/*******************************************************************************
	Filename		: keymap.js

	Called by		: index.html

	Created			: 27 August 2007 (22:18:35)
	Created by		: Rick Holmes
	Last Updated	: 28 August 2007 (09:39:04)

	Required files	: 

	Comments	: captures keyboard events, modified version of Keymap.js found in "JavaScript, The Definitive Guide" by David Flanagan
*******************************************************************************/	
function Keymap(bindings) {
    this.map = {};
    if (bindings) {
        for(name in bindings) this.map[name.toLowerCase( )] = bindings[name];
    }
}

Keymap.prototype.bind = function(key, func) {
    this.map[key.toLowerCase( )] = func;
};

Keymap.prototype.unbind = function(key) {
    delete this.map[key.toLowerCase( )];
};

Keymap.prototype.install = function(element) {
    var keymap = this;
    function handler(event) { return keymap.dispatch(event); }

    if (element.addEventListener) {
        element.addEventListener("keydown", handler, false);
        element.addEventListener("keypress", handler, false);
    }
    else if (element.attachEvent) {
        element.attachEvent("onkeydown", handler);
        element.attachEvent("onkeypress", handler);
    }
    else {
        element.onkeydown = element.onkeypress = handler;
    }
};

Keymap.keyCodeToFunctionKey = {
    8:"backspace", 9:"tab", 13:"return", 19:"pause", 27:"escape", 32:"space",
    33:"pageup", 34:"pagedown", 35:"end", 36:"home", 37:"left", 38:"up",
    39:"right", 40:"down", 44:"printscreen", 45:"insert", 46:"delete",
    112:"f1", 113:"f2", 114:"f3", 115:"f4", 116:"f5", 117:"f6", 118:"f7",
    119:"f8", 120:"f9", 121:"f10", 122:"f11", 123:"f12",
    144:"numlock", 145:"scrolllock"
};

Keymap.keyCodeToPrintableChar = {
    48:"0", 49:"1", 50:"2", 51:"3", 52:"4", 53:"5", 54:"6", 55:"7", 56:"8",
    57:"9", 59:";", 61:"=", 65:"a", 66:"b", 67:"c", 68:"d",
    69:"e", 70:"f", 71:"g", 72:"h", 73:"i", 74:"j", 75:"k", 76:"l", 77:"m",
    78:"n", 79:"o", 80:"p", 81:"q", 82:"r", 83:"s", 84:"t", 85:"u", 86:"v",
    87:"w", 88:"x", 89:"y", 90:"z", 107:"+", 109:"-", 110:".", 188:",",
    190:".", 191:"/", 192:"'", 219:"[", 220:"\\", 221:"]", 222:"\""
};

Keymap.prototype.dispatch = function(event) {
    var e = event || window.event;  // Handle IE event model

    var modifiers = ""
    var keyname = null;

    if (e.type == "keydown") {
        var code = e.keyCode;
        if (code == 16 || code == 17 || code == 18) return;

        keyname = Keymap.keyCodeToFunctionKey[code];

        if (!keyname && (e.altKey || e.ctrlKey))
            keyname = Keymap.keyCodeToPrintableChar[code];

        if (keyname) {
            if (e.altKey) modifiers += "alt_";
            if (e.ctrlKey) modifiers += "ctrl_";
            if (e.shiftKey) modifiers += "shift_";
        }
        else return;
    }
    else if (e.type == "keypress") {
        if (e.altKey || e.ctrlKey) return;

        if (e.charCode != undefined && e.charCode == 0) return;

        var code = e.charCode || e.keyCode;

        keyname=String.fromCharCode(code);

        var lowercase = keyname.toLowerCase( );
        if (keyname != lowercase) {
            keyname = lowercase;
            modifiers = "shift_";
        }
    }

    var func = this.map[modifiers+keyname];

    if (!func) func = this.map["default"];
    
    if (func) {  
        var target = e.target;
        if (!target) target = e.srcElement;
		  this.t=target;
        func(target, modifiers+keyname, e);

        if (e.stopPropagation) e.stopPropagation( );
        else e.cancelBubble = true;
        if (e.preventDefault) e.preventDefault( );
        else e.returnValue = false;
        return false;
    }
};