feat(01-03): create core Mai orchestration class

- Initialize ModelManager, ContextManager, and subsystems
- Provide main conversation interface with process_message
- Support both synchronous and async operations
- Add system status monitoring and conversation history
- Include graceful shutdown with signal handlers
- Background resource monitoring and maintenance tasks
- Model switching commands and information methods

src/mai.py

@@ -0,0 +1,240 @@
+"""Core Mai orchestration class."""
+
+import asyncio
+import logging
+from typing import Dict, Any, Optional
+import signal
+import sys
+
+from .models.model_manager import ModelManager
+from .models.context_manager import ContextManager
+
+
+class Mai:
+    """
+    Core Mai orchestration class.
+
+    Coordinates between model management, context management, and other systems
+    to provide a unified conversational interface.
+    """
+
+    def __init__(self, config_path: Optional[str] = None):
+        """Initialize Mai and all subsystems.
+
+        Args:
+            config_path: Optional path to configuration files
+        """
+        self.logger = logging.getLogger(__name__)
+        self.running = False
+
+        # Initialize subsystems
+        self.model_manager = ModelManager(config_path)
+        self.context_manager = self.model_manager.context_manager
+
+        # Setup signal handlers for graceful shutdown
+        self._setup_signal_handlers()
+
+        self.logger.info("Mai core initialized")
+
+    def process_message(self, message: str, conversation_id: str = "default") -> str:
+        """
+        Process a user message and return response.
+
+        Args:
+            message: User input message
+            conversation_id: Optional conversation identifier
+
+        Returns:
+            Generated response
+        """
+        try:
+            # Simple synchronous wrapper for async method
+            loop = asyncio.new_event_loop()
+            asyncio.set_event_loop(loop)
+            try:
+                response = loop.run_until_complete(
+                    self.model_manager.generate_response(message, conversation_id)
+                )
+                return response
+            finally:
+                loop.close()
+
+        except Exception as e:
+            self.logger.error(f"Error processing message: {e}")
+            return "I'm sorry, I encountered an error while processing your message."
+
+    async def process_message_async(
+        self, message: str, conversation_id: str = "default"
+    ) -> str:
+        """
+        Asynchronous version of process_message.
+
+        Args:
+            message: User input message
+            conversation_id: Optional conversation identifier
+
+        Returns:
+            Generated response
+        """
+        try:
+            response = await self.model_manager.generate_response(
+                message, conversation_id
+            )
+            return response
+        except Exception as e:
+            self.logger.error(f"Error processing async message: {e}")
+            return "I'm sorry, I encountered an error while processing your message."
+
+    def get_conversation_history(self, conversation_id: str = "default") -> list:
+        """
+        Retrieve conversation history.
+
+        Args:
+            conversation_id: Conversation identifier
+
+        Returns:
+            List of conversation messages
+        """
+        try:
+            return self.context_manager.get_conversation(conversation_id)
+        except Exception as e:
+            self.logger.error(f"Error retrieving conversation history: {e}")
+            return []
+
+    def get_system_status(self) -> Dict[str, Any]:
+        """
+        Return current system status for monitoring.
+
+        Returns:
+            Dictionary with system state information
+        """
+        try:
+            # Get model status
+            model_status = self.model_manager.get_current_model_status()
+
+            # Get conversation stats
+            conversation_stats = {}
+            for conv_id in ["default"]:  # Add more conv IDs as needed
+                stats = self.context_manager.get_conversation_stats(conv_id)
+                if stats:
+                    conversation_stats[conv_id] = stats
+
+            # Combine into comprehensive status
+            status = {
+                "mai_status": "running" if self.running else "stopped",
+                "model": model_status,
+                "conversations": conversation_stats,
+                "system_resources": model_status.get("resources", {}),
+            }
+
+            return status
+
+        except Exception as e:
+            self.logger.error(f"Error getting system status: {e}")
+            return {"mai_status": "error", "error": str(e)}
+
+    def start_background_tasks(self) -> None:
+        """Start background monitoring and maintenance tasks."""
+        try:
+
+            async def background_loop():
+                while self.running:
+                    try:
+                        # Update resource monitoring
+                        self.model_manager.resource_monitor.update_history()
+
+                        # Check for resource-triggered model switches
+                        if self.model_manager.current_model_instance:
+                            resources = self.model_manager.resource_monitor.get_current_resources()
+
+                            # Check if system is overloaded
+                            if self.model_manager.resource_monitor.is_system_overloaded():
+                                self.logger.warning(
+                                    "System resources exceeded thresholds, considering model switch"
+                                )
+                                # This would trigger proactive switching in next generation
+
+                        # Wait before next check (configurable interval)
+                        await asyncio.sleep(5)  # 5 second interval
+
+                    except Exception as e:
+                        self.logger.error(f"Error in background loop: {e}")
+                        await asyncio.sleep(10)  # Wait longer on error
+
+            # Start background task
+            asyncio.create_task(background_loop())
+            self.logger.info("Background monitoring tasks started")
+
+        except Exception as e:
+            self.logger.error(f"Failed to start background tasks: {e}")
+
+    def _setup_signal_handlers(self) -> None:
+        """Setup signal handlers for graceful shutdown."""
+
+        def signal_handler(signum, frame):
+            self.logger.info(f"Received signal {signum}, shutting down gracefully")
+            self.shutdown()
+            sys.exit(0)
+
+        signal.signal(signal.SIGINT, signal_handler)
+        signal.signal(signal.SIGTERM, signal_handler)
+
+    def shutdown(self) -> None:
+        """Clean up resources and shutdown gracefully."""
+        try:
+            self.running = False
+            self.logger.info("Shutting down Mai...")
+
+            # Shutdown model manager
+            if hasattr(self, "model_manager"):
+                self.model_manager.shutdown()
+
+            self.logger.info("Mai shutdown complete")
+
+        except Exception as e:
+            self.logger.error(f"Error during shutdown: {e}")
+
+    def list_available_models(self) -> list:
+        """
+        List all available models from ModelManager.
+
+        Returns:
+            List of available model information
+        """
+        try:
+            return self.model_manager.available_models
+        except Exception as e:
+            self.logger.error(f"Error listing models: {e}")
+            return []
+
+    async def switch_model(self, model_key: str) -> bool:
+        """
+        Manually switch to a specific model.
+
+        Args:
+            model_key: Model identifier to switch to
+
+        Returns:
+            True if switch successful, False otherwise
+        """
+        try:
+            return await self.model_manager.switch_model(model_key)
+        except Exception as e:
+            self.logger.error(f"Error switching model: {e}")
+            return False
+
+    def get_model_info(self, model_key: str) -> Optional[Dict[str, Any]]:
+        """
+        Get information about a specific model.
+
+        Args:
+            model_key: Model identifier
+
+        Returns:
+            Model information dictionary or None if not found
+        """
+        try:
+            return self.model_manager.model_configurations.get(model_key)
+        except Exception as e:
+            self.logger.error(f"Error getting model info: {e}")
+            return None

