public bool AddToHistory(NetPresentValueRequest netPresentValueRequest)
{
List <NPV_HISTORY_CASHFLOWS> lstCashFlows = new List <NPV_HISTORY_CASHFLOWS>();
int counter = 1;
foreach (decimal cashFlow in netPresentValueRequest.cashFlows)
{
lstCashFlows.Add(new NPV_HISTORY_CASHFLOWS()
{
ID = Guid.NewGuid(),
CASH_FLOW = cashFlow,
ORDER = counter
});
counter++;
}
NPV_HISTORY npv_history = new NPV_HISTORY()
{
ID = Guid.NewGuid(),
INITIAL_VALUE = netPresentValueRequest.initialValue,
LOWER_BOUND_DISCOUNT_RATE = netPresentValueRequest.lowerBoundDiscountRate,
UPPER_BOUND_DISCOUNT_RATE = netPresentValueRequest.upperBoundDiscountRate,
INCREMENT = netPresentValueRequest.increment,
CREATED_DATE = DateTime.Now,
NPV_HISTORY_CASHFLOWS = lstCashFlows
};
unitOfWork.NPVHistory.Add(npv_history);
return(unitOfWork.SaveChanges() > 0);
}
public async Task <int> AddNetPresentValue(Guid userId, NetPresentValueRequest request)
{
//if (await _context.NetPresentValues.AnyAsync(r => r.Name == request.Name))
// throw new Exception($"Error: NetPresentValue '{request.Name}' already exists");
var npv = new Entities.NetPresentValue()
{
Name = null,
InitialInvestment = request.InitialInvestment,
LowerBoundDiscountRate = request.LowerBoundDiscountRate,
UpperBoundDiscountRate = request.UpperBoundDiscountRate,
DiscountRateIncrement = request.DiscountRateIncrement,
CreatedDate = DateTime.UtcNow
};
/* https://devblogs.microsoft.com/cesardelatorre/using-resilient-entity-framework-core-sql-connections-and-transactions-retries-with-exponential-backoff/ */
var strategy = _context.Database.CreateExecutionStrategy();
await strategy.ExecuteAsync(async() =>
{
using (var transaction = _context.Database.BeginTransaction())
{
int saveCount = 0;
await _context.NetPresentValues.AddAsync(npv);
saveCount = await _context.SaveChangesAsync();
var cashFlows = request.CashFlows.Where(cf => cf.Amount != 0).Select(cf => new Entities.PeriodAmount()
{
NetPresentValueId = npv.NetPresentValueId,
Amount = cf.Amount,
Period = cf.Period
});
await _context.PeriodAmounts.AddRangeAsync(cashFlows);
saveCount = await _context.SaveChangesAsync();
var userNpv = new Entities.UserNetPresentValue()
{
UserId = userId,
NetPresentValueId = npv.NetPresentValueId
};
await _context.UserNetPresentValues.AddAsync(userNpv);
saveCount = await _context.SaveChangesAsync();
transaction.Commit();
}
});
return(npv.NetPresentValueId);
}
public IEnumerable <NPVPerDiscountRateDTO> ComputeNetPresentValues(NetPresentValueRequest netPresentValueRequest)
{
while (netPresentValueRequest.lowerBoundDiscountRate <= netPresentValueRequest.upperBoundDiscountRate)
{
decimal npv = ComputeNetPresentValue(netPresentValueRequest.cashFlows, netPresentValueRequest.initialValue, netPresentValueRequest.lowerBoundDiscountRate);
yield return(new NPVPerDiscountRateDTO()
{
DiscountRate = netPresentValueRequest.lowerBoundDiscountRate,
NPV = npv
});
netPresentValueRequest.lowerBoundDiscountRate += netPresentValueRequest.increment;
if (netPresentValueRequest.increment == 0)
{
break;
}
}
}
