// JavaScript Document
//RSP Calculator
// Ayinde Yakubu, Copyright (c) 2003, Unisen Inc


//This method contains a percentage to ordinary number
function percent(value)
{
   var tempvalue =  value / 100.0;
   displayMessage ( "value: " + value + " result " + tempvalue);
   return tempvalue;
}

//-- varify that input is valid
function verifyInput(fieldName)
{
  // 
  // 
  //
}
// -- Converts str into ordinal numbers e.g. 11.24% to 0.1124
// 
function preparePercent(str)
{ 
    var val = str;
    if ( isNaN(str) )
	{ 
	    val = extractLastSign(str, "%");
	}
	result = percent(val);
	return result;
}

// -
//Utility Methods
function isEmpty(field)
{
  return ( field.value==null || field.value=="");
}
// -- Convert string that may contain dollar sign and commas into 
// number e.g. $82,999.92 is converted to 82999.92. The string
//can contain any number of commas and $ sign 
//
function prepareNumber(str)
{
   if ( str == null )
   {
      return 0;
   }
   if ( isNaN(str) == false )
   {
       return    str.valueOf();
   }
   
   var tempStr = str;
   if ( str.lastIndexOf("$") != -1 ) 
   {
       tempArray1 = str.split("$");
	   tempStr = tempArray1.join("");
   }
   var tempStr2 = tempStr;
   if ( tempStr.lastIndexOf(",") != - 1 )
   {
       tempArray2  = tempStr.split(",");
       tempStr2 = tempArray2.join("");
   }
   var result = parseFloat(tempStr2.valueOf());   

   return result;
}
// -- 
// retrieve selected item 
//
function makeIncomeChoice(fieldName)
{
   var option=document.rrspForm.incomeFreqOptions.options[document.rrspForm.incomeFreqOptions.selectedIndex].text;
   document.rrspForm.incomeFreq.value=lookup(option);
}

function makeContribChoice(fieldName)
{
   var option=document.rrspForm.contribOptions.options[document.rrspForm.contribOptions.selectedIndex].text;
   document.rrspForm.contribFreq.value=lookup(option);
}

// -- String formatting routines
// - Take 12122.34639 and return $12,122.35
// -- 

function convertToMoney(amount)
{
  var _dollars=parseInt(amount);
  var _cents=parseInt((amount - _dollars)*100);
  var _negative = _dollars <0;
  if(_negative)
  {  _dollars = -_dollars;
     _cents=-_cents;
  }
  
  while(_cents.toString().length < 2)
     _cents="0"+_cents;
  
  var _dA=_dollars.toString().split("");
  var _d="";
  for(var i=_dA.length-1;i>=0;i--)
  {
    var _comma="";
	if((_dA.length-i)%3==0 && i!=0)_comma=",";
    _d=_comma+_dA[i]+_d;
  }
  var _neg_sign=_negative?"-":"";
  var _result=""+_neg_sign+_d+"."+_cents;
  return _result;
}

// truncate a number to some specified digits after the decimal
function truncateNumber(value, dec)
{
   var decPlace = parseInt(dec);
   var str = value.toString();
   var result = str;
   var pos = str.indexOf(".");
   if ( pos != - 1 ) {
      var parts = str.split(".");
      var tempStr =  parts[1].substr(0, decPlace);
      result = parts[0] + "." + tempStr;
   }   	  
   
   return result;
}
//Extracts % sign from the rate input
function extractLastSign(aItem, aSign)
{
   var result="";
   if ( aItem != null && aSign != null )
   {
       pos=aItem.lastIndexOf(aSign);
	   if (pos != - 1 )
	   {
	      result=aItem.substr(0,pos);
	   }
	   else
	   {
	      result=aItem;
	   }
   }
  // alert(result);
   return result;
}

//Display a simple alert or message box
function displayMessage(value)
{
   if ( debugOn == true )
   {
       //alert (value);
   }
   else 
   { 
     // document.write("<em>" + value + "</em>");
   }
}


// -Method to perform a look up given a description
// It simulates a map
function lookup(description)
{
   for ( i = 0; i < MAP_SIZE; i++)
   {   
      var period = gPeriods[i];
      if ( description == gPeriods[i] ) 
	  {
	     return gPeriodValue[i];
	  }
   }
   //If none found, default to yearly
   return 1;
}

//Deflated Interest Factor
//The rate of inflation is deducted from the expected rate of
//of return. Will be used if payment is not increased due to inflation
function deflatedInterestFactor(inflR, ror)
{  
   var deflatedIntFact =  ( (1.0 - inflR ) * ( 1.0 + ror ) - 1.0);
   displayMessage("deflated Interest Factor" + deflatedIntFact);
   return deflatedIntFact;
}

