/**
 * Keyboard shortcuts
 * See:http://www.openjs.com/scripts/events/keyboard_shortcuts/
 * Version : 2.01.B
 * By Binny V A
 * License : BSD
 */
shortcut = {
	'all_shortcuts':{},//All the shortcuts are stored in this array
	'add': function(shortcut_combination,callback,opt) {
	//Provide a set of default options
	var default_options = {
		 'type':'keydown',
			'propagate':false,
		 'disable_in_input':false,
		 'target':document,
		 'keycode':false
	}
	if(!opt) opt = default_options;
	else {
		 for(var dfo in default_options) {
		if(typeof opt[dfo] == 'undefined') opt[dfo] = default_options[dfo];
		 }
	}
	
	var ele = opt.target;
	if(typeof opt.target == 'string') ele = document.getElementById(opt.target);
	var ths = this;
	shortcut_combination = shortcut_combination.toLowerCase();
	
	//The function to be called at keypress
	var func = function(e) {
		 e = e || window.event;
		 
		 if(opt['disable_in_input']) { //Don't enable shortcut keys in Input, Textarea fields
		var element;
		if(e.target) element=e.target;
		else if(e.srcElement) element=e.srcElement;
		if(element.nodeType==3) element=element.parentNode;
		
		if(element.tagName == 'INPUT' || element.tagName == 'TEXTAREA') return;
		 }
	
		 //Find Which key is pressed
		 if (e.keyCode) code = e.keyCode;
		 else if (e.which) code = e.which;
		 var character = String.fromCharCode(code).toLowerCase();
			
		 if(code == 188) character=","; //If the user presses , when the type is onkeydown
		 if(code == 190) character="."; //If the user presses , when the type is onkeydown

		 var keys = shortcut_combination.split("+");
		 //Key Pressed - counts the number of valid keypresses - if it is same as the number of keys, the shortcut function is invoked
		 var kp = 0;
			
		 //Work around for stupid Shift key bug created by using lowercase - as a result the shift+num combination was broken
		 var shift_nums = {
		"`":"~",
		"1":"!",
		"2":"@",
		"3":"#",
		"4":"$",
		"5":"%",
		"6":"^",
		"7":"&",
		"8":"*",
		"9":"(",
		"0":")",
		"-":"_",
		"=":"+",
		";":":",
		"'":"\"",
		",":"<",
		".":">",
		"/":"?",
		"\\":"|"
		 }
		 //Special Keys - and their codes
		 var special_keys = {
		'esc':27,
		'escape':27,
		'tab':9,
		'space':32,
		'return':13,
		'enter':13,
		'backspace':8,
	
		'scrolllock':145,
		'scroll_lock':145,
		'scroll':145,
		'capslock':20,
		'caps_lock':20,
		'caps':20,
		'numlock':144,
		'num_lock':144,
		'num':144,
				
		'pause':19,
		'break':19,
				
		'insert':45,
		'home':36,
		'delete':46,
		'end':35,
				
		'pageup':33,
		'page_up':33,
		'pu':33,
	
		'pagedown':34,
		'page_down':34,
		'pd':34,
	
		'left':37,
		'up':38,
		'right':39,
		'down':40,
	
		'f1':112,
		'f2':113,
		'f3':114,
		'f4':115,
		'f5':116,
		'f6':117,
		'f7':118,
		'f8':119,
		'f9':120,
		'f10':121,
		'f11':122,
		'f12':123
		 }
	
		 var modifiers = { 
		shift: { wanted:false, pressed:false},
		ctrl : { wanted:false, pressed:false},
		alt  : { wanted:false, pressed:false},
		meta : { wanted:false, pressed:false}	//Meta is Mac specific
		 };
						
		 if(e.ctrlKey)	modifiers.ctrl.pressed = true;
		 if(e.shiftKey)	modifiers.shift.pressed = true;
		 if(e.altKey)	modifiers.alt.pressed = true;
		 if(e.metaKey)	 modifiers.meta.pressed = true;
						
		 for(var i=0; k=keys[i],i<keys.length; i++) {
		//Modifiers
		if(k == 'ctrl' || k == 'control') {
			  kp++;
			  modifiers.ctrl.wanted = true;

		} else if(k == 'shift') {
			  kp++;
			  modifiers.shift.wanted = true;

		} else if(k == 'alt') {
			  kp++;
			  modifiers.alt.wanted = true;
		} else if(k == 'meta') {
			  kp++;
			  modifiers.meta.wanted = true;
		} else if(k.length > 1) { //If it is a special key
			  if(special_keys[k] == code) kp++;
					
		} else if(opt['keycode']) {
			  if(opt['keycode'] == code) kp++;

		} else { //The special keys did not match
			  if(character == k) kp++;
			  else {
			if(shift_nums[character] && e.shiftKey) { //Stupid Shift key bug created by using lowercase
				   character = shift_nums[character]; 
				   if(character == k) kp++;
			}
			  }
		}
		 }
			
		 if(kp == keys.length && 
			modifiers.ctrl.pressed == modifiers.ctrl.wanted &&
			modifiers.shift.pressed == modifiers.shift.wanted &&
			modifiers.alt.pressed == modifiers.alt.wanted &&
			modifiers.meta.pressed == modifiers.meta.wanted) {
		callback(e);
	
		if(!opt['propagate']) { //Stop the event
					//e.cancelBubble is supported by IE - this will kill the bubbling process.
			  e.cancelBubble = true;
			  e.returnValue = false;
	
			  //e.stopPropagation works in Firefox.
			  if (e.stopPropagation) {
			e.stopPropagation();
			e.preventDefault();
			  }
			  return false;
		}
		 }
	}
	this.all_shortcuts[shortcut_combination] = {
		 'callback':func, 
		 'target':ele, 
		 'event': opt['type']
	};
	//Attach the function with the event
	if(ele.addEventListener) ele.addEventListener(opt['type'], func, false);
	else if(ele.attachEvent) ele.attachEvent('on'+opt['type'], func);
	else ele['on'+opt['type']] = func;
	},

	//Remove the shortcut - just specify the shortcut and I will remove the binding
	'remove':function(shortcut_combination) {
	shortcut_combination = shortcut_combination.toLowerCase();
	var binding = this.all_shortcuts[shortcut_combination];
	delete(this.all_shortcuts[shortcut_combination])
	if(!binding) return;
	var type = binding['event'];
	var ele = binding['target'];
	var callback = binding['callback'];

	if(ele.detachEvent) ele.detachEvent('on'+type, callback);
	else if(ele.removeEventListener) ele.removeEventListener(type, callback, false);
	else ele['on'+type] = false;
	}
}