/// <summary>
/// 使用優惠券
/// </summary>
/// <param name="order">訂單</param>
public virtual void Use(IOrder order)
{
if (!IsAvailable(order))
{
return;
}
var couponItem = new CouponOrderItem()
{
Name = Name,
Price = 0,
Count = 1,
Coupon = this
};
var amount = order.TotalAmount;
if (AllowReuse)
{
var discount = (100 - DiscountPercent) / 100m;
// amount * discount ^ count = Threshold
// discount ^ count = Threshold / amount;
// log_(Threshold / amount) discount = count
var count = Convert.ToUInt32(Math.Ceiling(
Math.Log(decimal.ToDouble(Threshold / amount), decimal.ToDouble(discount))
));
if (Count.HasValue)
{
count = Convert.ToUInt32(Math.Min(count, Count.Value));
}
couponItem.Price = amount - new decimal(Math.Pow(decimal.ToDouble(discount), count)) * amount;
couponItem.Price *= -1;
#region 使用並扣除數量
if (Count.HasValue)
{
Count -= count;
}
order.Items.Add(couponItem);
UsedOrder.Add(order);
#endregion
}
else
{
couponItem.Price = amount * DiscountPercent / 100m;
couponItem.Price *= -1;
#region 使用並扣除數量
Count -= 1;
order.Items.Add(couponItem);
UsedOrder.Add(order);
#endregion
}
}
/// <summary>
/// 使用優惠券
/// </summary>
/// <param name="order">訂單</param>
public void Use(IOrder order)
{
// 合併項目
Cashier.MergeOrderItem <TOrderItemIdentifier>(order);
while (IsAvailable(order))
{
// 適用於此優惠券項目
var setItems = order.Items
.Where(x =>
x is IOrderItem <TOrderItemIdentifier> item &&
Set.Keys.Contains(item.Id)
)
.Cast <IOrderItem <TOrderItemIdentifier> >();
// 查詢目前占用
var occupy = Cashier.GetTotalOccupyOrderItemCount(order);
// 取得目前已經使用的項目
CouponOrderItem couponOrderItem
= order.Items.SingleOrDefault(x => x is CouponOrderItem item && item.Coupon == this)
as CouponOrderItem;
// 如果沒有則加入
if (couponOrderItem == null)
{
couponOrderItem = new CouponOrderItem()
{
Coupon = this,
Name = Name,
Price = -DiscountPrice
};
order.Items.Add(couponOrderItem);
}
// 累計
couponOrderItem.Count++;
// 更新占用項目
foreach (var item in setItems)
{
if (!couponOrderItem.OccupyOrderItemCount.ContainsKey(item))
{
couponOrderItem.OccupyOrderItemCount[item] = 0;
}
couponOrderItem.OccupyOrderItemCount[item] += Set[item.Id];
}
}
}
/// <summary>
/// 使用優惠券
/// </summary>
/// <param name="order">訂單</param>
public override void Use(IOrder order)
{
// 合併項目
Cashier.MergeOrderItem <TOrderItemIdentifier>(order);
foreach (var orderItem in order.Items.ToArray())
{
if (IsAvailable(order, orderItem) &&
orderItem is IOrderItem <TOrderItemIdentifier> item)
{
var totalOccupy = Cashier.GetTotalOccupyOrderItemCount(order);
var thisItemUsedCouponCount
= totalOccupy.ContainsKey(item) ?
totalOccupy[item].Sum(x => x.Value) :
0;
var count = item.Count - (uint)thisItemUsedCouponCount;
if (Count.HasValue)
{
count = Math.Min(Count.Value, count);
}
var couponItem = new CouponOrderItem()
{
Coupon = this,
Name = Name,
Price = -DiscountPrice,
Count = count
};
couponItem.OccupyOrderItemCount[item] = count;
if (Count.HasValue)
{
Count -= couponItem.Count;
}
order.Items.Add(couponItem);
}
}
}
