/***************************************\
*	Financial Calculator(s)		*
*   March, 2005 by Harley H. Puthuff	*
*    Copyright 2005, Your Showcase	*
\***************************************/

/*
 * Global object
 */
var Our		= new Object();				// global Class/Object
Our.sponsor	= (typeof sponsor=='undefined') ? 'Your Showcase' : sponsor;
Our.calculator	= 0;					// object with calculations
Our.months	= new Array('Jan','Feb','Mar','Apr','May','Jun','Jul','Aug','Sep','Oct','Nov','Dec');
Our.date	= new Date();				// current date
Our.month	= Our.date.getMonth()+1;		// current month
Our.year	= Our.date.getFullYear();		// current year
Our.round	= function(v) {				// round to nearest cent
		  return (Math.round(v*100.0)/100.0);
		  };
Our.roundup	= function(v) {				// round up to nearest cent
		  return (Math.ceil(v*100.0)/100.0);
		  };
Our.rounddown	= function(v) {				// round down to nearest cent
		  return (Math.floor(v*100.0)/100.0);
		  };
Our.number	= function(v) {				// convert to number
		  var p=new String(v),r=new String(''),i,d;
		  for (i=0;i<p.length;i++) {
		    d=p.charAt(i);
		    if (((d=='-')&&(i==0))||(d=='.')||((d>='0')&&(d<='9'))) r+=d;
		    }
		  if (r=='') r='0';
		  return Number(r);
		  };
Our.currency	= function(v) {				// convert to currency ($)
		  var t='',c,p;
		  c=(this.round(this.number(v))).toString();
		  p=c.split('.');
		  if (p.length<2) p[1]='00';
		  if (p[1].length==1) p[1]=p[1]+'0';
		  if (p[1].length>2) p[1]=p[1].substring(0,2);
		  if (p[0].length==0) p[0]='0';
		  for (c=p[0]; c.length>3;) {
		    t=','+c.substr(c.length-3)+t;
		    c=c.substr(0,(c.length-3));
		    }
		  return(c+t+'.'+p[1]);
		  };
Our.term	= function(months,years) {		// convert to "nn month(s) and nn year(s)"
		  var m=this.number(months),y=this.number(years),s='';
		  if (m>11) {y+=Math.floor(m/12); m%=12;}
		  if (y>0) {s+=y.toString()+' year'; if (y>1) s+='s';}
		  if (m>0) {if (s.length>0) s+=' and '; s+=m.toString()+' month'; if (m>1) s+='s';}
		  return s;
		  };
Our.selectDate	= function() {				// returns text for date selector
		  var m,y,t,i,j,e,yr;
		  m=this.month; y=this.year;
		  if (++m>12) {m=1; y++;}
		  t='<select name=Month class=field size=1 style="font: bold 10pt verdana,sans; color: #00b; background: #fff;">';
		  for (i=0; i<12; i++) {
		    e=(i==(m-1))?' selected':'';
		    t+='<option'+e+'>'+this.months[i]+'</option>';
		    }
		  t+='</select>&nbsp;' +
		     '<select name=Year class=field size=1 style="font: bold 10pt verdana,sans; color: #00b; background: #fff;">';
		  for (i=-30; i<=5; i++) {
		    yr=y+i;
		    e=(yr.toString()==y.toString())?' selected':'';
		    t+='<option value='+yr.toString()+e+'>'+yr.toString()+'</option>';
		    }
		  t+='</select>';
		  return t;
		  };
Our.selectYears	= function() {				// returns text for #years selector
		  var i,yr,t;
		  t='<select name=Years class=field size=1 style="font: bold 10pt verdana,sans; color: #00b; background: #fff;">' +
		    '<option value=0>All years</option>';
		  for (i=1; i<=30; i++) {
		    yr=i.toString();
		    t+='<option value='+yr+(i==1?' selected':'')+'>'+yr+' year'+(i==1?'':'s')+'</option>';
		    }
		  t+='</select>';
		  return t;
		  };
/*
 * Constructor for a Calculator object:
 * P1 = loan amount or 0
 * P2 = loan term (years) or 0
 * P3 = loan rate (apr) or 0
 * P4 = loan monthly payment or 0
 * P5 = (optional) first payment month (1-12)
 * P6 = (optional) first payment year (2000-????)
