public void GetValueByRatesTest()
{
//Arrange
double value = 4;
double leftRate = 1.2;
double rightRate = 0.8;
double expected = 2.66666666667;
//Act
var actual = CalculationStation.GetValueByRates(value, leftRate, rightRate);
//Assert
//Close enough
Assert.IsTrue(Math.Abs(expected - actual) < 0.01);
}
//Calculation
public void MakeCalculation(bool isFirst)
{
//exit if already calculating or if data isn't loaded
if (isCalculating || !IsDataLoaded)
{
return;
}
try
{
isCalculating = true;
//Default to 1
double firstValue = FirstAmount != 0 ? FirstAmount : 1;
double secondValue = SecondAmount != 0 ? SecondAmount : 1;
int leftIndex = FirstCurrency;
int rightIndex = SecondCurrency;
//If they have the same currency, flip the last pair of currencies around
if (leftIndex == rightIndex)
{
leftIndex = CurrentState.SecondIndex;
rightIndex = CurrentState.FirstIndex;
FirstCurrency = leftIndex;
SecondCurrency = rightIndex;
}
//Order of calculations based on which block of elements was updated
if (isFirst)
{
SecondAmount = Math.Round(
CalculationStation.GetValueByRates(
firstValue,
_currencies[leftIndex].Rate,
_currencies[rightIndex].Rate
), 2);
}
else
{
//Don't calculate tax
FirstAmount = Math.Round(
CalculationStation.GetValueByRates(
secondValue,
_currencies[rightIndex].Rate,
_currencies[leftIndex].Rate
), 2);
}
CurrentState.FirstIndex = leftIndex;
CurrentState.SecondIndex = rightIndex;
double taxValue = 0;
//Show or hide Tax
if (_taxInput > 0)
{
taxValue = Math.Round(SecondAmount * (_taxInput * 0.01), 2);
TaxOutput = $"+{taxValue}";
TaxVisible = true;
}
else
{
_taxInput = 0;
TaxVisible = false;
}
//Final display
FirstOutput = $"{_firstAmount}";
SecondOutput = $"{_secondAmount + taxValue}";
FirstName = $"{_currencies[CurrentState.FirstIndex].Name}";
SecondName = $"{_currencies[CurrentState.SecondIndex].Name}";
}
catch (Exception ex)
{
Debug.WriteLine("\tView Model Calculation Failed: {0}", ex.Message);
}
finally
{
CurrentState = CurrentState;
isCalculating = false;
}
}
