(function($){

	
	var defaults = {
		
		reNumbers: /(-|-\$)?(\d+(,\d{3})*(\.\d{1,})?|\.\d{1,})/g
		
		, useFieldPlugin: (!!$.fn.getValue)
		
		, onParseError: null
		
		, onParseClear: null
	};
	

	$.Calculation = {
		version: "0.4a",
		setDefaults: function(options){
			$.extend(defaults, options);
		}
	};

	$.fn.parseNumber = function(options){
		var aValues = [];
		options = $.extend(options, defaults);
		
		this.each(
			function (){
				var
					
					$el = $(this),
					
					sMethod = ($el.is(":input") ? (defaults.useFieldPlugin ? "getValue" : "val") : "text"),
					
					v = $el[sMethod]().match(defaults.reNumbers, "");

				
				if( v == null ){
					v = 0;
					
					if( jQuery.isFunction(options.onParseError) ) options.onParseError.apply($el, [sMethod]);
					$.data($el[0], "calcParseError", true);

				} else {
					
					v = v[0].replace(/[^0-9.\-]/g, "");

					if( $.data($el[0], "calcParseError") && jQuery.isFunction(options.onParseClear) ){
						options.onParseClear.apply($el, [sMethod]);

						$.data($el[0], "calcParseError", false);
					} 
				}
				aValues.push(parseFloat(v, 10));
			}
		);


		return aValues;
	};

	$.fn.calc = function(expr, vars, cbFormat, cbDone){
		var

			$this = this,

			exprValue = "",

			$el,
		
			parsedVars = {},

			tmp,

			sMethod,

			hVars,

			bIsError = false;
		
		for( var k in vars ){
			if( !!vars[k] && !!vars[k].jquery ){
				parsedVars[k] = vars[k].parseNumber();
			} else {
				parsedVars[k] = vars[k];
			}
		}
		
		this.each(
			function (i, el){

				$el = $(this);

				sMethod = ($el.is(":input") ? (defaults.useFieldPlugin ? "setValue" : "val") : "text");


				hVars = {};
				for( var k in parsedVars ){
					if( typeof parsedVars[k] == "number" ){
						hVars[k] = parsedVars[k];
					} else if( typeof parsedVars[k] == "string" ){
						hVars[k] = parseFloat(parsedVars[k], 10);
					} else if( !!parsedVars[k] && (parsedVars[k] instanceof Array) ) {

						tmp = (parsedVars[k].length == $this.length) ? i : 0;
						hVars[k] = parsedVars[k][tmp];
					}
					

					if( isNaN(hVars[k]) ) hVars[k] = 0;
				}

				try {
					exprValue = eval( expr.replace(/([A-Za-z]+)/g, "hVars.$1") );

					if( !!cbFormat ) exprValue = cbFormat(exprValue);

				} catch(e){
					exprValue = e;
					bIsError = true;
				}

				$el[sMethod](exprValue.toString());
			}
		);

		if( !!cbDone ) cbDone(this);

		return this;
	};


	$.each(["sum", "avg", "min", "max"], function (i, method){
		$.fn[method] = function (bind, selector){

			if( arguments.length == 0 )
				return math[method](this.parseNumber());
	

			var bSelOpt = selector && selector.constructor == Object && !(selector instanceof jQuery);
			

			var opt = bind && bind.constructor == Object ? bind : {
				  bind: "keyup"
				, selector: (!bSelOpt) ? selector : null
				, oncalc: null
			};
	

			if( bSelOpt ) opt = jQuery.extend(opt, selector);
			

			if( !!opt.selector ) opt.selector = $(opt.selector);
			
			var self = this
				, sMethod
				, doCalc = function (){

					var value = math[method](self.parseNumber(opt));
		
					if( !!opt.selector ){

						sMethod = (opt.selector.is(":input") ? (defaults.useFieldPlugin ? "setValue" : "val") : "text");

						opt.selector[sMethod](value.toString());
					}

					if( jQuery.isFunction(opt.oncalc) ) opt.oncalc.apply(self, [value, opt]);
				};
			

			doCalc();
			
			return self.bind(opt.bind, doCalc);
		}
	});
	
	
	var math = {

		sum: function (a){
			var total = 0;

			$.each(a, function (i, v){

				total += v;
			});
	

			return total;
		},

		avg: function (a){

			return math.sum(a)/a.length;
		},

		min: function (a){
			return Math.min.apply(Math, a);
		},

		max: function (a){
			return Math.max.apply(Math, a);
		}
	};
	

})(jQuery);