private CalculatorResult ValidateInput(decimal mortgageLoan, double annualInterest, uint numberOfPayments)
{
var result = new CalculatorResult();
if (mortgageLoan < 0)
{
result.Succeed = false;
result.Error = new CalculatorError()
{
Code = MortgageCalculatorErrors.MortgageNotValid, Message = "Mortgage not valid"
};
this.log?.LogError($"{nameof(CalculateMontlyRateAsync)} Mortgage not valid", mortgageLoan);
}
else if (annualInterest < 0)
{
result.Succeed = false;
result.Error = new CalculatorError()
{
Code = MortgageCalculatorErrors.AnnualInterestNotValid, Message = "Annual interest not valid"
};
this.log?.LogError($"{nameof(CalculateMontlyRateAsync)} Annual interest not valid", annualInterest);
}
return(result);
}
public Task <CalculatorResult> CalculateMontlyRateAsync(decimal mortgageLoan, double annualInterest, uint numberOfPayments)
{
this.log?.LogTrace($"--> Enter {nameof(CalculateMontlyRateAsync)}", mortgageLoan, annualInterest,
numberOfPayments);
CalculatorResult result = null;
var sw = Stopwatch.StartNew();
result = ValidateInput(mortgageLoan, annualInterest, numberOfPayments);
if (result.Succeed)
{
double rate = 0;
if (annualInterest == 0)
{
rate = (double)mortgageLoan / numberOfPayments;
}
else
{
var montlyInterest = annualInterest / 12;
var k = Math.Pow(1 + montlyInterest, numberOfPayments);
rate = (double)mortgageLoan * (montlyInterest * k / (k - 1));
}
result.Result = (decimal)Math.Round(rate, 2, MidpointRounding.AwayFromZero);
}
sw.Stop();
this.log?.LogMetric($"{nameof (CalculateMontlyRateAsync)} Duration", sw.ElapsedMilliseconds);
this.log?.LogTrace($"<-- Exit {nameof(CalculateMontlyRateAsync)}", mortgageLoan, annualInterest,
numberOfPayments, result);
return(Task.FromResult(result));
}
