/**
 * @author       Richard Davey <rich@photonstorm.com>
 * @copyright    2018 Photon Storm Ltd.
 * @license      {@link https://github.com/photonstorm/phaser/blob/master/license.txt|MIT License}
 */

var AddToDOM = require('../dom/AddToDOM');
var AnimationManager = require('../animations/AnimationManager');
var CacheManager = require('../cache/CacheManager');
var CanvasPool = require('../display/canvas/CanvasPool');
var Class = require('../utils/Class');
var Config = require('./Config');
var CreateDOMContainer = require('./CreateDOMContainer');
var CreateRenderer = require('./CreateRenderer');
var DataManager = require('../data/DataManager');
var DebugHeader = require('./DebugHeader');
var Device = require('../device');
var DOMContentLoaded = require('../dom/DOMContentLoaded');
var EventEmitter = require('eventemitter3');
var FacebookInstantGamesPlugin = require('../fbinstant/FacebookInstantGamesPlugin');
var InputManager = require('../input/InputManager');
var PluginCache = require('../plugins/PluginCache');
var PluginManager = require('../plugins/PluginManager');
var ScaleManager = require('./ScaleManager');
var SceneManager = require('../scene/SceneManager');
var SoundManagerCreator = require('../sound/SoundManagerCreator');
var TextureManager = require('../textures/TextureManager');
var TimeStep = require('./TimeStep');
var VisibilityHandler = require('./VisibilityHandler');

/**
 * @classdesc
 * The Phaser.Game instance is the main controller for the entire Phaser game. It is responsible
 * for handling the boot process, parsing the configuration values, creating the renderer,
 * and setting-up all of the global Phaser systems, such as sound and input.
 * Once that is complete it will start the Scene Manager and then begin the main game loop.
 *
 * You should generally avoid accessing any of the systems created by Game, and instead use those
 * made available to you via the Phaser.Scene Systems class instead.
 *
 * @class Game
 * @memberOf Phaser
 * @constructor
 * @since 3.0.0
 *
 * @param {GameConfig} [GameConfig] - The configuration object for your Phaser Game instance.
 */
var Game = new Class({

    initialize:

    function Game (config)
    {
        /**
         * The parsed Game Configuration object.
         *
         * The values stored within this object are read-only and should not be changed at run-time.
         *
         * @name Phaser.Game#config
         * @type {Phaser.Boot.Config}
         * @readOnly
         * @since 3.0.0
         */
        this.config = new Config(config);

        /**
         * A reference to either the Canvas or WebGL Renderer that this Game is using.
         *
         * @name Phaser.Game#renderer
         * @type {(Phaser.Renderer.Canvas.CanvasRenderer|Phaser.Renderer.WebGL.WebGLRenderer)}
         * @since 3.0.0
         */
        this.renderer = null;

        /**
         * A reference to an HTML Div Element used as a DOM Element Container.
         * 
         * Only set if `createDOMContainer` is `true` in the game config (by default it is `false`) and
         * if you provide a parent element to insert the Phaser Game inside.
         *
         * See the DOM Element Game Object for more details.
         *
         * @name Phaser.Game#domContainer
         * @type {HTMLDivElement}
         * @since 3.12.0
         */
        this.domContainer = null;

        /**
         * A reference to the HTML Canvas Element that Phaser uses to render the game.
         * This is created automatically by Phaser unless you provide a `canvas` property
         * in your Game Config.
         *
         * @name Phaser.Game#canvas
         * @type {HTMLCanvasElement}
         * @since 3.0.0
         */
        this.canvas = null;

        /**
         * A reference to the Rendering Context belonging to the Canvas Element this game is rendering to.
         * If the game is running under Canvas it will be a 2d Canvas Rendering Context.
         * If the game is running under WebGL it will be a WebGL Rendering Context.
         * This context is created automatically by Phaser unless you provide a `context` property
         * in your Game Config.
         *
         * @name Phaser.Game#context
         * @type {(CanvasRenderingContext2D|WebGLRenderingContext)}
         * @since 3.0.0
         */
        this.context = null;

        /**
         * A flag indicating when this Game instance has finished its boot process.
         *
         * @name Phaser.Game#isBooted
         * @type {boolean}
         * @readOnly
         * @since 3.0.0
         */
        this.isBooted = false;