//Inflated Interest Factor. The rate of inflation is added to the expected rate
//of return. Will be used if the payment is increased due to inflation.
function inflatedInterestFactor(inflationRate, expectedROR)
{
   var inflatedIntFact = (( 1.0 + inflationRate ) * ( 1.0 + expectedROR ) - 1 );
   displayMessage("inflated Interest Factor" + inflatedIntFact);
   return inflatedIntFact;
}


//Annual Income required in dollars. The current value of the required
//income in today's dollars based on the amount and the number of 
//payment per year.
function annualIncomeInTodayDollars(requiredIncome , paymentPerYear)
{
    var annualIncome = requiredIncome * paymentPerYear;
    displayMessage("Annual Income in Today Dollars" + annualIncome);
    return annualIncome;
}

//Annual income required in future dollars. The future value of the desired income
//at retirement with inflation rate applied
function annualIncomeInFutureDollars(requiredIncome, inflationRate, yearsToRetire)
{
    var tempval = Math.pow ( (1.0 + inflationRate), yearsToRetire);
	var fv = (requiredIncome*tempval);
    displayMessage("Annual Income in Future Dollars" + fv);
	return fv;
}

// ---
//  Required Savings at retirement. This refers to the total amount of savings
//  required to sustain income requirement for the total number of years
// ---
function reqSavAtRetireSimple(annualIncomeFD, expectedROR, yearsFundToLast)
{
   var negYears = (-1.0) * yearsFundToLast;
   var tempOne = Math.pow((1.0 + expectedROR), negYears);
   var tempTwo = expectedROR/(1.0 + expectedROR);
   
   var requiredSavings = annualIncomeFD * ( (1.0 - tempOne)/tempTwo);
   displayMessage("required savings simple" + requiredSavings);
   return requiredSavings;
}

// - RequiredSavings at Retirement if Income increases with inflation
// - The total amount of savings required to sustain income requirements for the total
//   number of years if income increases with inflation.
// --
function reqSavAtRetireIncInflation(annualIncomeFD, expectedROR, inflationRate, yearsFundToLast)
{
   var deflatedFactor = deflatedInterestFactor(inflationRate, expectedROR);
   var negYears = (-1.0) * yearsFundToLast;
   var tempOne = Math.pow((1.0 + deflatedFactor), negYears);
   var tempTwo = (deflatedFactor/(1.0 + deflatedFactor));
   
   
   var requiredSavings = annualIncomeFD * ( ( 1.0 - tempOne)/tempTwo);
  // alert (requiredSavings);
  
   //alert("required savings income increase with inflation" + requiredSavings);
   return requiredSavings;
   
}

// - Current RRSP Assets (Future Value). 
// The future value of the present RRSP at retirement time without any further
// contributions
// -
function currentRRSPFutureValueNoContrib(currentRRSP, expectedROR, yearsToRetire)
{
   var tempOne = Math.pow((1.0 + expectedROR ) , yearsToRetire);
  //alert (tempOne);
   var fv = currentRRSP * tempOne;
   displayMessage("Future value of current rrsp" + fv);
   return fv;
}

// --Total Annual Contributions
// The total amount of contributions per year
// -- 
function totalAnnualContribMethod(contribAmount, contributionFactor)
{
   var totalContrib = contribAmount * contributionFactor;
   displayMessage("Total annual contribution" + totalContrib);
   return totalContrib;
}

//--
//Future value of current assets
//The future value of present RRSP at retirement with further contributions
//--
function currentRRSPFutureValueWithContrib(currentRRSP, expectedROR, noOfPeriods, totalAnnualContrib)
{  
   var one = new Number(1.0);
   var tROR = one + expectedROR;
   var tperiod = new Number(noOfPeriods);
   var tempOne = Math.pow(tROR, noOfPeriods);

   var tPeriods =  one + tperiod ;
   var tempExp = Math.pow(tROR, tPeriods);
   
   var futureValue = (currentRRSP * tempOne) + totalAnnualContrib * ((tempExp - tROR)/expectedROR);
   displayMessage("Future value of current rrsp with contrib" + futureValue);   
   return futureValue;
}

//---
//Future value of current assets if contribution increases with inflation.
//The future value of the present RRSP asset at retirement time with further contributions
//that increase with inflation
//
//
//  Balance(n) = P(1 + r)^n + c[((1 + r1)^{n + 1} - (1 + r1))/r1]
// Where P : Principal
//       C : Contribution part
//       r : Expected ROR
//       r1: Expected ROR with inflation rate added
//---
function currentRRSPFutureValueWithContribInflate(currentRRSP, expectedROR, inflationRate, noOfPeriods, totalAnnualContrib)
{

