/* jshint newcap: false */

/**
* @author       Richard Davey <rich@photonstorm.com>
* @copyright    2013 Photon Storm Ltd.
* @license      {@link https://github.com/photonstorm/phaser/blob/master/license.txt|MIT License}
*/

/**
* The State Manager is responsible for loading, setting up and switching game states.
* 
* @class Phaser.StateManager
* @constructor
* @param {Phaser.Game} game - A reference to the currently running game.
* @param {Phaser.State|Object} [pendingState=null] - A State object to seed the manager with.
*/
Phaser.StateManager = function (game, pendingState) {

    /**
    * @property {Phaser.Game} game - A reference to the currently running game.
    */
    this.game = game;

    /**
    * @property {Object} states - The object containing Phaser.States.
    */
    this.states = {};

    /**
    * @property {Phaser.State} _pendingState - The state to be switched to in the next frame.
    * @private
    */
    this._pendingState = null;

    if (typeof pendingState !== 'undefined' && pendingState !== null)
    {
        this._pendingState = pendingState;
    }

    /**
    * @property {boolean} _created - Flag that sets if the State has been created or not.
    * @private
    */
    this._created = false;

    /**
    * @property {string} current - The current active State object (defaults to null).
    */
    this.current = '';

    /**
    * @property {function} onInitCallback - This will be called when the state is started (i.e. set as the current active state).
    */
    this.onInitCallback = null;

    /**
    * @property {function} onPreloadCallback - This will be called when init states (loading assets...).
    */
    this.onPreloadCallback = null;
    
    /**
    * @property {function} onCreateCallback - This will be called when create states (setup states...).
    */
    this.onCreateCallback = null;

    /**
    * @property {function} onUpdateCallback - This will be called when State is updated, this doesn't happen during load (@see onLoadUpdateCallback).
    */
    this.onUpdateCallback = null;

    /**
    * @property {function} onRenderCallback - This will be called when the State is rendered, this doesn't happen during load (see onLoadRenderCallback).
    */
    this.onRenderCallback = null;

    /**
    * @property {function} onPreRenderCallback - This will be called before the State is rendered and before the stage is cleared.
    */
    this.onPreRenderCallback = null;

    /**
    * @property {function} onLoadUpdateCallback - This will be called when the State is updated but only during the load process.
    */
    this.onLoadUpdateCallback = null;

    /**
    * @property {function} onLoadRenderCallback - This will be called when the State is rendered but only during the load process.
    */
    this.onLoadRenderCallback = null;

    /**
    * @property {function} onPausedCallback - This will be called when the state is paused.
    */
    this.onPausedCallback = null;

    /**
    * @property {function} onShutDownCallback - This will be called when the state is shut down (i.e. swapped to another state).
    */
    this.onShutDownCallback = null;


};

Phaser.StateManager.prototype = {

    /**
    * The Boot handler is called by Phaser.Game when it first starts up.
    * @method Phaser.StateManager#boot
    * @private
    */
    boot: function () {

        this.game.onPause.add(this.pause, this);
        this.game.onResume.add(this.resume, this);

        if (this._pendingState !== null)
        {
            if (typeof this._pendingState === 'string')
            {
                //  State was already added, so just start it
                this.start(this._pendingState, false, false);
            }
            else
            {
                this.add('default', this._pendingState, true);
            }

        }

    },

    /**
    * Add a new State.
    * @method Phaser.StateManager#add
    * @param key {string} - A unique key you use to reference this state, i.e. "MainMenu", "Level1".
    * @param state {State} - The state you want to switch to.
    * @param autoStart {boolean} - Start the state immediately after creating it? (default true)
    */
    add: function (key, state, autoStart) {

        if (typeof autoStart === "undefined") { autoStart = false; }

        var newState;

        if (state instanceof Phaser.State)
        {
            newState = state;
        }
        else if (typeof state === 'object')
        {
            newState = state;
            newState.game = this.game;
        }
        else if (typeof state === 'function')
        {
            newState = new state(this.game);
        }

        this.states[key] = newState;

        if (autoStart)
        {
            if (this.game.isBooted)
            {
                this.start(key);
            }
            else
            {
                this._pendingState = key;
            }
        }

        return newState;

