public object Calculate(CalculationContext context, Calculation calculation)
{
Expression expression = new Expression(calculation.Formula);
var regex = new Regex(@"\[(.*?)\]");
var parameters = regex.Matches(calculation.Formula);
GetValue(context, expression, parameters);
var result = expression.Evaluate();
SetValue(result, calculation, context);
return result;
}
private static void GetValue(CalculationContext context, Expression expression, MatchCollection parameters)
{
foreach (var parameter in parameters)
{
var name = parameter.ToString().Replace("[", "").Replace("]", "");
object propValue = context;
foreach (string propName in name.Split('.'))
{
PropertyInfo propInfo = propValue.GetType().GetProperty(propName);
if (propValue.GetType().Equals(typeof(List<ExtendedDataElement>)))
{
List<ExtendedDataElement> extended = (List<ExtendedDataElement>) propValue;
propValue = extended.First(x => x.ElementName == propName).ElementValue;
break;
}
propValue = propInfo.GetValue(propValue, null);
}
expression.Parameters[name] = propValue;
}
}
public void Should_Take_Value_From_ExtendedProperties_Using_Name()
{
CalculationContext context = new CalculationContext()
{
ChargeElement = new ChargeElement() { Name = "Standing Charge", NetAmount = new decimal(12.71000) },
Bill = new Bill() { BillStartDate = new DateTime(2012, 2, 10), BillEndDate = new DateTime(2012, 3, 12), TaxPointDate = new DateTime(2012, 03, 12),ExtendedData = new List<ExtendedDataElement>(){new ExtendedDataElement(){ElementName = "PowerFactor", ElementValue = "123"}}},
Contract = new Contract() { }
};
var calculation = new Calculation()
{
Formula = "[ChargeElement.NetAmount] / [Bill.BillPeriod] * [Bill.ExtendedData.PowerFactor]",
Target = "ChargeElement.Quantity"
};
var calculationEngine = new CalculationEngine();
calculationEngine.Calculate(context, calculation);
Assert.AreEqual(50.43d, context.ChargeElement.Quantity);
}
public void Should_Store_Value_In_Extended_Data()
{
CalculationContext context = new CalculationContext()
{
ChargeElement = new ChargeElement() { Name = "Standing Charge", NetAmount = new decimal(12.71000) },
Bill = new Bill() { BillStartDate = new DateTime(2012, 2, 10), BillEndDate = new DateTime(2012, 3, 12), TaxPointDate = new DateTime(2012, 03, 12), ExtendedData = new List<ExtendedDataElement>() { new ExtendedDataElement() { ElementName = "PowerFactor", ElementValue = "123" } } },
Contract = new Contract() { }
};
var calculation = new Calculation()
{
Formula = "[ChargeElement.NetAmount] / [Bill.BillPeriod]",
Target = "Bill.ExtendedData.PowerFactor"
};
var calculationEngine = new CalculationEngine();
calculationEngine.Calculate(context, calculation);
Assert.AreEqual(0.41d, decimal.Parse(context.Bill.ExtendedData.First(x=>x.ElementName == "PowerFactor").ElementValue));
}
public void ShouldTakeFormulaAndUseCorrectPropertyValues()
{
CalculationContext context = new CalculationContext()
{
ChargeElement = new ChargeElement() { Name = "Standing Charge", NetAmount = new decimal(12.71000) },
Bill = new Bill() { BillStartDate = new DateTime(2012, 2, 10), BillEndDate = new DateTime(2012, 3, 12), TaxPointDate = new DateTime(2012, 03, 12) },
Contract = new Contract() {}
};
var calculation = new Calculation()
{
Formula = "[ChargeElement.NetAmount] / [Bill.BillPeriod]",
Target = "ChargeElement.Quantity"
};
var calculationEngine = new CalculationEngine();
calculationEngine.Calculate(context, calculation);
Assert.AreEqual(0.41d, context.ChargeElement.Quantity);
}
private static void SetValue(object result, Calculation calculation, CalculationContext context)
{
object proploc = context;
foreach (var propName in calculation.Target.Split('.'))
{
PropertyInfo propInfo = proploc.GetType().GetProperty(propName);
if (proploc.GetType().Equals(typeof(List<ExtendedDataElement>)))
{
List<ExtendedDataElement> extended = (List<ExtendedDataElement>)proploc;
extended.First(x => x.ElementName == propName).ElementValue = result.ToString();
break;
}
if (propInfo.Name == calculation.Target.Split('.').Last())
{
propInfo.SetValue(proploc, result, null);
break;
}
proploc = propInfo.GetValue(proploc, null);
}
}