/**
 * Mouse Interface
 * 
 * Provides methods to handle mouse inputs.
 * 
 * @class mouse
 * @namespace zerk.game.engine.system.control
 * @extends zerk.observable
 * @module zerk
 **/
/*
 * TODO Use DOM interface instead of native code
 */
zerk.define({
	
	name: 'zerk.game.engine.system.control.mouse',
	extend: 'zerk.observable'
	
},{
	
	/**
	 * Horizontal cursor position
	 * 
	 * @property mouseX
	 * @type Integer
	 */
	mouseX: null,
	
	/**
	 * Vertical cursor position
	 * 
	 * @property mouseX
	 * @type Integer
	 */
	mouseY: null,
	
	/**
	 * State of the left mouse button
	 * 
	 * @property mouseLeftDown
	 * @type Boolean
	 */
	mouseLeftDown: false,
	
	/**
	 * State of the right mouse button
	 * 
	 * @property mouseRightDown
	 * @type Boolean
	 */
	mouseRightDown: false,
	
	/**
	 * Coordinates of the last mouse position
	 * 
	 * @property _lastMousePosition
	 * @type {Object}
	 * @protected
	 */
	_lastMousePosition: null,
	
	/**
	 * State of the mouse joint
	 * 
	 * @property _mouseJointActive
	 * @type Boolean
	 * @protected
	 */
	_mouseJointActive: false,
	
	/**
	 * Back reference to control class
	 * 
	 * @property _control
	 * @type zerk.game.engine.system.control
	 */
	_control: null,
	
	_viewport: null,
	
	_config: null,
	
	/**
	 * Class constructor
	 * 
	 * @method init
	 * @param {zerk.game.engine} engine
	 */
	init: function(control,viewport,config) {
		
		zerk.parent('zerk.game.engine.system.control.mouse').init.apply(
			this,
			arguments
		);
		
		this._control=control;
		this._viewport=viewport;
		this._config=config;
		
		var self=this;
		
		var canvas=this._viewport.getCanvasElement('display');
		
		canvas.addEventListener(
			'mousedown',
			function(event) {
				
				return self._onMouseDown(event);
				
			}
		);
		
		canvas.addEventListener(
			'mouseup',
			function(event) {
				
				return self._onMouseUp(event);
				
			}
		);
		
		canvas.addEventListener(
			'mousemove',
			function(event) {
				
				return self._onMouseMove(event);
				
			}
		);
		
		canvas.addEventListener(
			'contextmenu',
			function(event) {
				
				return self._onContextMenu(event);
				
			},
			false
		);
		
		zerk.browser.registerEvent(
			document,
			'mousewheel',
			function(event) {
				
				self._onMouseScroll(event);
				
			}
		);
		
	},
	
	/**
	 * Returns the position of the cursor by given mouse event
	 * 
	 * @method _getCursorPosition
	 * @param {event} event Native mouse event
	 * @return {Object} Coordinate object
	 * @protected
	 */
	_getCursorPosition: function(event) {
		
		var position=this._viewport.getCanvasPosition('display');
		
		return {
			x: event.clientX-position.left,
			y: event.clientY-position.top
		};
		
	},
	
	/**
	 * Context menu event handler
	 * 
	 * @method _onContextMenu
	 * @param {event} event Native event
	 * @return {Boolean} Returns false
	 * @protected
	 */
	_onContextMenu: function(event) {
		
		event.preventDefault();
		
		return false;
		
	},
	
	/**
	 * Mouse down event handler
	 * 
	 * @method _onMouseDown
	 * @param {event} event Native event
	 * @return {Boolean}
	 * @protected
	 */
	_onMouseDown: function(event) {
		
		event.preventDefault();
		
		if (event.button==0) {
			
			this.mouseLeftDown=true;
			
			/*
			 * Trigger the mouse move event to interact 
			 * directly on click position
			 */
			this._onMouseMove(event);
			
		} else if (event.button==2) {
			
			this.mouseRightDown=true;
			
		}
		
		/**
		 * Fires when a mouse button is pressed
		 * 
		 * @param {DOMEvent} event
		 * @event mousedown 
		 */
		this.fireEvent('mousedown',event);
		
		return false;
		
	},
	
	/**
	 * Mouse up event handler
	 * 
	 * @method _onMouseUp
	 * @param {event} event Native event
	 * @return {Boolean} Returns false
	 * @protected
	 */
	_onMouseUp: function(event) {
		
		if (event.button==0) {  
			
			this.mouseLeftDown=false;
			
		} else if (event.button==2) {
			
			this.mouseRightDown=false;
			
		}
		
		/**
		 * Fires when a mouse button is released
		 * 
		 * @param {DOMEvent} event
		 * @event mouseup
		 */
		this.fireEvent('mouseup',event);
		
		return false;
		
	},
	
	/**
	 * Mouse move event handler
	 * 
	 * @method _onMouseMove
	 * @param {event} event Native event
	 * @protected
	 */
	_onMouseMove: function(event) {
		
		var position=this._getCursorPosition(event);
		
		if (this.mouseRightDown) {
			
			/*
			 * TODO Remove the mouse view from the controls system
			 */
			this._viewport.setX(
				this._viewport.getX()
				-this._viewport.fromScaleX(
					(position.x-this._lastMousePosition.x)
					*this._config.zoomSpeed
				)
			);
			
			this._viewport.setY(
				this._viewport.getY()
				-this._viewport.fromScaleX(
					(position.y-this._lastMousePosition.y)
					*this._config.zoomSpeed
				)
			);
			
		}
		
		this.mouseX=zerk.helper.toMeter(this._viewport.getX()
			+this._viewport.fromScaleX(
				position.x-(this._viewport.getWidth()/2))
			);
			
		this.mouseY=zerk.helper.toMeter(this._viewport.getY()
			+this._viewport.fromScaleY(
				position.y-(this._viewport.getHeight()/2))
			);
		
		this._lastMousePosition=this._getCursorPosition(event);
		
	},
	
	/**
	 * Mouse scroll event handler
	 * 
	 * @method _onMouseScroll
	 * @param {event} event Native event
	 * @protected
	 */
	_onMouseScroll: function(event) {
		
		event=((event) ? event : window.event);
		var delta=((event.detail) ? event.detail : event.wheelDelta*-1);
		
		/*
		 * TODO Remove the mouse zoom from the controls system
		 */
		if (this._config.enableWheelZoom) {
			
			if (delta<0) {
				
				this._viewport.zoomIn();
				
			} else {
				
				this._viewport.zoomOut();
				
			}
			
		}
		
	}
	
});