"""Socket.IO client manager for connecting to standalone servers.

This module provides intelligent client management that:
1. Detects existing standalone servers
2. Performs version compatibility checks
3. Handles graceful fallback to embedded servers
4. Manages connection lifecycle and reconnection

WHY this approach:
- Enables seamless integration with standalone servers
- Provides compatibility checking before connection
- Handles both local and remote server scenarios
- Maintains backward compatibility with embedded servers
"""

import asyncio
import json
import logging
import socket
import sys
import threading
import time
from datetime import datetime
from typing import Dict, Any, Optional, List, Tuple
import importlib.metadata

try:
    import requests
    import socketio
    DEPENDENCIES_AVAILABLE = True
except ImportError:
    DEPENDENCIES_AVAILABLE = False
    requests = None
    socketio = None

from ..core.logger import get_logger

# Get claude-mpm version for compatibility checking
try:
    CLAUDE_MPM_VERSION = importlib.metadata.version('claude-mpm')
except Exception:
    # Fallback for development
    CLAUDE_MPM_VERSION = "0.7.0-dev"


class ServerInfo:
    """Information about a detected Socket.IO server."""
    
    def __init__(self, host: str, port: int, response_data: Dict[str, Any]):
        self.host = host
        self.port = port
        self.server_version = response_data.get("server_version", "unknown")
        self.server_id = response_data.get("server_id", "unknown")
        self.socketio_version = response_data.get("socketio_version", "unknown")
        self.features = response_data.get("features", [])
        self.supported_client_versions = response_data.get("supported_client_versions", [])
        self.compatibility_matrix = response_data.get("compatibility_matrix", {})
        self.detected_at = datetime.utcnow()
    
    @property
    def url(self) -> str:
        return f"http://{self.host}:{self.port}"
    
    def is_compatible(self, client_version: str = CLAUDE_MPM_VERSION) -> Tuple[bool, List[str]]:
        """Check if this server is compatible with the client version."""
        warnings = []
        
        try:
            # Simple version comparison - in production use proper semver
            if client_version >= "0.7.0":
                return True, warnings
            else:
                warnings.append(f"Client version {client_version} may not be fully supported")
                return False, warnings
        except Exception as e:
            warnings.append(f"Could not parse version: {e}")
            return False, warnings


class SocketIOClientManager:
    """Manages Socket.IO client connections with server discovery and compatibility checking."""
    
    def __init__(self, client_version: str = CLAUDE_MPM_VERSION):
        self.client_version = client_version
        self.logger = get_logger("socketio_client_manager")
        
        # Connection state
        self.current_server: Optional[ServerInfo] = None
        self.client: Optional[socketio.AsyncClient] = None
        self.connected = False
        self.connection_thread: Optional[threading.Thread] = None
        self.running = False
        
        # Server discovery
        self.known_servers: Dict[str, ServerInfo] = {}
        self.last_discovery = None
        
        if not DEPENDENCIES_AVAILABLE:
            self.logger.warning("Socket.IO client dependencies not available")
    
    def discover_servers(self, ports: List[int] = None, hosts: List[str] = None) -> List[ServerInfo]:
        """Discover available Socket.IO servers.
        
        Args:
            ports: List of ports to check (default: [8765, 8766, 8767])
            hosts: List of hosts to check (default: ['localhost', '127.0.0.1'])
        
        Returns:
            List of discovered server info objects
        """
        if not DEPENDENCIES_AVAILABLE:
            return []
        
        ports = ports or [8765, 8766, 8767]
        hosts = hosts or ['localhost', '127.0.0.1']
        
        discovered = []
        
        for host in hosts:
            for port in ports:
                try:
                    # Quick port check first
                    with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
                        s.settimeout(0.5)
                        if s.connect_ex((host, port)) != 0:
                            continue
                    
                    # Try to get server version info
                    try:
                        response = requests.get(
                            f"http://{host}:{port}/version",
                            timeout=2.0
                        )
                        if response.status_code == 200:
                            data = response.json()
                            server_info = ServerInfo(host, port, data)
                            discovered.append(server_info)
                            
                            server_key = f"{host}:{port}"
                            self.known_servers[server_key] = server_info
                            
