/**
                                * The `Matter.Mouse` module contains methods for creating and manipulating mouse inputs.
                                *
                                * @class Mouse
                                */
                                
                                var Mouse = {};
                                
                                module.exports = Mouse;
                                
                                var Common = require('../core/Common');
                                
                                (function() {
                                
                                    /**
                                     * Creates a mouse input.
                                     * @method create
                                     * @param {HTMLElement} element
                                     * @return {mouse} A new mouse
                                     */
                                    Mouse.create = function(element) {
                                        var mouse = {};
                                
                                        if (!element) {
                                            Common.log('Mouse.create: element was undefined, defaulting to document.body', 'warn');
                                        }
                                        
                                        mouse.element = element || document.body;
                                        mouse.absolute = { x: 0, y: 0 };
                                        mouse.position = { x: 0, y: 0 };
                                        mouse.mousedownPosition = { x: 0, y: 0 };
                                        mouse.mouseupPosition = { x: 0, y: 0 };
                                        mouse.offset = { x: 0, y: 0 };
                                        mouse.scale = { x: 1, y: 1 };
                                        mouse.wheelDelta = 0;
                                        mouse.button = -1;
                                        mouse.pixelRatio = parseInt(mouse.element.getAttribute('data-pixel-ratio'), 10) || 1;
                                
                                        mouse.sourceEvents = {
                                            mousemove: null,
                                            mousedown: null,
                                            mouseup: null,
                                            mousewheel: null
                                        };
                                        
                                        mouse.mousemove = function(event) { 
                                            var position = Mouse._getRelativeMousePosition(event, mouse.element, mouse.pixelRatio),
                                                touches = event.changedTouches;
                                
                                            if (touches) {
                                                mouse.button = 0;
                                                event.preventDefault();
                                            }
                                
                                            mouse.absolute.x = position.x;
                                            mouse.absolute.y = position.y;
                                            mouse.position.x = mouse.absolute.x * mouse.scale.x + mouse.offset.x;
                                            mouse.position.y = mouse.absolute.y * mouse.scale.y + mouse.offset.y;
                                            mouse.sourceEvents.mousemove = event;
                                        };
                                        
                                        mouse.mousedown = function(event) {
                                            var position = Mouse._getRelativeMousePosition(event, mouse.element, mouse.pixelRatio),
                                                touches = event.changedTouches;
                                
                                            if (touches) {
                                                mouse.button = 0;
                                                event.preventDefault();
                                            } else {
                                                mouse.button = event.button;
                                            }
                                
                                            mouse.absolute.x = position.x;
                                            mouse.absolute.y = position.y;
                                            mouse.position.x = mouse.absolute.x * mouse.scale.x + mouse.offset.x;
                                            mouse.position.y = mouse.absolute.y * mouse.scale.y + mouse.offset.y;
                                            mouse.mousedownPosition.x = mouse.position.x;
                                            mouse.mousedownPosition.y = mouse.position.y;
                                            mouse.sourceEvents.mousedown = event;
                                        };
                                        
                                        mouse.mouseup = function(event) {
                                            var position = Mouse._getRelativeMousePosition(event, mouse.element, mouse.pixelRatio),
                                                touches = event.changedTouches;
                                
                                            if (touches) {
                                                event.preventDefault();
                                            }
                                            
                                            mouse.button = -1;
                                            mouse.absolute.x = position.x;
                                            mouse.absolute.y = position.y;
                                            mouse.position.x = mouse.absolute.x * mouse.scale.x + mouse.offset.x;
                                            mouse.position.y = mouse.absolute.y * mouse.scale.y + mouse.offset.y;
                                            mouse.mouseupPosition.x = mouse.position.x;
                                            mouse.mouseupPosition.y = mouse.position.y;
                                            mouse.sourceEvents.mouseup = event;
                                        };
                                
                                        mouse.mousewheel = function(event) {
                                            mouse.wheelDelta = Math.max(-1, Math.min(1, event.wheelDelta || -event.detail));
                                            event.preventDefault();
                                        };
                                
