components/LiteCharms.Features/ShoppingCarts/Commands/Handlers/UpdateShoppingCartItemCommandHandler.cs

using LiteCharms.Infrastructure.Database;

namespace LiteCharms.Features.ShoppingCarts.Commands.Handlers;

public class UpdateShoppingCartItemCommandHandler(IDbContextFactory<ShopDbContext> contextFactory) : IRequestHandler<UpdateShoppingCartItemCommand, Result>
{
    public async ValueTask<Result> Handle(UpdateShoppingCartItemCommand request, CancellationToken cancellationToken)
    {
		try
		{
            using var context = await contextFactory.CreateDbContextAsync(cancellationToken);

            if (!await context.ShoppingCarts.AnyAsync(c => c.Id == request.ShoppingCartId, cancellationToken))
                return Result.Fail($"Shopping could not be found with id {request.ShoppingCartId}");

            var item = await context.ShoppingCartItems.FirstOrDefaultAsync(i => i.ShoppingCartId == request.ShoppingCartId, cancellationToken);

            if(item is null)
                return Result.Fail($"Shopping cart item could not be found with id {request.ShoppingCartItemId}");

            item.Quantity = request.Quantity;

            return await context.SaveChangesAsync(cancellationToken) > 0
                ? Result.Ok()
                : Result.Fail($"Failed to update cart item quntity");
        }
		catch (Exception ex)
		{
            return Result.Fail(new Error(ex.Message).CausedBy(ex));
        }
    }
}