# Source: src/input/Mouse.js

    /**
    * @author       Richard Davey <rich@photonstorm.com>
    * @copyright    2016 Photon Storm Ltd.
    * @license      {@link https://github.com/photonstorm/phaser/blob/master/license.txt|MIT License}
    */

    /**
    * The Mouse class is responsible for handling all aspects of mouse interaction with the browser.
    *
    * It captures and processes mouse events that happen on the game canvas object.
    * It also adds a single `mouseup` listener to `window` which is used to capture the mouse being released
    * when not over the game.
    *
    * You should not normally access this class directly, but instead use a Phaser.Pointer object
    * which normalises all game input for you, including accurate button handling.
    *
    * @class Phaser.Mouse
    * @constructor
    * @param {Phaser.Game} game - A reference to the currently running game.
    */
    Phaser.Mouse = function (game) {

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

        /**
        * @property {Phaser.Input} input - A reference to the Phaser Input Manager.
        * @protected
        */
        this.input = game.input;

        /**
        * @property {object} callbackContext - The context under which callbacks are called.
        */
        this.callbackContext = this.game;

        /**
        * @property {function} mouseDownCallback - A callback that can be fired when the mouse is pressed down.
        */
        this.mouseDownCallback = null;

        /**
        * @property {function} mouseUpCallback - A callback that can be fired when the mouse is released from a pressed down state.
        */
        this.mouseUpCallback = null;

        /**
        * @property {function} mouseOutCallback - A callback that can be fired when the mouse is no longer over the game canvas.
        */
        this.mouseOutCallback = null;

        /**
        * @property {function} mouseOverCallback - A callback that can be fired when the mouse enters the game canvas (usually after a mouseout).
        */
        this.mouseOverCallback = null;

        /**
         * @property {function} mouseWheelCallback - A callback that can be fired when the mousewheel is used.
         */
        this.mouseWheelCallback = null;

        /**
        * @property {boolean} capture - If true the DOM mouse events will have event.preventDefault applied to them, if false they will propagate fully.
        */
        this.capture = false;

        /**
        * This property was removed in Phaser 2.4 and should no longer be used.
        * Instead please see the Pointer button properties such as `Pointer.leftButton`, `Pointer.rightButton` and so on.
        * Or Pointer.button holds the DOM event button value if you require that.
        * @property {number} button
        * @default
        */
        this.button = -1;

        /**
         * The direction of the _last_ mousewheel usage 1 for up -1 for down.
         * @property {number} wheelDelta
         */
        this.wheelDelta = 0;

        /**
        * Mouse input will only be processed if enabled.
        * @property {boolean} enabled
        * @default
        */
        this.enabled = true;

        /**
        * @property {boolean} locked - If the mouse has been Pointer Locked successfully this will be set to true.
        * @default
        */
        this.locked = false;

        /**
        * @property {boolean} stopOnGameOut - If true Pointer.stop will be called if the mouse leaves the game canvas.
        * @default
        */
        this.stopOnGameOut = false;

        /**
        * @property {Phaser.Signal} pointerLock - This event is dispatched when the browser enters or leaves pointer lock state.
        * @default
        */
        this.pointerLock = new Phaser.Signal();

        /**
        * The browser mouse DOM event. Will be null if no mouse event has ever been received.
        * Access this property only inside a Mouse event handler and do not keep references to it.
        * @property {MouseEvent|null} event
        * @default
        */
        this.event = null;

        /**
        * @property {function} _onMouseDown - Internal event handler reference.
        * @private
        */
        this._onMouseDown = null;

        /**
        * @property {function} _onMouseMove - Internal event handler reference.
        * @private
        */
        this._onMouseMove = null;

        /**
        * @property {function} _onMouseUp - Internal event handler reference.
        * @private
        */
        this._onMouseUp = null;

        /**
        * @property {function} _onMouseOut - Internal event handler reference.
        * @private
        */
        this._onMouseOut = null;

        /**
        * @property {function} _onMouseOver - Internal event handler reference.
        * @private
        */
        this._onMouseOver = null;

        /**
        * @property {function} _onMouseWheel - Internal event handler reference.
        * @private
        */
        this._onMouseWheel = null;

        /**
        * Wheel proxy event object, if required. Shared for all wheel events for this mouse.
        * @property {Phaser.Mouse~WheelEventProxy} _wheelEvent
        * @private
        */
        this._wheelEvent = null;

    };

    /**
    * @constant
    * @type {number}
    */
    Phaser.Mouse.NO_BUTTON = -1;

    /**
    * @constant
    * @type {number}
    */
    Phaser.Mouse.LEFT_BUTTON = 0;

