/// <summary>
/// Sets the line item tax rate.
/// </summary>
/// <param name="taxableItem">The taxable item.</param>
/// <param name="lineTaxResult">The line tax result.</param>
protected static void SetLineItemTaxRate(TaxableItem taxableItem, LineTaxResult lineTaxResult)
{
if (taxableItem == null)
{
throw new ArgumentNullException("taxableItem");
}
if (lineTaxResult == null)
{
throw new ArgumentNullException("lineTaxResult");
}
// Ignore any portion of the TaxAmount that is 'Exempt' when computing the rate.
decimal amount = lineTaxResult.TaxAmount - lineTaxResult.ExemptAmount;
SetLineItemTaxRate(taxableItem, amount);
}
/// <summary>
/// Calculate tax on the given line item.
/// </summary>
/// <param name="taxableItem">The taxable item.</param>
/// <param name="context">The context.</param>
/// <param name="transaction">Current transaction.</param>
private void CalculateTax(TaxableItem taxableItem, RequestContext context, SalesTransaction transaction)
{
ReadOnlyCollection <TaxCode> codes = this.GetTaxCodes(taxableItem, context, transaction);
LineTaxResult lineTaxResult = new LineTaxResult
{
HasExempt = false,
TaxRatePercent = decimal.Zero,
TaxAmount = decimal.Zero,
ExemptAmount = decimal.Zero
};
foreach (TaxCode code in codes)
{
var taxCodeAmount = code.CalculateTaxAmount(codes, this.taxCodeAmountRounder);
lineTaxResult.TaxAmount += taxCodeAmount;
// sum up the amounts that are exempt
if (code.Exempt)
{
lineTaxResult.HasExempt = true;
lineTaxResult.ExemptAmount += lineTaxResult.TaxAmount;
}
}
// Set the 'virtual tax rate', if extended price is ZERO, then just add the full amount
decimal extendedPrice = taxableItem.Price * Math.Abs(taxableItem.Quantity);
if (extendedPrice == decimal.Zero)
{
extendedPrice = decimal.One;
}
lineTaxResult.TaxRatePercent = (lineTaxResult.TaxAmount * 100) / extendedPrice;
SetLineItemTaxRate(taxableItem, lineTaxResult);
}
