namespace Netina.Core.EntityServices.DiscountHandlers;

public class CalculateOrderDiscountCommandHandler : IRequestHandler<CalculateOrderDiscountCommand , double>
{
    private readonly IRepositoryWrapper _repositoryWrapper;
    private readonly ICurrentUserService _currentUserService;

    public CalculateOrderDiscountCommandHandler(IRepositoryWrapper repositoryWrapper,ICurrentUserService currentUserService)
    {
        _repositoryWrapper = repositoryWrapper;
        _currentUserService = currentUserService;
    }
    public async Task<double> Handle(CalculateOrderDiscountCommand request, CancellationToken cancellationToken)
    {
        if (request.Order == null)
            throw new AppException("Order is null", ApiResultStatusCode.BadRequest);

        var discount = await _repositoryWrapper.SetRepository<Discount>()
            .TableNoTracking
            .FirstOrDefaultAsync(d => d.Code == request.DiscountCode, cancellationToken);

        if (discount == null)
            throw new AppException("تخفیف وجود منقضی شده است یا وجود ندارد", ApiResultStatusCode.NotFound);

        if (_currentUserService.UserId != null && Guid.TryParse(_currentUserService.UserId, out Guid userId))
        {
            var discountedUserOrder = await _repositoryWrapper.SetRepository<Order>()
                .TableNoTracking
                .FirstOrDefaultAsync(f => f.CustomerId == userId && f.DiscountCode == discount.Code, cancellationToken);
            if (discountedUserOrder != null)
                throw new AppException("شما یک بار از این کد تخفیف استفاده کرده اید", ApiResultStatusCode.BadRequest);
        }

        if (discount.IsForFirstPurchase)
        {
            if (_currentUserService.UserId != null && Guid.TryParse(_currentUserService.UserId, out Guid firstPurchaseUserId))
            {
                var userOrderCount = await _repositoryWrapper.SetRepository<Order>()
                    .TableNoTracking
                    .CountAsync(f => f.CustomerId == firstPurchaseUserId && f.DiscountCode == discount.Code, cancellationToken);
                if (userOrderCount > 0)
                    throw new AppException("شما قبلا خریدی داشته اید و نمیتوانید از تخفیف اولین خرید استفاده کنید", ApiResultStatusCode.BadRequest);
            }
        }

        double discountPrice = 0;
        double totalPrice = 0;
        if (discount.Type == DiscountType.All)
        {
            if (!discount.IsExpired())
            {
                totalPrice = request.Order.OrderProducts.Sum(op => op.ProductCost);
            }
        }
        else if (discount.Type == DiscountType.Category)
        {
            var categoryDiscount = await _repositoryWrapper.SetRepository<CategoryDiscount>()
                .TableNoTracking
                .FirstOrDefaultAsync(d => d.Code == request.DiscountCode, cancellationToken);
            if ( categoryDiscount!=null && !categoryDiscount.IsExpired())
            {
                totalPrice = request.Order.OrderProducts.Where(op => op.ProductCategoryId == categoryDiscount.CategoryId).Sum(op => op.ProductCost);

            }
        }
        else if (discount.Type == DiscountType.Product)
        {
            var productDiscount = await _repositoryWrapper.SetRepository<ProductDiscount>()
                .TableNoTracking
                .FirstOrDefaultAsync(d => d.Code == request.DiscountCode, cancellationToken);

            if (productDiscount != null && !productDiscount.IsExpired())
            {
                totalPrice = request.Order.OrderProducts.Where(op => op.ProductId == productDiscount!.ProductId).Sum(op => op.ProductCost);
                
            }
        }
        else if (discount.Type == DiscountType.Subscriber)
        {
            throw new NotImplementedException("Subscribe discount not implemented");
        }

        discountPrice = discount.AmountType == DiscountAmountType.Amount
            ? discount.DiscountAmount
            : ((totalPrice / 100) * discount.DiscountPercent);
        return discountPrice;
    }
}