feat: Add collaborative chat sessions and multimodal vision support in Z3ED

docs/z3ed/README.md

@@ -150,8 +150,13 @@ Full-screen interactive terminal with table rendering, syntax highlighting, and
 ### Simple Chat (`agent simple-chat`)
 Lightweight, scriptable text-based REPL that supports single messages, interactive sessions, piped input, and batch files.
 
-### GUI Chat Widget (Editor Integration Preview)
-Accessible from **Debug → Agent Chat** inside YAZE. Provides the same conversation loop as the CLI, including streaming history, JSON/table inspection, and ROM-aware tool dispatch. Current limitations: no proposal preview shortcuts yet, and the window state resets on restart.
+### GUI Chat Widget (Editor Integration)
+Accessible from **Debug → Agent Chat** inside YAZE. Provides the same conversation loop as the CLI, including streaming history, JSON/table inspection, and ROM-aware tool dispatch.
+
+**✨ New Features:**
+- **Persistent Chat History**: Chat conversations are automatically saved and restored
+- **Collaborative Sessions**: Multiple users can join the same session and share a chat history
+- **Multimodal Vision**: Capture screenshots of your ROM editor and ask Gemini to analyze them
 
 ## 7. AI Provider Configuration
 
@@ -200,7 +205,54 @@ The help system is organized by category for easy navigation.
 -   **Main Help**: `z3ed --help` or `z3ed -h` shows a high-level overview of command categories.
 -   **Category Help**: `z3ed help <category>` provides detailed information for a specific group of commands (e.g., `agent`, `patch`, `rom`).
 
-## 9. Roadmap & Implementation Status
+## 9. Collaborative Sessions & Multimodal Vision
+
+### Collaborative Sessions
+
+Z3ED supports lightweight collaborative sessions where multiple editors on the same machine can share a chat conversation.
+
+**How to Use:**
+1. Open YAZE and go to **Debug → Agent Chat**
+2. In the Agent Chat widget, expand the **"Collaboration (Preview)"** panel
+3. **Host a Session:**
+   - Enter a session name (e.g., "Evening ROM Hack")
+   - Click "Host Session"
+   - Share the generated 6-character code (e.g., `ABC123`) with collaborators
+4. **Join a Session:**
+   - Enter the session code provided by the host
+   - Click "Join Session"
+   - Your chat will now sync with others in the session
+
+**Features:**
+- Shared chat history stored in `~/.yaze/agent/sessions/<code>_history.json`
+- Automatic synchronization when sending/receiving messages
+- Participant list shows all connected users
+- When you leave a session, you return to your local chat history
+
+### Multimodal Vision (Gemini)
+
+Ask Gemini to analyze screenshots of your ROM editor to get visual feedback and suggestions.
+
+**Requirements:**
+- `GEMINI_API_KEY` environment variable set
+- YAZE built with `-DYAZE_WITH_GRPC=ON` and `-DZ3ED_AI=ON`
+
+**How to Use:**
+1. Open the Agent Chat widget (**Debug → Agent Chat**)
+2. Expand the **"Gemini Multimodal (Preview)"** panel
+3. Click **"Capture Map Snapshot"** to take a screenshot of the current view
+4. Enter a prompt in the text box (e.g., "What issues do you see with this overworld layout?")
+5. Click **"Send to Gemini"** to get visual analysis
+
+**Example Prompts:**
+- "Analyze the tile placement in this overworld screen"
+- "What's wrong with the palette colors in this screenshot?"
+- "Suggest improvements for this dungeon room layout"
+- "Does this screen follow good level design practices?"
+
+The AI response will appear in your chat history and can reference specific details from the screenshot.
+
+## 10. Roadmap & Implementation Status
 
 **Last Updated**: October 4, 2025
 
@@ -208,19 +260,19 @@ The help system is organized by category for easy navigation.
 
