# Source: sound/SoundManager.js

    /**
    * @author       Richard Davey <rich@photonstorm.com>
    * @copyright    2014 Photon Storm Ltd.
    * @license      {@link https://github.com/photonstorm/phaser/blob/master/license.txt|MIT License}
    */

    /**
    * Sound Manager constructor.
    * The Sound Manager is responsible for playing back audio via either the Legacy HTML Audio tag or via Web Audio if the browser supports it.
    * Note: On Firefox 25+ on Linux if you have media.gstreamer disabled in about:config then it cannot play back mp3 or m4a files.
    * The audio file type and the encoding of those files are extremely important. Not all browsers can play all audio formats.
    * There is a good guide to what's supported here: http://hpr.dogphilosophy.net/test/
    *
    * @class Phaser.SoundManager
    * @classdesc Phaser Sound Manager.
    * @constructor
    * @param {Phaser.Game} game reference to the current game instance.
    */
    Phaser.SoundManager = function (game) {

        /**
        * @property {Phaser.Game} game - Local reference to game.
        */
        this.game = game;

        /**
        * @property {Phaser.Signal} onSoundDecode - The event dispatched when a sound decodes (typically only for mp3 files)
        */
        this.onSoundDecode = new Phaser.Signal();

        /**
        * @property {boolean} _codeMuted - Internal mute tracking var.
        * @private
        * @default
        */
        this._codeMuted = false;

        /**
        * @property {boolean} _muted - Internal mute tracking var.
        * @private
        * @default
        */
        this._muted = false;

        /**
        * @property {Description} _unlockSource - Internal unlock tracking var.
        * @private
        * @default
        */
        this._unlockSource = null;

        /**
        * @property {number} _volume - The global audio volume. A value between 0 (silence) and 1 (full volume).
        * @private
        * @default
        */
        this._volume = 1;

        /**
        * @property {array} _sounds - An array containing all the sounds
        * @private
        */
        this._sounds = [];

        /**
        * @property {AudioContext} context - The AudioContext being used for playback.
        * @default
        */
        this.context = null;

        /**
        * @property {boolean} usingWebAudio - true if this sound is being played with Web Audio.
        * @readonly
        */
        this.usingWebAudio = true;

        /**
        * @property {boolean} usingAudioTag - true if the sound is being played via the Audio tag.
        * @readonly
        */
        this.usingAudioTag = false;

        /**
        * @property {boolean} noAudio - Has audio been disabled via the PhaserGlobal object? Useful if you need to use a 3rd party audio library instead.
        * @default
        */
        this.noAudio = false;

        /**
        * @property {boolean} connectToMaster - Used in conjunction with Sound.externalNode this allows you to stop a Sound node being connected to the SoundManager master gain node.
        * @default
        */
        this.connectToMaster = true;

        /**
        * @property {boolean} touchLocked - true if the audio system is currently locked awaiting a touch event.
        * @default
        */
        this.touchLocked = false;

        /**
        * @property {number} channels - The number of audio channels to use in playback.
        * @default
        */
        this.channels = 32;

    };

    Phaser.SoundManager.prototype = {

        /**
        * Initialises the sound manager.
        * @method Phaser.SoundManager#boot
        * @protected
        */
        boot: function () {

            if (this.game.device.iOS && this.game.device.webAudio === false)
            {
                this.channels = 1;
            }

            if (this.game.device.iOS || (window['PhaserGlobal'] && window['PhaserGlobal'].fakeiOSTouchLock))
            {
                this.game.input.touch.callbackContext = this;
                this.game.input.touch.touchStartCallback = this.unlock;
                this.game.input.mouse.callbackContext = this;
                this.game.input.mouse.mouseDownCallback = this.unlock;
                this.touchLocked = true;
            }
            else
            {
                //  What about iOS5?
                this.touchLocked = false;
            }

            if (window['PhaserGlobal'])
            {
                //  Check to see if all audio playback is disabled (i.e. handled by a 3rd party class)
                if (window['PhaserGlobal'].disableAudio === true)
                {
                    this.usingWebAudio = false;
                    this.noAudio = true;
                    return;
                }