                            self.logger.info(f"🔍 Discovered server: {server_info.server_id} "
                                           f"v{server_info.server_version} at {server_info.url}")
                    
                    except requests.RequestException:
                        # Not a standalone server, might be another service
                        continue
                        
                except Exception as e:
                    self.logger.debug(f"Error checking {host}:{port}: {e}")
                    continue
        
        self.last_discovery = datetime.utcnow()
        return discovered
    
    def find_best_server(self, discovered_servers: List[ServerInfo] = None) -> Optional[ServerInfo]:
        """Find the best compatible server from discovered servers."""
        if discovered_servers is None:
            discovered_servers = self.discover_servers()
        
        if not discovered_servers:
            return None
        
        # Score servers based on compatibility and features
        scored_servers = []
        
        for server in discovered_servers:
            compatible, warnings = server.is_compatible(self.client_version)
            
            if not compatible:
                self.logger.debug(f"Server {server.server_id} not compatible: {warnings}")
                continue
            
            # Simple scoring: newer versions and more features get higher scores
            score = 0
            
            # Version scoring (basic semantic versioning)
            try:
                version_parts = server.server_version.split('.')
                score += int(version_parts[0]) * 1000  # Major version
                score += int(version_parts[1]) * 100   # Minor version
                score += int(version_parts[2]) * 10    # Patch version
            except (ValueError, IndexError):
                pass
            
            # Feature scoring
            score += len(server.features) * 5
            
            scored_servers.append((score, server))
        
        if not scored_servers:
            self.logger.warning("No compatible servers found")
            return None
        
        # Return highest scored server
        scored_servers.sort(key=lambda x: x[0], reverse=True)
        best_server = scored_servers[0][1]
        
        self.logger.info(f"🎯 Selected best server: {best_server.server_id} "
                        f"v{best_server.server_version} at {best_server.url}")
        
        return best_server
    
    async def connect_to_server(self, server_info: ServerInfo) -> bool:
        """Connect to a specific server with compatibility verification."""
        if not DEPENDENCIES_AVAILABLE:
            return False
        
        try:
            # Perform compatibility check via HTTP first
            compat_response = requests.post(
                f"{server_info.url}/compatibility",
                json={"client_version": self.client_version},
                timeout=5.0
            )
            
            if compat_response.status_code == 200:
                compatibility = compat_response.json()
                if not compatibility.get("compatible", False):
                    self.logger.error(f"Server {server_info.server_id} rejected client version {self.client_version}")
                    return False
            
            # Create Socket.IO client
            self.client = socketio.AsyncClient(
                reconnection=True,
                reconnection_attempts=0,  # Infinite
                reconnection_delay=1,
                reconnection_delay_max=5,
                randomization_factor=0.5,
                logger=False,
                engineio_logger=False
            )
            
            # Setup event handlers
            self._setup_client_event_handlers()
            
            # Connect with authentication
            auth = {
                "claude_mpm_version": self.client_version,
                "client_id": f"claude-mpm-{time.time()}"
            }
            
            await self.client.connect(server_info.url, auth=auth)
            
            self.current_server = server_info
            self.connected = True
            
            self.logger.info(f"✅ Connected to server {server_info.server_id} at {server_info.url}")
            return True
            
        except Exception as e:
            self.logger.error(f"❌ Failed to connect to server {server_info.url}: {e}")
            if self.client:
                try:
                    await self.client.disconnect()
                except:
                    pass
                self.client = None
            return False
    
    def _setup_client_event_handlers(self):
        """Setup event handlers for the Socket.IO client."""
        
        @self.client.event
        async def connect():
            self.logger.info("🔗 Socket.IO client connected")
            self.connected = True
        
        @self.client.event
        async def disconnect():
            self.logger.info("🔌 Socket.IO client disconnected")
            self.connected = False
        
        @self.client.event
        async def connection_ack(data):
            self.logger.info("🤝 Received connection acknowledgment")
            compatibility = data.get("compatibility", {})
            if not compatibility.get("compatible", True):
                self.logger.warning(f"⚠️ Server compatibility warning: {compatibility.get('warnings', [])}")
        
        @self.client.event
        async def compatibility_warning(data):
            self.logger.warning(f"⚠️ Server compatibility warning: {data}")
        
        @self.client.event
        async def server_status(data):
            self.logger.debug(f"📊 Server status: {data.get('clients_connected', 0)} clients")
        
        @self.client.event
        async def claude_event(data):
            """Handle events broadcasted from other clients."""
            event_type = data.get("type", "unknown")
            self.logger.debug(f"📥 Received claude_event: {event_type}")
    
    async def emit_event(self, event_type: str, data: Dict[str, Any]) -> bool:
        """Emit an event to the connected server."""
        if not self.connected or not self.client:
            return False
        
        try:
            event_data = {
                "type": event_type,
                "timestamp": datetime.utcnow().isoformat() + "Z",
                "data": data,
                "client_version": self.client_version
            }
            
            await self.client.emit('claude_event', event_data)
            self.logger.debug(f"📤 Emitted event: {event_type}")
            return True
            
