waud/waud

import js.html.audio.GainNode;
import js.html.AudioElement;
import js.html.SourceElement;
import js.html.audio.AudioBufferSourceNode;
import js.html.audio.AudioContext;
import js.Browser;

class AudioManager {

    /**
    * Audio Types.
    *
    * @property types
    * @protected
    * @type {Map}
    */
    public var types:Map<String, String>;

    /**
    * Audio Context instance.
    *
    * @property audioContext
    * @protected
    * @type {AudioContext}
    */
    public var audioContext(default, null):Dynamic;

    /**
    * Master Gain Node
    *
    * @property gainNode
    * @protected
    * @type {GainNode}
    */
    public var masterGainNode(default, null):GainNode;

    /**
    * Audio buffer list.
    *
    * @property bufferList
    * @protected
    * @type {Map}
    */
    public var bufferList:Map<String, Dynamic>;

    /**
    * Audio Context Class determined based on the browser type. Refer {{#crossLink "AudioManager/checkWebAudioAPISupport:method"}}{{/crossLink}} method.
    *
    * @property AudioContextClass
    * @static
    * @private
    * @type {AudioContext|webkitAudioContext}
    */
    static var AudioContextClass:Dynamic;

    static inline var AUDIO_CONTEXT:String = "this.audioContext";

    /**
    * Audio Manager class instantiated in {{#crossLink "Waud/init:method"}}Waud.init{{/crossLink}} method.
    *
    * @class AudioManager
    * @constructor
    * @example
    *         Waud.audioManager
    */
    public function new() {
        bufferList = new Map();

        types = new Map();
        types.set("mp3", "audio/mpeg");
        types.set("ogg", "audio/ogg");
        types.set("wav", "audio/wav");
        types.set("aac", "audio/aac");
        types.set("m4a", "audio/x-m4a");
    }

    /**
    * Function to check web audio api support.
    *
    * Used by {{#crossLink "Waud/init:method"}}Waud.init{{/crossLink}} method.
    *
    * @method checkWebAudioAPISupport
    */
    public function checkWebAudioAPISupport():Bool {
        return (Reflect.field(Browser.window, "AudioContext") != null || Reflect.field(Browser.window, "webkitAudioContext") != null);
    }

    /**
    * Function to unlock audio on `touchend` event.
    *
    * Used by {{#crossLink "Waud/enableTouchUnlock:method"}}Waud.enableTouchUnlock{{/crossLink}} method.
    *
    * @method unlockAudio
    */
    public function unlockAudio() {
        if (audioContext != null) {
            var bfr = audioContext.createBuffer(1, 1, Waud.preferredSampleRate);
            var src:AudioBufferSourceNode = audioContext.createBufferSource();
            src.buffer = bfr;
            src.connect(audioContext.destination);
            if (Reflect.field(src, "start") != null) src.start(0);
            else untyped __js__("src").noteOn(0);
            if (src.onended != null) src.onended = _unlockCallback;
            else haxe.Timer.delay(_unlockCallback, 1);
            resumeContext();
        }
        else {
            var audio:AudioElement = Browser.document.createAudioElement();
            var source:SourceElement = Browser.document.createSourceElement();
            source.src = "data:audio/wave;base64,UklGRjIAAABXQVZFZm10IBIAAAABAAEAQB8AAEAfAAABAAgAAABmYWN0BAAAAAAAAABkYXRhAAAAAA==";
            audio.appendChild(source);
            Browser.document.appendChild(audio);
            audio.play();
            _unlockCallback();
        }
    }

    inline function _unlockCallback() {
        if (Waud.__touchUnlockCallback != null) Waud.__touchUnlockCallback();
        Waud.dom.ontouchend = null;
    }

    /**
    * Function to create audio context.
    *
    * Used by {{#crossLink "Waud/init:method"}}Waud.init{{/crossLink}} method.
    *
    * @method createAudioContext
    * @return AudioContext
    */
    public function createAudioContext():AudioContext {
        if (audioContext == null) {
            try {
                if (Reflect.field(Browser.window, "AudioContext") != null) {
                    audioContext = untyped __js__("new AudioContext()");
                }
                else if (Reflect.field(Browser.window, "webkitAudioContext") != null) {
                    audioContext = untyped __js__("new webkitAudioContext()");
                }
                masterGainNode = createGain();
            }
            catch (e:Dynamic) {
                audioContext = null;
            }
        }
        return audioContext;
    }

    public function createGain():GainNode {
        if (audioContext.createGain != null) return audioContext.createGain();
        else return Reflect.callMethod(audioContext, Reflect.field(audioContext, "createGainNode"), []);
    }

    /**
    * Function to close audio context and reset all variables.
    *
    * Used by {{#crossLink "Waud/destroy:method"}}Waud.destroy{{/crossLink}} method.
    *
    * @method destroy
    */
    public function destroy() {
        if (audioContext != null && untyped __js__(AUDIO_CONTEXT).close != null && untyped __js__(AUDIO_CONTEXT).close != "") {
            untyped __js__(AUDIO_CONTEXT).close();
        }
        audioContext = null;
        bufferList = null;
        types = null;
    }

    /**
    * This function suspends the progression of time in the audio context, temporarily halting audio hardware access and reducing CPU/battery usage in the process.
    * This is useful if you want an application to power down the audio hardware when it will not be using an audio context for a while.
    *
    * @method suspendContext
    * @example
    *     Waud.audioManager.suspendContext();
    */
    public function suspendContext() {
        if (audioContext != null && audioContext.state != null && audioContext.suspend != null) {
            audioContext.suspend();
        }
    }

    /**
    * This function resumes the progression of time in an audio context that has previously been suspended.
    *
    * @method resumeContext
    * @example
    *     Waud.audioManager.resumeContext();
    */
    public function resumeContext() {
        if (audioContext != null && audioContext.state != null && audioContext.resume != null) {
            audioContext.resume();
        }
    }
}