                //  Check if the Web Audio API is disabled (for testing Audio Tag playback during development)
                if (window['PhaserGlobal'].disableWebAudio === true)
                {
                    this.usingWebAudio = false;
                    this.usingAudioTag = true;
                    this.noAudio = false;
                    return;
                }
            }

            if (!!window['AudioContext'])
            {
                try {
                    this.context = new window['AudioContext']();
                } catch (error) {
                    this.context = null;
                    this.usingWebAudio = false;
                    this.noAudio = true;
                }
            }
            else if (!!window['webkitAudioContext'])
            {
                try {
                    this.context = new window['webkitAudioContext']();
                } catch (error) {
                    this.context = null;
                    this.usingWebAudio = false;
                    this.noAudio = true;
                }
            }

            if (!!window['Audio'] && this.context === null)
            {
                this.usingWebAudio = false;
                this.usingAudioTag = true;
                this.noAudio = false;
            }

            if (this.context !== null)
            {
                if (typeof this.context.createGain === 'undefined')
                {
                    this.masterGain = this.context.createGainNode();
                }
                else
                {
                    this.masterGain = this.context.createGain();
                }

                this.masterGain.gain.value = 1;
                this.masterGain.connect(this.context.destination);
            }

        },

        /**
        * Enables the audio, usually after the first touch.
        * @method Phaser.SoundManager#unlock
        */
        unlock: function () {

            if (this.touchLocked === false)
            {
                return;
            }

            //  Global override (mostly for Audio Tag testing)
            if (this.game.device.webAudio === false || (window['PhaserGlobal'] && window['PhaserGlobal'].disableWebAudio === true))
            {
                //  Create an Audio tag?
                this.touchLocked = false;
                this._unlockSource = null;
                this.game.input.touch.callbackContext = null;
                this.game.input.touch.touchStartCallback = null;
                this.game.input.mouse.callbackContext = null;
                this.game.input.mouse.mouseDownCallback = null;
            }
            else
            {
                // Create empty buffer and play it
                var buffer = this.context.createBuffer(1, 1, 22050);
                this._unlockSource = this.context.createBufferSource();
                this._unlockSource.buffer = buffer;
                this._unlockSource.connect(this.context.destination);
                this._unlockSource.noteOn(0);
            }

        },

        /**
        * Stops all the sounds in the game.
        *
        * @method Phaser.SoundManager#stopAll
        */
        stopAll: function () {

            for (var i = 0; i < this._sounds.length; i++)
            {
                if (this._sounds[i])
                {
                    this._sounds[i].stop();
                }
            }

        },

        /**
        * Pauses all the sounds in the game.
        *
        * @method Phaser.SoundManager#pauseAll
        */
        pauseAll: function () {

            for (var i = 0; i < this._sounds.length; i++)
            {
                if (this._sounds[i])
                {
                    this._sounds[i].pause();
                }
            }

        },

        /**
        * Resumes every sound in the game.
        *
        * @method Phaser.SoundManager#resumeAll
        */
        resumeAll: function () {

            for (var i = 0; i < this._sounds.length; i++)
            {
                if (this._sounds[i])
                {
                    this._sounds[i].resume();
                }
            }

        },

        /**
        * Decode a sound by its assets key.
        *
        * @method Phaser.SoundManager#decode
        * @param {string} key - Assets key of the sound to be decoded.
        * @param {Phaser.Sound} [sound] - Its buffer will be set to decoded data.
        */
        decode: function (key, sound) {

            sound = sound || null;

            var soundData = this.game.cache.getSoundData(key);

            if (soundData)
            {
                if (this.game.cache.isSoundDecoded(key) === false)
                {
                    this.game.cache.updateSound(key, 'isDecoding', true);

                    var that = this;

                    this.context.decodeAudioData(soundData, function (buffer) {
                        that.game.cache.decodedSound(key, buffer);
                        if (sound)
                        {
                            that.onSoundDecode.dispatch(key, sound);
                        }
                    });
                }
            }

        },

        /**
        * Updates every sound in the game.
        *
        * @method Phaser.SoundManager#update
        */
        update: function () {

            if (this.touchLocked)
            {
                if (this.game.device.webAudio && this._unlockSource !== null)
                {
                    if ((this._unlockSource.playbackState === this._unlockSource.PLAYING_STATE || this._unlockSource.playbackState === this._unlockSource.FINISHED_STATE))
                    {
                        this.touchLocked = false;
                        this._unlockSource = null;
                        this.game.input.touch.callbackContext = null;
                        this.game.input.touch.touchStartCallback = null;
                    }
                }
            }

            for (var i = 0; i < this._sounds.length; i++)
            {
                this._sounds[i].update();
            }

        },

        /**
        * Adds a new Sound into the SoundManager.
        *
        * @method Phaser.SoundManager#add
        * @param {string} key - Asset key for the sound.
        * @param {number} [volume=1] - Default value for the volume.
        * @param {boolean} [loop=false] - Whether or not the sound will loop.
        * @param {boolean} [connect=true] - Controls if the created Sound object will connect to the master gainNode of the SoundManager when running under WebAudio.
        * @return {Phaser.Sound} The new sound instance.
        */
        add: function (key, volume, loop, connect) {

            if (typeof volume === 'undefined') { volume = 1; }
            if (typeof loop === 'undefined') { loop = false; }
            if (typeof connect === 'undefined') { connect = this.connectToMaster; }

            var sound = new Phaser.Sound(this.game, key, volume, loop, connect);

            this._sounds.push(sound);

            return sound;

