radio/libjs/wController/player.js

"use strict";

var Uint64 = require("../wType/uint64");
var Address = require("../wType/address");

var Controller = require("./controller");
var Button = require("./button");
var ImageById = require("./imageById");
var Vocabulary = require("./vocabulary");
var Audio = require("./file/audio");
var Model = require("./localModel");

var Enum = require("../utils/enum");
var StateMachine = require("../utils/stateMachine");

var Player = Controller.inherit({
    className: "Player",
    constructor: function(addr) {
        Controller.fn.constructor.call(this, addr);
        
        this.controls = Object.create(null);
        this.views = Object.create(null);
        this.mode = PlayerMode.straight.playback;
        this.progress = new ProgressModel();
        this.volume = new Slider();
        this.volume.setValue(1);
        this.progress.on("seekingStart", this._onSeekingStart, this);
        this.progress.on("seekingEnd", this._onSeekingEnd, this);
        this.progress.enable(false);
        this.volume.on("value", this._onVolume, this);
        this._audio = null;
        this._createStateMachine();
        this._createPlayingInfrastructure();
        
        this.addHandler("get");
        this.addHandler("viewsChange");
        this.addHandler("play");
        this.addHandler("pause");
        
        this._playbackInterval = setInterval(this._onInterval.bind(this), intervalPrecision);
    },
    destructor: function() {
        this._clearInterval(this._playbackInterval);
        this._destroyPlayingInfrastructure();
        this._fsm.destructor();
        this.progress.destructor();
        
        Controller.fn.destructor.call(this);
    },
    _addControl: function(type, address) {
        var t = type.valueOf();
        
        if (this.controls[t] !== undefined) {
            throw new Error("An attempt to add multiple instances of " + ItemType.reversed[t] + " into Player");
        }
        
        if (ItemType.reversed[t] !== undefined) {
            switch (t) {
                case ItemType.straight.playPause:
                case ItemType.straight.prev:
                case ItemType.straight.next:
                    var btn = new Button(address.clone());
                    btn.itemType = t;
                    this.controls[t] = btn;
                    this.addController(btn);
                    this.trigger("newElement", btn, t);
                    break;
                default:
                    this.trigger("serviceMessage", "An attempt to add ItemType " + ItemType.reversed[t] + " to controls of the Player, but it's not qualified to be a control", 1);
            }
        } else {
            this.trigger("serviceMessage", "An unrecgnized item ItemType in Player: " + t, 1);
        }
    },
    _addView: function(type, address) {
        var t = type.valueOf();
        var ctrl;
        var supported = false;
        
        if (this.views[t] !== undefined) {
            throw new Error("An attempt to add multiple instances of " + ItemType.reversed[t] + " into Player");
        }
        
        if (ItemType.reversed[t] !== undefined) {
            switch (t) {
                case ItemType.straight.queue:
                    this.trigger("serviceMessage", "Queue is not supported yet in Player", 1);
                    break;
                case ItemType.straight.currentPlayback:
                    ctrl = new Vocabulary(address.clone());
                    ctrl.on("newElement", this._onNewPlaybackElement, this);
                    ctrl.on("removeElement", this._onRemovePlaybackElement, this);
                    supported = true;
                    break;
                case ItemType.straight.picture:
                    ctrl = new ImageById(null, address.back());
                    ctrl.ItemType = t;
                    this.views[t] = ctrl;
                    
                    this.trigger("newElement", ctrl, t);
                    supported = false;                  //just to avoid adding with addController, since ImageById is not a controller
                    break;
                default:
                    this.trigger("serviceMessage", "An attempt to add ItemType " + ItemType.reversed[t] + " to views of the Player, but it's not qualified to be a view", 1);
            }
        } else {
            this.trigger("serviceMessage", "An unrecognized item ItemType in Player: " + t, 1);
        }
        
        if (supported) {
            ctrl.ItemType = t;
            this.views[t] = ctrl;
            this.addController(ctrl);
            
            this.trigger("newElement", ctrl, t);
        }
    },
    _checkIfEnough: function() {
        var diff = this._currentTime - this._seekingTime - this._ctx.currentTime;
        if (diff > threshold) {
            this._fsm.manipulation("enough");
        } else {
            this._fsm.manipulation("notEnough");
        }
    },
    _createPlayingInfrastructure: function() {
        this._ctx = new AudioContext();
        this._decoder = new Mp3Decoder();
        this._gainNode = this._ctx.createGain();
        this._gainNode.connect(this._ctx.destination);
        this._currentTime = 0;
        this._seekingTime = 0;
        this._buffers = [];
        this._sources = [];
        
