"""Audio playback, fan control, and PipeWire sink management for the wake alarm."""

from __future__ import annotations

import logging
import math
import os
from pathlib import Path
import shutil
import struct
import subprocess
import sys
import tempfile
import time
import wave

from python_pkg.wake_alarm._constants import (
    ALARM_AUDIO_CARD,
    ALARM_AUDIO_PROFILE,
    ALARM_AUDIO_SINK,
    ALARM_AUDIO_SINK_POLL_SECONDS,
    ALARM_AUDIO_SINK_WAIT_SECONDS,
)

_logger = logging.getLogger(__name__)

_TONE_CACHE: dict[int, Path] = {}
_TONE_TIMEOUT_SECONDS: float = 6.0
_TONE_DURATION_SECONDS: float = 1.5
_TONE_FRAMERATE: int = 48000
_TONE_AMPLITUDE: int = 32760  # near s16 max for the loudest sine we can emit

# Number of back-to-back PC-speaker beeps per _play_tone call.
# pcspkr volume is hardware-fixed, so we lean on repetition + duration to be
# loud enough to actually wake the user.
_PCSPKR_REPEATS: int = 3
_PCSPKR_GAP_SECONDS: float = 0.12

# Motherboard PC speaker exposed by the pcspkr kernel module.
# Writing EV_SND/SND_TONE input_event structs makes it beep — bypasses
# PipeWire/ALSA entirely, so it stays audible even when no real sink exists.
_PCSPKR_DEVICE: str = "/dev/input/by-path/platform-pcspkr-event-spkr"
_PCSPKR_EV_SND: int = 0x12
_PCSPKR_SND_TONE: int = 0x02
# struct input_event: timeval (long sec, long usec), u16 type, u16 code, s32 val
_PCSPKR_EVENT_FMT: str = "llHHi"

# Extra PipeWire sinks to always play alarm audio on (alongside the default).
# alsa_output...hdmi-stereo = GA102 → G27Q (has built-in speaker, always on).
_EXTRA_PIPEWIRE_SINKS: tuple[str, ...] = ("alsa_output.pci-0000_01_00.1.hdmi-stereo",)

# NCT Super I/O chip names that expose a single pwm1 fan control channel.
_NCT_CHIP_NAMES: frozenset[str] = frozenset(
    {
        "nct6775",
        "nct6779",
        "nct6791",
        "nct6792",
        "nct6793",
        "nct6795",
        "nct6796",
        "nct6797",
        "nct6798",
        "nct6799",
    }
)

# Installed by install.sh, controlled via sudoers NOPASSWD entry.
_FAN_SCRIPT: str = "/usr/local/bin/wake-alarm-fans.sh"
_SUDO_BIN: str = "/usr/bin/sudo"


def _beep_soft() -> None:
    """Play a soft system beep via terminal bell."""
    sys.stdout.write("\a")
    sys.stdout.flush()


def _speaker_test_path() -> str:
    """Resolve absolute path to speaker-test binary."""
    path = shutil.which("speaker-test")
    if path is None:
        msg = "speaker-test not found on PATH"
        raise FileNotFoundError(msg)
    return path


def _beep_pcspkr(frequency: int, duration_seconds: float) -> None:
    """Beep the motherboard PC speaker via evdev (audible without any sink).

    Silently no-ops when the device is missing or unwritable so the call is
    always safe from the alarm hot path.
    """
    try:
        # buffering=0 so the write hits the device immediately.
        with Path(_PCSPKR_DEVICE).open("wb", buffering=0) as dev:
            dev.write(
                struct.pack(
                    _PCSPKR_EVENT_FMT,
                    0,
                    0,
                    _PCSPKR_EV_SND,
                    _PCSPKR_SND_TONE,
                    int(frequency),
                ),
            )
            time.sleep(duration_seconds)
            dev.write(
                struct.pack(
                    _PCSPKR_EVENT_FMT,
                    0,
                    0,
                    _PCSPKR_EV_SND,
                    _PCSPKR_SND_TONE,
                    0,
                ),
            )
    except OSError:
        _logger.warning(
            "PC speaker beep at %d Hz failed (device %s)",
            frequency,
            _PCSPKR_DEVICE,
            exc_info=True,
        )


