#!/usr/bin/env python3
"""Generates the three sound effects of the FredyGames build of Blobby Volley 2.

The original bums.wav, pfiff.wav and chat.wav have no author or licence line in the repository, so this
build replaces them with sounds synthesised here from plain sine waves and a seeded noise generator.
They are original to the FredyGames build and released under CC0 1.0 (public domain).

  python3 -I make-sounds.py <output-dir>

Output is deterministic: 16-bit mono PCM, 44100 Hz.
"""
import math
import random
import struct
import sys
import wave

RATE = 44100


def write(path, samples):
    with wave.open(path, "wb") as w:
        w.setnchannels(1)
        w.setsampwidth(2)
        w.setframerate(RATE)
        w.writeframes(b"".join(struct.pack("<h", max(-32767, min(32767, int(s * 32767)))) for s in samples))


def bums():
    """Ball impact: a low thump that falls in pitch, with a short burst of noise at the start."""
    rng = random.Random(1)
    n = int(RATE * 0.22)
    out = []
    phase = 0.0
    for i in range(n):
        t = i / RATE
        freq = 70 + 130 * math.exp(-t * 28)
        phase += 2 * math.pi * freq / RATE
        env = math.exp(-t * 17)
        noise = (rng.random() * 2 - 1) * math.exp(-t * 90) * 0.5
        out.append(0.85 * env * math.sin(phase) + noise)
    return out


def pfiff():
    """Referee whistle: a 2.6 kHz tone with fast vibrato and a little breath noise."""
    rng = random.Random(2)
    n = int(RATE * 0.45)
    out = []
    phase = 0.0
    for i in range(n):
        t = i / RATE
        freq = 2600 + 120 * math.sin(2 * math.pi * 38 * t)
        phase += 2 * math.pi * freq / RATE
        env = min(1.0, t / 0.015) * min(1.0, (n - i) / (RATE * 0.06))
        tone = 0.5 * math.sin(phase) + 0.15 * math.sin(2 * phase)
        out.append(env * (tone + 0.06 * (rng.random() * 2 - 1)))
    return out


def chat():
    """Message blip: two short rising notes."""
    out = []
    for freq, length in ((880.0, 0.07), (1318.5, 0.11)):
        n = int(RATE * length)
        for i in range(n):
            t = i / RATE
            env = min(1.0, t / 0.005) * math.exp(-t * 18)
            out.append(0.6 * env * math.sin(2 * math.pi * freq * t))
    return out


if __name__ == "__main__":
    d = sys.argv[1]
    write(d + "/bums.wav", bums())
    write(d + "/pfiff.wav", pfiff())
    write(d + "/chat.wav", chat())