$(document).ready(function() {
	$('#fuelused').keyup(calcUsed);
	$('#fueltypeused').change(calcUsed);
	$('#fuelunit').change(calcUsed);	
	$('#fueltypespent').change(updatePrice);
	$('#fuelspent').keyup(calcSpent);
	$('#fuelpence').keyup(calcSpent);	
	$('#fueltypecon').change(calcCon);	
	$('#consumption').keyup(calcCon);	
	$('#contype').change(calcCon);		
	$('#distance').keyup(calcCon);
	$('#dunit').html('(miles)');
});

function calcUsed () {
	var cpl = getcpl('used');
	var volume = $('#fuelused').val();
	if ($('#fuelunit').val() != "Litres") {
		volume = volume * 3.7854;
	}
	var co2u = cpl * volume;
	co2u = co2u.toFixed(2);
	if(co2u <= 0) {
		co2u = "Please enter a value greater than 0";
	}
	$('#CO2U').html(co2u);
}

function calcSpent() {
	var cpl = getcpl('spent');
	var volume = $('#fuelspent').val() / $('#fuelpence').val() * 100;
	var co2s = cpl * volume;
	co2s = co2s.toFixed(2);
	if(co2s <= 0) {
		co2 = "Please enter a value greater than 0";
	}
	$('#CO2S').html(co2s);	
}

function calcCon() {
	var cpl = getcpl('con');
	var distance = $('#distance').val();
	var consumption = $('#consumption').val();
	var contype= $('#contype').val();	
	var dunit = "(km)";
	if($('#distance').val() <= 0) {
		var co2t = "Please enter a value greater than 0";
	} else {
		if(contype == "m") {
			consumption = 282.481/consumption;
			distance = distance*1.609;
			dunit = "(miles)";
		}
		var volume = distance*(consumption/100);
		var co2c = (cpl*volume).toFixed(2);
	}	
	$('#dunit').html(dunit);	
	$('#CO2C').html(co2c);
}

function getcpl (fname) {
	if ($('#fueltype'+fname).val() == "Petrol") {
		var cpl = 2.39;
	} else {
		var cpl = 2.62;
	}
	return(cpl);
}

function updatePrice() {
	if($('#fueltypespent').val() == 'Petrol') {
		$('#fuelpence').val(petrol);
	} else {
		$('#fuelpence').val(diesel);
	}
	calcSpent();
}