 */
function Calculator(name,amount,term,rate,payment,month,year,years) {
    var x,y;
    this.name = new String(name);
    this.amount = Our.number(amount);
    this.term = Our.number(term);
    this.rate = Our.number(rate);
    this.payment = Our.number(payment);
    this.firstMonth = Our.month;
    this.firstYear = Our.year;
    if (++this.firstMonth > 12) {this.firstMonth = 1; ++this.firstYear;}
    x = Our.number(month); if (x > 0) this.firstMonth = x;
    y = Our.number(year); if (y > 0) this.firstYear = y;
    this.limit = Our.number(years) * 12;
    if (this.limit == 0) this.limit = this.term * 12;
    if (this.term == 0) {
	var mpr = this.rate / 1200;
	var months = (Math.log(this.payment) - Math.log(this.payment - (this.amount * mpr))) / Math.log(1 + mpr);
	this.term = Math.ceil(months / 12);
	}
    if (this.rate == 0) {
	var months = this.term * 12.0;
	var lastrate = 0.0;
	var thisrate = 80.0;
	var adjustment,mpr,principal;
	while (1) {
	    adjustment = Math.abs(thisrate - lastrate) / 2.0;
	    mpr = thisrate / 1200.0;
	    principal = this.payment *
		((Math.pow((1.0 + mpr), months) - 1.0) / (mpr * Math.pow((1.0 + mpr), months)));
	    if (Math.round(principal) == this.amount) {
		this.rate = Math.round(thisrate * 100.0) / 100.0;
		break;
		}
	    lastrate = thisrate;
	    if (principal > this.amount)
		thisrate += adjustment;
	    else
		thisrate -= adjustment;
	    }
	}
    this.months = this.term * 12.0;
    this.apr = this.rate / 100.0;
    this.mpr = this.apr / 12.0;
    if (this.amount == 0) {
	this.amount = this.payment *
		((Math.pow((1.0 + this.mpr), this.months) - 1.0) /
		(this.mpr * Math.pow((1.0 + this.mpr), this.months)));
	}
    if (this.payment == 0) {
	this.payment =
	    (this.amount * Math.pow((1.0 + this.mpr), this.months) * this.mpr) /
	    (Math.pow((1.0 + this.mpr), this.months) - 1.0);
	this.payment = Our.roundup(this.payment);
	}
    x = (this.firstYear*12) + (this.firstMonth-1) + (this.months-1);
    this.lastMonth = (x%12)+1;
    this.lastYear = Math.floor(x/12);
    this.numberOfPayments = this.months;
    this.totalOfPayments = this.payment * this.numberOfPayments;
    this.financeCharge = this.totalOfPayments - this.amount;
    }
/*
 * Calculator method: show mortgage/loan details
 * returns text for a page with mortgage details
 */
Calculator.prototype.details = function () {
    return(
	'<html>\n' +
	'<head>\n' +
	'<title>' + this.name + '</title>\n' +
	'<style type=text/css>\n' +
	' body {font: bold 10pt verdana,sans; color: #00b; background: #ffe; margin: 1px; text-align: center;}\n' +
	' table {border: none; width: 90%; height: 100%;}\n' +
	' th.h {font: bold 12pt georgia,serif; color: #b00; text-align: center;}\n' +
	' th.l {font: bold 10pt georgia,serif; color: #000; text-align: left;}\n' +
	' th.r {font: bold 12pt verdana,sans; color: #00b; text-align: right;}\n' +
	' .action {font: bold 10pt georgia,serif; color: #000; width: 180px; height: 30px; cursor: hand;}\n' +
	'</style>\n' +
	'</head>\n' +
	'<body><form style="display: inline"><table>\n' +
	'<tr><th class=h colspan=2>Results for ' + this.name + ' calculations</th></tr>\n' +
	'<tr><th class=l>Amount Financed</th><th class=r>$ ' + Our.currency(this.amount) + '</th></tr>\n' +
	'<tr><th class=l>Term</th><th class=r>' + this.term.toString() + ' years</th></tr>\n' +
	'<tr><th class=l>Interest Rate</th><th class=r>' + Our.currency(this.rate) + '%</th></tr>\n' +
	'<tr><th class=l>Monthly Payment</th><th class=r>$ ' + Our.currency(this.payment) + '</th></tr>\n' +
	'<tr><th class=l>First Payment</th><th class=r>' + Our.months[this.firstMonth-1] +
	 ', ' + this.firstYear.toString() + '</th></tr>\n' +
	'<tr><th class=l>Last Payment</th><th class=r>' + Our.months[this.lastMonth-1] +
