feat: fix gemini imagen model namings

Author: Piotr Stachaczynski

src/MaIN.Core/.nuspec

@@ -2,7 +2,7 @@
 <package>
   <metadata>
     <id>MaIN.NET</id>
-    <version>0.6.0</version>
+    <version>0.6.1</version>
     <authors>Wisedev</authors>
     <owners>Wisedev</owners>
     <icon>favicon.png</icon>

src/MaIN.Services/Services/ChatService.cs

@@ -59,7 +59,7 @@ public async Task<ChatResult> Completions(
     }
 
     var result = chat.Visual 
-        ? await imageGenServiceFactory.CreateService(chat.Backend.Value).Send(chat) 
+        ? await imageGenServiceFactory.CreateService(chat.Backend.Value)!.Send(chat) 
         : await llmServiceFactory.CreateService(chat.Backend.Value).Send(chat, new ChatRequestOptions()
         {
             InteractiveUpdates = interactiveUpdates,

src/MaIN.Services/Services/ImageGenServices/GeminiImageGenService.cs

@@ -20,10 +20,14 @@ internal class GeminiImageGenService(IHttpClientFactory httpClientFactory, MaINS
         string apiKey = _settings.GeminiKey ?? Environment.GetEnvironmentVariable("GEMINI_API_KEY")
             ?? throw new InvalidOperationException("Gemini API key is not configured");
 
+        if (string.IsNullOrEmpty(chat.Model))
+        {
+            chat.Model = Models.IMAGEN_GENERATE;
+        }
         client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", apiKey);
         var requestBody = new
         {
-            model = Models.IMAGEN_GENERATE,
+            model = chat.Model,
             prompt = BuildPromptFromChat(chat),
             response_format = "b64_json", // necessary for gemini api
             size = ServiceConstants.Defaults.ImageSize,
@@ -74,7 +78,7 @@ private static ChatResult CreateChatResult(byte[] imageBytes)
 
     private struct Models
     {
-        public const string IMAGEN_GENERATE = "imagen-3.0-generate-002";
+        public const string IMAGEN_GENERATE = "imagen-4.0-fast-generate-001";
     }
 }