        this._ctx.suspend();
    },
    _createStateMachine: function() {
        this._fsm = new StateMachine("initial", graphs[this.mode]);
        this._fsm.on("stateChanged", this._onStateChanged, this);
    },
    _destroyPlayingInfrastructure: function() {
        this._ctx.close();
        this._decoder.delete();
    },
    getCurrentPlaybackTime: function() {
        return this._ctx.currentTime + this._seekingTime;
    },
    _h_get: function(ev) {
        var data = ev.getData();
        
        var controls = data.at("controls");
        var views = data.at("views");
        var mode = data.at("mode").valueOf();
        var size, i, vc;
        
        size = controls.length();
        for (i = 0; i < size; ++i) {
            vc = controls.at(i);
            this._addControl(vc.at("type"), vc.at("address"));
        }
        
        size = views.length();
        for (i = 0; i < size; ++i) {
            vc = views.at(i);
            this._addView(vc.at("type"), vc.at("address"));
        }
        
        if (this.mode !== mode) {
            if (PlayerMode.reversed[mode] === undefined) {
                throw new Error("Unsupported mode of player: " + mode);
            }
            this.mode = mode;
        }
        
        this.initialized = true;
        this.trigger("data");
    },
    _h_pause: function(ev) {
        this._fsm.manipulation("pause");
    },
    _h_play: function(ev) {
        this._fsm.manipulation("play");
    },
    _h_viewsChange: function(ev) {
        var data = ev.getData();
        
        var add = data.at("add");
        var remove = data.at("remove");
        var size, i, vc;
        
        size = remove.length();
        for (i = 0; i < size; ++i) {
            this._removeView(remove.at(i).valueOf());
        }
        
        size = add.length();
        for (i = 0; i < size; ++i) {
            vc = add.at(i);
            this._addView(vc.at("type"), vc.at("address"));
        }
    },
    _onAudioNewSlice: function(frames) {
        var arr = new Uint8Array(frames.valueOf());
        this._decoder.addFragment(arr);
        
        while (this._decoder.hasMore()) {
            var sb = this._decoder.decode(9999);
            if (sb === undefined) {
                break;
            } else {
                this._buffers.push(sb);
                
                var startTime = this._currentTime - this._seekingTime;
                if (startTime < this._ctx.currentTime) {
                    var offset = startTime - this._ctx.currentTime + sb.duration;
                    if (offset > 0) {
                        var src = this._ctx.createBufferSource();
                        src.buffer = sb;
                        src.connect(this._gainNode);
                        src.start(0, Math.abs(startTime - this._ctx.currentTime));
                        this._sources.push(src);
                    }
                } else {
                    var src = this._ctx.createBufferSource();
                    src.buffer = sb;
                    src.connect(this._gainNode);
                    src.start(startTime);
                    this._sources.push(src);
                }
                
                this._currentTime += sb.duration;
            }
        }
        
        this.progress.setLoad(this._currentTime / this._audio.getDuration());
        
        this._fsm.manipulation("newFrames");
        if (this._audio.hasMore()) {
            this._audio.requestSlice(audioPortion);
        } else {
            this._fsm.manipulation("noMoreFrames");
        }
    },
    _onControllerReady: function() {
        this._fsm.manipulation("controllerReady");
    },
    _onInterval: function() {
        if (this._audio && this._audio.initialized && seekingStates.indexOf(this._fsm.state()) === -1) {
            var duration = this._audio.getDuration();
            this.progress.setValue(this.getCurrentPlaybackTime() / duration);
            this._checkIfEnough();
            
            if (this.progress.value >= 0.9999) {
                var next = this.controls[ItemType.straight.next];
                if (next && next.enabled) {
                    next.activate();
                } else {
                    this._fsm.manipulation("pause");
                    this._onSeekingStart();
                    this._onSeek(0);
                    this._onSeekingEnd(0);
                    this.controls[ItemType.straight.playPause].activate();
                }
            }
        }
    },
    _onNewPlaybackElement: function(key, element) {
        switch (key) {
            case "image":
                var address = new Address(["images", element.toString()]);
                this._addView(new Uint64(ItemType.straight.picture), address);
                address.destructor();
                break;
            case "audio":
                if (this.mode === PlayerMode.straight.playback) {
                    this._audio = new Audio(new Address(["music", element.toString()]));
                    this.addForeignController("Corax", this._audio);
                    this._audio.on("slice", this._onAudioNewSlice, this);
                    this._audio.on("ready", this._onControllerReady, this);
                    this._fsm.manipulation("controller");
                }
                break;
        }
    },
    _onRemovePlaybackElement: function(key) {
        switch (key) {
            case "image":
                this._removeView(ItemType.straight.picture);
                break;
            case "audio":
                this.removeForeignController(this._audio);
                this._audio.destructor();
                this._audio = null;
        }
    },
    _onSeekingStart: function() {
        this._fsm.manipulation("startSeeking");
    },
    _onSeekingEnd: function(progress) {
        if (seekingStates.indexOf(this._fsm.state()) !== -1) {
            for (var i = 0; i < this._sources.length; ++i) {
                this._sources[i].stop();
            }
            this._sources = [];
            
