import asyncio
import json
import websockets
from typing import Dict, Any, Set
import subprocess
import shlex
from queue import Queue
import threading
import time
import logging
from datetime import datetime

logger = logging.getLogger(__name__)

class TerminalStreamManager:
    """Manages real-time terminal streaming with WebSocket connections."""
    
    def __init__(self):
        self.clients: Set[websockets.WebSocketServerProtocol] = set()
        self.command_queue = Queue()
        self.is_running = False
        self.current_process = None
        self.server = None
        self.server_thread = None
        self.loop = None
        
    async def register_client(self, websocket):
        """Register a new WebSocket client."""
        self.clients.add(websocket)
        await websocket.send(json.dumps({
            'type': 'connected',
            'message': '🚀 Terminal connected successfully',
            'timestamp': datetime.now().isoformat()
        }))
        logger.info(f"Terminal client connected. Total clients: {len(self.clients)}")
    
    async def unregister_client(self, websocket):
        """Unregister a WebSocket client."""
        self.clients.discard(websocket)
        logger.info(f"Terminal client disconnected. Total clients: {len(self.clients)}")
        
    async def broadcast(self, message: Dict[str, Any]):
        """Broadcast message to all connected clients."""
        if self.clients:
            disconnected = set()
            message['timestamp'] = datetime.now().isoformat()
            
            for client in self.clients:
                try:
                    await client.send(json.dumps(message))
                except websockets.exceptions.ConnectionClosed:
                    disconnected.add(client)
                except Exception as e:
                    logger.error(f"Error broadcasting to client: {e}")
                    disconnected.add(client)
            
            # Clean up disconnected clients
            for client in disconnected:
                self.clients.discard(client)
    
    async def execute_command(self, command: str):
        """Execute a command and stream output in real-time."""
        await self.broadcast({
            'type': 'command_start',
            'command': command,
            'message': f'$ {command}'
        })
        
        try:
            # Security: Use shell=False and sanitize input
            safe_command = shlex.split(command)
            
            self.current_process = subprocess.Popen(
                safe_command,
                stdout=subprocess.PIPE,
                stderr=subprocess.PIPE,
                text=True,
                bufsize=1,
                universal_newlines=True
            )
            
            # Stream output in real-time
            while True:
                # Check if process is still running
                if self.current_process.poll() is not None:
                    # Process finished, read remaining output
                    remaining_stdout = self.current_process.stdout.read()
                    remaining_stderr = self.current_process.stderr.read()
                    
                    if remaining_stdout:
                        await self.broadcast({
                            'type': 'output',
                            'data': remaining_stdout,
                            'stream': 'stdout'
                        })
                    
                    if remaining_stderr:
                        await self.broadcast({
                            'type': 'output',
                            'data': remaining_stderr,
                            'stream': 'stderr'
                        })
                    
                    break
                
                # Read available output
                try:
                    # Use select or polling for non-blocking read
                    import select
                    ready, _, _ = select.select([self.current_process.stdout, self.current_process.stderr], [], [], 0.1)
                    
                    for stream in ready:
                        if stream == self.current_process.stdout:
                            line = stream.readline()
                            if line:
                                await self.broadcast({
                                    'type': 'output',
                                    'data': line,
                                    'stream': 'stdout'
                                })
                        elif stream == self.current_process.stderr:
                            line = stream.readline()
                            if line:
                                await self.broadcast({
                                    'type': 'output',
                                    'data': line,
                                    'stream': 'stderr'
                                })
                except:
                    # Fallback for systems without select
                    await asyncio.sleep(0.1)
            
            # Send completion message
            await self.broadcast({
                'type': 'command_complete',
                'exit_code': self.current_process.returncode,
                'message': f'Process exited with code {self.current_process.returncode}'
            })
            
        except Exception as e:
            await self.broadcast({
                'type': 'error',
                'data': str(e),
                'stream': 'system'
            })
        finally:
            self.current_process = None
    
    async def handle_client(self, websocket, path):
        """Handle WebSocket client connections."""
        await self.register_client(websocket)
        try:
            async for message in websocket:
                try:
                    data = json.loads(message)
                    
                    if data.get('type') == 'command':
                        command = data.get('command', '').strip()
                        if command:
                            await self.execute_command(command)
                    
                    elif data.get('type') == 'interrupt':
                        if self.current_process:
                            self.current_process.terminate()
                            await self.broadcast({
                                'type': 'interrupted',
                                'message': 'Process interrupted by user'
                            })
                    
                except json.JSONDecodeError:
                    await websocket.send(json.dumps({
                        'type': 'error',
                        'message': 'Invalid JSON message'
                    }))
                    
        except websockets.exceptions.ConnectionClosed:
            pass
        finally:
            await self.unregister_client(websocket)
    
    def stop_server(self):
        """Stop the WebSocket server gracefully."""
        if self.server:
            logger.info("Stopping terminal WebSocket server...")
            self.is_running = False
            
            # Close all client connections
            if self.clients:
                import asyncio
                try:
                    loop = asyncio.get_event_loop()
                    for client in self.clients.copy():
                        try:
                            loop.create_task(client.close())
                        except Exception as e:
                            logger.warning(f"Error closing client connection: {e}")
                    self.clients.clear()
                except Exception as e:
                    logger.warning(f"Error closing client connections: {e}")
            
            # Terminate current process if running
            if self.current_process:
                try:
                    self.current_process.terminate()
                    self.current_process = None
                except Exception as e:
                    logger.warning(f"Error terminating process: {e}")
            
            # Close the server
            try:
                if hasattr(self.server, 'close'):
                    self.server.close()
                
                # Stop the event loop if it exists
                if self.loop and self.loop.is_running():
                    self.loop.call_soon_threadsafe(self.loop.stop)
                
                logger.info("Terminal WebSocket server stopped")
            except Exception as e:
                logger.error(f"Error stopping WebSocket server: {e}")
        else:
            logger.info("Terminal WebSocket server was not running")

# Global terminal manager instance
terminal_manager = TerminalStreamManager()

async def start_websocket_server(host='localhost', port=8765):
    """Start the WebSocket server for terminal streaming."""
    logger.info(f"Starting terminal WebSocket server on {host}:{port}")
    
    async def handler(websocket, path):
        await terminal_manager.handle_client(websocket, path)
    
    server = await websockets.serve(handler, host, port)
    terminal_manager.server = server
    terminal_manager.is_running = True
    return server

def run_websocket_server():
    """Run WebSocket server in a separate thread."""
    def start_server():
        loop = asyncio.new_event_loop()
        asyncio.set_event_loop(loop)
        terminal_manager.loop = loop
        
        try:
            server = loop.run_until_complete(start_websocket_server())
            logger.info("Terminal WebSocket server started successfully")
            loop.run_forever()
        except Exception as e:
            logger.error(f"Error starting WebSocket server: {e}")
        finally:
            logger.info("WebSocket server loop ended")
    
    thread = threading.Thread(target=start_server, daemon=True)
    terminal_manager.server_thread = thread
    thread.start()
    return thread