    /**
    * @constant
    * @type {number}
    */
    Phaser.Mouse.MIDDLE_BUTTON = 1;

    /**
    * @constant
    * @type {number}
    */
    Phaser.Mouse.RIGHT_BUTTON = 2;

    /**
    * @constant
    * @type {number}
    */
    Phaser.Mouse.BACK_BUTTON = 3;

    /**
    * @constant
    * @type {number}
    */
    Phaser.Mouse.FORWARD_BUTTON = 4;

    /**
     * @constant
     * @type {number}
     */
    Phaser.Mouse.WHEEL_UP = 1;

    /**
     * @constant
     * @type {number}
     */
    Phaser.Mouse.WHEEL_DOWN = -1;

    Phaser.Mouse.prototype = {

        /**
        * Starts the event listeners running.
        * @method Phaser.Mouse#start
        */
        start: function () {

            if (this.game.device.android && this.game.device.chrome === false)
            {
                //  Android stock browser fires mouse events even if you preventDefault on the touchStart, so ...
                return;
            }

            if (this._onMouseDown !== null)
            {
                //  Avoid setting multiple listeners
                return;
            }

            var _this = this;

            this._onMouseDown = function (event) {
                return _this.onMouseDown(event);
            };

            this._onMouseMove = function (event) {
                return _this.onMouseMove(event);
            };

            this._onMouseUp = function (event) {
                return _this.onMouseUp(event);
            };

            this._onMouseUpGlobal = function (event) {
                return _this.onMouseUpGlobal(event);
            };

            this._onMouseOutGlobal = function (event) {
                return _this.onMouseOutGlobal(event);
            };

            this._onMouseOut = function (event) {
                return _this.onMouseOut(event);
            };

            this._onMouseOver = function (event) {
                return _this.onMouseOver(event);
            };

            this._onMouseWheel = function (event) {
                return _this.onMouseWheel(event);
            };

            var canvas = this.game.canvas;

            canvas.addEventListener('mousedown', this._onMouseDown, true);
            canvas.addEventListener('mousemove', this._onMouseMove, true);
            canvas.addEventListener('mouseup', this._onMouseUp, true);

            if (!this.game.device.cocoonJS)
            {
                window.addEventListener('mouseup', this._onMouseUpGlobal, true);
                window.addEventListener('mouseout', this._onMouseOutGlobal, true);
                canvas.addEventListener('mouseover', this._onMouseOver, true);
                canvas.addEventListener('mouseout', this._onMouseOut, true);
            }

            var wheelEvent = this.game.device.wheelEvent;

            if (wheelEvent)
            {
                canvas.addEventListener(wheelEvent, this._onMouseWheel, true);

                if (wheelEvent === 'mousewheel')
                {
                    this._wheelEvent = new WheelEventProxy(-1/40, 1);
                }
                else if (wheelEvent === 'DOMMouseScroll')
                {
                    this._wheelEvent = new WheelEventProxy(1, 1);
                }
            }

        },

        /**
        * The internal method that handles the mouse down event from the browser.
        * @method Phaser.Mouse#onMouseDown
        * @param {MouseEvent} event - The native event from the browser. This gets stored in Mouse.event.
        */
        onMouseDown: function (event) {

            this.event = event;

            if (this.capture)
            {
                event.preventDefault();
            }

            if (this.mouseDownCallback)
            {
                this.mouseDownCallback.call(this.callbackContext, event);
            }

            if (!this.input.enabled || !this.enabled)
            {
                return;
            }

            event['identifier'] = 0;

            this.input.mousePointer.start(event);

        },

        /**
        * The internal method that handles the mouse move event from the browser.
        * @method Phaser.Mouse#onMouseMove
        * @param {MouseEvent} event - The native event from the browser. This gets stored in Mouse.event.
        */
        onMouseMove: function (event) {

            this.event = event;

            if (this.capture)
            {
                event.preventDefault();
            }

            if (this.mouseMoveCallback)
            {
                this.mouseMoveCallback.call(this.callbackContext, event);
            }

            if (!this.input.enabled || !this.enabled)
            {
                return;
            }

            event['identifier'] = 0;

            this.input.mousePointer.move(event);

        },

        /**
        * The internal method that handles the mouse up event from the browser.
        * @method Phaser.Mouse#onMouseUp
        * @param {MouseEvent} event - The native event from the browser. This gets stored in Mouse.event.
        */
        onMouseUp: function (event) {

            this.event = event;

            if (this.capture)
            {
                event.preventDefault();
            }

            if (this.mouseUpCallback)
            {
                this.mouseUpCallback.call(this.callbackContext, event);
            }

            if (!this.input.enabled || !this.enabled)
            {
                return;
            }

            event['identifier'] = 0;

            this.input.mousePointer.stop(event);