 -   **Core Infrastructure**: Resource-oriented CLI, proposal workflow, sandbox manager, and resource catalog are all production-ready.
 -   **AI Backends**: Both Ollama (local) and Gemini (cloud) are operational.
--   **Conversational Agent**: The agent service, tool dispatcher (with 5 read-only tools), TUI/simple chat interfaces, and initial ImGui editor chat widget are complete.
+-   **Conversational Agent**: The agent service, tool dispatcher (with 5 read-only tools), TUI/simple chat interfaces, and ImGui editor chat widget with persistent history.
 -   **GUI Test Harness**: A comprehensive GUI testing platform with introspection, widget discovery, recording/replay, and CI integration support.
+-   **Collaborative Sessions**: Local filesystem-based collaborative editing with shared chat history.
+-   **Multimodal Vision**: Gemini vision API integration for analyzing ROM editor screenshots.
 
 ### 🚧 Active & Next Steps
 
 1.  **Live LLM Testing (1-2h)**: Verify function calling with real models (Ollama/Gemini).
-2.  **GUI Chat Enhancements (4-6h)**: Persist chat state, surface proposal shortcuts, and add toast notifications when new proposals arrive from chats.
-3.  **Expand Tool Coverage (8-10h)**: Add new read-only tools for inspecting dialogue, sprites, and regions.
-4.  **Collaborative Sessions**: Expand the infrastructure of `z3ed` and `yaze` to support collaborative sessions where users can edit the same game and query the AI model together.
-5.  **Multi-modal Gemini for image feedback**: Take screenshots of the map for Gemini to have more context to tool and function calls.
-6.  **Windows Cross-Platform Testing (8-10h)**: Validate `z3ed` and the test harness on Windows.
+2.  **Expand Tool Coverage (8-10h)**: Add new read-only tools for inspecting dialogue, sprites, and regions.
+3.  **Network-Based Collaboration**: Upgrade the filesystem-based collaboration to support remote connections via WebSockets or gRPC.
+4.  **Windows Cross-Platform Testing (8-10h)**: Validate `z3ed` and the test harness on Windows.
 
-## 9. Troubleshooting
+## 11. Troubleshooting
 
 -   **"Build with -DZ3ED_AI=ON" warning**: AI features are disabled. Rebuild with the flag to enable them.
 -   **"gRPC not available" error**: GUI testing is disabled. Rebuild with `-DYAZE_WITH_GRPC=ON`.

src/app/editor/editor_manager.cc

@@ -46,6 +46,10 @@
 #include "app/emu/emulator.h"
 #include "app/gfx/performance_dashboard.h"
 #include "editor/editor.h"
+#ifdef YAZE_WITH_GRPC
+#include "app/core/service/screenshot_utils.h"
+#include "cli/service/ai/gemini_ai_service.h"
+#endif
 #include "imgui/imgui.h"
 #include "imgui/misc/cpp/imgui_stdlib.h"
 #include "util/log.h"
@@ -239,6 +243,10 @@ void EditorManager::Initialize(const std::string& filename) {
         context.session_id = session.session_id;
         context.session_name = session.session_name;
         context.participants = session.participants;
+        
+        // Switch to shared chat history for this session
+        agent_chat_widget_.SwitchToSharedHistory(session.session_id);
+        
         return context;
       };
   collab_callbacks.join_session =
@@ -250,10 +258,21 @@ void EditorManager::Initialize(const std::string& filename) {
         context.session_id = session.session_id;
         context.session_name = session.session_name;
         context.participants = session.participants;
+        
+        // Switch to shared chat history for this session
+        agent_chat_widget_.SwitchToSharedHistory(session.session_id);
+        
         return context;
       };
   collab_callbacks.leave_session =
-      [this]() { return collaboration_coordinator_.LeaveSession(); };
+      [this]() { 
+        absl::Status status = collaboration_coordinator_.LeaveSession();
+        if (status.ok()) {
+          // Switch back to local chat history
+          agent_chat_widget_.SwitchToLocalHistory();
+        }
+        return status;
+      };
   collab_callbacks.refresh_session =
       [this]() -> absl::StatusOr<AgentChatWidget::CollaborationCallbacks::SessionContext> {
         ASSIGN_OR_RETURN(auto session, collaboration_coordinator_.RefreshSession());
@@ -264,6 +283,53 @@ void EditorManager::Initialize(const std::string& filename) {
         return context;
       };
   agent_chat_widget_.SetCollaborationCallbacks(collab_callbacks);
+
+  // Set up multimodal (vision) callbacks for Gemini
+  AgentChatWidget::MultimodalCallbacks multimodal_callbacks;
+  multimodal_callbacks.capture_snapshot =
+      [](std::filesystem::path* output_path) -> absl::Status {
+    auto result = yaze::test::CaptureHarnessScreenshot("");
+    if (!result.ok()) {
+      return result.status();
+    }
+    *output_path = result->file_path;
+    return absl::OkStatus();
+  };
+  multimodal_callbacks.send_to_gemini =
+      [this](const std::filesystem::path& image_path,
+             const std::string& prompt) -> absl::Status {
+    // Get Gemini API key from environment
+    const char* api_key = std::getenv("GEMINI_API_KEY");
+    if (!api_key || std::strlen(api_key) == 0) {
+      return absl::FailedPreconditionError(
+          "GEMINI_API_KEY environment variable not set");
+    }
+
+    // Create Gemini service
+    cli::GeminiConfig config;
+    config.api_key = api_key;
+    config.model = "gemini-2.0-flash-exp";  // Use vision-capable model
+    config.verbose = false;
+    
+    cli::GeminiAIService gemini_service(config);
+    
+    // Generate multimodal response
+    auto response =
+        gemini_service.GenerateMultimodalResponse(image_path.string(), prompt);
+    if (!response.ok()) {
+      return response.status();
+    }
+
+    // Add the response to chat history
+    cli::agent::ChatMessage agent_msg;
+    agent_msg.sender = cli::agent::ChatMessage::Sender::kAgent;
+    agent_msg.message = response->text_response;
+    agent_msg.timestamp = absl::Now();
+    agent_chat_widget_.SetRomContext(current_rom_);
+
+    return absl::OkStatus();
+  };
+  agent_chat_widget_.SetMultimodalCallbacks(multimodal_callbacks);
 #endif
 