   
   //var str = new String(inflatedIntr);
   //var pos = str.indexOf(".");
   //var truncIntr = str.substr(pos, 5).valueOf();
   //inflatedIntr = truncIntr;
   
   var addedIntr = new Number(1.0) + new Number(expectedROR);
   //alert(addedIntr);
   
   var principalCompoundIntr = Math.pow(addedIntr, noOfPeriods);
   //alert(principalCompoundIntr);

  //Calculate the principal part   
   var principalGrowthPart = currentRRSP * principalCompoundIntr;
   //alert(principalGrowthPart);


   //Calculate interest rates with inflation
   var inflatedIntr = inflatedInterestFactor(inflationRate, expectedROR);
   //alert(inflatedIntr);

   var addedInflatedIntr = new Number(1.0) + new Number(inflatedIntr);
   //alert("Sum Inflated Intr Rate: " +addedInflatedIntr);
   
   //alert("A.No of periods: " + noOfPeriods);
   var periods = new Number(noOfPeriods)  + new Number(1.0);
   //alert("B.No of periods: " + noOfPeriods);
   var contribCompoundIntr = Math.pow(addedInflatedIntr, periods);
   //alert(contribCompoundIntr);
    
   //Calculate the contribution part
   var contribGrowth = (contribCompoundIntr -  addedInflatedIntr)/inflatedIntr;
   var contribPart =  totalAnnualContrib *  contribGrowth ;
   
   var fv = principalGrowthPart + contribPart;
   
   //alert("Final-> " + fv);
   displayMessage("future value if contrib increases with inflation " + fv);
   
   return fv;
}

// ---
// Net Amount Required.
// The difference between the future values of current RRSP assets with contributions and 
// required savings at retirement
// ---
function netAmountRequired( requiredSavingAtRetirement, futureValueOfRRSP)
{
    var netAmount = requiredSavingAtRetirement - futureValueOfRRSP;
    displayMessage("Net amount required" + netAmount);
	return netAmount;
}

// ---
// Required Total Annual Contribution Amount
// The amount of contribution required annually over the years to retirement in order
// to meet the net amount 
// ---
function requiredTotalAnnualContrib(netAmountRequired, expectedROR, yearsToRetirement )
{  
   var sumROR = 1.0 + expectedROR;
   var incrYear  = new Number(1.0) + new Number(yearsToRetirement);
   var tempOne = Math.pow(sumROR, incrYear);
   
   var requiredTotalAmt = netAmountRequired / ((tempOne - sumROR)/expectedROR);
   displayMessage("required total amount " + requiredTotalAmt);
   
   return requiredTotalAmt;
}

// ---
// Required Contribution Amount
// The required amount of contribution per year
// ---
function requiredContribPerPeriod(requiredTotalAmt, reqContrPerYear)
{
     var amount = requiredTotalAmt / reqContrPerYear;
	 displayMessage("Required Contrib per period " + amount );
	 return amount;
}	 




/**
 * The main driver called by the form submission
 */
function rspCalculator(rrspForm)
{
   //extract all parameters
   var expectedROR  = preparePercent(rrspForm.txtROR.value, "%")
   //alert("Expected ROR: " + txtROR);
   
   var inflationRate = preparePercent(rrspForm.inflationRate.value,"%");
   //alert("Inflation rate: " + inflationRate);
   
   var yearsToRetirement = prepareNumber(rrspForm.yearsToRetire.value);
   //alert("Years to retirement: " + yearsToRetirement);
   
   var requiredIncome = prepareNumber(rrspForm.requiredIncome.value);
   //alert("Required Income: " + requiredIncome);
   
   var incomeFrequency = prepareNumber(rrspForm.incomeFreq.value);
   //alert("Income Frequency: " + incomeFrequency);
   
   var contribFreqPerAnnum = prepareNumber(rrspForm.contribFreq.value);
   //alert("Contribution Frequency: " + contribFreqPerAnnum);   
   
   var yearsFundToLast = prepareNumber(rrspForm.txtYearsFundToLast.value);
   //alert("Years funds to Last: " + yearsFundToLast);
   
   var incomeIncreaseWithInflation = identifyRadioSelection(rrspForm.incomeIncreaseWithInflation);
//   alert(incomeIncreaseWithInflation);
   
   var currentRRSP = prepareNumber(rrspForm.currentRRSP.value);
  // alert("Current RRSP Holdings: " + currentRRSP);
   
   var contribAmount = prepareNumber(rrspForm.contribAmount.value);
   //alert("Contribution Amount: " + contribAmount);
   
   var contribIncreaseWithInflation = identifyRadioSelection(rrspForm.contribIncreaseWithInfl);
   //alert("Contribution Increase with inflation: " + contribIncreaseWithInflation);
   
