,
203 (elementTop
+ elementHeight
- viewHeight
));
209 * Invoked when the track element is clicked.
210 * @param {boolean} keepCurrentTrack Keep the current track or not.
212 generatePlayOrder: function(keepCurrentTrack
) {
213 console
.assert((keepCurrentTrack
!== undefined),
214 'The argument "forward" is undefined');
216 if (this.tracks
.length
=== 0) {
221 // Creates sequenced array.
224 map(function(unused
, index
) { return index
; });
227 // Randomizes the play order array (Schwarzian-transform algorithm).
228 this.playOrder
= this.playOrder
230 return {weight
: Math
.random(), index
: a
};
232 .sort(function(a
, b
) { return a
.weight
- b
.weight
})
233 .map(function(a
) { return a
.index
});
235 if (keepCurrentTrack
) {
236 // Puts the current track at the beginning of the play order.
237 this.playOrder
= this.playOrder
238 .filter(function(value
) {
239 return this.currentTrackIndex
!== value
;
241 this.playOrder
.splice(0, 0, this.currentTrackIndex
);
245 if (!keepCurrentTrack
)
246 this.currentTrackIndex
= this.playOrder
[0];
250 * Sets the current track.
251 * @param {!TrackInfo} track TrackInfo to be set as the current
254 selectTrack: function(track
) {
256 for (var i
= 0; i
< this.tracks
.length
; i
++) {
257 if (this.tracks
[i
].url
=== track
.url
) {
263 // TODO(yoshiki): Clean up the flow and the code around here.
264 if (this.currentTrackIndex
== index
)
265 this.replayCurrentTrack();
267 this.currentTrackIndex
= index
;
272 * Request to replay the current music.
274 replayCurrentTrack: function() {
279 * Returns the current track.
280 * @return {TrackInfo} track TrackInfo of the current track.
282 getCurrentTrack: function() {
283 if (this.tracks
.length
=== 0)
286 return this.tracks
[this.currentTrackIndex
];
290 * Returns the next (or previous) track in the track list. If there is no
291 * next track, returns -1.
293 * @param {boolean} forward Specify direction: forward or previous mode.
294 * True: forward mode, false: previous mode.
295 * @param {boolean} cyclic Specify if cyclically or not: It true, the first
296 * track is succeeding to the last track, otherwise no track after the
298 * @return {number} The next track index.
300 getNextTrackIndex: function(forward
, cyclic
) {
301 if (this.tracks
.length
=== 0)
304 var defaultTrackIndex
=
305 forward
? this.playOrder
[0] : this.playOrder
[this.tracks
.length
- 1];
307 var currentPlayOrder
= this.playOrder
.indexOf(this.currentTrackIndex
);
309 (0 <= currentPlayOrder
&& currentPlayOrder
< this.tracks
.length
),
310 'Insufficient TrackList.playOrder. The current track is not on the ' +
313 var newPlayOrder
= currentPlayOrder
+ (forward
? +1 : -1);
314 if (newPlayOrder
=== -1 || newPlayOrder
=== this.tracks
.length
)
315 return cyclic
? defaultTrackIndex
: -1;
317 var newTrackIndex
= this.playOrder
[newPlayOrder
];
319 (0 <= newTrackIndex
&& newTrackIndex
< this.tracks
.length
),
320 'Insufficient TrackList.playOrder. New Play Order: ' + newPlayOrder
);
322 return newTrackIndex
;
325 })(); // Anonymous closure