//Send this a number, and this function will return the number
//to two significant decimal places.

function floor(number)
{
 return Math.floor(number*Math.pow(10,2))/Math.pow(10,2);
}

//This is the constructor, the calculate method and the accessor methods
//for the RentVsBuyCalculator

//Define global variables
var DEFAULT_INVESTMENT_RATE = new Number(0.08);

//ownership benefit accessor method
function getOwnershipBenefit()
{
 if ((this.rentingCost - this.ownershipCost) >0)
 {
 return (this.rentingCost - this.ownershipCost);
 }
 else
 {
 return 0;
 }
}

//renting cost accessor method
function getRentingCost()
{
 return this.rentingCost;
}

//ownership cost accessor method
function getOwnershipCost()
{
 return this.ownershipCost;
}

//tax savings accessor method
function getTaxSavings()
{
 return this.taxSavings;
}

//closing costs accessor method
function getClosingCosts()
{
 return this.closingCosts;
}

//gross costs accessor method
function getGrossCosts()
{
 return this.grossCosts;
}

//equity earned accessor method
function getEquityEarned()
{
 return this.equityEarned;
}

//potential savings accessor method
function getPotentialSavings()
{
 return ((this.rentingCost - this.ownershipCost) * DEFAULT_INVESTMENT_RATE);
}

//this method is the new AmortScheduleCalculator object constructor
function RentVsBuyCalculator()
{
 //variables
 this.rentingCost = new Number();
 this.ownershipCost = new Number();
 this.taxSavings = new Number();
 this.closingCosts = new Number();
 this.equityEarned = new Number();
 this.grossCosts = new Number();
 this.className = "RentVsBuyCalculator";

 //methods
 this.getOwnershipBenefit = getOwnershipBenefit;
 this.getRentingCost = getRentingCost;
 this.getTaxSavings = getTaxSavings;
 this.getClosingCosts = getClosingCosts;
 this.getGrossCosts = getGrossCosts;
 this.getEquityEarned = getEquityEarned;
 this.getPotentialSavings = getPotentialSavings;
 this.calculate = RentVsBuyCalculatorCalculate;

 return this;
}



// this is the calculate method
function RentVsBuyCalculatorCalculate (salesPrice, interestRate, loanAmt, loanTerm, monthlyMI, federalTaxRate, appreciationRate, discountPoints, expectedYearsToOwn, monthlyRent, annualRentIncrease, annualPropertyTax, annualMiscOwnershipFees, annualMiscRentalFees)
{
 var totalAppreciation = new Number(0);
 var totalPrincipalPaid = new Number(0);
 var totalInterestPaid = new Number(0);
 var totalPMI = new Number(0);
 var year = new Number(0);

 var rvb = new RentVsBuyCalculator();

 var amort = new AmortScheduleCalculator();
 amort = amort.calculate(loanAmt,salesPrice,interestRate,0,0,1,expectedYearsToOwn*12,0,0,0,0,federalTaxRate,monthlyMI,false,loanTerm,loanTerm,0,0,0,0,0,0);

 totalPrincipalPaid = amort.getTotalNormalPrincipal();
 totalInterestPaid = amort.getTotalNormalInterest();
 totalPMI = amort.getTotalPMI();
 var annualRent = monthlyRent * 12;

 // Forcast appreciation/increases
 for (year = 0; year < expectedYearsToOwn; year++)
 {
 // Calculate all of the rental costs for the term expected
 rvb.rentingCost += annualRent;
 annualRent += annualRent * annualRentIncrease;

 // Calculate the annual appreciation in equity
 if (year > 0)
 {
 totalAppreciation += salesPrice * appreciationRate;
 }
 }

 rvb.rentingCost += (annualMiscRentalFees * expectedYearsToOwn);

 rvb.equityEarned = (salesPrice + totalAppreciation + totalPrincipalPaid - loanAmt);


 // Calculate annual property tax if not passed, use 1.5% as default
 // if (annualPropertyTax == 0)
 // annualPropertyTax = ( salesPrice * DEFAULT_PROPERTY_TAX_RATE );

 // Calculate total tax savings (interest, property tax, closing costs)
 var totalPropertyTax = new Number(annualPropertyTax * expectedYearsToOwn);

 rvb.taxSavings = amort.getTotalTaxSavings() + (totalPropertyTax * federalTaxRate) + (discountPoints * loanAmt * federalTaxRate);

 // Get closing costs
 var closingTemp = new EstimatedClosingCosts();

 rvb.closingCosts = closingTemp.calculate(loanAmt, loanTerm, interestRate, discountPoints, (salesPrice - loanAmt));

 rvb.ownershipCost = (totalInterestPaid + totalPrincipalPaid + totalPMI + totalPropertyTax + rvb.closingCosts + (annualMiscOwnershipFees * expectedYearsToOwn)) - (rvb.taxSavings + rvb.equityEarned);

 rvb.grossCosts= (totalInterestPaid + totalPrincipalPaid + totalPMI + totalPropertyTax + rvb.closingCosts + (annualMiscOwnershipFees * expectedYearsToOwn));

 return rvb;
}