                                        Mouse.setElement(mouse, mouse.element);
                                
                                        return mouse;
                                    };
                                
                                    /**
                                     * Sets the element the mouse is bound to (and relative to).
                                     * @method setElement
                                     * @param {mouse} mouse
                                     * @param {HTMLElement} element
                                     */
                                    Mouse.setElement = function(mouse, element) {
                                        mouse.element = element;
                                
                                        element.addEventListener('mousemove', mouse.mousemove);
                                        element.addEventListener('mousedown', mouse.mousedown);
                                        element.addEventListener('mouseup', mouse.mouseup);
                                        
                                        element.addEventListener('mousewheel', mouse.mousewheel);
                                        element.addEventListener('DOMMouseScroll', mouse.mousewheel);
                                
                                        element.addEventListener('touchmove', mouse.mousemove);
                                        element.addEventListener('touchstart', mouse.mousedown);
                                        element.addEventListener('touchend', mouse.mouseup);
                                    };
                                
                                    /**
                                     * Clears all captured source events.
                                     * @method clearSourceEvents
                                     * @param {mouse} mouse
                                     */
                                    Mouse.clearSourceEvents = function(mouse) {
                                        mouse.sourceEvents.mousemove = null;
                                        mouse.sourceEvents.mousedown = null;
                                        mouse.sourceEvents.mouseup = null;
                                        mouse.sourceEvents.mousewheel = null;
                                        mouse.wheelDelta = 0;
                                    };
                                
                                    /**
                                     * Sets the mouse position offset.
                                     * @method setOffset
                                     * @param {mouse} mouse
                                     * @param {vector} offset
                                     */
                                    Mouse.setOffset = function(mouse, offset) {
                                        mouse.offset.x = offset.x;
                                        mouse.offset.y = offset.y;
                                        mouse.position.x = mouse.absolute.x * mouse.scale.x + mouse.offset.x;
                                        mouse.position.y = mouse.absolute.y * mouse.scale.y + mouse.offset.y;
                                    };
                                
                                    /**
                                     * Sets the mouse position scale.
                                     * @method setScale
                                     * @param {mouse} mouse
                                     * @param {vector} scale
                                     */
                                    Mouse.setScale = function(mouse, scale) {
                                        mouse.scale.x = scale.x;
                                        mouse.scale.y = scale.y;
                                        mouse.position.x = mouse.absolute.x * mouse.scale.x + mouse.offset.x;
                                        mouse.position.y = mouse.absolute.y * mouse.scale.y + mouse.offset.y;
                                    };
                                    
                                    /**
                                     * Gets the mouse position relative to an element given a screen pixel ratio.
                                     * @method _getRelativeMousePosition
                                     * @private
                                     * @param {} event
                                     * @param {} element
                                     * @param {number} pixelRatio
                                     * @return {}
                                     */
                                    Mouse._getRelativeMousePosition = function(event, element, pixelRatio) {
                                        var elementBounds = element.getBoundingClientRect(),
                                            rootNode = (document.documentElement || document.body.parentNode || document.body),
                                            scrollX = (window.pageXOffset !== undefined) ? window.pageXOffset : rootNode.scrollLeft,
                                            scrollY = (window.pageYOffset !== undefined) ? window.pageYOffset : rootNode.scrollTop,
                                            touches = event.changedTouches,
                                            x, y;
                                        
                                        if (touches) {
                                            x = touches[0].pageX - elementBounds.left - scrollX;
                                            y = touches[0].pageY - elementBounds.top - scrollY;
                                        } else {
                                            x = event.pageX - elementBounds.left - scrollX;
                                            y = event.pageY - elementBounds.top - scrollY;
                                        }
                                
                                        return { 
                                            x: x / (element.clientWidth / (element.width || element.clientWidth) * pixelRatio),
                                            y: y / (element.clientHeight / (element.height || element.clientHeight) * pixelRatio)
                                        };
                                    };
                                
                                })();