feat: Add support for prompt versioning and function calling in Gemini AI service

src/cli/flags.cc

@@ -14,3 +14,7 @@ ABSL_FLAG(std::string, gemini_api_key, "",
           "Gemini API key (can also use GEMINI_API_KEY environment variable)");
 ABSL_FLAG(std::string, ollama_host, "http://localhost:11434",
           "Ollama server host URL");
+ABSL_FLAG(std::string, prompt_version, "default",
+          "Prompt version to use: 'default' or 'v2'");
+ABSL_FLAG(bool, use_function_calling, false,
+          "Enable native Gemini function calling (incompatible with JSON output mode)");

src/cli/service/ai/gemini_ai_service.cc

@@ -43,16 +43,21 @@ namespace yaze {
 namespace cli {
 
 GeminiAIService::GeminiAIService(const GeminiConfig& config) 
-    : config_(config), function_calling_enabled_(false) {  // Disable function calling - use JSON output instead
+    : config_(config), function_calling_enabled_(config.use_function_calling) {
   std::cerr << "🔧 GeminiAIService constructor: start" << std::endl;
+  std::cerr << "🔧 Function calling: " << (function_calling_enabled_ ? "enabled" : "disabled (JSON output mode)") << std::endl;
+  std::cerr << "🔧 Prompt version: " << config_.prompt_version << std::endl;
   
 #ifdef CPPHTTPLIB_OPENSSL_SUPPORT
   // Initialize OpenSSL for HTTPS support
   InitializeOpenSSL();
 #endif
   
-  // Load command documentation into prompt builder
-  if (auto status = prompt_builder_.LoadResourceCatalogue(""); !status.ok()) {
+  // Load command documentation into prompt builder with specified version
+  std::string catalogue_path = config_.prompt_version == "v2" 
+      ? "assets/agent/prompt_catalogue_v2.yaml"
+      : "assets/agent/prompt_catalogue.yaml";
+  if (auto status = prompt_builder_.LoadResourceCatalogue(catalogue_path); !status.ok()) {
     std::cerr << "⚠️  Failed to load agent prompt catalogue: "
               << status.message() << std::endl;
   }
@@ -61,11 +66,38 @@ GeminiAIService::GeminiAIService(const GeminiConfig& config)
   
   if (config_.system_instruction.empty()) {
     std::cerr << "🔧 GeminiAIService: building system instruction" << std::endl;
-    // Use enhanced prompting by default
-    if (config_.use_enhanced_prompting) {
-      config_.system_instruction = prompt_builder_.BuildSystemInstructionWithExamples();
-    } else {
-      config_.system_instruction = BuildSystemInstruction();
+    
+    // Try to load version-specific system prompt file
+    std::string prompt_file = config_.prompt_version == "v2"
+        ? "assets/agent/system_prompt_v2.txt"
+        : "assets/agent/system_prompt.txt";
+    
+    std::vector<std::string> search_paths = {
+        prompt_file,
+        "../" + prompt_file,
+        "../../" + prompt_file
+    };
+    
+    bool loaded = false;
+    for (const auto& path : search_paths) {
+      std::ifstream file(path);
+      if (file.good()) {
+        std::stringstream buffer;
+        buffer << file.rdbuf();
+        config_.system_instruction = buffer.str();
+        std::cerr << "✓ Loaded prompt from: " << path << std::endl;
+        loaded = true;
+        break;
+      }
+    }
+    
+    if (!loaded) {
+      // Fallback to builder
+      if (config_.use_enhanced_prompting) {
+        config_.system_instruction = prompt_builder_.BuildSystemInstructionWithExamples();
+      } else {
+        config_.system_instruction = BuildSystemInstruction();
+      }
     }
     std::cerr << "🔧 GeminiAIService: system instruction built" << std::endl;
   }

src/cli/service/ai/gemini_ai_service.h

@@ -19,6 +19,8 @@ struct GeminiConfig {
   int max_output_tokens = 2048;
   mutable std::string system_instruction;  // Mutable to allow lazy initialization
   bool use_enhanced_prompting = true;  // Enable few-shot examples
+  bool use_function_calling = false;  // Use native Gemini function calling
+  std::string prompt_version = "default";  // Which prompt file to use (default, v2, etc.)
   
   GeminiConfig() = default;
   explicit GeminiConfig(const std::string& key) : api_key(key) {}

src/cli/service/ai/service_factory.cc

@@ -17,6 +17,8 @@ ABSL_DECLARE_FLAG(std::string, ai_provider);
 ABSL_DECLARE_FLAG(std::string, ai_model);
 ABSL_DECLARE_FLAG(std::string, gemini_api_key);
 ABSL_DECLARE_FLAG(std::string, ollama_host);
+ABSL_DECLARE_FLAG(std::string, prompt_version);
+ABSL_DECLARE_FLAG(bool, use_function_calling);
 
 namespace yaze {
 namespace cli {
@@ -83,7 +85,10 @@ std::unique_ptr<AIService> CreateAIService(const AIServiceConfig& config) {
     if (!config.model.empty()) {
       gemini_config.model = config.model;
     }
+    gemini_config.prompt_version = absl::GetFlag(FLAGS_prompt_version);
+    gemini_config.use_function_calling = absl::GetFlag(FLAGS_use_function_calling);
     std::cerr << "🔧 Model: " << gemini_config.model << std::endl;
+    std::cerr << "🔧 Prompt version: " << gemini_config.prompt_version << std::endl;
 
     std::cerr << "🔧 Creating Gemini service instance..." << std::endl;
     auto service = std::make_unique<GeminiAIService>(gemini_config);