	 ', ' + this.lastYear.toString() + '</th></tr>\n' +
	'<tr><th class=l>Number of Payments</th><th class=r>' + this.numberOfPayments.toString() + '</th></tr>\n' +
	'<tr><th class=l>Finance Charge</th><th class=r>$ ' + Our.currency(this.financeCharge) + '</th></tr>\n' +
	'<tr><th class=l>Total of Payments</th><th class=r>$ ' + Our.currency(this.totalOfPayments) + '</th></tr>\n' +
	'<tr><th colspan=2><input type=button class=action value="Print Results" onClick=window.print()></th></tr>\n' +
	'</table></form></body>\n' +
	'</html>'
	);
    };
/*
 * Calculator method: show amortization
 * returns text for a page with amortization
 */

Calculator.prototype.amortization = function() {
    var title = this.name + ' Amortization';
    var row = 'even';
    var text =
	'<html>\n' +
	'<head>\n' +
	'<title>' + title + '</title>\n' +
	'<style type="text/css">\n' +
	' body {background: #FFFFF0; color: #6666CC; font-family: verdana,sans-serif;\n' +
	'  font-size: 12pt; font-weight: normal; text-align: center;}\n' +
	' .odd {background: #ffffff;}\n' +
	' .even {background: #f8f8f8;}\n' +
	' .head {font: bold 12pt georgia,serif; color: #b00; text-align: center;}\n' +
	' .tc {font: 8pt verdana,sans; color: #000; text-align: left; vertical-align: middle; white-space: nowrap;}\n' +
	' .vc {font: bold 8pt verdana,sans; color: #00b; text-align: right; vertical-align: middle; white-space: nowrap;}\n' +
	' .ch {font: 7pt tahoma,sans; background: #00b; color: #fff; text-align: right; vertical-align: bottom;}\n' +
	' .cd {font: 7pt tahoma,sans; color: #000; text-align: right; vertical-align: middle; white-space: nowrap;}\n' +
	' .action {font: bold 10pt georgia,serif; color: #000; cursor: hand;}\n' +
	'</style>\n' +
	'</head>\n' +
	'<body><form name=amortization>\n' +
	'<p class=head>' + title + '</p>\n';
    text +=
	'<table border=0 cellspacing=2 cellpadding=0 width=100%>\n' +
	'<tr><th width=50% align=left><table border=0 width=90% cellspacing=0 cellpadding=1>\n' +
	'<tr><th class=tc>Mortgage amount</th><th class=vc>' + Our.currency(this.amount) + '</th></tr>\n' +
	'<tr><th class=tc>Term</th><th class=vc>' + this.term.toString() + ' years</th></tr>\n' +
	'<tr><th class=tc>First payment</th><th class=vc>' + Our.months[this.firstMonth-1] + 
	' ' + this.firstYear.toString() + '</th></tr>\n' +
	'<tr><th class=tc>Last payment</th><th class=vc>' + Our.months[this.lastMonth-1] + 
	' ' + this.lastYear.toString() + '</th></tr>\n' +
	'</table></th><th width=50% align=right><table border=0 width=90% cellspacing=0 cellpadding=1>\n' +
	'<tr><th class=tc>Interest Rate</th><th class=vc>' + this.rate.toString() + '%</th></tr>\n' +
	'<tr><th class=tc>Monthly payment</th><th class=vc>' + Our.currency(this.payment) + '</th></tr>\n' +
	'<tr><th class=tc>Total interest</th><th class=vc>' + Our.currency(this.financeCharge) + '</th></tr>\n' +
	'<tr><th class=tc>Total of payments</th><th class=vc>' + Our.currency(this.totalOfPayments) + '</th></tr>\n' +
	'</table></th></tr>' +
	'</table>\n';
    this.current = new Object();
	this.current.number = 1;
	this.current.date = '';
	this.current.balance = this.amount;
	this.current.month = this.firstMonth-1;
	this.current.year = this.firstYear;
	this.current.payment = this.payment;
	this.current.interest = 0.00;
	this.current.principal = 0.00;
	this.current.ytdInterest = 0.00;
	this.current.ytdPrincipal = 0.00;
	this.current.totalInterest = 0.00;
	this.current.totalPrincipal = 0.00;
	this.current.remaining = 0.00;
    text +=
	'<p><table cellspacing=0 cellpadding=0 style="border: none; width: 100%;">\n';
    while (this.current.balance > 0.00) {
	if ((this.current.number == 1) || (this.current.month == 0)) {
	    text +=
		'<tr>\n' +
		'<th class=ch style="text-align: left">#</th>\n' +
		'<th class=ch>Date</th>\n' +