            var ct = this.getCurrentPlaybackTime();
            var duration = this._audio.getDuration();
            var targetTime = duration * progress;
            this._seekingTime += targetTime - ct;
            
            var nc = 0;
            
            for (var i = 0; i < this._buffers.length; ++i) {
                var buffer = this._buffers[i];
                var startTime = nc - targetTime;
                if (startTime < 0) {
                    var offset = startTime + buffer.duration;
                    if (offset > 0) {
                        var src = this._ctx.createBufferSource();
                        src.buffer = buffer;
                        src.connect(this._gainNode);
                        src.start(0, Math.abs(startTime));
                        this._sources.push(src);
                    }
                } else {
                    var src = this._ctx.createBufferSource();
                    src.buffer = buffer;
                    src.connect(this._gainNode);
                    src.start(this._ctx.currentTime + startTime);
                    this._sources.push(src);
                }
                
                nc += buffer.duration;
            }
        }
        this._fsm.manipulation("stopSeeking");
    },
    _onStateChanged: function(e) {
        switch (e.newState) {
            case "initial":
                if (e.manipulation === "noController") {
                    this.progress.enable(false);
                    this.removeForeignController(this._audio);
                    this._audio.destructor();
                    this._audio = null;
                    this._destroyPlayingInfrastructure();
                    this._createPlayingInfrastructure();
                }
                break;
            case "initialPlaying":
                if (e.manipulation === "noController") {
                    this.progress.enable(false);
                    this._ctx.suspend();
                    
                    this.removeForeignController(this._audio);
                    this.audio.destructor();
                    this._audio = null;
                    this._destroyPlayingInfrastructure();
                    this._createPlayingInfrastructure();
                }
                break;
            case "controllerNotReady":
                break
            case "controllerNotReadyPlaying":
                break
            case "hasController":
                break;
            case "hasControllerPlaying":
                if (this._audio.hasMore()) {
                    this._audio.requestSlice(audioPortion);
                } else {
                    this._fsm.manipulation("noMoreFrames");
                }
                break;
            case "buffering":
                if (e.oldState === "hasController") {
                    this.progress.enable(true);
                }
                break;
            case "bufferingPlaying":
                if (e.oldState === "playing") {
                    this._ctx.suspend();
                } else if (e.oldState === "hasControllerPlaying") {
                    this.progress.enable(true);
                }
                break;
            case "seeking":
                break;
            case "seekingPlaying":
                if (e.oldState === "playing") {
                    this._ctx.suspend();
                }
                break;
            case "seekingAllLoaded":
                break;
            case "seekingPlayingAllLoaded":
                if (e.oldState === "playingAllLoaded") {
                    this._ctx.suspend();
                }
                break;
            case "paused":
                switch (e.oldState) {
                    case "playing":
                        this._ctx.suspend();
                        break;
                }
                break;
            case "pausedAllLoaded":
                switch (e.oldState) {
                    case "playingAllLoaded":
                        this._ctx.suspend();
                        break;
                }
                break;
            case "playing":
                this._ctx.resume();
                break;
            case "playingAllLoaded":
                switch (e.oldState) {
                    case "pausedAllLoaded":
                    case "bufferingPlaying":
                    case "seekingPlayingAllLoaded":
                        this._ctx.resume();
                        break;
                }
                break;
        }
    },
    _onVolume: function(volume) {
        this._gainNode.gain.cancelScheduledValues(this._ctx.currentTime);
        this._gainNode.gain.exponentialRampToValueAtTime(volume, this._ctx.currentTime + 0.01);
    },
    _removeControl: function(type) {
        var ctrl = this.controls[type];
        if (ctrl !== undefined) {
            this.trigger("removeElement", type);
            this.removeController(ctrl);
            ctrl.destructor();
        }
    },
    _removeView: function(type) {
        var view = this.views[type];
        if (view !== undefined) {
            this.trigger("removeElement", type);
            