def _ensure_tone_wav(frequency: int) -> Path:
    """Generate (and cache) a mono 48 kHz sine WAV at *frequency* Hz."""
    cached = _TONE_CACHE.get(frequency)
    if cached is not None and cached.exists():
        return cached
    path = Path(tempfile.gettempdir()) / f"wake_alarm_tone_{frequency}.wav"
    n_frames = int(_TONE_FRAMERATE * _TONE_DURATION_SECONDS)
    with wave.open(str(path), "wb") as wav:
        wav.setnchannels(1)
        wav.setsampwidth(2)
        wav.setframerate(_TONE_FRAMERATE)
        frames = bytearray()
        for i in range(n_frames):
            sample = int(
                _TONE_AMPLITUDE
                * math.sin(2 * math.pi * frequency * i / _TONE_FRAMERATE),
            )
            frames.extend(struct.pack("<h", sample))
        wav.writeframesraw(bytes(frames))
    _TONE_CACHE[frequency] = path
    return path


def _try_player(binary: str, wav: Path) -> bool:
    """Run *binary* on *wav* with a generous timeout. Return True on success."""
    path = shutil.which(binary)
    if path is None:
        return False
    try:
        result = subprocess.run(
            [path, str(wav)],
            capture_output=True,
            timeout=_TONE_TIMEOUT_SECONDS,
            check=False,
        )
    except (OSError, subprocess.TimeoutExpired):
        _logger.warning("%s failed playing %s", binary, wav.name, exc_info=True)
        return False
    if result.returncode != 0:
        _logger.warning(
            "%s exited %d for %s: %s",
            binary,
            result.returncode,
            wav.name,
            result.stderr.decode(errors="replace").strip()[:200],
        )
        return False
    return True


def _play_tone(frequency: int) -> None:
    """Play a sine tone via paplay/aplay/speaker-test, fall back to soft beep.

    Always also beeps the motherboard PC speaker (multiple times) so the
    alarm stays loud and audible even when PipeWire only has the auto_null
    sink.
    """
    for i in range(_PCSPKR_REPEATS):
        _beep_pcspkr(frequency, _TONE_DURATION_SECONDS)
        if i < _PCSPKR_REPEATS - 1:
            time.sleep(_PCSPKR_GAP_SECONDS)
    try:
        wav = _ensure_tone_wav(frequency)
    except OSError:
        _logger.warning(
            "Could not generate tone WAV at %d Hz; using soft beep",
            frequency,
            exc_info=True,
        )
        _beep_soft()
        return
    for binary in ("paplay", "aplay"):
        if _try_player(binary, wav):
            return
    try:
        subprocess.run(
            [
                _speaker_test_path(),
                "-t",
                "sine",
                "-f",
                str(frequency),
                "-l",
                "1",
            ],
            capture_output=True,
            timeout=_TONE_TIMEOUT_SECONDS,
            check=False,
        )
    except (FileNotFoundError, OSError, subprocess.TimeoutExpired):
        _logger.warning(
            "All tone players failed at %d Hz; falling back to soft beep",
            frequency,
            exc_info=True,
        )
        _beep_soft()


def _play_on_extra_devices(frequency: int) -> None:
    """Fire-and-forget: play a sine tone on each extra PipeWire sink."""
    try:
        path = _speaker_test_path()
    except FileNotFoundError:
        _logger.warning("speaker-test missing; skipping extra-device beep")
        return
    for sink in _EXTRA_PIPEWIRE_SINKS:
        _play_tone_on_sink(path, sink, frequency)


def _play_tone_on_sink(path: str, sink: str, frequency: int) -> None:
    """Launch speaker-test for *sink*; log a warning on OSError."""
    try:
        subprocess.Popen(
            [path, "-t", "sine", "-f", str(frequency), "-l", "1"],
            env={**os.environ, "PIPEWIRE_NODE": sink},
            stdout=subprocess.DEVNULL,
            stderr=subprocess.DEVNULL,
        )
    except OSError:
        _logger.warning("Failed to play tone on sink %s", sink, exc_info=True)


