#!/usr/bin/env python3
"""Live beat detection utility with custom/aubio/hybrid modes."""

from __future__ import annotations

import argparse
import collections
import queue
import sys
import time
from typing import Deque

try:
    import numpy as np
except ImportError as exc:
    raise SystemExit(
        "Missing dependency: numpy. Install with `pip install numpy`."
    ) from exc

try:
    import sounddevice as sd
except ImportError as exc:
    raise SystemExit(
        "Missing dependency: sounddevice. Install with `pip install sounddevice`."
    ) from exc

try:
    import requests
except ImportError:
    requests = None


def parse_args() -> argparse.Namespace:
    parser = argparse.ArgumentParser(description="Beat detector utility")
    parser.add_argument(
        "--mode",
        choices=("custom", "aubio", "hybrid"),
        default="aubio",
        help="Detection mode",
    )
    parser.add_argument("--device", default=None, help="Input device name or index")
    parser.add_argument(
        "--sample-rate",
        type=int,
        default=0,
        help="Audio sample rate (0 = use selected device default)",
    )
    parser.add_argument("--hop-size", type=int, default=256, help="Frame hop size in samples")
    parser.add_argument("--win-mult", type=int, default=2, help="Aubio window size multiplier")
    parser.add_argument(
        "--min-band-hz",
        type=float,
        default=45.0,
        help="Low frequency bound used for beat energy",
    )
    parser.add_argument(
        "--max-band-hz",
        type=float,
        default=180.0,
        help="High frequency bound used for beat energy",
    )
    parser.add_argument(
        "--energy-weight",
        type=float,
        default=0.7,
        help="Weight for low-band energy component (0..1)",
    )
    parser.add_argument(
        "--flux-weight",
        type=float,
        default=0.3,
        help="Weight for spectral flux component (0..1)",
    )
    parser.add_argument(
        "--threshold-multiplier",
        type=float,
        default=1.35,
        help="Custom-mode threshold multiplier vs adaptive baseline",
    )
    parser.add_argument(
        "--ema-alpha",
        type=float,
        default=0.08,
        help="Adaptive baseline smoothing (higher reacts faster)",
    )
    parser.add_argument(
        "--min-ioi-ms",
        type=float,
        default=85.0,
        help="Minimum time between beats in milliseconds",
    )
    parser.add_argument(
        "--bpm-window",
        type=int,
        default=8,
        help="How many recent beat intervals to use for BPM estimate",
    )
    parser.add_argument(
        "--post-url",
        default="",
        help="Optional HTTP URL to POST beat events",
    )
    parser.add_argument(
        "--aubio-method",
        default="default",
        choices=("default", "specdiff", "hfc", "complex", "phase", "energy"),
        help="Aubio tempo method",
    )
    parser.add_argument(
        "--aubio-threshold",
        type=float,
        default=0.12,
        help="Aubio detection threshold",
    )
    parser.add_argument(
        "--silence-gate-db",
        type=float,
        default=-58.0,
        help="Ignore beat triggers when frame RMS is below this dB level",
    )
    return parser.parse_args()


def _estimate_bpm(beat_times: Deque[float]) -> float | None:
    if len(beat_times) < 3:
        return None
    intervals = np.diff(np.array(beat_times, dtype=np.float64))
    valid = intervals[(intervals > 0.2) & (intervals < 2.0)]
    if valid.size == 0:
        return None
    return 60.0 / float(np.median(valid))


def _load_aubio_if_needed(mode: str):
    if mode == "custom":
        return None
    try:
        import aubio
        return aubio
    except ImportError:
        dist_packages = "/usr/lib/python3/dist-packages"
        if dist_packages not in sys.path:
            sys.path.append(dist_packages)
        try:
            import aubio
            return aubio
        except ImportError:
            raise SystemExit("aubio not installed; use --mode custom or install aubio")


class BeatDetectRuntime:
    """Reusable detector runtime so web and CLI can share logic."""

