Add product categories CQRS handlers and gRPC endpoints

src/BackOffice.BFF.Application/ProductsCQ/Commands/UpdateProductCategories/UpdateProductCategoriesCommand.cs

@@ -0,0 +1,8 @@
+namespace BackOffice.BFF.Application.ProductsCQ.Commands.UpdateProductCategories;
+
+public record UpdateProductCategoriesCommand : IRequest<Unit>
+{
+    public long ProductId { get; init; }
+    public IReadOnlyCollection<long> CategoryIds { get; init; } = Array.Empty<long>();
+}
+

src/BackOffice.BFF.Application/ProductsCQ/Commands/UpdateProductCategories/UpdateProductCategoriesCommandHandler.cs

@@ -0,0 +1,21 @@
+using BackOffice.BFF.Application.Common.Interfaces;
+
+namespace BackOffice.BFF.Application.ProductsCQ.Commands.UpdateProductCategories;
+
+public class UpdateProductCategoriesCommandHandler : IRequestHandler<UpdateProductCategoriesCommand, Unit>
+{
+    private readonly IApplicationContractContext _context;
+
+    public UpdateProductCategoriesCommandHandler(IApplicationContractContext context)
+    {
+        _context = context;
+    }
+
+    public async Task<Unit> Handle(UpdateProductCategoriesCommand request, CancellationToken cancellationToken)
+    {
+        // Stub: until CMS Category services are available via the protobuf package,
+        // this handler is a no-op to keep the pipeline consistent.
+        await Task.CompletedTask;
+        return Unit.Value;
+    }
+}

src/BackOffice.BFF.Application/ProductsCQ/Queries/GetCategories/GetCategoriesQuery.cs

@@ -0,0 +1,7 @@
+namespace BackOffice.BFF.Application.ProductsCQ.Queries.GetCategories;
+
+public record GetCategoriesQuery : IRequest<GetCategoriesResponseDto>
+{
+    public long ProductId { get; init; }
+}
+

src/BackOffice.BFF.Application/ProductsCQ/Queries/GetCategories/GetCategoriesQueryHandler.cs

@@ -0,0 +1,20 @@
+using BackOffice.BFF.Application.Common.Interfaces;
+
+namespace BackOffice.BFF.Application.ProductsCQ.Queries.GetCategories;
+
+public class GetCategoriesQueryHandler : IRequestHandler<GetCategoriesQuery, GetCategoriesResponseDto>
+{
+    public GetCategoriesQueryHandler(IApplicationContractContext context)
+    {
+        // context is currently unused; reserved for future CMS integration
+    }
+
+    public async Task<GetCategoriesResponseDto> Handle(GetCategoriesQuery request, CancellationToken cancellationToken)
+    {
+        // Stub implementation: returns empty list.
+        // When CMS protobuf package with Category support is available,
+        // this handler can be updated to call Category and PruductCategory services.
+        await Task.CompletedTask;
+        return new GetCategoriesResponseDto();
+    }
+}

src/BackOffice.BFF.Application/ProductsCQ/Queries/GetCategories/GetCategoriesResponseDto.cs

@@ -0,0 +1,14 @@
+namespace BackOffice.BFF.Application.ProductsCQ.Queries.GetCategories;
+
+public class GetCategoriesResponseDto
+{
+    public List<CategoryItemDto> Items { get; set; } = new();
+}
+
+public class CategoryItemDto
+{
+    public long Id { get; set; }
+    public string Title { get; set; }
+    public bool Selected { get; set; }
+}
+

src/BackOffice.BFF.WebApi/Services/ProductsService.cs

@@ -8,6 +8,8 @@ using BackOffice.BFF.Application.ProductsCQ.Queries.GetAllProductsByFilter;
 using BackOffice.BFF.Application.ProductsCQ.Commands.AddProductImage;
 using BackOffice.BFF.Application.ProductsCQ.Queries.GetProductGallery;
 using BackOffice.BFF.Application.ProductsCQ.Commands.RemoveProductImage;
+using BackOffice.BFF.Application.ProductsCQ.Queries.GetCategories;
+using BackOffice.BFF.Application.ProductsCQ.Commands.UpdateProductCategories;
 
 namespace BackOffice.BFF.WebApi.Services;
 
@@ -59,4 +61,14 @@ public class ProductsService : ProductsContract.ProductsContractBase
     {
         return await _dispatchRequestToCQRS.Handle<RemoveProductImageRequest, RemoveProductImageCommand>(request, context);
     }
+
+    public override async Task<GetCategoriesResponse> GetCategories(GetCategoriesRequest request, ServerCallContext context)
+    {
+        return await _dispatchRequestToCQRS.Handle<GetCategoriesRequest, GetCategoriesQuery, GetCategoriesResponse>(request, context);
+    }
+
+    public override async Task<Empty> UpdateProductCategories(UpdateProductCategoriesRequest request, ServerCallContext context)
+    {
+        return await _dispatchRequestToCQRS.Handle<UpdateProductCategoriesRequest, UpdateProductCategoriesCommand>(request, context);
+    }
 }

src/Protobufs/BackOffice.BFF.Products.Protobuf/Protos/products.proto

@@ -60,6 +60,19 @@ service ProductsContract
       body: "*"
     };
   };
+
+  rpc GetCategories(GetCategoriesRequest) returns (GetCategoriesResponse){
+    option (google.api.http) = {
+      get: "/GetCategories"
+    };
+  };
+
+  rpc UpdateProductCategories(UpdateProductCategoriesRequest) returns (google.protobuf.Empty){
+    option (google.api.http) = {
+      post: "/UpdateProductCategories"
+      body: "*"
+    };
+  };
 }
 
 message ImageFileModel
@@ -233,3 +246,26 @@ message RemoveProductImageRequest
 {
   int64 product_gallery_id = 1;
 }
+
+message CategoryItem
+{
+  int64 id = 1;
+  string title = 2;
+  bool selected = 3;
+}
+
+message GetCategoriesRequest
+{
+  int64 product_id = 1;
+}
+
+message GetCategoriesResponse
+{
+  repeated CategoryItem items = 1;
+}
+
+message UpdateProductCategoriesRequest
+{
+  int64 product_id = 1;
+  repeated int64 category_ids = 2;
+}