// feedback while filling out form...

var numOfFields = 8;// number of form items (not auto at the moment)
var feedbackArr = new Array();
var i = 0;
while (i <= numOfFields) {
	feedbackArr[i] = false;// set all as false first
	i++;
}
function calcFeedback(fieldNum, fieldName) {
	// if not at the beginning, check if any ealier fields are false...
	var i = 0;
	while (i < fieldNum) {// for each field BEFORE current one (and not after)
		if (feedbackArr[i] == false) {// if it's false, show the cross icon
			document.getElementById('feedback' + i).style.backgroundPosition = '-31px -103px';
		}
		i++;
	}
	
	// now look at the current field value...
	if (document.getElementById(fieldName).value == '' || isNaN(document.getElementById(fieldName).value)) {// if current field is empty or NaN onblur...
		document.getElementById('feedback' + fieldNum).style.backgroundPosition = '-31px -103px';// show the cross
		feedbackArr[fieldNum] = false;// mark as false
	} else {// if it's got content...
		document.getElementById('feedback' + fieldNum).style.backgroundPosition = '0 -103px';// show the tick
		feedbackArr[fieldNum] = true;// mark as true
	}
}


// when form submitted...

function costCalculate() {
	var i = 0;
	var allCorrect = true;// assume all are correct...
	while (i <= numOfFields) {
		if (feedbackArr[i] == false) {// if it's false, show the cross icon
			document.getElementById('feedback' + i).style.backgroundPosition = '-31px -103px';
			allCorrect = false;// all are not correct
		}
		i++
	}
	if (allCorrect == true) {// if no errors were found, then it will still be true...
		var gemComparison = document.getElementById('gem-comparison').value;
		var mileageYear = document.getElementById('mileage-week').value * 52;
		var gallonsPerYear = mileageYear / document.getElementById('miles-per-gallon').value;
		var costPerGallon = document.getElementById('cost-per-litre').value * 4.54609188;
		var engineType = document.getElementById('engine-type').value;
		var chosenEngine = 'Petrol';
		if (engineType == 10.1) {
			chosenEngine = 'Diesel';
		}
		var costPerKWH = document.getElementById('cost-per-kwh').value;

		switch (gemComparison) {
			case '1':
				gemComparison = 'e2';
				var totalRunElec = 5 * costPerKWH / 35 * mileageYear;
				break;
			case '2':
				gemComparison = 'e4';// full charge uses 5KW, 30 miles per full charge
				var totalRunElec = 5 * costPerKWH / 30 * mileageYear;
				break;
			case '3':
				gemComparison = 'eS';
				var totalRunElec = 5 * costPerKWH / 30 * mileageYear;
				break;
			case '4':
				gemComparison = 'eL';
				var totalRunElec = 5 * costPerKWH / 30 * mileageYear;
				break;
			case '5':
				gemComparison = 'eLXD';// charge 8.33 KW
				var totalRunElec = 8.33 * costPerKWH / 50 * mileageYear;
				break;
			case '6':
				gemComparison = 'Quadriga';
				var totalRunElec = 5 * costPerKWH / 30 * mileageYear;
				break;
		}

		var roadTax = document.getElementById('road-tax').value;
		var congestionCharges = document.getElementById('congestion-charges').value;
		var serviceCharges = document.getElementById('service-charges').value;
		var totalTotal = (Math.round(gallonsPerYear * costPerGallon) + Number(roadTax) + Number(congestionCharges) + Number(serviceCharges));
	
		$('#chosen-engine').html(chosenEngine);// add the right engine title
		$('#total-run').html(Math.round(gallonsPerYear * costPerGallon));// gallons per year * cost per gallon
		$('#total-tax').html(Number(roadTax));
		$('#total-congestion').html(Number(congestionCharges));
		$('#total-service').html(Number(serviceCharges));
		$('#total-co2').html(Math.round(Number(gallonsPerYear) * Number(engineType)));// gallons per year * 8.8/10.1 (petrol/diesil)
		$('#total-offset').html(Math.round(Number(gallonsPerYear) * Number(engineType) / 100));// total-co2 / 100 (roughly: 100Kg = £1)
		$('#total-total').html(totalTotal);

		$('#chosen-gem-comparison').html(gemComparison);// add the right model title to the electric results side
		$('#total-run-elec').html(Math.round(totalRunElec));
		$('#total-total-elec').html(Math.round(totalRunElec));
		
		$('#total-savings').html(Math.round(totalTotal - Number(totalRunElec)));

		$('#calc-results').slideDown("slow");
	}
}