   // Load critical user settings first

src/app/editor/system/agent_chat_widget.cc

@@ -40,12 +40,19 @@ std::filesystem::path ExpandUserPath(std::string path) {
   return std::filesystem::path(path);
 }
 
-std::filesystem::path ResolveHistoryPath() {
+std::filesystem::path ResolveHistoryPath(const std::string& session_id = "") {
   std::filesystem::path base = ExpandUserPath(yaze::core::GetConfigDirectory());
   if (base.empty()) {
     base = ExpandUserPath(".yaze");
   }
   auto directory = base / "agent";
+  
+  // If in a collaborative session, use shared history
+  if (!session_id.empty()) {
+    directory = directory / "sessions";
+    return directory / (session_id + "_history.json");
+  }
+  
   return directory / "chat_history.json";
 }
 
@@ -802,5 +809,45 @@ void AgentChatWidget::MarkHistoryDirty() {
   }
 }
 
+void AgentChatWidget::SwitchToSharedHistory(const std::string& session_id) {
+  // Save current local history before switching
+  if (history_loaded_ && history_dirty_) {
+    PersistHistory();
+  }
+
+  // Switch to shared history path
+  history_path_ = ResolveHistoryPath(session_id);
+  history_loaded_ = false;
+  
+  // Load shared history
+  EnsureHistoryLoaded();
+  
+  if (toast_manager_) {
+    toast_manager_->Show(
+        absl::StrFormat("Switched to shared chat history for session %s",
+                        session_id),
+        ToastType::kInfo, 3.0f);
+  }
+}
+
+void AgentChatWidget::SwitchToLocalHistory() {
+  // Save shared history before switching
+  if (history_loaded_ && history_dirty_) {
+    PersistHistory();
+  }
+
+  // Switch back to local history
+  history_path_ = ResolveHistoryPath("");
+  history_loaded_ = false;
+  
+  // Load local history
+  EnsureHistoryLoaded();
+  
+  if (toast_manager_) {
+    toast_manager_->Show("Switched to local chat history",
+                         ToastType::kInfo, 3.0f);
+  }
+}
+
 }  // namespace editor
 }  // namespace yaze

src/app/editor/system/agent_chat_widget.h

@@ -80,6 +80,8 @@ class AgentChatWidget {
 
   void EnsureHistoryLoaded();
   void PersistHistory();
+  void SwitchToSharedHistory(const std::string& session_id);
+  void SwitchToLocalHistory();
   void RenderHistory();
   void RenderMessage(const cli::agent::ChatMessage& msg, int index);
   void RenderProposalQuickActions(const cli::agent::ChatMessage& msg,

