var errMsg = "";

function trim(trimThis)
{
	if(trimThis==undefined)
		return null;
	else
	{
		trimThis = trimThis.replace("^\s+", "");
		trimThis = trimThis.replace("\s+$", "");
	}
	if(trimThis=="")
		return null;
	
	return trimThis;
}

function checkContactInfo()
{

	var name = document.getElementById("contactInfoName").value;
	var telNum = document.getElementById("contactInfoTelephoneNumber").value;
	var email = document.getElementById("contactInfoEMail").value;
	
	name = trim(name);
	telNum = trim(telNum);
	email = trim(email);
	
	if(name==null)
		errMsg = "Please enter your name";
	else if(telNum==null && email==null)
		errMsg = "Please enter one of telephone number or email";
}

function checkOutputInfo()
{
	var volt = document.getElementById("volt").value;
	var watt = document.getElementById("watt").value;
	var amp = document.getElementById("amp").value;
	
	if(volt==undefined || volt=="" || isNaN(volt))
		errMsg = "Please enter the correct voltage";
	else if(watt==undefined || watt=="" || isNaN(watt))
		errMsg = "Please enter the correct wattage";
	else if(amp==undefined || amp=="" || isNaN(amp))
		errMsg = "Please enter the correct amperage";
	
}

function checkQuantityInfo()
{
	var quantity = document.getElementById("quantity").value;
	if(quantity==undefined || quantity=="" || isNaN(quantity))
		errMsg = "Please enter the correct quantity";	
	
	
}

function checkInfo()
{
	try{
		checkOutputInfo();
		if(errMsg=="")
			checkQuantityInfo();
		else
			return;
		
		if(errMsg=="")
			checkContactInfo();
		else
			return;
	}
	catch(e)
	{
		errMsg = "Please make sure you enter all the required fields indicated by a red star";
		return null;
	}
}

function validateData()
{
	//clear any error messages
	errMsg = "";
	checkInfo();
	if(errMsg!="")
	{
		alert(errMsg);
		return false;
	}
	return true;
}

function calculateWatts()
{
	try
	{
		var volt = document.getElementById("volt").value;
		var amp = document.getElementById("amp").value;
		if(volt!=undefined && amp!=undefined)
			return (trim(volt)*trim(amp)).toFixed(2);
	}
	catch(e)
	{
		errMsg = "Please enter correct volt and amp values";
		return null;
	}
}

function calculateAmps()
{
	try
	{
		var volt = document.getElementById("volt").value;
		var watt = document.getElementById("watt").value;
		var amp =  (volt/watt).toFixed(2);
		return amp;
	}
	catch(e)
	{
		errMsg = "Please enter correct volt and watt values";
		return null;
	}
	
}

function populateWatts()
{
	var watts = calculateWatts();
	if(watts!=null && !isNaN(watts))
	{
		var wattsNode = document.getElementById("watt");
		wattsNode.value = watts;
	}
}

function populateAmps()
{
	var amps = calculateAmps();
	if(amps!=null && !isNaN(amps))
	{
		var ampsNode = document.getElementById("amp");
		ampsNode.value = amps;
	}
}