sideline/engine/display/backends/websocket.py

"""
WebSocket display backend - broadcasts frame buffer to connected web clients.
"""

import asyncio
import json
import threading
import time
from typing import Protocol

try:
    import websockets
except ImportError:
    websockets = None


class Display(Protocol):
    """Protocol for display backends."""

    width: int
    height: int

    def init(self, width: int, height: int) -> None:
        """Initialize display with dimensions."""
        ...

    def show(self, buffer: list[str]) -> None:
        """Show buffer on display."""
        ...

    def clear(self) -> None:
        """Clear display."""
        ...

    def cleanup(self) -> None:
        """Shutdown display."""
        ...


def get_monitor():
    """Get the performance monitor."""
    try:
        from engine.effects.performance import get_monitor as _get_monitor

        return _get_monitor()
    except Exception:
        return None


class WebSocketDisplay:
    """WebSocket display backend - broadcasts to HTML Canvas clients."""

    width: int = 80
    height: int = 24

    def __init__(
        self,
        host: str = "0.0.0.0",
        port: int = 8765,
        http_port: int = 8766,
    ):
        self.host = host
        self.port = port
        self.http_port = http_port
        self.width = 80
        self.height = 24
        self._clients: set = set()
        self._server_running = False
        self._http_running = False
        self._server_thread: threading.Thread | None = None
        self._http_thread: threading.Thread | None = None
        self._available = True
        self._max_clients = 10
        self._client_connected_callback = None
        self._client_disconnected_callback = None
        self._frame_delay = 0.0

        try:
            import websockets as _ws

            self._available = _ws is not None
        except ImportError:
            self._available = False

    def is_available(self) -> bool:
        """Check if WebSocket support is available."""
        return self._available

    def init(self, width: int, height: int, reuse: bool = False) -> None:
        """Initialize display with dimensions and start server.

        Args:
            width: Terminal width in characters
            height: Terminal height in rows
            reuse: If True, skip starting servers (assume already running)
        """
        self.width = width
        self.height = height

        if not reuse or not self._server_running:
            self.start_server()
            self.start_http_server()

    def show(self, buffer: list[str], border: bool = False) -> None:
        """Broadcast buffer to all connected clients."""
        t0 = time.perf_counter()

        # Get metrics for border display
        fps = 0.0
        frame_time = 0.0
        monitor = get_monitor()
        if monitor:
            stats = monitor.get_stats()
            avg_ms = stats.get("avg_ms", 0) if stats else 0
            frame_count = stats.get("frame_count", 0) if stats else 0
            if avg_ms and frame_count > 0:
                fps = 1000.0 / avg_ms
                frame_time = avg_ms

        # Apply border if requested
        if border:
            from engine.display import render_border

            buffer = render_border(buffer, self.width, self.height, fps, frame_time)

        if self._clients:
            frame_data = {
                "type": "frame",
                "width": self.width,
                "height": self.height,
                "lines": buffer,
            }
            message = json.dumps(frame_data)

            disconnected = set()
            for client in list(self._clients):
                try:
                    asyncio.run(client.send(message))
                except Exception:
                    disconnected.add(client)

            for client in disconnected:
                self._clients.discard(client)
                if self._client_disconnected_callback:
                    self._client_disconnected_callback(client)

        elapsed_ms = (time.perf_counter() - t0) * 1000
        monitor = get_monitor()
        if monitor:
            chars_in = sum(len(line) for line in buffer)
            monitor.record_effect("websocket_display", elapsed_ms, chars_in, chars_in)

    def clear(self) -> None:
        """Broadcast clear command to all clients."""
        if self._clients:
            clear_data = {"type": "clear"}
            message = json.dumps(clear_data)
            for client in list(self._clients):
                try:
                    asyncio.run(client.send(message))
                except Exception:
                    pass

    def cleanup(self) -> None:
        """Stop the servers."""
        self.stop_server()
        self.stop_http_server()

    async def _websocket_handler(self, websocket):
        """Handle WebSocket connections."""
        if len(self._clients) >= self._max_clients:
            await websocket.close()
            return

        self._clients.add(websocket)
        if self._client_connected_callback:
            self._client_connected_callback(websocket)

        try:
            async for message in websocket:
                try:
                    data = json.loads(message)
                    if data.get("type") == "resize":
                        self.width = data.get("width", 80)
                        self.height = data.get("height", 24)
                except json.JSONDecodeError:
                    pass
        except Exception:
            pass
        finally:
            self._clients.discard(websocket)
            if self._client_disconnected_callback:
                self._client_disconnected_callback(websocket)

    async def _run_websocket_server(self):
        """Run the WebSocket server."""
        async with websockets.serve(self._websocket_handler, self.host, self.port):
            while self._server_running:
                await asyncio.sleep(0.1)

    async def _run_http_server(self):
        """Run simple HTTP server for the client."""
        import os
        from http.server import HTTPServer, SimpleHTTPRequestHandler

        client_dir = os.path.join(
            os.path.dirname(os.path.dirname(os.path.dirname(__file__))), "client"
        )

        class Handler(SimpleHTTPRequestHandler):
            def __init__(self, *args, **kwargs):
                super().__init__(*args, directory=client_dir, **kwargs)

            def log_message(self, format, *args):
                pass

        httpd = HTTPServer((self.host, self.http_port), Handler)
        while self._http_running:
            httpd.handle_request()

    def _run_async(self, coro):
        """Run coroutine in background."""
        try:
            asyncio.run(coro)
        except Exception as e:
            print(f"WebSocket async error: {e}")

    def start_server(self):
        """Start the WebSocket server in a background thread."""
        if not self._available:
            return
        if self._server_thread is not None:
            return

        self._server_running = True
        self._server_thread = threading.Thread(
            target=self._run_async, args=(self._run_websocket_server(),), daemon=True
        )
        self._server_thread.start()

    def stop_server(self):
        """Stop the WebSocket server."""
        self._server_running = False
        self._server_thread = None

    def start_http_server(self):
        """Start the HTTP server in a background thread."""
        if not self._available:
            return
        if self._http_thread is not None:
            return

        self._http_running = True

        self._http_running = True
        self._http_thread = threading.Thread(
            target=self._run_async, args=(self._run_http_server(),), daemon=True
        )
        self._http_thread.start()

    def stop_http_server(self):
        """Stop the HTTP server."""
        self._http_running = False
        self._http_thread = None

    def client_count(self) -> int:
        """Return number of connected clients."""
        return len(self._clients)

    def get_ws_port(self) -> int:
        """Return WebSocket port."""
        return self.port

    def get_http_port(self) -> int:
        """Return HTTP port."""
        return self.http_port

    def set_frame_delay(self, delay: float) -> None:
        """Set delay between frames in seconds."""
        self._frame_delay = delay

    def get_frame_delay(self) -> float:
        """Get delay between frames."""
        return self._frame_delay

    def set_client_connected_callback(self, callback) -> None:
        """Set callback for client connections."""
        self._client_connected_callback = callback

    def set_client_disconnected_callback(self, callback) -> None:
        """Set callback for client disconnections."""
        self._client_disconnected_callback = callback

    def get_dimensions(self) -> tuple[int, int]:
        """Get current dimensions.

        Returns:
            (width, height) in character cells
        """
        return (self.width, self.height)