        },

        /**
        * The internal method that handles the mouse up event from the window.
        *
        * @method Phaser.Mouse#onMouseUpGlobal
        * @param {MouseEvent} event - The native event from the browser. This gets stored in Mouse.event.
        */
        onMouseUpGlobal: function (event) {

            if (!this.input.mousePointer.withinGame)
            {
                if (this.mouseUpCallback)
                {
                    this.mouseUpCallback.call(this.callbackContext, event);
                }

                event['identifier'] = 0;

                this.input.mousePointer.stop(event);
            }

        },

        /**
        * The internal method that handles the mouse out event from the window.
        *
        * @method Phaser.Mouse#onMouseOutGlobal
        * @param {MouseEvent} event - The native event from the browser. This gets stored in Mouse.event.
        */
        onMouseOutGlobal: function (event) {

            this.event = event;

            if (this.capture)
            {
                event.preventDefault();
            }

            this.input.mousePointer.withinGame = false;

            if (!this.input.enabled || !this.enabled)
            {
                return;
            }

            //  If we get a mouseout event from the window then basically
            //  something serious has gone down, usually along the lines of
            //  the browser opening a context-menu or similar.
            //  On OS X Chrome especially this is bad news, as it blocks
            //  us then getting a mouseup event, so we need to force that through.
            //
            //  No matter what, we must cancel the left and right buttons

            this.input.mousePointer.stop(event);
            this.input.mousePointer.leftButton.stop(event);
            this.input.mousePointer.rightButton.stop(event);

        },

        /**
        * The internal method that handles the mouse out event from the browser.
        *
        * @method Phaser.Mouse#onMouseOut
        * @param {MouseEvent} event - The native event from the browser. This gets stored in Mouse.event.
        */
        onMouseOut: function (event) {

            this.event = event;

            if (this.capture)
            {
                event.preventDefault();
            }

            this.input.mousePointer.withinGame = false;

            if (this.mouseOutCallback)
            {
                this.mouseOutCallback.call(this.callbackContext, event);
            }

            if (!this.input.enabled || !this.enabled)
            {
                return;
            }

            if (this.stopOnGameOut)
            {
                event['identifier'] = 0;

                this.input.mousePointer.stop(event);
            }

        },

        /**
        * The internal method that handles the mouse over event from the browser.
        *
        * @method Phaser.Mouse#onMouseOver
        * @param {MouseEvent} event - The native event from the browser. This gets stored in Mouse.event.
        */
        onMouseOver: function (event) {

            this.event = event;

            if (this.capture)
            {
                event.preventDefault();
            }

            this.input.mousePointer.withinGame = true;

            if (this.mouseOverCallback)
            {
                this.mouseOverCallback.call(this.callbackContext, event);
            }

        },

        /**
         * The internal method that handles the mouse wheel event from the browser.
         *
         * @method Phaser.Mouse#onMouseWheel
         * @param {MouseEvent} event - The native event from the browser.
         */
        onMouseWheel: function (event) {

            if (this._wheelEvent) {
                event = this._wheelEvent.bindEvent(event);
            }

            this.event = event;

            if (this.capture)
            {
                event.preventDefault();
            }

            // reverse detail for firefox
            this.wheelDelta = Phaser.Math.clamp(-event.deltaY, -1, 1);

            if (this.mouseWheelCallback)
            {
                this.mouseWheelCallback.call(this.callbackContext, event);
            }

        },

        /**
        * If the browser supports it you can request that the pointer be locked to the browser window.
        * This is classically known as 'FPS controls', where the pointer can't leave the browser until the user presses an exit key.
        * If the browser successfully enters a locked state the event Phaser.Mouse.pointerLock will be dispatched and the first parameter will be 'true'.
        * @method Phaser.Mouse#requestPointerLock
        */
        requestPointerLock: function () {

            if (this.game.device.pointerLock)
            {
                var element = this.game.canvas;

                element.requestPointerLock = element.requestPointerLock || element.mozRequestPointerLock || element.webkitRequestPointerLock;

                element.requestPointerLock();

                var _this = this;

                this._pointerLockChange = function (event) {
                    return _this.pointerLockChange(event);
                };

                document.addEventListener('pointerlockchange', this._pointerLockChange, true);
                document.addEventListener('mozpointerlockchange', this._pointerLockChange, true);
                document.addEventListener('webkitpointerlockchange', this._pointerLockChange, true);
            }

