feat: add changeCartCurrency mutation

src/VirtoCommerce.XCart.Core/Commands/ChangeCartCurrencyCommand.cs

@@ -0,0 +1,9 @@
+using VirtoCommerce.XCart.Core.Commands.BaseCommands;
+
+namespace VirtoCommerce.XCart.Core.Commands
+{
+    public class ChangeCartCurrencyCommand : CartCommand
+    {
+        public string NewCurrencyCode { get; set; }
+    }
+}

src/VirtoCommerce.XCart.Core/Schemas/InputChangeCartCurrencyType.cs

@@ -0,0 +1,12 @@
+using GraphQL.Types;
+
+namespace VirtoCommerce.XCart.Core.Schemas
+{
+    public class InputChangeCartCurrencyType : InputCartBaseType
+    {
+        public InputChangeCartCurrencyType()
+        {
+            Field<NonNullGraphType<StringGraphType>>("newCurrencyCode", "Second cart currency");
+        }
+    }
+}

src/VirtoCommerce.XCart.Data/Commands/ChangeCartCurrencyCommandHandler.cs

@@ -0,0 +1,59 @@
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+using VirtoCommerce.XCart.Core;
+using VirtoCommerce.XCart.Core.Commands;
+using VirtoCommerce.XCart.Core.Commands.BaseCommands;
+using VirtoCommerce.XCart.Core.Models;
+using VirtoCommerce.XCart.Core.Services;
+
+namespace VirtoCommerce.XCart.Data.Commands
+{
+    public class ChangeCartCurrencyCommandHandler : CartCommandHandler<ChangeCartCurrencyCommand>
+    {
+        private readonly ICartProductService _cartProductService;
+
+        public ChangeCartCurrencyCommandHandler(
+            ICartAggregateRepository cartAggregateRepository,
+            ICartProductService cartProductService)
+            : base(cartAggregateRepository)
+        {
+            _cartProductService = cartProductService;
+        }
+
+        public override async Task<CartAggregate> Handle(ChangeCartCurrencyCommand request, CancellationToken cancellationToken)
+        {
+            // get (or create) both carts
+            var currentCurrencyCartAggregate = await GetOrCreateCartFromCommandAsync(request);
+
+            var newCurrencyCartRequest = new ChangeCartCurrencyCommand
+            {
+                StoreId = request.StoreId ?? currentCurrencyCartAggregate.Cart.StoreId,
+                CartName = request.CartName ?? currentCurrencyCartAggregate.Cart.Name,
+                CartType = request.CartType ?? currentCurrencyCartAggregate.Cart.Type,
+                UserId = request.UserId ?? currentCurrencyCartAggregate.Cart.CustomerId,
+                OrganizationId = request.OrganizationId ?? currentCurrencyCartAggregate.Cart.OrganizationId,
+                CultureName = request.CultureName ?? currentCurrencyCartAggregate.Cart.LanguageCode,
+                CurrencyCode = request.NewCurrencyCode,
+            };
+
+            var newCurrencyCartAggregate = await GetOrCreateCartFromCommandAsync(newCurrencyCartRequest);
+
+            // get items to convert          
+            var excludedProductsIds = newCurrencyCartAggregate.LineItems.Select(x => x.ProductId).ToArray();
+
+            var newCartItems = currentCurrencyCartAggregate.LineItems
+                .Where(x => !excludedProductsIds.Contains(x.ProductId))
+                .Select(x => new NewCartItem(x.ProductId, x.Quantity)
+                {
+                    Comment = x.Note,
+                })
+                .ToArray();
+
+            await newCurrencyCartAggregate.AddItemsAsync(newCartItems);
+
+            await CartRepository.SaveAsync(newCurrencyCartAggregate);
+            return newCurrencyCartAggregate;
+        }
+    }
+}

src/VirtoCommerce.XCart.Data/Schemas/PurchaseSchema.cs

@@ -829,6 +829,25 @@ public void Build(ISchema schema)
 
             schema.Mutation.AddField(margeCartField);
 
+            var changeCartCurrency = FieldBuilder.Create<CartAggregate, CartAggregate>(GraphTypeExtenstionHelper.GetActualType<CartType>())
+                                 .Name("changeCartCurrency")
+                                 .Argument(GraphTypeExtenstionHelper.GetActualComplexType<NonNullGraphType<InputChangeCartCurrencyType>>(), SchemaConstants.CommandName)
+                                 .ResolveSynchronizedAsync(CartPrefix, "userId", _distributedLockService, async context =>
+                                 {
+                                     var cartCommand = context.GetCartCommand<ChangeCartCurrencyCommand>();
+
+                                     await CheckAuthByCartCommandAsync(context, cartCommand);
+
+                                     //We need to add cartAggregate to the context to be able use it on nested cart types resolvers (e.g for currency)
+                                     var cartAggregate = await _mediator.Send(cartCommand);
+
+                                     //store cart aggregate in the user context for future usage in the graph types resolvers
+                                     context.SetExpandedObjectGraph(cartAggregate);
+                                     return cartAggregate;
+                                 }).FieldType;
+
+            schema.Mutation.AddField(changeCartCurrency);
+
             /// <example>
             /// This is an example JSON request for a mutation
             /// {