//Calculator class
Calculator = function(strFormID)
{

	//Validate fields
	this.validate = function()
	{

		//Init local variables
		var strErrorMessage	= '';
		var strInvalidItem	= '';
		var blnIsValid		= true;
		var form			= this.getForm();

		//Validate step by step
		if (form.WeeklyHours.value.length == 0)
		{

			strErrorMessage	= 'Please enter your weekly hours!';
			strInvalidItem	= 'WeeklyHours';

		}
		else if (isNaN(form.WeeklyHours.value))
		{

			strErrorMessage	= 'Please check your weekly hours - non numeric value!';
			strInvalidItem	= 'WeeklyHours';

		}
		else if (form.HourlyRate.value.length == 0)
		{

			strErrorMessage	= 'Please enter your hourly rate!';
			strInvalidItem	= 'HourlyRate';

		}
		else if (isNaN(form.HourlyRate.value))
		{

			strErrorMessage	= 'Please check your hourly rate - non numeric value!';
			strInvalidItem	= 'HourlyRate';

		}
		else if (form.WeeklyExpenses.value.length == 0)
		{

			strErrorMessage	= 'Please enter your weekly expenses!';
			strInvalidItem	= 'WeeklyExpenses';

		}
		else if (isNaN(form.WeeklyExpenses.value))
		{

			strErrorMessage	= 'Please check your weekly expenses - non numeric value!';
			strInvalidItem	= 'WeeklyExpenses';

		}

		//Validate
		if(strErrorMessage)
		{

			//Write the error
			this.writeError(strErrorMessage);
			
			//Set the focus to invalid item
			form.elements[strInvalidItem].focus();

			//Set Invalid
			blnIsValid = false;

		}

		//Return
		return blnIsValid;

	}

	//Calculate the amounts and display their values
	this.calculate = function()
	{
		
		//Hide errors
		this.hideErrors();
		
		//Validate the fields
		if(!this.validate())
		{
			return false;
		}

		//Get the forms
		var form				= this.getForm();
		var illustrationForm	= this.getIllustrationForm();

		//Init local variables
		var floatWeeklyHours	= this.cleanFloat(form.WeeklyHours.value);
		var floatHourlyRate		= this.cleanFloat(form.HourlyRate.value);
		var floatWeeklyExpenses	= this.cleanFloat(form.WeeklyExpenses.value);
		var floatFee			= this.cleanFloat(form.Fee.value);
		var floatPension		= this.cleanFloat(form.Pension.value);
		var intTaxCodeNumber	= form.TaxCodeNumber.value;
		var strTaxCodeLetter	= form.TaxCodeLetter.value;
		var intPAYEWeeks		= form.PAYEWeeks.value;

		//Set illustrations hidden values
		illustrationForm.WeeklyHours.value		= floatWeeklyHours;
		illustrationForm.HourlyRate.value		= floatHourlyRate;
		illustrationForm.Fee.value				= floatFee;
		illustrationForm.WeeklyExpenses.value	= floatWeeklyExpenses;
		illustrationForm.Pension.value			= floatPension;
		illustrationForm.TaxCodeNumber.value	= intTaxCodeNumber;
		illustrationForm.TaxCodeLetter.value	= strTaxCodeLetter;
		illustrationForm.PAYEWeeks.value		= intPAYEWeeks;

		//Update description values
		$('#idPAYEWeeksForDesc').attr('innerHTML',intPAYEWeeks);
		$('#idTaxCodeForDesc').attr('innerHTML',intTaxCodeNumber + '' + strTaxCodeLetter);

		if(floatPension > 0)
		{
			$('#idPensionContainerForDesc').show();
			$('#idPensionForDesc').attr('innerHTML',floatPension);
		}

