"""Smart Assistant Pi client entry point.

CRITICAL: set PA_ALSA_PLUGHW BEFORE importing sounddevice (see findings.md §1).
"""
import os
os.environ.setdefault("PA_ALSA_PLUGHW", "1")

import asyncio
import queue
import signal
import sys
import threading
from pathlib import Path

import numpy as np
import sounddevice as sd  # safe to import now

from client.audio import (
    AudioStreams,
    FRAME_SAMPLES,
    resample_24k_to_16k,
)
from client.config import ConfigMissingError, load_config
from client.log import get_logger
from client.playback import PlaybackWorker
from client.session import Session
from client.state import StateMachine
from client.wakeword import WakewordDetector

_log = get_logger("main")

ASSISTANT_STATE_DIR = Path(os.environ["HOME"]) / "assistant" / "state"
WAKE_WAV = ASSISTANT_STATE_DIR / "wake.wav"
SLEEP_WAV = ASSISTANT_STATE_DIR / "sleep.wav"


def _build_bridge_thread(
    mic_queue: queue.Queue,
    sm: StateMachine,
    wakeword: WakewordDetector,
    session: Session,
    playback: PlaybackWorker,
    stop_event: threading.Event,
) -> threading.Thread:
    def run():
        while not stop_event.is_set():
            try:
                pcm16_bytes = mic_queue.get(timeout=0.25)
            except queue.Empty:
                continue
            if sm.wakeword_enabled:
                frame = np.frombuffer(pcm16_bytes, dtype=np.int16)
                if frame.size != FRAME_SAMPLES:
                    continue
                feed = resample_24k_to_16k(frame)
                if wakeword.predict(feed):
                    if sm.wake_fired():
                        if WAKE_WAV.exists():
                            playback.enqueue_wav(WAKE_WAV, "wake")
                        else:
                            # Even with no wav, fire the done marker so the
                            # playback_done(for=wake) envelope is sent.
                            playback.enqueue_done_marker("wake")
                        session.call_soon_threadsafe_send_wake()
            elif sm.uplink_enabled:
                session.call_soon_threadsafe_send_binary(pcm16_bytes)
            # else: ASSISTANT_SPEAKING / WAKE_PENDING / IDLE_PENDING -> drop
    t = threading.Thread(target=run, name="bridge", daemon=True)
    return t


def _make_callbacks(sm: StateMachine, playback: PlaybackWorker):
    class _CB:
        def on_session_started(self, conversation_id: str) -> None:
            _log.info("session_started conversation_id=%s", conversation_id)
            sm.session_started()

        def on_assistant_audio(self, pcm16: bytes) -> None:
            sm.assistant_audio_arrived()
            playback.enqueue_audio(pcm16)

        def on_assistant_done(self) -> None:
            _log.info("assistant_done")
            sm.assistant_done()

        def on_session_ended(self, reason: str) -> None:
            _log.info("session_ended reason=%s", reason)
            sm.session_ended()
            if SLEEP_WAV.exists():
                playback.enqueue_wav(SLEEP_WAV, "sleep")
            else:
                playback.enqueue_done_marker("sleep")
    return _CB()


def main() -> None:
    try:
        cfg = load_config()
    except ConfigMissingError as exc:
        raise SystemExit(str(exc)) from exc

    _log.info("device_id=%s backend=%s", cfg.device_id, cfg.backend_ws)

    mic_queue: queue.Queue = queue.Queue(maxsize=64)
    streams = AudioStreams.open(sd, mic_queue=mic_queue)
    streams.start()

    sm = StateMachine()

    session_ref: list[Session] = []

    def on_playback_done(label: str) -> None:
        _log.info("playback_done for=%s", label)
        if not session_ref:
            return
        session = session_ref[0]
        session.call_soon_threadsafe_send_playback_done(label)
        if label == "sleep":
            sm.sleep_played()

    playback = PlaybackWorker(streams, on_done=on_playback_done)
    playback.start()

    wakeword = WakewordDetector()

    callbacks = _make_callbacks(sm, playback)
    session = Session(
        backend_ws=cfg.backend_ws,
        device_token=cfg.device_token,
        device_id=cfg.device_id,
        callbacks=callbacks,
    )
    session_ref.append(session)

    def set_volume_handler(args: dict) -> dict:
        level = int(args.get("level", -1))
        playback.set_volume(level)
        return {"ok": True, "level": level}

    session.register_tool("set_volume", set_volume_handler)

    stop_event = threading.Event()
    bridge = _build_bridge_thread(mic_queue, sm, wakeword, session, playback, stop_event)
    bridge.start()

    def _shutdown(signum, _frame):
        _log.info("signal %d received; shutting down", signum)
        stop_event.set()
        try:
            playback.stop()
        finally:
            streams.close()
        sys.exit(0)

    signal.signal(signal.SIGTERM, _shutdown)
    signal.signal(signal.SIGINT, _shutdown)

    try:
        asyncio.run(session.run_forever())
    finally:
        stop_event.set()
        playback.stop()
        streams.close()


if __name__ == "__main__":
    main()