		'<th class=ch>Interest</th>\n' +
		'<th class=ch>Principal</th>\n' +
		'<th class=ch>Int-YTD</th>\n' +
		'<th class=ch>Prin-YTD</th>\n' +
		'<th class=ch>Total Int</th>\n' +
		'<th class=ch>Total Prin</th>\n' +
		'<th class=ch>Remaining</th>\n' +
		'</tr>\n';
	    }
	this.current.date = Our.months[this.current.month] + ' ' + this.current.year.toString();
	this.current.interest = Our.rounddown(this.current.balance * this.mpr);
	this.current.principal = this.current.payment - this.current.interest;
	if (this.current.principal > this.current.balance) this.current.principal = this.current.balance;
	this.current.ytdInterest += this.current.interest;
	this.current.ytdPrincipal += this.current.principal;
	this.current.totalInterest += this.current.interest;
	this.current.totalPrincipal += this.current.principal;
	this.current.remaining = this.current.balance - this.current.principal;
	row = (row == 'odd') ? 'even' : 'odd';
	text += '<tr class=' + row + '>\n';
	text += '<th class=cd style="text-align: left">' + this.current.number.toString() + '</th>\n';
	text += '<th class=cd>' + this.current.date + '</th>\n';
	text += '<th class=cd>' + Our.currency(this.current.interest) + '</th>\n';
	text += '<th class=cd>' + Our.currency(this.current.principal) + '</th>\n';
	text += '<th class=cd>' + Our.currency(this.current.ytdInterest) + '</th>\n';
	text += '<th class=cd>' + Our.currency(this.current.ytdPrincipal) + '</th>\n';
	text += '<th class=cd>' + Our.currency(this.current.totalInterest) + '</th>\n';
	text += '<th class=cd>' + Our.currency(this.current.totalPrincipal) + '</th>\n';
	text += '<th class=cd>' + Our.currency(this.current.remaining) + '</th>\n';
	text += '</tr>\n';
	if (++this.current.number > this.limit) break;
	this.current.balance = this.current.remaining;
	if (++this.current.month > 11) {
	    this.current.month = 0; ++this.current.year;
	    this.current.ytdInterest = 0.00;
	    this.current.ytdPrincipal = 0.00;
	    }
	}
    text +=
	'</table></p>\n' +
	'<p><input type=button class=action value="Print Amortization" onClick="window.print()"></p>\n' +
	'</form></body>\n' +
	'</html>\n';
    return text;
    };
/*
 * Evaluate the input fields and perform a calculation (if necessary)
 */
function calculate() {
    var f = document.parameters,values=0;
    var Amount = Our.number(f.Amount.value); if (Amount>0) ++values;
    var Rate = Our.number(f.Rate.value); if (Rate>0) ++values;
    var Term = Our.number(f.Term.value); if (Term>0) ++values;
    var Payment = Our.number(f.Payment.value); if (Payment>0) ++values;
    var Month = f.Month.selectedIndex+1;
    var Year = f.Year.options[f.Year.selectedIndex].value;
    var Years = f.Years.options[f.Years.selectedIndex].value;
    if (Years == 0) Years = Term;
    if (values < 3) {
	alert('I need at least three of the four values!');
	f.Amount.focus();
	return;
	}
    if ((Amount>0) && (Rate>0) && (Term>0)) Payment=0;
    Our.calculator = new Calculator('Your Mortgage',Amount,Term,Rate,Payment,Month,Year,Years);
    f.Amount.value = Our.currency(Our.calculator.amount);
    f.Rate.value = Our.currency(Our.calculator.rate) + '%';
    f.Term.value = Math.floor(Our.calculator.term).toString() + ' years';
    f.Payment.value = Our.currency(Our.calculator.payment);
    results.location = "javascript:parent.Our.calculator.details()";
    }
/*
 * Show splash page in the results frame
 */
function splash() {
    return(
	'<html>\n' +
	'<head>\n' +
	'<style type=text/css>\n' +
	' body {font: bold 12pt georgia,serif; color: #00f; background: #ffe; text-align: center; margin: 1px;}\n' +
	' .title {font: bold 28pt georgia,serif; color: #b00;}\n' +
	'</style>\n' +
	'</head>\n' +
	'<body>\n' + Our.sponsor + '<br><small><i>presents</i></small>\n' +
