CreateUpdateSellableItemBlock.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Sitecore.Commerce.Core;
using Sitecore.Commerce.Plugin.Catalog;
using Sitecore.Commerce.Plugin.Pricing;
using Sitecore.Framework.Conditions;
using Sitecore.Framework.Pipelines;
using Sitecore.Services.Examples.Catalog.Pipelines.Arguments;

namespace Sitecore.Services.Examples.Catalog.Pipelines.Blocks
{
    [PipelineDisplayName("CreateUpdateSellableItem.CreateUpdateSellableItemBlock")]
    public class CreateUpdateSellableItemBlock : PipelineBlock<List<CreateUpdateSellableItemArgument>, bool, CommercePipelineExecutionContext>
    {
        private readonly CommerceCommander _commander;
        public CreateUpdateSellableItemBlock(CommerceCommander commander)
        {
            _commander = commander;
        }

        public override async Task<bool> Run(List<CreateUpdateSellableItemArgument> arg, CommercePipelineExecutionContext context)
        {
            Condition.Requires(arg).IsNotNull($"{Name}: The argument can not be null");

            var result = new List<string>();

            foreach (var sellableItemArg in arg)
            {
                var id = $"{CommerceEntity.IdPrefix<SellableItem>()}{sellableItemArg.ProductId}";
                //Will be created if not found
                var foundEntity = await _commander.Pipeline<FindEntityPipeline>().Run(new FindEntityArgument(typeof(SellableItem), id, false), context) ??
                                  await _commander.Command<CreateSellableItemCommand>().Process(context.CommerceContext, 
                                      sellableItemArg.ProductId,sellableItemArg.Name,sellableItemArg.DisplayName,sellableItemArg.Description);

                if (!(foundEntity is SellableItem sellableItem)) continue;

                UpdateCreateListPrice(sellableItem.GetPolicy<ListPricingPolicy>(), sellableItemArg.ListPrice);

                sellableItem.Description = sellableItemArg.Description;
                sellableItem.DisplayName = sellableItemArg.DisplayName;
                sellableItem.Name = sellableItemArg.Name;

                foreach (var variantArgs in sellableItemArg.Variants)
                {
                    var variant = sellableItem.GetVariation(variantArgs.VariantId);
                    if (variant == null)
                    {
                        variant = new ItemVariationComponent
                        {
                            Id = variantArgs.VariantId
                        };
                        sellableItem.GetComponent<ItemVariationsComponent>().ChildComponents.Add(variant);
                    }

                    UpdateCreateListPrice(variant.GetPolicy<ListPricingPolicy>(), variantArgs.ListPrice);
                }

                var persistResult = await _commander.Pipeline<PersistEntityPipeline>()
                    .Run(new PersistEntityArgument(sellableItem), context);

                result.Add(persistResult.Entity.Id);
            }

            var ok = result.Count != 0;
            return await Task.FromResult(ok);
        }
        private static void UpdateCreateListPrice(ListPricingPolicy pricePolicy, decimal price)
        {
            var money = pricePolicy.Prices.FirstOrDefault(x => x.CurrencyCode.Equals("USD", StringComparison.OrdinalIgnoreCase));

            if (money == null)
            {
                pricePolicy.AddPrice(new Money(price));
            }
            else
            {
                money.Amount = price;
            }
        }
    }
}