/**
 * 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;
        }
}