	'<p><img src=/weblibrary/javascript/MortgageCalculator.jpg border=0></p>\n' +
	'<p class=title>Your<br>Mortgage<br>Calculator</p>\n' +
	'</body>\n' +
	'</html>'
	);
    }
/*
 * Clear all values and restart
 */
function restart() {
    var f = document.parameters,values=0;
    f.Amount.value = f.Rate.value = f.Term.value = f.Payment.value = '';
    Our.calculator = 0;
    results.location = "javascript:parent.splash()";
    f.Amount.focus();
    }
/*
 * insert the calculator html
 */
var d=window.document;
d.writeln('<form name=parameters style="display: inline;" onSubmit="return false;">');
d.writeln('<style type=text/css>');
d.writeln('.calculator {font: bold 10pt verdana,sans; color: #00b; background: #eed;' +
	  ' border: thin outset; width: 740px; height: 450px;}');
d.writeln('.tag {font: bold 10pt georgia,serif; color: #000; text-align: left; white-space: nowrap;}');
d.writeln('.val {font: bold 10pt georgia,serif; color: #000; text-align: center;}');
d.writeln('.heading {font: italic bold 12pt georgia,serif; color: #b00;}');
d.writeln('.prompt {font: normal 8pt verdana,sans; color: #000; text-align: left; margin: 10px 0px;}');
d.writeln('.field {font: bold 12pt verdana,sans; color: #00b; background: #fff; text-align: right; border: thin inset;}');
d.writeln('.action {font: bold 10pt georgia,serif; color: #000; width: 180px; height: 30px; cursor: hand;}');
d.writeln('.copyright {font: normal 8pt verdana,sans; color: #000; text-align: center;}');
d.writeln('</style>');
d.writeln('<table class=calculator cellspacing=0 cellpadding=3><tr>');
d.writeln('<th width=250><table cellspacing=0 cellpadding=2 height=100%>');
d.writeln(' <tr><th class=heading colspan=2 valign=top>Mortgage Calculator</th></tr>');
d.writeln(' <tr><th class=prompt colspan=2>');
d.writeln('  Fill in any three of the values shown below then click the [Calculate...] button and the');
d.writeln('  fourth value will be automatically calculated for you. You may then show the amortization,');
d.writeln('  print the results, or perform another calculation.');
d.writeln(' </th></tr>');
d.writeln(' <tr><th class=tag>Mortgage Amount</th><th class=val><input class=field name=Amount size=12></th></tr>');
d.writeln(' <tr><th class=tag>Interest Rate</th><th class=val><input class=field name=Rate size=12></th></tr>');
d.writeln(' <tr><th class=tag>Term (years)</th><th class=val><input class=field name=Term size=12></th></tr>');
d.writeln(' <tr><th class=tag>Payments</th><th class=val><input class=field name=Payment size=12></th></tr>');
d.writeln(' <tr><th class=tag>Starting Date</th><th class=val>'+Our.selectDate()+'</th></tr>');
d.writeln(' <tr><th class=tag>Amortize for:</th><th class=val>'+Our.selectYears()+'</th></tr>');
d.writeln(' <tr><th colspan=2 class=val><input type=submit class=action value="Calculate Mortgage" onClick="calculate()"></th></tr>');
d.writeln(' <tr><th colspan=2 class=val><input type=button class=action value="Show Amortization"' +
	  '  onClick="if (typeof Our.calculator==\'object\')' +
	  '  results.location=\'javascript:parent.Our.calculator.amortization()\'"></th></tr>');
d.writeln(' <tr><th colspan=2 class=val><input type=button class=action value="Print the Results"' +
	  '  onClick="window.print()"></th></tr>');
d.writeln(' <tr><th colspan=2 class=val><input type=button class=action value="Clear all Fields" onClick="restart()"></th></tr>');
d.writeln(' <tr><th class=copyright colspan=2 valign=bottom>Copyright &copy;2005</th></tr>');
d.writeln('</table></th>');
d.writeln('<th height=100%>');
d.writeln(' <iframe name=results width=100% height=100% marginheight=1 marginwidth=1 noresize scrolling=auto></iframe>');
d.writeln('</th>');
d.writeln('</tr></table>');
d.writeln('</form>');
results.location='javascript:parent.splash()';