        except Exception as e:
            self.logger.error(f"❌ Failed to emit event {event_type}: {e}")
            return False
    
    def start_connection_manager(self):
        """Start the connection manager in a background thread."""
        if self.running:
            return
        
        self.running = True
        self.connection_thread = threading.Thread(target=self._run_connection_manager, daemon=True)
        self.connection_thread.start()
        self.logger.info("🚀 Connection manager started")
    
    def stop_connection_manager(self):
        """Stop the connection manager."""
        self.running = False
        
        if self.connection_thread:
            self.connection_thread.join(timeout=5)
        
        if self.client and self.connected:
            try:
                # Disconnect from server
                loop = asyncio.new_event_loop()
                loop.run_until_complete(self.client.disconnect())
                loop.close()
            except Exception as e:
                self.logger.error(f"Error disconnecting client: {e}")
        
        self.logger.info("🛑 Connection manager stopped")
    
    def _run_connection_manager(self):
        """Run the connection manager loop."""
        loop = asyncio.new_event_loop()
        asyncio.set_event_loop(loop)
        
        try:
            loop.run_until_complete(self._connection_manager_loop())
        except Exception as e:
            self.logger.error(f"Connection manager error: {e}")
        finally:
            loop.close()
    
    async def _connection_manager_loop(self):
        """Main connection manager loop."""
        connection_attempts = 0
        max_connection_attempts = 3
        
        while self.running:
            try:
                if not self.connected:
                    if connection_attempts < max_connection_attempts:
                        # Try to find and connect to a server
                        best_server = self.find_best_server()
                        
                        if best_server:
                            success = await self.connect_to_server(best_server)
                            if success:
                                connection_attempts = 0  # Reset on successful connection
                            else:
                                connection_attempts += 1
                        else:
                            self.logger.info("📡 No Socket.IO servers found, will retry...")
                            connection_attempts += 1
                    else:
                        # Too many failed attempts, wait longer
                        self.logger.warning(f"⏳ Max connection attempts reached, waiting 30s...")
                        await asyncio.sleep(30)
                        connection_attempts = 0  # Reset after longer wait
                
                # Periodic health check
                if self.connected and self.client:
                    try:
                        await self.client.emit('ping')
                    except Exception as e:
                        self.logger.warning(f"Health check failed: {e}")
                        self.connected = False
                
                await asyncio.sleep(5)  # Check every 5 seconds
                
            except Exception as e:
                self.logger.error(f"Error in connection manager loop: {e}")
                await asyncio.sleep(5)
    
    # Compatibility methods for existing WebSocket server interface
    
    def broadcast_event(self, event_type: str, data: Dict[str, Any]):
        """Legacy compatibility method for broadcasting events."""
        if self.connected:
            # Schedule emit in the connection thread
            try:
                loop = asyncio.new_event_loop()
                loop.run_until_complete(self.emit_event(event_type, data))
                loop.close()
            except Exception as e:
                self.logger.error(f"Error broadcasting event {event_type}: {e}")
    
    def session_started(self, session_id: str, launch_method: str, working_dir: str):
        """Compatibility method for session start events."""
        self.broadcast_event("session.start", {
            "session_id": session_id,
            "launch_method": launch_method,
            "working_directory": working_dir
        })
    
    def session_ended(self):
        """Compatibility method for session end events."""
        self.broadcast_event("session.end", {})
    
    def claude_status_changed(self, status: str, pid: Optional[int] = None, message: str = ""):
        """Compatibility method for Claude status events."""
        self.broadcast_event("claude.status", {
            "status": status,
            "pid": pid,
            "message": message
        })
    
    def agent_delegated(self, agent: str, task: str, status: str = "started"):
        """Compatibility method for agent delegation events."""
        self.broadcast_event("agent.delegation", {
            "agent": agent,
            "task": task,
            "status": status
        })
    
    def todo_updated(self, todos: List[Dict[str, Any]]):
        """Compatibility method for todo update events."""
        self.broadcast_event("todo.update", {
            "todos": todos
        })
    
    @property
    def running_status(self) -> bool:
        """Compatibility property."""
        return self.running


# Global instance for easy access
_client_manager: Optional[SocketIOClientManager] = None


def get_client_manager() -> SocketIOClientManager:
    """Get or create the global client manager instance."""
    global _client_manager
    if _client_manager is None:
        _client_manager = SocketIOClientManager()
    return _client_manager


def start_client_manager():
    """Start the global client manager."""
    manager = get_client_manager()
    manager.start_connection_manager()
    return manager


def stop_client_manager():
    """Stop the global client manager."""
    global _client_manager
    if _client_manager:
        _client_manager.stop_connection_manager()
        _client_manager = None