    },

    /**
    * Delete the given state.
    * @method Phaser.StateManager#remove
    * @param {string} key - A unique key you use to reference this state, i.e. "MainMenu", "Level1".
    */
    remove: function (key) {

        if (this.current == key)
        {
            this.callbackContext = null;

            this.onInitCallback = null;
            this.onShutDownCallback = null;

            this.onPreloadCallback = null;
            this.onLoadRenderCallback = null;
            this.onLoadUpdateCallback = null;
            this.onCreateCallback = null;
            this.onUpdateCallback = null;
            this.onRenderCallback = null;
            this.onPausedCallback = null;
            this.onDestroyCallback = null;
        }

        delete this.states[key];

    },

    /**
    * Start the given state
    * @method Phaser.StateManager#start
    * @param {string} key - The key of the state you want to start.
    * @param {boolean} [clearWorld] - clear everything in the world? (Default to true)
    * @param {boolean} [clearCache] - clear asset cache? (Default to false and ONLY available when clearWorld=true)
    */
    start: function (key, clearWorld, clearCache) {

        if (typeof clearWorld === "undefined") { clearWorld = true; }
        if (typeof clearCache === "undefined") { clearCache = false; }

        if (this.game.isBooted === false)
        {
            this._pendingState = key;
            return;
        }

        if (this.checkState(key) === false)
        {
            return;
        }
        else
        {
            //  Already got a state running?
            if (this.current)
            {
                this.onShutDownCallback.call(this.callbackContext, this.game);
            }

            if (clearWorld)
            {
                this.game.tweens.removeAll();

                this.game.world.destroy();

                if (clearCache === true)
                {
                    this.game.cache.destroy();
                }
            }

            this.setCurrentState(key);
        }

        if (this.onPreloadCallback)
        {
            this.game.load.reset();
            this.onPreloadCallback.call(this.callbackContext, this.game);

            //  Is the loader empty?
            if (this.game.load.totalQueuedFiles() === 0)
            {
                this.game.loadComplete();
            }
            else
            {
                //  Start the loader going as we have something in the queue
                this.game.load.start();
            }
        }
        else
        {
            //  No init? Then there was nothing to load either
            this.game.loadComplete();
        }

    },
    
    /**
    * Used by onInit and onShutdown when those functions don't exist on the state
    * @method Phaser.StateManager#dummy
    * @private
    */
    dummy: function () {
    },

    /**
    * Description.
    * @method Phaser.StateManager#checkState
    * @param {string} key - The key of the state you want to check.
    * @return {boolean} Description.
    */
    checkState: function (key) {

        if (this.states[key])
        {
            var valid = false;

            if (this.states[key]['preload']) { valid = true; }

            if (valid === false && this.states[key]['loadRender']) { valid = true; }
            if (valid === false && this.states[key]['loadUpdate']) { valid = true; }
            if (valid === false && this.states[key]['create']) { valid = true; }
            if (valid === false && this.states[key]['update']) { valid = true; }
            if (valid === false && this.states[key]['preRender']) { valid = true; }
            if (valid === false && this.states[key]['render']) { valid = true; }
            if (valid === false && this.states[key]['paused']) { valid = true; }

            if (valid === false)
            {
                console.warn("Invalid Phaser State object given. Must contain at least a one of the required functions.");
                return false;
            }

            return true;
        }
        else
        {
            console.warn("Phaser.StateManager - No state found with the key: " + key);
            return false;
        }

    },

    /**
    * Links game properties to the State given by the key.
    * @method Phaser.StateManager#link
    * @param {string} key - State key.
    * @protected
    */
    link: function (key) {

        this.states[key].game = this.game;
        this.states[key].add = this.game.add;
        this.states[key].camera = this.game.camera;
        this.states[key].cache = this.game.cache;
        this.states[key].input = this.game.input;
        this.states[key].load = this.game.load;
        this.states[key].math = this.game.math;
        this.states[key].sound = this.game.sound;
        this.states[key].stage = this.game.stage;
        this.states[key].time = this.game.time;
        this.states[key].tweens = this.game.tweens;
        this.states[key].world = this.game.world;
        this.states[key].particles = this.game.particles;
        this.states[key].physics = this.game.physics;
        this.states[key].rnd = this.game.rnd;

