/**
 * Keyboard Interface
 * 
 * Provides methods to handle keyboard inputs.
 * 
 * @class keyboard
 * @namespace zerk.game.engine.system.control
 * @extends zerk.observable
 * @module zerk
 **/
/*
 * TODO Complete keycode list
 */
/*
 * TODO Use DOM interface instead of native code
 */
zerk.define({
	
	name: 'zerk.game.engine.system.control.keyboard',
	extend: 'zerk.observable'
	
},{
	
	/**
	 * State of the backspace key
	 * 
	 * @property pressedBackspace
	 * @type Boolean
	 */
	pressedBackspace: false,
	
	/**
	 * State of the tab key
	 * 
	 * @property pressedTab
	 * @type Boolean
	 */
	pressedTab: false,
	
	/**
	 * State of the enter key
	 * 
	 * @property pressedEnter
	 * @type Boolean
	 */
	pressedEnter: false,
	
	/**
	 * State of the shift key
	 * 
	 * @property pressedShift
	 * @type Boolean
	 */
	pressedShift: false,
	
	/**
	 * State of the ctrl key
	 * 
	 * @property pressedCtrl
	 * @type Boolean
	 */
	pressedCtrl: false,
	
	/**
	 * State of the alt key
	 * 
	 * @property pressedAlt
	 * @type Boolean
	 */
	pressedAlt: false,
	
	/**
	 * State of the pause key
	 * 
	 * @property pressedPause
	 * @type Boolean
	 */
	pressedPause: false,
	
	/**
	 * State of the capslock key
	 * 
	 * @property pressedCapsLock
	 * @type Boolean
	 */
	pressedCapsLock: false,
	
	/**
	 * State of the escape key
	 * 
	 * @property pressedEscape
	 * @type Boolean
	 */
	pressedEscape: false,
	
	/**
	 * State of the space key
	 * 
	 * @property pressedSpace
	 * @type Boolean
	 */
	pressedSpace: false,
	
	/**
	 * State of the pageup key
	 * 
	 * @property pressedPageUp
	 * @type Boolean
	 */
	pressedPageUp: false,
	
	/**
	 * State of the pagedown key
	 * 
	 * @property pressedPageDown
	 * @type Boolean
	 */
	pressedPageDown: false,
	
	/**
	 * State of the end key
	 * 
	 * @property pressedEnd
	 * @type Boolean
	 */
	pressedEnd: false,
	
	/**
	 * State of the home key
	 * 
	 * @property pressedHome
	 * @type Boolean
	 */
	pressedHome: false,
	
	/**
	 * State of the arrow left key
	 * 
	 * @property pressedArrowLeft
	 * @type Boolean
	 */
	pressedArrowLeft: false,
	
	/**
	 * State of the arrow up key
	 * 
	 * @property pressedArrowUp
	 * @type Boolean
	 */
	pressedArrowUp: false,
	
	/**
	 * State of the arrow right key
	 * 
	 * @property pressedArrowRight
	 * @type Boolean
	 */
	pressedArrowRight: false,
	
	/**
	 * State of the arrow down key
	 * 
	 * @property pressedArrowDown
	 * @type Boolean
	 */
	pressedArrowDown: false,
	
	/**
	 * Back reference to control class
	 * 
	 * @property _control
	 * @type zerk.game.engine.system.control
	 */
	_control: null,
	
	/**
	 * Key map
	 * 
	 * @property _keyMap
	 * @type Object
	 * @protected
	 */
	_keyMap: null,
	
	/**
	 * Class constructor
	 * 
	 * @method init
	 * @param {zerk.game.engine} engine
	 */
	init: function(control) {
		
		zerk.parent('zerk.game.engine.system.control.keyboard').init.apply(
			this,
			arguments
		);
		
		this._control=control;
		
		this._keyMap={
			key8: 'Backspace',
			key9: 'Tab',
			key13: 'Enter',
			key16: 'Shift',
			key17: 'Ctrl',
			key18: 'Alt',
			key19: 'Pause',
			key20: 'CapsLock',
			key27: 'Escape',
			key32: 'Space',
			key33: 'PageUp',
			key34: 'PageDown',
			key35: 'End',
			key36: 'Home',
			key37: 'ArrowLeft', 
			key38: 'ArrowUp',
			key39: 'ArrowRight',
			key40: 'ArrowDown'
		};
		
		var self=this;
		
		document.addEventListener(
			'keypress',
			function(event) {
				
				self._onKeyPress(event);
				
			}
		);
		
		document.addEventListener(
			'keydown',
			function(event) {
				
				self._onKeyDown(event);
				
			}
		);
		
		document.addEventListener(
			'keyup',
			function(event) {
				
				self._onKeyUp(event);
				
			}
		);
		
	},
	
	/**
	 * Key down event handler
	 * 
	 * @method _onKeyDown
	 * @param {DOMEvent} event DOM event
	 * @protected
	 */
	_onKeyDown: function(event) {
		
		var keyName='key'+event.keyCode;
		
		if (typeof this._keyMap[keyName]!=='undefined') {
			this['pressed'+this._keyMap[keyName]]=true;
		}
		
		/**
		 * Fires when a key is pressed
		 * 
		 * @param {DOMEvent} event
		 * @event keypress 
		 */
		this.fireEvent('keydown',event);
		
	},
	
	/**
	 * Key up event handler
	 * 
	 * @method _onKeyUp
	 * @param {DOMEvent} event DOM event
	 * @protected
	 */
	_onKeyUp: function(event) {
		
		var keyName='key'+event.keyCode;
		
		if (typeof this._keyMap[keyName]!=='undefined') {
			this['pressed'+this._keyMap[keyName]]=false;
		}
		
		/**
		 * Fires when a key is released
		 * 
		 * @param {DOMEvent} event
		 * @event keyup
		 */
		this.fireEvent('keyup',event);
		
	},
	
	/**
	 * Key press event handler
	 * 
	 * @method _onKeyPress
	 * @param {DOMEvent} event DOM event
	 * @protected
	 */
	_onKeyPress: function(event) {
		
		this.fireEvent('keypress',event);
		
	}
	
});