        /**
         * A flag indicating if this Game is currently running its game step or not.
         *
         * @name Phaser.Game#isRunning
         * @type {boolean}
         * @readOnly
         * @since 3.0.0
         */
        this.isRunning = false;

        /**
         * An Event Emitter which is used to broadcast game-level events from the global systems.
         *
         * @name Phaser.Game#events
         * @type {Phaser.Events.EventEmitter}
         * @since 3.0.0
         */
        this.events = new EventEmitter();

        /**
         * An instance of the Animation Manager.
         *
         * The Animation Manager is a global system responsible for managing all animations used within your game.
         *
         * @name Phaser.Game#anims
         * @type {Phaser.Animations.AnimationManager}
         * @since 3.0.0
         */
        this.anims = new AnimationManager(this);

        /**
         * An instance of the Texture Manager.
         *
         * The Texture Manager is a global system responsible for managing all textures being used by your game.
         *
         * @name Phaser.Game#textures
         * @type {Phaser.Textures.TextureManager}
         * @since 3.0.0
         */
        this.textures = new TextureManager(this);

        /**
         * An instance of the Cache Manager.
         *
         * The Cache Manager is a global system responsible for caching, accessing and releasing external game assets.
         *
         * @name Phaser.Game#cache
         * @type {Phaser.Cache.CacheManager}
         * @since 3.0.0
         */
        this.cache = new CacheManager(this);

        /**
         * An instance of the Data Manager
         *
         * @name Phaser.Game#registry
         * @type {Phaser.Data.DataManager}
         * @since 3.0.0
         */
        this.registry = new DataManager(this);

        /**
         * An instance of the Input Manager.
         *
         * The Input Manager is a global system responsible for the capture of browser-level input events.
         *
         * @name Phaser.Game#input
         * @type {Phaser.Input.InputManager}
         * @since 3.0.0
         */
        this.input = new InputManager(this, this.config);

        /**
         * An instance of the Scene Manager.
         *
         * The Scene Manager is a global system responsible for creating, modifying and updating the Scenes in your game.
         *
         * @name Phaser.Game#scene
         * @type {Phaser.Scenes.SceneManager}
         * @since 3.0.0
         */
        this.scene = new SceneManager(this, this.config.sceneConfig);

        /**
         * A reference to the Device inspector.
         *
         * Contains information about the device running this game, such as OS, browser vendor and feature support.
         * Used by various systems to determine capabilities and code paths.
         *
         * @name Phaser.Game#device
         * @type {Phaser.DeviceConf}
         * @since 3.0.0
         */
        this.device = Device;

        /**
         * An instance of the Scale Manager.
         *
         * The Scale Manager is a global system responsible for handling game scaling events.
         *
         * @name Phaser.Game#scaleManager
         * @type {Phaser.Boot.ScaleManager}
         * @since 3.12.0
         */
        this.scaleManager = new ScaleManager(this, this.config);

        /**
         * An instance of the base Sound Manager.
         *
         * The Sound Manager is a global system responsible for the playback and updating of all audio in your game.
         *
         * @name Phaser.Game#sound
         * @type {Phaser.Sound.BaseSoundManager}
         * @since 3.0.0
         */
        this.sound = SoundManagerCreator.create(this);

        /**
         * An instance of the Time Step.
         *
         * The Time Step is a global system responsible for setting-up and responding to the browser frame events, processing
         * them and calculating delta values. It then automatically calls the game step.
         *
         * @name Phaser.Game#loop
         * @type {Phaser.Boot.TimeStep}
         * @since 3.0.0
         */
        this.loop = new TimeStep(this, this.config.fps);

        /**
         * An instance of the Plugin Manager.
         *
         * The Plugin Manager is a global system that allows plugins to register themselves with it, and can then install
         * those plugins into Scenes as required.
         *
         * @name Phaser.Game#plugins
         * @type {Phaser.Plugins.PluginManager}
         * @since 3.0.0
         */
        this.plugins = new PluginManager(this, this.config);

        /**
         * An instance of the Facebook Instant Games Manager.
         *
         * @name Phaser.Game#facebook
         * @type {any}
         * @since 3.12.0
         */
        this.facebook = new FacebookInstantGamesPlugin(this);

        /**
         * Is this Game pending destruction at the start of the next frame?
         *
         * @name Phaser.Game#pendingDestroy
         * @type {boolean}
         * @private
         * @since 3.5.0
         */
        this.pendingDestroy = false;