        },

        /**
        * Internal pointerLockChange handler.
        *
        * @method Phaser.Mouse#pointerLockChange
        * @param {Event} event - The native event from the browser. This gets stored in Mouse.event.
        */
        pointerLockChange: function (event) {

            var element = this.game.canvas;

            if (document.pointerLockElement === element || document.mozPointerLockElement === element || document.webkitPointerLockElement === element)
            {
                //  Pointer was successfully locked
                this.locked = true;
                this.pointerLock.dispatch(true, event);
            }
            else
            {
                //  Pointer was unlocked
                this.locked = false;
                this.pointerLock.dispatch(false, event);
            }

        },

        /**
        * Internal release pointer lock handler.
        * @method Phaser.Mouse#releasePointerLock
        */
        releasePointerLock: function () {

            document.exitPointerLock = document.exitPointerLock || document.mozExitPointerLock || document.webkitExitPointerLock;

            document.exitPointerLock();

            document.removeEventListener('pointerlockchange', this._pointerLockChange, true);
            document.removeEventListener('mozpointerlockchange', this._pointerLockChange, true);
            document.removeEventListener('webkitpointerlockchange', this._pointerLockChange, true);

        },

        /**
        * Stop the event listeners.
        * @method Phaser.Mouse#stop
        */
        stop: function () {

            var canvas = this.game.canvas;

            canvas.removeEventListener('mousedown', this._onMouseDown, true);
            canvas.removeEventListener('mousemove', this._onMouseMove, true);
            canvas.removeEventListener('mouseup', this._onMouseUp, true);
            canvas.removeEventListener('mouseover', this._onMouseOver, true);
            canvas.removeEventListener('mouseout', this._onMouseOut, true);

            var wheelEvent = this.game.device.wheelEvent;

            if (wheelEvent)
            {
                canvas.removeEventListener(wheelEvent, this._onMouseWheel, true);
            }

            window.removeEventListener('mouseup', this._onMouseUpGlobal, true);
            window.removeEventListener('mouseout', this._onMouseOutGlobal, true);

            document.removeEventListener('pointerlockchange', this._pointerLockChange, true);
            document.removeEventListener('mozpointerlockchange', this._pointerLockChange, true);
            document.removeEventListener('webkitpointerlockchange', this._pointerLockChange, true);

        }

    };

    Phaser.Mouse.prototype.constructor = Phaser.Mouse;

    /* jshint latedef:nofunc */
    /**
    * A purely internal event support class to proxy 'wheelscroll' and 'DOMMouseWheel'
    * events to 'wheel'-like events.
    *
    * See https://developer.mozilla.org/en-US/docs/Web/Events/mousewheel for choosing a scale and delta mode.
    *
    * @method Phaser.Mouse#WheelEventProxy
    * @private
    * @param {number} scaleFactor - Scale factor as applied to wheelDelta/wheelDeltaX or details.
    * @param {integer} deltaMode - The reported delta mode.
    */
    function WheelEventProxy (scaleFactor, deltaMode) {

        /**
        * @property {number} _scaleFactor - Scale factor as applied to wheelDelta/wheelDeltaX or details.
        * @private
        */
        this._scaleFactor = scaleFactor;

        /**
        * @property {number} _deltaMode - The reported delta mode.
        * @private
        */
        this._deltaMode = deltaMode;

        /**
        * @property {any} originalEvent - The original event _currently_ being proxied; the getters will follow suit.
        * @private
        */
        this.originalEvent = null;

    }

    WheelEventProxy.prototype = {};
    WheelEventProxy.prototype.constructor = WheelEventProxy;

    WheelEventProxy.prototype.bindEvent = function (event) {

        // Generate stubs automatically
        if (!WheelEventProxy._stubsGenerated && event)
        {
            var makeBinder = function (name) {

                return function () {
                    var v = this.originalEvent[name];
                    return typeof v !== 'function' ? v : v.bind(this.originalEvent);
                };

            };

            for (var prop in event)
            {
                if (!(prop in WheelEventProxy.prototype))
                {
                    Object.defineProperty(WheelEventProxy.prototype, prop, {
                        get: makeBinder(prop)
                    });
                }
            }
            WheelEventProxy._stubsGenerated = true;
        }

        this.originalEvent = event;
        return this;

    };

    Object.defineProperties(WheelEventProxy.prototype, {
        "type": { value: "wheel" },
        "deltaMode": { get: function () { return this._deltaMode; } },
        "deltaY": {
            get: function () {
                return (this._scaleFactor * (this.originalEvent.wheelDelta || this.originalEvent.detail)) || 0;
            }
        },
        "deltaX": {
            get: function () {
                return (this._scaleFactor * this.originalEvent.wheelDeltaX) || 0;
            }
        },
        "deltaZ": { value: 0 }
    });