		//Calculate with JSON-AJAX
		$.getJSON('http://www.ibalance.co.uk/calcs/calculator.asp?in_callback=?', {in_calcType:'umbrellaVPAYE',in_hours:floatWeeklyHours,in_rate:floatHourlyRate,in_expenses:floatWeeklyExpenses,in_fee:floatFee,pension:floatPension,TaxCodeNo:intTaxCodeNumber,TaxCodeLetter:strTaxCodeLetter,NoPeriods:intPAYEWeeks,autocalc:'true'},

			function(data) {

				//Calculator object
				var objCalculator = new Calculator();

				//Init values
				var floatPayeTakeHome	= objCalculator.cleanFloat(data.ag_takeHome);
				var floatOurTakeHome	= objCalculator.cleanFloat(data.um_takeHome);
				var floatOurVsPaye		= objCalculator.cleanFloat(data.increasePrecent);
				var floatOurSaving		= objCalculator.cleanFloat(data.increasePerYear);
				var floatPaye			= objCalculator.cleanFloat(data.um_paye);
				var floatNIC			= objCalculator.cleanFloat(data.um_nic);
				var floatWeeklyHours	= objCalculator.cleanFloat(form.WeeklyHours.value);
				var floatGross			= floatWeeklyHours * form.HourlyRate.value;

				if(data.um_expensesRestriction == 'TRUE')
				{

					$('#idExpensesNotes > td').html('Due to National Minimum Wage a maximum of £' + data.um_expensesLimit + ' of expenses can be considered.');
					$('#idExpensesNotes').fadeIn();

				} else {
					$('#idExpensesNotes').hide();
				}

				$('#idOurValues').animate({
					'opacity': 0
					},250
				);
				
				$('#idOurValues').animate({
					'opacity': 1
					},250
				);

				//Write illustration details
				$('#idHourlyRateForIllustration').attr('innerHTML','£' + objCalculator.formatNumber(floatHourlyRate));
				$('#idWeeklyHoursForIllustration').attr('innerHTML',objCalculator.formatNumber(floatWeeklyHours));
				$('#idGross').attr('innerHTML','£' + objCalculator.formatNumber(floatGross));
				$('#idPAYE').attr('innerHTML','-£' + objCalculator.formatNumber(Math.abs(floatPaye)));
				$('#idNIC').attr('innerHTML','-£' + objCalculator.formatNumber(Math.abs(floatNIC)));
				$('#idOurFee').attr('innerHTML','-£' + objCalculator.formatNumber(Math.abs(floatFee)));
				$('#idTakeHomePay').attr('innerHTML','£' + objCalculator.formatNumber(floatOurTakeHome));
				$('#idTakeHomePayPercent').attr('innerHTML',objCalculator.formatNumber(floatOurTakeHome/floatGross*100));

				//Calculate illustration percentages
				var floatTakeHomePayPercentage	= parseInt(floatOurTakeHome/floatGross*100);
				var floatNICPercentage			= parseInt(floatNIC/floatGross*100);
				var floatOurFeePercentage		= parseInt(floatFee/floatGross*100);

				//Get the illustration chart
				//var strChartUrl = 'http://chart.apis.google.com/chart?cht=p3&chs=520x190&chf=bg,s,f3efef&chma=0,0,0,0&chd=t:'+floatTakeHomePayPercentage+','+floatNICPercentage+','+floatOurFeePercentage+'&chl=Take Home Pay|NIC|Redego Fee';
				var strChartUrl = 'http://chart.apis.google.com/chart?cht=bhg&chs=520x130&chf=bg,s,f3efef&chm=N,000000,0,-1,12,,l:-40&chco=aca4a4|cc0000|b8b5b5&chxt=x,y&chxr=0,0,' + (floatGross + 50) + '&chxl=1:|Agency*|Redego|Gross&chd=t:' + floatGross + ',' + floatOurTakeHome + ',' + floatPayeTakeHome + '&chds=0,' + (floatGross + 50);

				//Insert the chart image
				$('#idIllustrationChart').attr('src',strChartUrl);