        /**
         * Remove the Canvas once the destroy is over?
         *
         * @name Phaser.Game#removeCanvas
         * @type {boolean}
         * @private
         * @since 3.5.0
         */
        this.removeCanvas = false;

        /**
         * Remove everything when the game is destroyed.
         * You cannot create a new Phaser instance on the same web page after doing this.
         *
         * @name Phaser.Game#noReturn
         * @type {boolean}
         * @private
         * @since 3.12.0
         */
        this.noReturn = false;

        /**
         * Does the window the game is running in currently have focus or not?
         * This is modified by the VisibilityHandler.
         *
         * @name Phaser.Game#hasFocus
         * @type {boolean}
         * @readOnly
         * @since 3.9.0
         */
        this.hasFocus = false;

        /**
         * Is the mouse pointer currently over the game canvas or not?
         * This is modified by the VisibilityHandler.
         *
         * @name Phaser.Game#isOver
         * @type {boolean}
         * @readOnly
         * @since 3.10.0
         */
        this.isOver = true;

        //  Wait for the DOM Ready event, then call boot.
        DOMContentLoaded(this.boot.bind(this));
    },

    /**
     * Game boot event.
     *
     * This is an internal event dispatched when the game has finished booting, but before it is ready to start running.
     * The global systems use this event to know when to set themselves up, dispatching their own `ready` events as required.
     *
     * @event Phaser.Game#boot
     */

    /**
     * This method is called automatically when the DOM is ready. It is responsible for creating the renderer,
     * displaying the Debug Header, adding the game canvas to the DOM and emitting the 'boot' event.
     * It listens for a 'ready' event from the base systems and once received it will call `Game.start`.
     *
     * @method Phaser.Game#boot
     * @protected
     * @fires Phaser.Game#boot
     * @since 3.0.0
     */
    boot: function ()
    {
        if (!PluginCache.hasCore('EventEmitter'))
        {
            console.warn('Core Phaser Plugins missing. Cannot start.');
            return;
        }

        this.isBooted = true;

        this.config.preBoot(this);

        CreateRenderer(this);

        CreateDOMContainer(this);

        DebugHeader(this);

        AddToDOM(this.canvas, this.config.parent);

        this.events.emit('boot');

        //  The Texture Manager has to wait on a couple of non-blocking events before it's fully ready.
        //  So it will emit this internal event when done:
        this.events.once('texturesready', this.texturesReady, this);
    },

    /**
     * Called automatically when the Texture Manager has finished setting up and preparing the
     * default textures.
     *
     * @method Phaser.Game#texturesReady
     * @private
     * @fires Phaser.Game#ready
     * @since 3.12.0
     */
    texturesReady: function ()
    {
        //  Start all the other systems
        this.events.emit('ready');

        this.start();
    },

    /**
     * Called automatically by Game.boot once all of the global systems have finished setting themselves up.
     * By this point the Game is now ready to start the main loop running.
     * It will also enable the Visibility Handler.
     *
     * @method Phaser.Game#start
     * @protected
     * @since 3.0.0
     */
    start: function ()
    {
        this.isRunning = true;

        this.config.postBoot(this);

        if (this.renderer)
        {
            this.loop.start(this.step.bind(this));
        }
        else
        {
            this.loop.start(this.headlessStep.bind(this));
        }

        VisibilityHandler(this);

        var eventEmitter = this.events;

        eventEmitter.on('hidden', this.onHidden, this);
        eventEmitter.on('visible', this.onVisible, this);
        eventEmitter.on('blur', this.onBlur, this);
        eventEmitter.on('focus', this.onFocus, this);
    },

    /**
     * Game Pre-Step event.
     *
     * This event is dispatched before the main Step starts.
     * By this point none of the Scene updates have happened.
     * Hook into it from plugins or systems that need to update before the Scene Manager does.
     *
     * @event Phaser.Game#prestepEvent
     * @param {number} time - [description]
     * @param {number} delta - [description]
     */

    /**
     * Game Step event.
     *
     * This event is dispatched after Pre-Step and before the Scene Manager steps.
     * Hook into it from plugins or systems that need to update before the Scene Manager does, but after core Systems.
     *
     * @event Phaser.Game#stepEvent
     * @param {number} time - [description]
     * @param {number} delta - [description]
     */

