Hi

I'm trying to replace the default Product Adapter, as products are in a custom db table.

I've looked at the documentation here https://docs.umbraco.com/umbraco-commerce/key-concepts/product-adapters

and created a Product Adapter like this

public class CustomProductAdapter : IProductAdapter
{
    private readonly ICustomProductsService _customProductsService;

    public CustomProductAdapter(CustomProductAdapter _customProductsService)
    {
        _customProductsService = customProductsService;
    }

    public IProductSnapshot GetProductSnapshot(Guid storeId, string productReference, string languageIsoCode)
    {
        var product = _customProductsService.GetByProductReference(productReference);

        if (product != null)
        {
            return new CustomProductSnapshot(product, languageIsoCode);
        }

        return null;
    }

    public IProductSnapshot GetProductSnapshot(Guid storeId, string productReference, string productVariantReference, string languageIsoCode)
    {


        return null;
    }

    public bool TryGetProductReference(Guid storeId, string sku, out string productReference, out string productVariantReference)
    {
        // Try lookup a product / variant reference by store + sku

        productReference = "";
        productVariantReference = "";

        return false;
    }

    public PagedResult<IProductSummary> SearchProductSummaries(Guid storeId, string languageIsoCode, string searchTerm, long currentPage = 1, long itemsPerPage = 50)
    {
        // Search for products matching the given search term and convert to a IProductSummary

        return null;
    }

    public IEnumerable<Attribute> GetProductVariantAttributes(Guid storeId, string productReference, string languageIsoCode)
    {
        throw new NotImplementedException();
    }

    public PagedResult<IProductVariantSummary> SearchProductVariantSummaries(Guid storeId, string productReference, string languageIsoCode, string searchTerm, IDictionary<string, IEnumerable<string>> attributes, long currentPage = 1, long itemsPerPage = 50)
    {
        throw new NotImplementedException();
    }

Which is added to Startup like this

public static IUmbracoCommerceBuilder AddMyCommerceServices(this IUmbracoCommerceBuilder builder)
{
    // Replacing the default Product Adapter implementation
    builder.Services.AddUnique<IProductAdapter, CustomProductAdapter>();

    return builder;
}

And added it to startup like this

.AddUmbracoCommerce(builder =>
{
    builder.AddMyCommerceServices();
})

However I get an error when trying to add products to the cart like this

order.AddProduct(addProduct.ProductReference, addProduct.Quantity);

The error I get is this

ArgumentNullException: Value cannot be null. (Parameter 'productSnapshot')

Not sure what it is I'm missing 🤔