    def __init__(self, args):
        self.args = args
        self.aubio = _load_aubio_if_needed(args.mode)
        self.sample_rate = 0
        self.frame_size = 0
        self.tempo = None
        self.band_mask = None
        self.freqs = None
        self.window = None
        self.prev_mag = None
        self.kick_mask = None
        self.snare_mask = None
        self.hat_mask = None
        self.baseline = 1e-6
        self.beat_times: Deque[float] = collections.deque(
            maxlen=max(2, args.bpm_window + 1)
        )
        self.last_trigger_s = 0.0
        self.debounce_s = float(args.min_ioi_ms) / 1000.0

    def setup(self, sample_rate: int):
        self.sample_rate = int(sample_rate)
        self.frame_size = max(128, int(self.args.hop_size))
        win_size = max(1024, self.frame_size * max(2, self.args.win_mult))
        freqs = np.fft.rfftfreq(self.frame_size, d=1.0 / self.sample_rate)
        self.freqs = freqs
        self.band_mask = (freqs >= self.args.min_band_hz) & (
            freqs <= self.args.max_band_hz
        )
        self.kick_mask = (freqs >= 40.0) & (freqs <= 140.0)
        self.snare_mask = (freqs >= 140.0) & (freqs <= 3000.0)
        self.hat_mask = (freqs >= 5000.0) & (freqs <= 12000.0)
        if not np.any(self.band_mask):
            raise ValueError("Invalid band range for current sample rate")
        self.window = np.hanning(self.frame_size).astype(np.float32)
        self.prev_mag = np.zeros(freqs.shape[0], dtype=np.float32)
        self.baseline = 1e-6
        self.last_trigger_s = 0.0
        self.beat_times.clear()
        self.tempo = None
        if self.aubio is not None:
            self.tempo = self.aubio.tempo(
                self.args.aubio_method, win_size, self.frame_size, self.sample_rate
            )
            if hasattr(self.tempo, "set_threshold"):
                self.tempo.set_threshold(float(self.args.aubio_threshold))
            if hasattr(self.tempo, "set_minioi_ms"):
                self.tempo.set_minioi_ms(float(self.args.min_ioi_ms))

    def _classify_hit(self, mag: np.ndarray):
        total = float(np.mean(mag) + 1e-9)
        kick = float(np.mean(mag[self.kick_mask])) / total if np.any(self.kick_mask) else 0.0
        snare = float(np.mean(mag[self.snare_mask])) / total if np.any(self.snare_mask) else 0.0
        hat = float(np.mean(mag[self.hat_mask])) / total if np.any(self.hat_mask) else 0.0
        scores = {
            "kick": kick,
            "snare": snare,
            "hat": hat,
        }
        label, value = max(scores.items(), key=lambda kv: kv[1])
        if value < 1.15:
            return "unknown", value
        return label, value

    def process_frame(self, frame: np.ndarray, now_s: float | None = None):
        if self.window is None or self.band_mask is None:
            raise RuntimeError("Runtime not setup")
        if frame.shape[0] != self.frame_size:
            if frame.shape[0] > self.frame_size:
                frame = frame[: self.frame_size]
            else:
                frame = np.pad(frame, (0, self.frame_size - frame.shape[0]))

        f32 = frame.astype(np.float32)
        rms = float(np.sqrt(np.mean(f32 * f32) + 1e-12))
        db = 20.0 * np.log10(max(rms, 1e-12))
        if db < float(self.args.silence_gate_db):
            return None
        mag = np.abs(np.fft.rfft(f32 * self.window)).astype(np.float32)
        band_energy = float(np.mean(mag[self.band_mask]))
        flux = float(np.mean(np.maximum(0.0, mag - self.prev_mag)))
        self.prev_mag[:] = mag

        weight_sum = max(1e-6, self.args.energy_weight + self.args.flux_weight)
        score = ((self.args.energy_weight * band_energy) + (self.args.flux_weight * flux)) / weight_sum
        self.baseline = ((1.0 - self.args.ema_alpha) * self.baseline) + (
            self.args.ema_alpha * score
        )
        threshold = self.baseline * self.args.threshold_multiplier
        custom_hit = score > threshold