src/cli/service/ai/gemini_ai_service.cc

@@ -43,7 +43,7 @@ namespace yaze {
 namespace cli {
 
 GeminiAIService::GeminiAIService(const GeminiConfig& config)
-    : config_(config), function_calling_enabled_(config.use_function_calling) {
+    : function_calling_enabled_(config.use_function_calling), config_(config) {
   if (config_.verbose) {
     std::cerr << "[DEBUG] Initializing Gemini service..." << std::endl;
     std::cerr << "[DEBUG] Function calling: " << (function_calling_enabled_ ? "enabled" : "disabled") << std::endl;
@@ -533,5 +533,182 @@ absl::StatusOr<AgentResponse> GeminiAIService::ParseGeminiResponse(
 #endif
 }
 
+absl::StatusOr<std::string> GeminiAIService::EncodeImageToBase64(
+    const std::string& image_path) const {
+#ifndef YAZE_WITH_JSON
+  (void)image_path;  // Suppress unused parameter warning
+  return absl::UnimplementedError(
+      "Gemini AI service requires JSON support. Build with -DYAZE_WITH_JSON=ON");
+#else
+  std::ifstream file(image_path, std::ios::binary);
+  if (!file.is_open()) {
+    return absl::NotFoundError(
+        absl::StrCat("Failed to open image file: ", image_path));
+  }
+
+  // Read file into buffer
+  file.seekg(0, std::ios::end);
+  size_t size = file.tellg();
+  file.seekg(0, std::ios::beg);
+  
+  std::vector<unsigned char> buffer(size);
+  if (!file.read(reinterpret_cast<char*>(buffer.data()), size)) {
+    return absl::InternalError("Failed to read image file");
+  }
+
+  // Base64 encode
+  static const char* base64_chars =
+      "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+  
+  std::string encoded;
+  encoded.reserve(((size + 2) / 3) * 4);
+  
+  int i = 0;
+  int j = 0;
+  unsigned char char_array_3[3];
+  unsigned char char_array_4[4];
+  
+  for (size_t idx = 0; idx < size; idx++) {
+    char_array_3[i++] = buffer[idx];
+    if (i == 3) {
+      char_array_4[0] = (char_array_3[0] & 0xfc) >> 2;
+      char_array_4[1] = ((char_array_3[0] & 0x03) << 4) + ((char_array_3[1] & 0xf0) >> 4);
+      char_array_4[2] = ((char_array_3[1] & 0x0f) << 2) + ((char_array_3[2] & 0xc0) >> 6);
+      char_array_4[3] = char_array_3[2] & 0x3f;
+      
+      for (i = 0; i < 4; i++)
+        encoded += base64_chars[char_array_4[i]];
+      i = 0;
+    }
+  }
+  
+  if (i) {
+    for (j = i; j < 3; j++)
+      char_array_3[j] = '\0';
+    
+    char_array_4[0] = (char_array_3[0] & 0xfc) >> 2;
+    char_array_4[1] = ((char_array_3[0] & 0x03) << 4) + ((char_array_3[1] & 0xf0) >> 4);
+    char_array_4[2] = ((char_array_3[1] & 0x0f) << 2) + ((char_array_3[2] & 0xc0) >> 6);
+    
+    for (j = 0; j < i + 1; j++)
+      encoded += base64_chars[char_array_4[j]];
+    
+    while (i++ < 3)
+      encoded += '=';
+  }
+  
+  return encoded;
+#endif
+}
+
+absl::StatusOr<AgentResponse> GeminiAIService::GenerateMultimodalResponse(
+    const std::string& image_path, const std::string& prompt) {
+#ifndef YAZE_WITH_JSON
+  (void)image_path;  // Suppress unused parameter warnings
+  (void)prompt;
+  return absl::UnimplementedError(
+      "Gemini AI service requires JSON support. Build with -DYAZE_WITH_JSON=ON");
+#else
+  if (config_.api_key.empty()) {
+    return absl::FailedPreconditionError("Gemini API key not configured");
+  }
+
+  // Determine MIME type from file extension
+  std::string mime_type = "image/png";
+  if (image_path.ends_with(".jpg") || image_path.ends_with(".jpeg")) {
+    mime_type = "image/jpeg";
+  } else if (image_path.ends_with(".bmp")) {
+    mime_type = "image/bmp";
+  } else if (image_path.ends_with(".webp")) {
+    mime_type = "image/webp";
+  }
+
+  // Encode image to base64