    /**
     * Game Post-Step event.
     *
     * This event is dispatched after the Scene Manager has updated.
     * Hook into it from plugins or systems that need to do things before the render starts.
     *
     * @event Phaser.Game#poststepEvent
     * @param {number} time - [description]
     * @param {number} delta - [description]
     */

    /**
     * Game Pre-Render event.
     *
     * This event is dispatched immediately before any of the Scenes have started to render.
     * The renderer will already have been initialized this frame, clearing itself and preparing to receive
     * the Scenes for rendering, but it won't have actually drawn anything yet.
     *
     * @event Phaser.Game#prerenderEvent
     * @param {(Phaser.Renderer.Canvas.CanvasRenderer|Phaser.Renderer.WebGL.WebGLRenderer)} renderer - A reference to the current renderer.
     */

    /**
     * Game Post-Render event.
     *
     * This event is dispatched right at the end of the render process.
     * Every Scene will have rendered and drawn to the canvas.
     *
     * @event Phaser.Game#postrenderEvent
     * @param {(Phaser.Renderer.Canvas.CanvasRenderer|Phaser.Renderer.WebGL.WebGLRenderer)} renderer - A reference to the current renderer.
     */

    /**
     * The main Game Step. Called automatically by the Time Step, once per browser frame (typically as a result of
     * Request Animation Frame, or Set Timeout on very old browsers.)
     *
     * The step will update the global managers first, then proceed to update each Scene in turn, via the Scene Manager.
     *
     * It will then render each Scene in turn, via the Renderer. This process emits `prerender` and `postrender` events.
     *
     * @method Phaser.Game#step
     * @fires Phaser.Game#prestepEvent
     * @fires Phaser.Game#stepEvent
     * @fires Phaser.Game#poststepEvent
     * @fires Phaser.Game#prerenderEvent
     * @fires Phaser.Game#postrenderEvent
     * @since 3.0.0
     *
     * @param {integer} time - The current timestamp as generated by the Request Animation Frame or SetTimeout.
     * @param {number} delta - The delta time, in ms, elapsed since the last frame.
     */
    step: function (time, delta)
    {
        if (this.pendingDestroy)
        {
            return this.runDestroy();
        }

        var eventEmitter = this.events;

        //  Global Managers like Input and Sound update in the prestep

        eventEmitter.emit('prestep', time, delta);

        //  This is mostly meant for user-land code and plugins

        eventEmitter.emit('step', time, delta);

        //  Update the Scene Manager and all active Scenes

        this.scene.update(time, delta);

        //  Our final event before rendering starts

        eventEmitter.emit('poststep', time, delta);

        var renderer = this.renderer;

        //  Run the Pre-render (clearing the canvas, setting background colors, etc)

        renderer.preRender();

        eventEmitter.emit('prerender', renderer, time, delta);

        //  The main render loop. Iterates all Scenes and all Cameras in those scenes, rendering to the renderer instance.

        this.scene.render(renderer);

        //  The Post-Render call. Tidies up loose end, takes snapshots, etc.

        renderer.postRender();

        //  The final event before the step repeats. Your last chance to do anything to the canvas before it all starts again.

        eventEmitter.emit('postrender', renderer, time, delta);
    },

    /**
     * A special version of the Game Step for the HEADLESS renderer only.
     *
     * The main Game Step. Called automatically by the Time Step, once per browser frame (typically as a result of
     * Request Animation Frame, or Set Timeout on very old browsers.)
     *
     * The step will update the global managers first, then proceed to update each Scene in turn, via the Scene Manager.
     *
     * This process emits `prerender` and `postrender` events, even though nothing actually displays.
     *
     * @method Phaser.Game#headlessStep
     * @fires Phaser.Game#prerenderEvent
     * @fires Phaser.Game#postrenderEvent
     * @since 3.2.0
     *
     * @param {integer} time - The current timestamp as generated by the Request Animation Frame or SetTimeout.
     * @param {number} delta - The delta time elapsed since the last frame.
     */
    headlessStep: function (time, delta)
    {
        var eventEmitter = this.events;

        //  Global Managers

        eventEmitter.emit('prestep', time, delta);

        eventEmitter.emit('step', time, delta);

        //  Scenes

        this.scene.update(time, delta);

        eventEmitter.emit('poststep', time, delta);

