/**
 * 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);
      
      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;
  }
}