"""Render lintunes/sounds/tink.wav — the quiet "done" chime.

A bell-ish 1.6 kHz partial with a softer inharmonic overtone, a 3 ms attack
(no click) and a fast exponential decay. Run once; the WAV is committed.

    python3 scripts/make_tink.py
"""
import wave
from pathlib import Path

import numpy as np

RATE = 44100
LENGTH = 0.35          # seconds; the decay is inaudible well before this
PEAK_DBFS = -18.0


def render() -> np.ndarray:
    t = np.arange(int(RATE * LENGTH)) / RATE
    tone = (np.sin(2 * np.pi * 1600 * t)
            + 0.35 * np.sin(2 * np.pi * 1600 * 2.76 * t) * np.exp(-t * 40))
    envelope = np.exp(-t * 18) * np.minimum(t / 0.003, 1.0)
    signal = tone * envelope
    signal /= np.abs(signal).max()
    return signal * 10 ** (PEAK_DBFS / 20)


def main():
    out = Path(__file__).resolve().parent.parent / "lintunes" / "sounds" / "tink.wav"
    out.parent.mkdir(parents=True, exist_ok=True)
    pcm = (render() * 32767).astype("<i2")
    with wave.open(str(out), "wb") as f:
        f.setnchannels(1)
        f.setsampwidth(2)
        f.setframerate(RATE)
        f.writeframes(pcm.tobytes())
    print(out)


if __name__ == "__main__":
    main()