components/LiteCharms.Features/Shop/Orders/Commands/Handlers/CreateOrderCommandHandler.cs

using LiteCharms.Features.Shop;
using LiteCharms.Features.Shop.Postgres;
using LiteCharms.Models;

namespace LiteCharms.Features.Orders.Commands.Handlers;

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

            if(!await context.Customers.AnyAsync(c => c.Id == request.CustomerId, cancellationToken))
                return Result.Fail<Guid>(new Error($"Customer {request.CustomerId} does not exist."));

            if(!await context.ShoppingCarts.AnyAsync(sc => sc.Id == request.ShoppingCartId, cancellationToken))
                return Result.Fail<Guid>(new Error($"Shopping cart {request.ShoppingCartId} does not exist."));

            if(request.QuoteId.HasValue && !await context.Quotes.AnyAsync(q => q.Id == request.QuoteId.Value, cancellationToken))
                return Result.Fail<Guid>(new Error($"Quote {request.QuoteId.Value} does not exist."));

            var newOrder = context.Orders.Add(new Entities.Order
            {
                CreatedAt = DateTime.UtcNow,
                Status = OrderStatus.Pending,
                CustomerId = request.CustomerId,
                QuoteId = request.QuoteId,
                ShoppingCartId = request.ShoppingCartId,
                DepositRequired = request.DepositRequired,
                Requirements = request.Requirements,
                Notes = request.Notes,
                Terms = request.Terms
            });

            return await context.SaveChangesAsync(cancellationToken) > 0
                ? Result.Ok(newOrder.Entity.Id)
                : Result.Fail<Guid>(new Error($"Failed to create customer {request.CustomerId} order using shopping cart {request.ShoppingCartId}."));
        }
		catch (Exception ex)
		{
            return Result.Fail<Guid>(new Error(ex.Message).CausedBy(ex));
        }
    }
}