        aubio_hit = False
        aubio_bpm = None
        if self.tempo is not None:
            aubio_hit = bool(self.tempo(f32)[0])
            val = float(self.tempo.get_bpm())
            aubio_bpm = val if val > 0 else None

        if now_s is None:
            now_s = time.time()
        if (now_s - self.last_trigger_s) < self.debounce_s:
            return None

        if self.args.mode == "custom":
            should_trigger = custom_hit
        elif self.args.mode == "aubio":
            should_trigger = aubio_hit
        else:
            should_trigger = custom_hit or aubio_hit
        if not should_trigger:
            return None

        self.last_trigger_s = now_s
        self.beat_times.append(now_s)
        bpm = aubio_bpm if aubio_bpm is not None else _estimate_bpm(self.beat_times)
        strength = score / max(1e-9, self.baseline)
        beat_type, beat_type_conf = self._classify_hit(mag)
        if self.args.mode == "custom":
            src = "custom"
        elif self.args.mode == "aubio":
            src = "aubio"
        elif custom_hit and aubio_hit:
            src = "both"
        elif custom_hit:
            src = "custom"
        else:
            src = "aubio"
        return {
            "ts": now_s,
            "bpm": bpm,
            "src": src,
            "score": score,
            "threshold": threshold,
            "strength": strength,
            "beat_type": beat_type,
            "beat_type_confidence": beat_type_conf,
            "db": db,
        }


def main() -> int:
    args = parse_args()
    runtime = BeatDetectRuntime(args)

    if args.post_url and requests is None:
        raise SystemExit("`requests` is required for --post-url (pip install requests)")

    if args.sample_rate > 0:
        sample_rate = args.sample_rate
    else:
        dev_info = sd.query_devices(args.device, "input")
        sample_rate = int(dev_info["default_samplerate"])

    runtime.setup(sample_rate=sample_rate)
    frame_size = runtime.frame_size
    audio_q: "queue.Queue[np.ndarray]" = queue.Queue(maxsize=64)

    def audio_callback(indata, frames, _time_info, status):
        _ = frames
        if status:
            print(f"audio status: {status}")
        mono = np.asarray(indata[:, 0], dtype=np.float32)
        if not audio_q.full():
            audio_q.put_nowait(mono)

    print(
        "Listening... Ctrl+C to stop. "
        f"mode={args.mode} sr={sample_rate} hop={frame_size} "
        f"band={args.min_band_hz:.0f}-{args.max_band_hz:.0f}Hz "
        f"custom_th={args.threshold_multiplier:.2f} aubio_th={args.aubio_threshold:.2f} "
        f"min_ioi={args.min_ioi_ms:.0f}ms"
    )

    with sd.InputStream(
        device=args.device,
        channels=1,
        samplerate=sample_rate,
        blocksize=frame_size,
        callback=audio_callback,
    ):
        try:
            while True:
                try:
                    frame = audio_q.get(timeout=0.1)
                except queue.Empty:
                    continue
                if frame.shape[0] != frame_size:
                    if frame.shape[0] > frame_size:
                        frame = frame[:frame_size]
                    else:
                        frame = np.pad(frame, (0, frame_size - frame.shape[0]))

                event = runtime.process_frame(frame, now_s=time.time())
                if event is None:
                    continue
                now_s = event["ts"]
                bpm = event["bpm"]
                bpm_text = f"{bpm:.1f}" if isinstance(bpm, (float, int)) else "--"
                src = event["src"]
                print(
                    f"[{args.mode}] BEAT bpm={bpm_text} src={src} type={event['beat_type']} "
                    f"type_conf={event['beat_type_confidence']:.2f} strength={event['strength']:.2f} "
                    f"db={event['db']:.1f} "
                    f"score={event['score']:.3e} threshold={event['threshold']:.3e}"
                )

                if args.post_url and requests is not None:
                    try:
                        requests.post(
                            args.post_url,
                            json={"beat": True, "source": src, "ts": now_s, "bpm": bpm},
                            timeout=0.5,
                        )
                    except Exception as exc:
                        print(f"post failed: {exc}")
        except KeyboardInterrupt:
            print("\nStopped.")
    return 0


if __name__ == "__main__":
    raise SystemExit(main())