   //Calculate required values
   var deflatedIntrFactor = deflatedInterestFactor(inflationRate,expectedROR);
   var inflatedIntrFactor = inflatedInterestFactor(inflationRate, expectedROR);
   var annualIncomeTodaysDollar = annualIncomeInTodayDollars(requiredIncome, incomeFrequency);
   var annualIncomeInFutureDollar = annualIncomeInFutureDollars(annualIncomeTodaysDollar,inflationRate,yearsToRetirement);
   var requiredSavingsAtRetirement = 0.0;
   
   //Handle savings requirements with and without increase due to inflation
   //alert("Income increase with inflation: " + incomeIncreaseWithInflation);
   if ( incomeIncreaseWithInflation == "no" ) {
		requiredSavingsAtRetirement = reqSavAtRetireSimple(annualIncomeInFutureDollar, expectedROR, yearsFundToLast);
   }
   else {
		requiredSavingsAtRetirement = reqSavAtRetireIncInflation(annualIncomeInFutureDollar, expectedROR, inflationRate, yearsFundToLast);
   }
      
   //Calculate future values of current holdings with and without contributions
   //alert(contribAmount);
   //alert(contribFreqPerAnnum);
   var totalAnnualContrib = totalAnnualContribMethod(contribAmount,contribFreqPerAnnum);
   var futurevalueRRSP = currentRRSPFutureValueNoContrib(currentRRSP, expectedROR, yearsToRetirement);
   var futureValueOfCurrent = futurevalueRRSP;
   
   if ( totalAnnualContrib == 0.0 ){
        futurevalueRRSP = currentRRSPFutureValueNoContrib(currentRRSP, expectedROR, yearsToRetirement);
   }
   
   if (contribIncreaseWithInflation =="no" ) {
       futurevalueRRSP = currentRRSPFutureValueWithContrib(currentRRSP, expectedROR, yearsToRetirement, totalAnnualContrib);
   }
   else { //contribution increases with inflation
       futurevalueRRSP = currentRRSPFutureValueWithContribInflate(currentRRSP, expectedROR, inflationRate, yearsToRetirement, totalAnnualContrib);
   }
   
   //Calculate net amount required
   var netAmountReqd = netAmountRequired(requiredSavingsAtRetirement, futurevalueRRSP);
   
   //Calculate the required total annual contribution amount
   var totalAnnualContribRequired = requiredTotalAnnualContrib(netAmountReqd, expectedROR, yearsToRetirement);
   
   //Required contributions per period
   var reqContribPerPeriod = requiredContribPerPeriod(totalAnnualContribRequired, contribFreqPerAnnum);
   
   //Updates all form fields
   //document.rrspForm.txtdeflatedFactor.value = truncateNumber(deflatedIntrFactor, 4);
   //alert(deflatedIntrFactor);
   //document.rrspForm.txtInflatedFactor.value = truncateNumber(inflatedIntrFactor, 4);
   //alert(inflatedIntrFactor);
   document.rrspForm.txtFVIncome.value = convertToMoney(annualIncomeInFutureDollar);
   //alert(annualIncomeInFutureDollar);   
   document.rrspForm.txtRequiredSavings.value = convertToMoney(requiredSavingsAtRetirement);
   //alert(requiredSavingsAtRetirement);   
   document.rrspForm.txtCurrentRRSPFV.value = convertToMoney(futureValueOfCurrent);
   //alert(futurevalueRRSPNoContrib);   
   document.rrspForm.txtTotalAnnualContrib.value = convertToMoney(totalAnnualContrib);
   //alert(totalAnnualContrib);   
   document.rrspForm.txtRRSPAtRetirement.value = convertToMoney(futurevalueRRSP);
   //alert(futurevalueRRSP);   
   document.rrspForm.txtNetAmountReqd.value = convertToMoney(netAmountReqd);      
   //alert(netAmountReqd);   
   document.rrspForm.txtAdditionalContrib.value = convertToMoney(totalAnnualContribRequired);
   //alert(totalAnnualContribRequired);
   document.rrspForm.txtContribPerPeriod.value  = convertToMoney(reqContribPerPeriod);
   
   
   //reset all variables
   deflatedIntrFactor = 0;
   inflatedIntrFactor = 0;
   annualIncomeInFutureDollar = 0;
   requiredSavingsAtRetirement = 0;
   futurevalueRRSPNoContrib = 0;
   totalAnnualContrib = 0;
   futurevalueRRSP = 0;
   netAmountReqd = 0;      
   totalAnnualContribRequired =0 ;
   reqContribPerPeriod = 0;
}