    },

    /**
    * Sets the current State. Should not be called directly (use StateManager.start)
    * @method Phaser.StateManager#setCurrentState
    * @param {string} key - State key.
    * @protected
    */
    setCurrentState: function (key) {

        this.callbackContext = this.states[key];

        this.link(key);

        //  Used when the state is set as being the current active state
        this.onInitCallback = this.states[key]['init'] || this.dummy;

        this.onPreloadCallback = this.states[key]['preload'] || null;
        this.onLoadRenderCallback = this.states[key]['loadRender'] || null;
        this.onLoadUpdateCallback = this.states[key]['loadUpdate'] || null;
        this.onCreateCallback = this.states[key]['create'] || null;
        this.onUpdateCallback = this.states[key]['update'] || null;
        this.onPreRenderCallback = this.states[key]['preRender'] || null;
        this.onRenderCallback = this.states[key]['render'] || null;
        this.onPausedCallback = this.states[key]['paused'] || null;

        //  Used when the state is no longer the current active state
        this.onShutDownCallback = this.states[key]['shutdown'] || this.dummy;

        this.current = key;
        this._created = false;

        this.onInitCallback.call(this.callbackContext, this.game);

    },

    /**
    * @method Phaser.StateManager#loadComplete
    * @protected
    */
    loadComplete: function () {

        if (this._created === false && this.onCreateCallback)
        {
            this._created = true;
            this.onCreateCallback.call(this.callbackContext, this.game);
        }
        else
        {
            this._created = true;
        }

    },

    /**
    * @method Phaser.StateManager#pause
    * @protected
    */
    pause: function () {

        if (this._created && this.onPausedCallback)
        {
            this.onPausedCallback.call(this.callbackContext, this.game, true);
        }

    },

    /**
    * @method Phaser.StateManager#resume
    * @protected
    */
    resume: function () {

        if (this._created && this.onre)
        {
            this.onPausedCallback.call(this.callbackContext, this.game, false);
        }

    },

    /**
    * @method Phaser.StateManager#update
    * @protected
    */
    update: function () {

        if (this._created && this.onUpdateCallback)
        {
            this.onUpdateCallback.call(this.callbackContext, this.game);
        }
        else
        {
            if (this.onLoadUpdateCallback)
            {
                this.onLoadUpdateCallback.call(this.callbackContext, this.game);
            }
        }

    },

    /**
    * @method Phaser.StateManager#preRender
    * @protected
    */
    preRender: function () {

        if (this.onPreRenderCallback)
        {
            this.onPreRenderCallback.call(this.callbackContext, this.game);
        }

    },

    /**
    * @method Phaser.StateManager#render
    * @protected
    */
    render: function () {

        if (this._created && this.onRenderCallback)
        {
            if (this.game.renderType === Phaser.CANVAS)
            {
                this.game.context.save();
                this.game.context.setTransform(1, 0, 0, 1, 0, 0);
            }

            this.onRenderCallback.call(this.callbackContext, this.game);

            if (this.game.renderType === Phaser.CANVAS)
            {
                this.game.context.restore();
            }
        }
        else
        {
            if (this.onLoadRenderCallback)
            {
                this.onLoadRenderCallback.call(this.callbackContext, this.game);
            }
        }

    },

    /**
    * Nuke the entire game from orbit
    * @method Phaser.StateManager#destroy
    */
    destroy: function () {

        this.callbackContext = null;

        this.onInitCallback = null;
        this.onShutDownCallback = null;

        this.onPreloadCallback = null;
        this.onLoadRenderCallback = null;
        this.onLoadUpdateCallback = null;
        this.onCreateCallback = null;
        this.onUpdateCallback = null;
        this.onRenderCallback = null;
        this.onPausedCallback = null;
        this.onDestroyCallback = null;

        this.game = null;
        this.states = {};
        this._pendingState = null;

    }

};