(function($) {
	$.fn.fuelsavingscalc = function(options) {
	var defaults = {
			advantage: 0.4
		};
	var options = $.extend(defaults, options);
	
	var aircelladvantage = options.advantage;

	// get values from form
	var mpg = $('#mpg_reg').val();
	var fuelcost = $('#fuelcost_reg').val();
	var milesyear = $('#milesyear_reg').val();
	var vehicles = $('#vehicles_reg').val();
	//convert valuse to numbers
	var mpg_reg_num = parseFloat(mpg);
	var fuelcost_num = parseFloat(fuelcost.replace("$",""));
	var milesyear_num = parseFloat(milesyear.replace(",",""));
	var vehicles_num = parseFloat(vehicles);	

	
	//calculate aircell value
	var mpg_aircell_num = (mpg_reg_num + aircelladvantage);
	
	//calculate cost per truck
	var costpertruck_reg = ((milesyear_num / mpg_reg_num) * fuelcost_num);
	var costpertruck_aircell = ((milesyear_num / mpg_aircell_num) * fuelcost_num);	
	
	//calculate total fuel costs
	var thetotalfuelcost_reg = (costpertruck_reg * vehicles_num);
	var thetotalfuelcost_aircell = (costpertruck_aircell * vehicles_num);
	
	//caculate savings
	var pertruck_savings = (costpertruck_reg - costpertruck_aircell);
	var fleet_savings = (thetotalfuelcost_reg - thetotalfuelcost_aircell);
	
	//aircell investment
	var aircellprice = (vehicles_num * 179.95);
	
	// savings after investment
	var savings = (thetotalfuelcost_reg - thetotalfuelcost_aircell) - aircellprice;
	
	//write text to fields
	$('#mpg_aircell').text("" + mpg_aircell_num);		
	$('#fuelcost_aircell').text("" + fuelcost_num);	
	$('#milesyear_aircell').text("" + milesyear_num);		
	$('#vehicles_aircell').text("" + vehicles);	
	
	$('#fuelcostpertruck_reg').text("" + costpertruck_reg);
	$('#fuelcostpertruck_aircell').text("" + costpertruck_aircell);
	
	$('#totalfuelcost_reg').text("" + thetotalfuelcost_reg);
	$('#totalfuelcost_aircell').text("" + thetotalfuelcost_aircell);
	

	$('#fuelcostpertruck_savings').text("" + pertruck_savings);
	$('#totalfuelcost_savings').text("" + fleet_savings);	
	
	$('#aircellinvestment').text("" + aircellprice);
	$('#net_savings').text("" + savings);
	
};

})(jQuery);