"""Generate synthetic mechanical keyboard switch samples."""

import math
import struct
import wave
from pathlib import Path

SAMPLE_RATE = 48000
OUT_DIR = Path(__file__).resolve().parent.parent / "assets" / "samples"


def write_wav(path: Path, samples: list[float]) -> None:
    pcm = b"".join(
        struct.pack("<h", max(-32768, min(32767, int(s * 32767)))) for s in samples
    )
    with wave.open(str(path), "w") as wf:
        wf.setnchannels(1)
        wf.setsampwidth(2)
        wf.setframerate(SAMPLE_RATE)
        wf.writeframes(pcm)


def envelope(length: int, attack: float, decay: float) -> list[float]:
    env = []
    attack_samples = int(attack * SAMPLE_RATE)
    decay_samples = int(decay * SAMPLE_RATE)
    for i in range(length):
        if i < attack_samples:
            env.append(i / max(attack_samples, 1))
        elif i < attack_samples + decay_samples:
            t = (i - attack_samples) / max(decay_samples, 1)
            env.append(1.0 - t)
        else:
            env.append(0.0)
    return env


def generate_click(
    freq: float,
    duration: float,
    attack: float,
    decay: float,
    noise_mix: float = 0.0,
    click_burst: bool = False,
) -> list[float]:
    length = int(duration * SAMPLE_RATE)
    env = envelope(length, attack, decay)
    out = []
    for i in range(length):
        t = i / SAMPLE_RATE
        tone = math.sin(2 * math.pi * freq * t) * (0.7 if not click_burst else 0.4)
        if click_burst and t < 0.008:
            tone += math.sin(2 * math.pi * (freq * 2.8) * t) * 0.5
        noise = 0.0
        if noise_mix > 0:
            noise = (((i * 1103515245 + 12345) & 0x7FFFFFFF) / 0x7FFFFFFF - 0.5) * noise_mix
        out.append((tone + noise) * env[i])
    peak = max(abs(s) for s in out) or 1.0
    return [s / peak * 0.85 for s in out]


def main() -> None:
    OUT_DIR.mkdir(parents=True, exist_ok=True)

    profiles = {
        "cherry-mx-blue.wav": generate_click(
            2800, 0.09, 0.001, 0.085, noise_mix=0.15, click_burst=True
        ),
        "cherry-mx-red.wav": generate_click(
            1200, 0.05, 0.002, 0.045, noise_mix=0.08
        ),
        "cherry-mx-brown.wav": generate_click(
            1800, 0.07, 0.002, 0.065, noise_mix=0.12, click_burst=True
        ),
    }

    for name, samples in profiles.items():
        write_wav(OUT_DIR / name, samples)
        print(f"Wrote {OUT_DIR / name}")


if __name__ == "__main__":
    main()