def _find_fan_hwmon() -> str | None:
    """Return the hwmon directory for an NCT fan controller, or None."""
    for name_path in Path("/sys/class/hwmon").glob("hwmon*/name"):
        try:
            chip = name_path.read_text().strip()
        except OSError:
            _logger.warning("Could not read %s", name_path, exc_info=True)
            continue
        if chip in _NCT_CHIP_NAMES:
            return str(name_path.parent)
    _logger.warning(
        "No NCT super-I/O hwmon entry found; fan ramp will be skipped",
    )
    return None


def _max_fans() -> bool:
    """Ramp every NCT pwm channel to 100% speed via the helper script.

    The helper records prior state under /run/wake-alarm-fans.state so
    _restore_fans() can put things back without arguments. Safe: higher fan
    speed only lowers temperatures, never damages hardware.

    Returns:
        True when the ramp script ran successfully, False otherwise.
    """
    if _find_fan_hwmon() is None:
        return False
    try:
        result = subprocess.run(
            [_SUDO_BIN, "-n", _FAN_SCRIPT, "max"],
            check=False,
            capture_output=True,
            timeout=5,
        )
    except (OSError, subprocess.TimeoutExpired):
        _logger.warning(
            "Fan script %s not runnable; skipping fan ramp",
            _FAN_SCRIPT,
            exc_info=True,
        )
        return False
    if result.returncode != 0:
        _logger.warning(
            "Fan script %s exited %d: %s",
            _FAN_SCRIPT,
            result.returncode,
            result.stderr.decode(errors="replace").strip(),
        )
        return False
    return True


def _restore_fans(*, active: bool) -> None:
    """Restore fan speed if _max_fans() previously succeeded."""
    if not active:
        return
    try:
        subprocess.run(
            [_SUDO_BIN, "-n", _FAN_SCRIPT, "restore"],
            check=False,
            capture_output=True,
            timeout=5,
        )
    except (OSError, subprocess.TimeoutExpired):
        _logger.warning(
            "Failed to restore fan state via %s",
            _FAN_SCRIPT,
            exc_info=True,
        )


def _set_max_brightness() -> None:
    """Set all connected monitors to maximum brightness via xrandr."""
    xrandr = shutil.which("xrandr")
    if xrandr is None:
        _logger.warning("xrandr not on PATH; skipping max-brightness")
        return
    try:
        result = subprocess.run(
            [xrandr, "--query"],
            capture_output=True,
            text=True,
            timeout=5,
            check=False,
        )
    except (OSError, subprocess.TimeoutExpired):
        _logger.warning("xrandr --query failed; skipping max-brightness", exc_info=True)
        return
    for line in result.stdout.splitlines():
        if " connected" in line:
            output = line.split()[0]
            try:
                subprocess.run(
                    [xrandr, "--output", output, "--brightness", "1.0"],
                    check=False,
                    capture_output=True,
                    timeout=5,
                )
            except (OSError, subprocess.TimeoutExpired):
                _logger.warning(
                    "Failed to set brightness on %s",
                    output,
                    exc_info=True,
                )


def _beep_medium(frequency: int = 1000) -> None:
    """Play a medium beep (sine tone via paplay/aplay/speaker-test)."""
    _play_tone(frequency)


def _beep_loud(frequency: int = 1000) -> None:
    """Play a loud sine tone via paplay/aplay/speaker-test."""
    _play_tone(frequency)


def _pactl_path() -> str | None:
    """Return the absolute path to pactl, or None when not installed."""
    return shutil.which("pactl")


def _alarm_sink_present(pactl: str) -> bool:
    """Return True when the dedicated alarm HDMI sink exists in PipeWire."""
    try:
        result = subprocess.run(
            [pactl, "list", "short", "sinks"],
            capture_output=True,
            timeout=3,
            check=False,
        )
    except (OSError, subprocess.TimeoutExpired):
        _logger.warning("pactl list sinks failed", exc_info=True)
        return False
    return ALARM_AUDIO_SINK in result.stdout.decode(errors="replace")


