(function ($) {

AblePlayer.prototype.initDescription = function() {

// set default mode for delivering description (open vs closed)

// based on availability and user preference

// called when player is being built, or when a user

// toggles the Description button or changes a description-related preference

// In the latter two scendarios, this.refreshingDesc == true via control.js > handleDescriptionToggle()

// The following variables are applicable to delivery of description:

// prefDesc == 1 if user wants description (i.e., Description button is on); else 0

// prefDescFormat == either 'video' or 'text'

// prefDescPause == 1 to pause video when description starts; else 0

// prefVisibleDesc == 1 to visibly show text-based description area; else 0

// hasOpenDesc == true if a described version of video is available via data-desc-src attribute

// hasClosedDesc == true if a description text track is available

// this.useDescFormat == either 'video' or 'text'; the format ultimately delivered

// descOn == true if description of either type is on

if (!this.refreshingDesc) {

// this is the initial build

// first, check to see if there's an open-described version of this video

// checks only the first source since if a described version is provided,

// it must be provided for all sources

this.descFile = this.$sources.first().attr('data-desc-src');

if (typeof this.descFile !== 'undefined') {

this.hasOpenDesc = true;

}

else {

// there's no open-described version via data-desc-src, but what about data-youtube-desc-src?

if (this.youTubeDescId) {

this.hasOpenDesc = true;

}

else { // there are no open-described versions from any source

this.hasOpenDesc = false;

}

}

}

// update this.useDescFormat based on media availability & user preferences

if (this.prefDesc) {

if (this.hasOpenDesc && this.hasClosedDesc) {

// both formats are available. Use whichever one user prefers

this.useDescFormat = this.prefDescFormat;

this.descOn = true;

}

else if (this.hasOpenDesc) {

this.useDescFormat = 'video';

this.descOn = true;

}

else if (this.hasClosedDesc) {

this.useDescFormat = 'text';

this.descOn = true;

}

}

else { // description button is off

if (this.refreshingDesc) { // user just now toggled it off

this.prevDescFormat = this.useDescFormat;

this.useDescFormat = false;

this.descOn = false;

}

else { // desc has always been off

this.useDescFormat = false;

}

}

if (this.descOn) {

if (this.useDescFormat === 'video') {

if (!this.usingAudioDescription()) {

// switched from non-described to described version

this.swapDescription();

}

// hide description div

this.$descDiv.hide();

this.$descDiv.removeClass('able-clipped');

}

else if (this.useDescFormat === 'text') {

this.$descDiv.show();

if (this.prefVisibleDesc) { // make it visible to everyone

this.$descDiv.removeClass('able-clipped');

}

else { // keep it visible to screen readers, but hide from everyone else

this.$descDiv.addClass('able-clipped');

}

if (!this.swappingSrc) {

this.showDescription(this.getElapsed());

}

}

}

else { // description is off.

if (this.prevDescFormat === 'video') { // user was previously using description via video

if (this.usingAudioDescription()) {

this.swapDescription();

}

}

else if (this.prevDescFormat === 'text') { // user was previously using text description

// hide description div from everyone, including screen reader users

this.$descDiv.hide();

this.$descDiv.removeClass('able-clipped');

}

}

this.refreshingDesc = false;

};

// Returns true if currently using audio description, false otherwise.

AblePlayer.prototype.usingAudioDescription = function () {

if (this.player === 'youtube') {

return (this.activeYouTubeId === this.youTubeDescId);

}

else {

return (this.$sources.first().attr('data-desc-src') === this.$sources.first().attr('src'));

}

};

AblePlayer.prototype.swapDescription = function() {

// swap described and non-described source media, depending on which is playing

// this function is only called in two circumstances:

// 1. Swapping to described version when initializing player (based on user prefs & availability)

// 2. User is toggling description

var thisObj, i, origSrc, descSrc, srcType, jwSourceIndex, newSource;

thisObj = this;

// get current time, and start new video at the same time

// NOTE: There is some risk in resuming playback at the same start time

// since the described version might include extended audio description (with pauses)

// and might therefore be longer than the non-described version

// The benefits though would seem to outweigh this risk

this.swapTime = this.getElapsed(); // video will scrub to this time after loaded (see event.js)

if (this.descOn) {

// user has requested the described version

this.showAlert(this.tt.alertDescribedVersion);

