#!/usr/bin/env python3
"""
tone_server.py — Sine-wave tone HTTP server for iMX8 audio test rig.
Target: iMX8 Debian Bookworm.

  pip3 install flask numpy pyaudio   (pyaudio already installed)

Endpoints
---------
POST /play   { "freq": 1000, "vol": 0.8, "duration": 1.0 }
POST /stop
GET  /status
"""

import math
import subprocess
import threading

import numpy as np
import pyaudio
from flask import Flask, jsonify, request

# ── ALSA routing (SGTL5000 on iMX8) ──────────────────────────────────────────
def _alsa_init():
    for cmd in [
        ['amixer', '-c', '0', 'sset', 'Headphone Mux', 'DAC'],
        ['amixer', '-c', '0', 'sset', 'DAP Mux',       'I2S'],
        ['amixer', '-c', '0', 'sset', 'Headphone',     'unmute'],
        ['amixer', '-c', '0', 'sset', 'Lineout',       'unmute'],
    ]:
        try:
            subprocess.run(cmd, capture_output=True, timeout=2)
        except Exception:
            pass

# ── Audio ─────────────────────────────────────────────────────────────────────
SAMPLE_RATE  = 44100
BLOCK_FRAMES = 512

_pa   = pyaudio.PyAudio()
_lock = threading.Lock()
_state = {
    'stream': None,
    'timer':  None,
    'freq':   1000.0,
    'vol':    0.0,
    'phase':  0,
}


def _callback(in_data, frame_count, time_info, status):
    freq  = _state['freq']
    vol   = _state['vol']
    phase = _state['phase']
    t     = (np.arange(frame_count, dtype=np.float64) + phase) / SAMPLE_RATE
    buf   = (vol * np.sin(2.0 * math.pi * freq * t) * 32767).astype(np.int16)
    _state['phase'] = (phase + frame_count) % (SAMPLE_RATE * 100)
    return (buf.tobytes(), pyaudio.paContinue)


def _do_stop():
    """Stop active stream and cancel auto-stop timer. Call with _lock held."""
    t = _state['timer']
    s = _state['stream']
    _state['timer']  = None
    _state['stream'] = None
    if t:
        t.cancel()
    if s:
        try:
            s.stop_stream()
            s.close()
        except Exception:
            pass


def _timer_stop():
    with _lock:
        _do_stop()


# ── Flask app ─────────────────────────────────────────────────────────────────
app = Flask(__name__)


@app.route('/play', methods=['POST'])
def play():
    body     = request.get_json(force=True) or {}
    freq     = float(body.get('freq',     1000.0))
    vol      = max(0.0, min(1.0, float(body.get('vol',      0.8))))
    duration = max(0.05,         float(body.get('duration', 1.0)))

    with _lock:
        _do_stop()
        _state['freq']  = freq
        _state['vol']   = vol
        _state['phase'] = 0

        s = _pa.open(
            rate=SAMPLE_RATE,
            channels=1,
            format=pyaudio.paInt16,
            output=True,
            frames_per_buffer=BLOCK_FRAMES,
            stream_callback=_callback,
        )
        s.start_stream()
        _state['stream'] = s

        t = threading.Timer(duration, _timer_stop)
        _state['timer'] = t
        t.start()

    print(f"[play] {freq:.0f} Hz  vol={vol:.2f}  dur={duration:.2f}s")
    return jsonify({'status': 'ok', 'freq': freq, 'vol': vol, 'duration': duration})


@app.route('/stop', methods=['POST'])
def stop():
    with _lock:
        _do_stop()
    print("[stop]")
    return jsonify({'status': 'ok'})


@app.route('/status', methods=['GET'])
def status():
    with _lock:
        playing = _state['stream'] is not None
    return jsonify({'playing': playing, 'freq': _state['freq'], 'vol': _state['vol']})


if __name__ == '__main__':
    _alsa_init()
    print("Tone server starting on 0.0.0.0:5000")
    try:
        app.run(host='0.0.0.0', port=5000, threaded=True)
    finally:
        with _lock:
            _do_stop()
        _pa.terminate()