/// <summary>
/// Transfers money from the source account to the destination account.
/// </summary>
/// <param name="sourceAccount">The source account.</param>
/// <param name="destAccount">The dest account.</param>
/// <param name="amount">The amount to transfer.</param>
/// <param name="mode">The conversion mode.</param>
/// <param name="description">The description of the transaction.</param>
/// <returns></returns>
/// <exception cref="System.ArgumentNullException">
/// </exception>
/// <exception cref="System.ArgumentException">Amount should be greater than 0</exception>
/// <exception cref="BankingServiceException">The account does not have enough amount of money</exception>
public async Task TransferMoney(IAccount sourceAccount, IAccount destAccount, decimal amount, AmountConversionMode mode, string description)
{
if (sourceAccount == null)
{
throw new ArgumentNullException(nameof(sourceAccount));
}
if (destAccount == null)
{
throw new ArgumentNullException(nameof(destAccount));
}
if (amount <= 0)
{
throw new ArgumentException("Amount should be greater than 0", nameof(amount));
}
if (sourceAccount.Balance < amount)
{
throw new BankingServiceException("The account does not have enough amount of money");
}
using (var transaction = _databaseContext.DemandTransaction())
{
try
{
// get exchange rates and commissions
decimal exhangeRate;
decimal commissionPercent;
if (string.Equals(sourceAccount.Currency, destAccount.Currency, StringComparison.InvariantCultureIgnoreCase))
{
exhangeRate = 1.0m;
commissionPercent = 0.0m;
}
else
{
exhangeRate = await _exchangeRateService.GetExhangeRateAsync(sourceAccount.Currency, destAccount.Currency);
commissionPercent = DefaultCommission;
}
// calc bank commission and new balances
var commission = Math.Round(amount * commissionPercent, 2);
// in case of commission, source description should include it
string sourceDescription;
string destDescription;
switch (mode)
{
case AmountConversionMode.SourceToTarget:
// source account is charged to pay the bank commission
var sourceAmount = amount;
var destAmount = Math.Round(exhangeRate * (amount - commission), 2);
sourceAccount.Balance = sourceAccount.Balance - amount;
destAccount.Balance = destAccount.Balance + destAmount;
sourceDescription = $"{description} Amount {sourceAmount.ToString("N2", CultureInfo.InvariantCulture)} {sourceAccount.Currency}.";
destDescription = $"{description} Amount {destAmount.ToString("N2", CultureInfo.InvariantCulture)} {destAccount.Currency}.";
if (commission > 0)
{
sourceDescription += $" Bank commission {commission.ToString("N2", CultureInfo.InvariantCulture)} {sourceAccount.Currency}";
}
break;
case AmountConversionMode.TargetToSource:
// destination account is charged to pay the bank commission
sourceAmount = Math.Round(amount / exhangeRate, 2);
destAmount = amount - commission;
sourceAccount.Balance = sourceAccount.Balance - sourceAmount;
destAccount.Balance = destAccount.Balance + destAmount;
sourceDescription = $"{description} Amount {sourceAmount.ToString("N2", CultureInfo.InvariantCulture)} {sourceAccount.Currency}.";
destDescription = $"{description} Amount {destAmount.ToString("N2", CultureInfo.InvariantCulture)} {destAccount.Currency}.";
if (commission > 0)
{
destDescription += $" Bank commission {commission.ToString("N2", CultureInfo.InvariantCulture)} {destAccount.Currency}";
}
break;
default:
throw new ArgumentOutOfRangeException(nameof(mode), mode, null);
}
// write journals
_journalService.WriteTransferJournal(sourceAccount, destAccount, sourceDescription, destDescription);
// update database
_databaseContext.Accounts.Update(sourceAccount);
_databaseContext.Accounts.Update(destAccount);
// update bank revenues, if any
if (commission > 0)
{
_bankBalanceService.AddRevenue(commission, $"A commission for money transfer from the account {sourceAccount.AccountNumber} to the account {destAccount.AccountNumber}");
}
// commit transaction
transaction.Commit();
}
catch
{
transaction.Rollback();
throw;
}
}
}