			}

		);

		//Rename calculate button
		$('#idCalculateButton').val('Recalculate');

		//Display illustration
		this.displayIllustration();

		//Go to anchor
		window.location = '#Calculator';

	}

	//Init email field
	this.initEmailField = function() {

		//Check current value
		if($('#idEmail').val() == '' || $('#idEmail').val() == $('#idEmail').attr('title')) //No email address entered or it has the default value
		{

			$('#idEmail').val( $('#idEmail').attr('title') );
			$('#idEmail').addClass('watermark');

		}
		else //Email address already entered
		{

			$('#idEmail').removeClass('watermark');

		}

	}

	//Todos onfocus email field
	this.onfocusEmailField = function()
	{

		//Check current value
		if($('#idEmail').val() == $('#idEmail').attr('title')) //No email address entered or it has the default value
		{
			$('#idEmail').val('');
		}
		
		//Remove watermark
		$('#idEmail').removeClass('watermark');

	}

	//Display illustration
	this.displayIllustration = function()
	{
		$('#idCalculatorIllustration').show();

		this.displayChart();
	}

	//Display chart with animation
	this.displayChart = function()
	{
		$('#idIllustrationChart').hide();
		$('#idIllustrationChart').fadeIn(2000);
	}

	//Send illustration as an email
	this.sendIllustration = function()
	{

		//Init local variables
		var strEmail = $('#idEmail').val();

		//Check email address
		if(strEmail.length = 0)
		{

			this.writeEmailError('Please enter your email address!');

			return false;

		}
		else if(!isEmailAddress(strEmail))
		{

			this.writeEmailError('Please enter a valid email address!');

			return false;

		}

		//Everything is ok
		return true;

	}

	//Hide email sent message (and display email field again)
	this.hideEmailSent = function(strMethod)
	{

		if(!strMethod)
		{
			strMethod = 'slow';
		}

		$('#idIllustrationSent').fadeOut(strMethod);

	}

	//Clean float
	this.cleanFloat = function(mixNumber)
	{
		return parseFloat(mixNumber.replace(',',''));
	}

	//Format number as we like
	this.formatNumber = function(floatNumber,intDecimalDigits)
	{

		if(isNaN(intDecimalDigits))
		{
			intDecimalDigits = 2;
		}

		return this.addCommas(floatNumber.toFixed(intDecimalDigits));
	}

	//Add commas as thousand separator
	this.addCommas = function(nStr)
	{
		nStr += '';
		x = nStr.split('.');
		x1 = x[0];
		x2 = x.length > 1 ? '.' + x[1] : '';
		var rgx = /(\d+)(\d{3})/;
		while (rgx.test(x1)) {
			x1 = x1.replace(rgx, '$1' + ',' + '$2');
		}
		return x1 + x2;
	}

	//Write the error
	this.writeError = function(strErrorMessage,strErrorContainerID)
	{

		//Get the container
		if(!strErrorContainerID)
		{
			strErrorContainerID = 'CalculatorError';
		}

		//Set the errormessage
		$('#' + strErrorContainerID + ' > td:first').attr('innerHTML',strErrorMessage);

		//Show error the container
		$('#' + strErrorContainerID).show();

	}

	//Email error happened
	this.writeEmailError = function(strErrorMessage)
	{

		this.writeError(strErrorMessage,'EmailError');

		$('#idEmail').focus();

	}

	//Hide error
	this.hideErrors = function()
	{
		$('#CalculatorError').hide();
		$('#EmailError').hide();
	}

	//Get the calculator form
	this.getForm = function()
	{
		return document.forms[this.formID];
	}

	//Get the illustration form
	this.getIllustrationForm = function()
	{
		return document.forms['idCalculatorIllustration'];
	}

	//Constructor
	this.construct = function()
	{
		this.formID	= strFormID;
	}

	//Run the constructor automatically on object creating
	this.construct();

}