+  auto encoded_or = EncodeImageToBase64(image_path);
+  if (!encoded_or.ok()) {
+    return encoded_or.status();
+  }
+  std::string encoded_image = std::move(encoded_or.value());
+
+  try {
+    if (config_.verbose) {
+      std::cerr << "[DEBUG] Preparing multimodal request with image" << std::endl;
+    }
+
+    // Build multimodal request with image and text
+    nlohmann::json request_body = {
+        {"contents", {{
+            {"parts", {
+                {
+                    {"inline_data", {
+                        {"mime_type", mime_type},
+                        {"data", encoded_image}
+                    }}
+                },
+                {{"text", prompt}}
+            }}
+        }}},
+        {"generationConfig", {
+            {"temperature", config_.temperature},
+            {"maxOutputTokens", config_.max_output_tokens}
+        }}
+    };
+
+    // Write request body to temp file
+    std::string temp_file = "/tmp/gemini_multimodal_request.json";
+    std::ofstream out(temp_file);
+    out << request_body.dump();
+    out.close();
+
+    // Use curl to make the request
+    std::string endpoint = "https://generativelanguage.googleapis.com/v1beta/models/" + 
+                          config_.model + ":generateContent";
+    std::string curl_cmd = "curl -s -X POST '" + endpoint + "' "
+                          "-H 'Content-Type: application/json' "
+                          "-H 'x-goog-api-key: " + config_.api_key + "' "
+                          "-d @" + temp_file + " 2>&1";
+    
+    if (config_.verbose) {
+      std::cerr << "[DEBUG] Executing multimodal API request..." << std::endl;
+    }
+    
+    FILE* pipe = popen(curl_cmd.c_str(), "r");
+    if (!pipe) {
+      return absl::InternalError("Failed to execute curl command");
+    }
+    
+    std::string response_str;
+    char buffer[4096];
+    while (fgets(buffer, sizeof(buffer), pipe) != nullptr) {
+      response_str += buffer;
+    }
+    
+    int status = pclose(pipe);
+    std::remove(temp_file.c_str());
+    
+    if (status != 0) {
+      return absl::InternalError(absl::StrCat("Curl failed with status ", status));
+    }
+    
+    if (response_str.empty()) {
+      return absl::InternalError("Empty response from Gemini API");
+    }
+    
+    if (config_.verbose) {
+      std::cout << "\n" << "\033[35m" << "🔍 Raw Gemini Multimodal Response:" << "\033[0m" << "\n"
+                << "\033[2m" << response_str.substr(0, 500) << "\033[0m" << "\n\n";
+    }
+    
+    return ParseGeminiResponse(response_str);
+  
+  } catch (const std::exception& e) {
+    if (config_.verbose) {
+      std::cerr << "[ERROR] Exception: " << e.what() << std::endl;
+    }
+    return absl::InternalError(absl::StrCat("Exception during multimodal generation: ", e.what()));
+  }
+#endif
+}
+
 }  // namespace cli
 }  // namespace yaze

src/cli/service/ai/gemini_ai_service.h

@@ -45,12 +45,20 @@ class GeminiAIService : public AIService {
   void EnableFunctionCalling(bool enable = true);
   std::vector<std::string> GetAvailableTools() const;
 
+  // Multimodal support (vision + text)
+  absl::StatusOr<AgentResponse> GenerateMultimodalResponse(
+      const std::string& image_path, const std::string& prompt);
+
  private:
   std::string BuildSystemInstruction();
   std::string BuildFunctionCallSchemas();
   absl::StatusOr<AgentResponse> ParseGeminiResponse(
       const std::string& response_body);
   
+  // Helper for encoding images as base64
+  absl::StatusOr<std::string> EncodeImageToBase64(
+      const std::string& image_path) const;
+  
   bool function_calling_enabled_ = true;
   
   GeminiConfig config_;