            if (type !== ItemType.straight.picture) {
                this.removeController(view);
            }
            if (type === ItemType.straight.currentPlayback) {
                if (this.views[ItemType.straight.picture]) {
                    this._removeView(ItemType.straight.picture);
                }
                this._fsm.manipulation("noController");
            }
            delete this.views[type];
            view.destructor();
        }
    }
});

var ItemType = new Enum("ItemType");
ItemType.add("playPause");
ItemType.add("currentPlayback");
ItemType.add("queue");
ItemType.add("picture");
ItemType.add("prev");
ItemType.add("next");

var PlayerMode = new Enum("PlayerMode");
PlayerMode.add("playback");

Player.ItemType = ItemType;

var graphs = Object.create(null);
graphs[PlayerMode.straight.playback] = {
    "initial": {
        controller: "controllerNotReady",
        play: "initialPlaying"
    },
    "initialPlaying": {
        pause: "initial",
        controller: "controllerNotReadyPlaying"
    },
    "controllerNotReady": {
        play: "controllerNotReadyPlaying",
        controllerReady: "hasController"
    },
    "controllerNotReadyPlaying": {
        pause: "controllerNotReady",
        controllerReady: "hasControllerPlaying"
    },
    "hasController": {
        newFrames: "bufferingPlaying",
        play: "hasControllerPlaying",
        noController: "initial"
    },
    "hasControllerPlaying": {
        newFrames: "bufferingPlaying",
        pause: "hasController",
        noController: "initialPlaying"
    },
    "buffering": {
        play: "bufferingPlaying",
        enough: "paused",
        noMoreFrames: "pausedAllLoaded",
        startSeeking: "seeking",
        noController: "initial"
    },
    "bufferingPlaying": {
        pause: "buffering",
        enough: "playing",
        noMoreFrames: "playingAllLoaded",
        startSeeking: "seekingPlaying",
        noController: "initialPlaying"
    },
    "seeking": {
        stopSeeking: "buffering",
        noMoreFrames: "seekingAllLoaded",
        noController: "initial"
    },
    "seekingPlaying": {
        stopSeeking: "bufferingPlaying",
        noMoreFrames: "playingAllLoaded",
        noController: "initialPlaying"
    },
    "seekingAllLoaded": {
        stopSeeking: "pausedAllLoaded",
        noController: "initial"
    },
    "seekingPlayingAllLoaded": {
        stopSeeking: "playingAllLoaded",
        noController: "initialPlaying"
    },
    "paused": {
        play: "playing",
        notEnough: "buffering",
        noController: "initial",
        noMoreFrames: "pausedAllLoaded",
        startSeeking: "seeking"
    },
    "pausedAllLoaded": {
        play: "playingAllLoaded",
        noController: "initial",
        startSeeking: "seekingAllLoaded"
    },
    "playing": {
        pause: "paused",
        notEnough: "bufferingPlaying",
        noMoreFrames: "playingAllLoaded",
        noController: "initialPlaying",
        startSeeking: "seekingPlaying"
    },
    "playingAllLoaded": {
        pause: "pausedAllLoaded",
        noController: "initialPlaying",
        startSeeking: "seekingPlayingAllLoaded"
    }
}
var seekingStates = ["seeking", "seekingPlaying", "seekingAllLoaded", "seekingPlayingAllLoaded"]

var audioPortion = 1024 * 50;   //bytes to download for each portion
var threshold = 2;              //seconds to buffer before playing
var intervalPrecision = 100;    //millisecond of how often to check the playback

var Slider = Model.inherit({
    className: "Slider",
    constructor: function(properties) {
        Model.fn.constructor.call(this, properties);
        
        this.enabled = true;
        this.value = 0;
        this.initialized = true;
    },
    enable: function(en) {
        if (en !== this.enabled) {
            this.enabled = en;
            this.trigger("enabled", en);
        }
    },
    setValue: function(p) {
        if (p !== this.value) {
            this.value = p;
            this.trigger("value", p);
        }
    }
});

var ProgressModel = Slider.inherit({
    className: "ProgressModel",
    constructor: function(properties) {
        Slider.fn.constructor.call(this, properties);
        
        this.value = 0;
    },
    setLoad: function(l) {
        if (l !== this.load) {
            this.load = l;
            this.trigger("load", l);
        }
    }
});

module.exports = Player;