From 6aece5a76981069c64a3ee1bd0ed49af5e7cfb96 Mon Sep 17 00:00:00 2001
From: David Nguyen <david.nguyen@goutezplanb.com>
Date: Thu, 19 Feb 2026 18:56:37 -0500
Subject: [PATCH] Handle generic types in proto message name generation

Generic types like Translation<T> now produce qualified message names
(e.g. TranslationOfFaqTranslationQueryItem) to avoid duplicate message
definitions in generated .proto files.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
---
 .../ProtoFileGenerator.cs                       | 12 ++++++++----
 Svrnty.CQRS.Grpc.Generators/ProtoTypeMapper.cs  | 17 ++++++++++++++++-
 2 files changed, 24 insertions(+), 5 deletions(-)

diff --git a/Svrnty.CQRS.Grpc.Generators/ProtoFileGenerator.cs b/Svrnty.CQRS.Grpc.Generators/ProtoFileGenerator.cs
index 100bc3a..d96273d 100644
--- a/Svrnty.CQRS.Grpc.Generators/ProtoFileGenerator.cs
+++ b/Svrnty.CQRS.Grpc.Generators/ProtoFileGenerator.cs
@@ -413,17 +413,21 @@ internal class ProtoFileGenerator
 
     private void GenerateComplexTypeMessage(INamedTypeSymbol? type)
     {
-        if (type == null || _generatedMessages.Contains(type.Name))
+        if (type == null)
+            return;
+
+        var messageName = ProtoFileTypeMapper.GetProtoMessageName(type);
+        if (_generatedMessages.Contains(messageName))
             return;
 
         // Don't generate messages for system types or primitives
         if (type.ContainingNamespace?.ToString().StartsWith("System") == true)
             return;
 
-        _generatedMessages.Add(type.Name);
+        _generatedMessages.Add(messageName);
 
-        _messagesBuilder.AppendLine($"// {type.Name} entity");
-        _messagesBuilder.AppendLine($"message {type.Name} {{");
+        _messagesBuilder.AppendLine($"// {messageName} entity");
+        _messagesBuilder.AppendLine($"message {messageName} {{");
 
         // Collect nested complex types to generate after closing this message
         var nestedComplexTypes = new List<INamedTypeSymbol>();
diff --git a/Svrnty.CQRS.Grpc.Generators/ProtoTypeMapper.cs b/Svrnty.CQRS.Grpc.Generators/ProtoTypeMapper.cs
index d4a7f58..9e7b237 100644
--- a/Svrnty.CQRS.Grpc.Generators/ProtoTypeMapper.cs
+++ b/Svrnty.CQRS.Grpc.Generators/ProtoTypeMapper.cs
@@ -1,4 +1,5 @@
 using System;
+using System.Linq;
 using Microsoft.CodeAnalysis;
 
 namespace Svrnty.CQRS.Grpc.Generators;
@@ -151,13 +152,27 @@ internal static class ProtoFileTypeMapper
         // Complex types (classes/records) become message types
         if (typeSymbol.TypeKind == TypeKind.Class || typeSymbol.TypeKind == TypeKind.Struct)
         {
-            return typeName; // Reference the message type by name
+            return GetProtoMessageName(typeSymbol); // Reference the message type by name (handles generics)
         }
 
         // Fallback
         return "string"; // Default to string for unknown types
     }
 
+    /// <summary>
+    /// Gets the proto message name for a type, handling generic types by qualifying
+    /// with type arguments. e.g. Translation&lt;FaqTranslationQueryItem&gt; becomes TranslationOfFaqTranslationQueryItem.
+    /// </summary>
+    public static string GetProtoMessageName(ITypeSymbol typeSymbol)
+    {
+        if (typeSymbol is INamedTypeSymbol namedType && namedType.IsGenericType && namedType.TypeArguments.Length > 0)
+        {
+            var typeArgs = string.Join("And", namedType.TypeArguments.Select(t => GetProtoMessageName(t)));
+            return $"{namedType.Name}Of{typeArgs}";
+        }
+        return typeSymbol.Name;
+    }
+
     /// <summary>
     /// Converts C# PascalCase property name to proto snake_case field name.
     /// Uses simple conversion: add underscore before each uppercase letter (except first).