src/models/model_manager.py

@@ -266,7 +266,7 @@ class ModelManager:
                 )
 
                 # Unload current model (silent - no user notification per CONTEXT.md)
-                if self.current_model_instance:
+                if self.current_model_instance and self.current_model_key:
                     try:
                         self.lm_adapter.unload_model(self.current_model_key)
                     except Exception as e:
@@ -359,8 +359,14 @@ class ModelManager:
                     raise ValueError("Model returned empty or inadequate response")
 
                 # Add messages to context
-                self.context_manager.add_message(conversation_id, "user", message)
-                self.context_manager.add_message(conversation_id, "assistant", response)
+                from .conversation import MessageRole
+
+                self.context_manager.add_message(
+                    conversation_id, MessageRole.USER, message
+                )
+                self.context_manager.add_message(
+                    conversation_id, MessageRole.ASSISTANT, response
+                )
 
                 # Check if we should consider switching (slow response or struggling)
                 if await self._should_consider_switching(response_time_ms, response):
@@ -589,7 +595,7 @@ class ModelManager:
     def shutdown(self) -> None:
         """Clean up resources and unload models."""
         try:
-            if self.current_model_instance:
+            if self.current_model_instance and self.current_model_key:
                 self.lm_adapter.unload_model(self.current_model_key)
                 self.current_model_key = None
                 self.current_model_instance = None