def _current_default_sink(pactl: str) -> str | None:
    """Return the current default sink name, or None on failure / empty."""
    try:
        result = subprocess.run(
            [pactl, "get-default-sink"],
            capture_output=True,
            timeout=3,
            check=False,
        )
    except (OSError, subprocess.TimeoutExpired):
        _logger.warning("pactl get-default-sink failed", exc_info=True)
        return None
    name = result.stdout.decode(errors="replace").strip()
    return name or None


def _activate_alarm_audio() -> str | None:
    """Force the monitor's HDMI output on and route the alarm to it.

    At wake time the Bluetooth speaker is disconnected and PipeWire only has the
    ``auto_null`` sink, so the alarm is silent. This forces the HDMI card
    profile on, waits for its sink to appear, makes it the default sink, and
    raises it to full volume - empirically the only output audible on this
    machine at wake time (the G27Q monitor's built-in speaker).

    Returns:
        The previous default sink name (to restore on close), or ``None`` when
        the alarm audio sink could not be activated.
    """
    pactl = _pactl_path()
    if pactl is None:
        _logger.warning("pactl not on PATH; cannot activate alarm audio")
        return None
    subprocess.run(
        [pactl, "set-card-profile", ALARM_AUDIO_CARD, ALARM_AUDIO_PROFILE],
        capture_output=True,
        timeout=3,
        check=False,
    )
    attempts = max(
        1,
        int(ALARM_AUDIO_SINK_WAIT_SECONDS / ALARM_AUDIO_SINK_POLL_SECONDS),
    )
    for _ in range(attempts):
        if _alarm_sink_present(pactl):
            break
        time.sleep(ALARM_AUDIO_SINK_POLL_SECONDS)
    else:
        _logger.warning(
            "Alarm audio sink %s did not appear after %.0fs; alarm may be silent",
            ALARM_AUDIO_SINK,
            ALARM_AUDIO_SINK_WAIT_SECONDS,
        )
        return None
    old_default = _current_default_sink(pactl)
    for cmd in (
        [pactl, "set-default-sink", ALARM_AUDIO_SINK],
        [pactl, "set-sink-mute", ALARM_AUDIO_SINK, "0"],
        [pactl, "set-sink-volume", ALARM_AUDIO_SINK, "100%"],
    ):
        subprocess.run(cmd, capture_output=True, timeout=3, check=False)
    _logger.warning("Alarm audio routed to %s at 100%%", ALARM_AUDIO_SINK)
    return old_default


def _restore_alarm_audio(old_default: str | None) -> None:
    """Restore the default sink captured by :func:`_activate_alarm_audio`."""
    if old_default is None:
        return
    pactl = _pactl_path()
    if pactl is None:
        return
    subprocess.run(
        [pactl, "set-default-sink", old_default],
        capture_output=True,
        timeout=3,
        check=False,
    )


def _warn_if_no_real_sink() -> None:
    """Log a loud warning if PipeWire only has the auto_null sink."""
    pactl = _pactl_path()
    if pactl is None:
        _logger.warning("pactl not on PATH; cannot verify audio sinks")
        return
    try:
        result = subprocess.run(
            [pactl, "list", "short", "sinks"],
            capture_output=True,
            timeout=5,
            check=False,
        )
    except (OSError, subprocess.TimeoutExpired):
        _logger.warning("pactl list sinks failed", exc_info=True)
        return
    sinks_text = result.stdout.decode(errors="replace").strip()
    sink_names = [
        line.split("\t")[1] for line in sinks_text.splitlines() if "\t" in line
    ]
    real_sinks = [s for s in sink_names if s != "auto_null"]
    if not real_sinks:
        _logger.warning(
            "ONLY auto_null PipeWire sink available — alarm will be SILENT. Sinks: %s",
            sink_names or "<none>",
        )
    else:
        _logger.info("Audio sinks available: %s", sink_names)