}

else {

// user has requested the non-described version

this.showAlert(this.tt.alertNonDescribedVersion);

}

if (this.player === 'html5') {

if (this.usingAudioDescription()) {

// the described version is currently playing. Swap to non-described

for (i=0; i < this.$sources.length; i++) {

// for all <source> elements, replace src with data-orig-src

origSrc = this.$sources[i].getAttribute('data-orig-src');

srcType = this.$sources[i].getAttribute('type');

if (origSrc) {

this.$sources[i].setAttribute('src',origSrc);

}

if (srcType === 'video/mp4') {

jwSourceIndex = i;

}

}

// No need to check for this.initializing

// This function is only called during initialization

// if swapping from non-described to described

this.swappingSrc = true;

}

else {

// the non-described version is currently playing. Swap to described.

for (i=0; i < this.$sources.length; i++) {

// for all <source> elements, replace src with data-desc-src (if one exists)

// then store original source in a new data-orig-src attribute

origSrc = this.$sources[i].getAttribute('src');

descSrc = this.$sources[i].getAttribute('data-desc-src');

srcType = this.$sources[i].getAttribute('type');

if (descSrc) {

this.$sources[i].setAttribute('src',descSrc);

this.$sources[i].setAttribute('data-orig-src',origSrc);

}

if (srcType === 'video/mp4') {

jwSourceIndex = i;

}

}

this.swappingSrc = true;

}

// now reload the source file.

if (this.player === 'html5') {

this.media.load();

}

else if (this.player === 'youtube') {

// TODO: Load new youTubeId

}

else if (this.player === 'jw' && this.jwPlayer) {

newSource = this.$sources[jwSourceIndex].getAttribute('src');

this.jwPlayer.load({file: newSource});

}

}

else if (this.player === 'youtube') {

if (this.usingAudioDescription()) {

// the described version is currently playing. Swap to non-described

this.activeYouTubeId = this.youTubeId;

this.showAlert(this.tt.alertNonDescribedVersion);

}

else {

// the non-described version is currently playing. Swap to described.

this.activeYouTubeId = this.youTubeDescId;

this.showAlert(this.tt.alertDescribedVersion);

}

if (typeof this.youTubePlayer !== 'undefined') {

// retrieve/setup captions for the new video from YouTube

this.setupAltCaptions().then(function() {

if (thisObj.playing) {

// loadVideoById() loads and immediately plays the new video at swapTime

thisObj.youTubePlayer.loadVideoById(thisObj.activeYouTubeId,thisObj.swapTime);

}

else {

// cueVideoById() loads the new video and seeks to swapTime, but does not play

thisObj.youTubePlayer.cueVideoById(thisObj.activeYouTubeId,thisObj.swapTime);

}

});

}

}

};

AblePlayer.prototype.showDescription = function(now) {

// there's a lot of redundancy between this function and showCaptions

// Trying to combine them ended up in a mess though. Keeping as is for now.

if (this.swappingSrc) {

return;

}

var d, thisDescription;

var flattenComponentForDescription = function (component) {

var result = [];

if (component.type === 'string') {

result.push(component.value);

}

else {

for (var ii in component.children) {

result.push(flattenComponentForDescription(component.children[ii]));

}

}

return result.join('');

}

var cues;

if (this.selectedDescriptions) {

cues = this.selectedDescriptions.cues;

}

else if (this.descriptions.length >= 1) {

cues = this.descriptions[0].cues;

}

else {

cues = [];

}

for (d in cues) {

if ((cues[d].start <= now) && (cues[d].end > now)) {

thisDescription = d;

break;

}

}

if (typeof thisDescription !== 'undefined') {

if (this.currentDescription !== thisDescription) {

// temporarily remove aria-live from $status in order to prevent description from being interrupted

this.$status.removeAttr('aria-live');

// load the new description into the container div

this.$descDiv.html(flattenComponentForDescription(cues[thisDescription].components));

if (this.prefDescPause) {

this.pauseMedia();

}

this.currentDescription = thisDescription;

}

}

else {

this.$descDiv.html('');

this.currentDescription = -1;

// restore aria-live to $status

this.$status.attr('aria-live','polite');

}

};

})(jQuery);