private DiscountApplied ComputeDiscount(BasketItem item, ActivePromo promo)
{
DiscountApplied da = new DiscountApplied(item.PackageId);
int discountMultiplier = item.Quantity / promo.MinQty;
switch (promo.DiscountTypeId)
{
case 1: //Dollar price reduction on item.
da.DiscountedPrice = discountMultiplier * promo.DiscountValue;
break;
case 2: //Price reduction based on discount value in percent
double discountPercent = (double)promo.DiscountValue / 100;
da.DiscountedPrice = discountMultiplier * Convert.ToInt32(discountPercent * item.Price);
break;
case 3: //Increase the quantity based on discount value.
da.AddedQuantity = discountMultiplier * promo.DiscountValue;
break;
default:
break;
}
return(da);
}
public async Task <ActionResult <List <DiscountApplied> > > ApplyPromoAsync([FromBody] List <BasketItem> orders)
{
List <ActivePromo> promos = new List <ActivePromo>();
await using (var command = _context.Database.GetDbConnection().CreateCommand())
{
command.CommandText = "SELECT p.PackageId, d.MinQuantity, d.DiscountValue, d.DiscountTypeId FROM Promos p INNER JOIN Discounts d ON p.DiscountId=d.Id INNER JOIN DiscountTypes dt ON d.DiscountTypeId=dt.Id";
_context.Database.OpenConnection();
using (IDataReader dr = command.ExecuteReader())
{
while (dr.Read())
{
promos.Add(new ActivePromo()
{
PackageId = Convert.ToInt32(dr[0]),
MinQty = Convert.ToInt32(dr[1]),
DiscountValue = Convert.ToInt32(dr[2]),
DiscountTypeId = Convert.ToInt32(dr[3])
});
}
}
}
List <DiscountApplied> discountOnBasketItems = new List <DiscountApplied>();
//Loop for each item in the basket.
foreach (BasketItem odr in orders)
{
List <ActivePromo> promosOnItem = promos.Where(p => p.PackageId == odr.PackageId && p.MinQty <= odr.Quantity).ToList <ActivePromo>();
//Compute discount foreach promos on item.
List <DiscountApplied> discountsOnItem = new List <DiscountApplied>();
foreach (ActivePromo promo in promosOnItem)
{
discountsOnItem.Add(ComputeDiscount(odr, promo));
}
if (promosOnItem.Count > 0)
{
//Best discount priority: 1. If quantity is higher, 2. discounted price is higher
DiscountApplied bestDiscountOnItem = discountsOnItem.OrderByDescending(x => x.AddedQuantity).ThenByDescending(x => x.DiscountedPrice).First();
discountOnBasketItems.Add(bestDiscountOnItem);
}
}
return(discountOnBasketItems);
}