        //  Render

        eventEmitter.emit('prerender');

        eventEmitter.emit('postrender');
    },

    /**
     * Game Pause event.
     *
     * This event is dispatched when the game loop enters a paused state, usually as a result of the Visibility Handler.
     *
     * @event Phaser.Game#pauseEvent
     */

    /**
     * Called automatically by the Visibility Handler.
     * This will pause the main loop and then emit a pause event.
     *
     * @method Phaser.Game#onHidden
     * @protected
     * @fires Phaser.Game#pauseEvent
     * @since 3.0.0
     */
    onHidden: function ()
    {
        this.loop.pause();

        this.events.emit('pause');
    },

    /**
     * Game Resume event.
     *
     * This event is dispatched when the game loop leaves a paused state and resumes running.
     *
     * @event Phaser.Game#resumeEvent
     */

    /**
     * Called automatically by the Visibility Handler.
     * This will resume the main loop and then emit a resume event.
     *
     * @method Phaser.Game#onVisible
     * @protected
     * @fires Phaser.Game#resumeEvent
     * @since 3.0.0
     */
    onVisible: function ()
    {
        this.loop.resume();

        this.events.emit('resume');
    },

    /**
     * Called automatically by the Visibility Handler.
     * This will set the main loop into a 'blurred' state, which pauses it.
     *
     * @method Phaser.Game#onBlur
     * @protected
     * @since 3.0.0
     */
    onBlur: function ()
    {
        this.hasFocus = false;

        this.loop.blur();
    },

    /**
     * Called automatically by the Visibility Handler.
     * This will set the main loop into a 'focused' state, which resumes it.
     *
     * @method Phaser.Game#onFocus
     * @protected
     * @since 3.0.0
     */
    onFocus: function ()
    {
        this.hasFocus = true;

        this.loop.focus();
    },

    /**
     * Game Resize event.
     *
     * @event Phaser.Game#resizeEvent
     * @param {number} width - The new width of the Game.
     * @param {number} height - The new height of the Game.
     */

    /**
     * Updates the Game Config with the new width and height values given.
     * Then resizes the Renderer and Input Manager scale.
     *
     * @method Phaser.Game#resize
     * @since 3.2.0
     *
     * @param {number} width - The new width of the game.
     * @param {number} height - The new height of the game.
     */
    resize: function (width, height)
    {
        this.config.width = width;
        this.config.height = height;

        if (this.domContainer)
        {
            this.domContainer.style.width = width + 'px';
            this.domContainer.style.height = height + 'px';
        }

        this.renderer.resize(width, height);

        this.input.resize();

        this.scene.resize(width, height);

        this.events.emit('resize', width, height);
    },

    /**
     * Flags this Game instance as needing to be destroyed on the next frame.
     * It will wait until the current frame has completed and then call `runDestroy` internally.
     * 
     * If you **do not** need to run Phaser again on the same web page you can set the `noReturn` argument to `true` and it will free-up
     * memory being held by the core Phaser plugins. If you do need to create another game instance on the same page, leave this as `false`.
     *
     * @method Phaser.Game#destroy
     * @since 3.0.0
     *
     * @param {boolean} removeCanvas - Set to `true` if you would like the parent canvas element removed from the DOM, or `false` to leave it in place.
     * @param {boolean} [noReturn=false] - If `true` all the core Phaser plugins are destroyed. You cannot create another instance of Phaser on the same web page if you do this.
     */
    destroy: function (removeCanvas, noReturn)
    {
        if (noReturn === undefined) { noReturn = false; }
        
        this.pendingDestroy = true;

        this.removeCanvas = removeCanvas;
        this.noReturn = noReturn;
    },

    /**
     * Destroys this Phaser.Game instance, all global systems, all sub-systems and all Scenes.
     *
     * @method Phaser.Game#runDestroy
     * @private
     * @since 3.5.0
     */
    runDestroy: function ()
    {
        this.events.emit('destroy');

        this.events.removeAllListeners();

        this.scene.destroy();

        if (this.renderer)
        {
            this.renderer.destroy();
        }

        if (this.removeCanvas && this.canvas)
        {
            CanvasPool.remove(this.canvas);

            if (this.canvas.parentNode)
            {
                this.canvas.parentNode.removeChild(this.canvas);
            }
        }

        if (this.domContainer)
        {
            this.domContainer.parentNode.removeChild(this.domContainer);
        }

        this.loop.destroy();
        
        this.pendingDestroy = false;
    }

});

module.exports = Game;