        },

        /**
        * Removes a Sound from the SoundManager. The removed Sound is destroyed before removal.
        *
        * @method Phaser.SoundManager#remove
        * @param {Phaser.Sound} sound - The sound object to remove.
        * @return {boolean} True if the sound was removed successfully, otherwise false.
        */
        remove: function (sound) {

            var i = this._sounds.length;

            while (i--)
            {
                if (this._sounds[i] === sound)
                {
                    this._sounds[i].destroy(false);
                    this._sounds.splice(i, 1);
                    return true;
                }
            }

            return false;

        },

        /**
        * Removes all Sounds from the SoundManager that have an asset key matching the given value.
        * The removed Sounds are destroyed before removal.
        *
        * @method Phaser.SoundManager#removeByKey
        * @param {string} key - The key to match when removing sound objects.
        * @return {number} The number of matching sound objects that were removed.
        */
        removeByKey: function (key) {

            var i = this._sounds.length;
            var removed = 0;

            while (i--)
            {
                if (this._sounds[i].key === key)
                {
                    this._sounds[i].destroy(false);
                    this._sounds.splice(i, 1);
                    removed++;
                }
            }

            return removed;

        },

        /**
        * Adds a new Sound into the SoundManager and starts it playing.
        *
        * @method Phaser.SoundManager#play
        * @param {string} key - Asset key for the sound.
        * @param {number} [volume=1] - Default value for the volume.
        * @param {boolean} [loop=false] - Whether or not the sound will loop.
        * @return {Phaser.Sound} The new sound instance.
        */
        play: function (key, volume, loop) {

            var sound = this.add(key, volume, loop);

            sound.play();

            return sound;

        },

        /**
        * Internal mute handler called automatically by the Sound.mute setter.
        *
        * @method Phaser.SoundManager#setMute
        * @private
        */
        setMute: function () {

            if (this._muted)
            {
                return;
            }

            this._muted = true;

            if (this.usingWebAudio)
            {
                this._muteVolume = this.masterGain.gain.value;
                this.masterGain.gain.value = 0;
            }

            //  Loop through sounds
            for (var i = 0; i < this._sounds.length; i++)
            {
                if (this._sounds[i].usingAudioTag)
                {
                    this._sounds[i].mute = true;
                }
            }

        },

        /**
        * Internal mute handler called automatically by the Sound.mute setter.
        *
        * @method Phaser.SoundManager#unsetMute
        * @private
        */
        unsetMute: function () {

            if (!this._muted || this._codeMuted)
            {
                return;
            }

            this._muted = false;

            if (this.usingWebAudio)
            {
                this.masterGain.gain.value = this._muteVolume;
            }

            //  Loop through sounds
            for (var i = 0; i < this._sounds.length; i++)
            {
                if (this._sounds[i].usingAudioTag)
                {
                    this._sounds[i].mute = false;
                }
            }

        }

    };

    Phaser.SoundManager.prototype.constructor = Phaser.SoundManager;

    /**
    * @name Phaser.SoundManager#mute
    * @property {boolean} mute - Gets or sets the muted state of the SoundManager. This effects all sounds in the game.
    */
    Object.defineProperty(Phaser.SoundManager.prototype, "mute", {

        get: function () {

            return this._muted;

        },

        set: function (value) {

            value = value || null;

            if (value)
            {
                if (this._muted)
                {
                    return;
                }

                this._codeMuted = true;
                this.setMute();
            }
            else
            {
                if (!this._muted)
                {
                    return;
                }

                this._codeMuted = false;
                this.unsetMute();
            }
        }

    });

    /**
    * @name Phaser.SoundManager#volume
    * @property {number} volume - Gets or sets the global volume of the SoundManager, a value between 0 and 1.
    */
    Object.defineProperty(Phaser.SoundManager.prototype, "volume", {

        get: function () {

            if (this.usingWebAudio)
            {
                return this.masterGain.gain.value;
            }
            else
            {
                return this._volume;
            }

        },

        set: function (value) {

            this._volume = value;

            if (this.usingWebAudio)
            {
                this.masterGain.gain.value = value;
            }
            else
            {
                //  Loop through the sound cache and change the volume of all html audio tags
                for (var i = 0; i < this._sounds.length; i++)
                {
                    if (this._sounds[i].usingAudioTag)
                    {
                        this._sounds[i].volume = this._sounds[i].volume * value;
                    }
                }
            }

        }

    });