"""Headless runtime: wake word → master → speaker, without Qt.

Used on displayless satellites (Raspberry Pi + mic + speaker) via
``python -m javis_slave --headless``.  Reuses :class:`AudioEngine`,
:class:`MasterClient` and the MCP control HTTP server exactly like the GUI
app; state and errors go to the log instead of the screen.
"""
from __future__ import annotations

import asyncio
import signal
import sys
from typing import Optional

from .api_client import MasterClient, MasterError
from .audio_engine import AudioEngine
from .config import SlaveConfig, load_config, save_config
from .http_server import build_http_app
from .logging_setup import get_logger

log = get_logger("slave.headless")

# Re-try the initial engine start (mic not ready at boot, master down) this often.
_START_RETRY_S = 10.0


async def pair_cli(cfg: SlaveConfig, client: MasterClient, host: str, port: int,
                   code: str, name: str) -> None:
    """Pair from the command line and persist credentials."""
    if not await client.check_health(host, port):
        raise MasterError(
            f"Master at {host}:{port} not reachable — is api.enabled: true in its config.yaml?")
    result = await client.pair(host, port, code, name)
    cfg.master_host = host
    cfg.master_port = port
    cfg.api_key = result.api_key
    cfg.device_name = name
    cfg.room = result.room
    cfg.wake_word = result.wake_word
    save_config(cfg)
    log.info(f"paired with master {host}:{port} as {name!r} (room={result.room!r})")


async def run_headless_async(cfg: SlaveConfig, client: MasterClient) -> int:
    if not cfg.paired:
        log.error("device is not paired. Run:  python -m javis_slave --pair HOST:PORT CODE --name NAME")
        return 2

    engine: Optional[AudioEngine] = None
    engine_task: Optional[asyncio.Task] = None
    state = {"value": "idle", "error": None}
    stop = asyncio.Event()

    def _on_state(s: str) -> None:
        if s != state["value"]:
            state["value"] = s
            log.info(f"state -> {s}")

    def _on_error(msg: str) -> None:
        state["error"] = msg
        log.error(msg)

    def _on_turn(user: str, reply: str) -> None:
        log.info(f"user:  {user}")
        log.info(f"javis: {reply}")

    def _on_room(room) -> None:
        log.info(f"room: {room or '(none)'}")

    def _on_connection(ok: bool, retry: int, backoff: float) -> None:
        if not ok:
            log.warning(f"master unreachable (attempt {retry}, next try in {backoff:.0f}s)")

    async def _start_engine() -> None:
        nonlocal engine, engine_task
        while not stop.is_set():
            eng = AudioEngine(cfg, client)
            eng.on_state = _on_state
            eng.on_error = _on_error
            eng.on_turn = _on_turn
            eng.on_room = _on_room
            eng.on_connection = _on_connection
            try:
                await eng.start()
            except Exception as exc:  # noqa: BLE001
                log.error(f"audio engine failed to start ({exc}); retrying in {_START_RETRY_S:.0f}s")
                try:
                    await asyncio.wait_for(stop.wait(), timeout=_START_RETRY_S)
                except asyncio.TimeoutError:
                    continue
                return
            engine = eng
            engine_task = asyncio.create_task(eng.run())
            log.info(f"listening for wake word '{cfg.wake_word.model}' (room={cfg.room!r})")
            return

    async def _stop_engine() -> None:
        nonlocal engine, engine_task
        if engine_task is not None:
            engine_task.cancel()
            try:
                await engine_task
            except asyncio.CancelledError:
                pass
            engine_task = None
        if engine is not None:
            await engine.stop()
            engine = None

    async def _restart() -> None:
        await _stop_engine()
        await _start_engine()

    # MCP control server (same endpoints as the GUI app).
    http_task: Optional[asyncio.Task] = None
    server = None
    try:
        from uvicorn import Config as UvConfig, Server
        http_app = build_http_app(
            cfg,
            lambda: engine, lambda: state["value"], lambda: state["error"],
            lambda: (engine.last_rms, engine.last_score) if engine else (0.0, 0.0),
            on_restart=_restart,
            master_client_getter=lambda: client,
        )
        server = Server(UvConfig(app=http_app, host=cfg.api_host, port=cfg.api_port,
                                 log_level="warning", loop="none", lifespan="off"))
        http_task = asyncio.create_task(server.serve())
        log.info(f"MCP control server on http://{cfg.api_host}:{cfg.api_port}")
    except Exception as exc:  # noqa: BLE001
        log.error(f"HTTP server not started: {exc}")

    loop = asyncio.get_running_loop()
    for sig in (signal.SIGINT, signal.SIGTERM):
        try:
            loop.add_signal_handler(sig, stop.set)
        except (NotImplementedError, RuntimeError):
            pass  # Windows: fall back to KeyboardInterrupt

    await _start_engine()
    try:
        await stop.wait()
    except (KeyboardInterrupt, asyncio.CancelledError):
        # Windows has no add_signal_handler: asyncio.run cancels us on Ctrl+C.
        # Swallow it so the teardown below still runs.
        pass
    log.info("shutting down …")
    await _stop_engine()
    if server is not None:
        server.should_exit = True
    if http_task is not None:
        try:
            await asyncio.wait_for(http_task, timeout=5.0)
        except (asyncio.TimeoutError, asyncio.CancelledError, Exception):  # noqa: BLE001
            http_task.cancel()
    await client.aclose()
    return 0


def run_headless(pair: Optional[tuple[str, int, str, str]] = None) -> int:
    cfg = load_config()
    save_config(cfg)
    client = MasterClient(cfg)

    async def _main() -> int:
        if pair is not None:
            host, port, code, name = pair
            try:
                await pair_cli(cfg, client, host, port, code, name)
            except MasterError as exc:
                log.error(f"pairing failed: {exc}")
                await client.aclose()
                return 1
        return await run_headless_async(cfg, client)

    try:
        return asyncio.run(_main())
    except KeyboardInterrupt:
        return 0


if __name__ == "__main__":
    sys.exit(run_headless())