#!/usr/bin/env python3
"""Gera os tres efeitos sonoros do OpenSSN do fredygames.com (explosao, ping de sonar, lancamento de torpedo).

Os tres .ogg do pacote original nao tem origem registrada, entao o build os tira e usa estes, sintetizados aqui
(ruido filtrado e senoides, semente fixa: a saida e sempre a mesma). Dedicados ao dominio publico (CC0 1.0), como
as imagens e os dados do jogo.

Uso: python3 -I make-sounds.py <pasta-de-saida>
"""
import math
import random
import struct
import sys
import wave

RATE = 22050


def write(path, samples):
    peak = max(abs(x) for x in samples) or 1.0
    with wave.open(path, "wb") as w:
        w.setnchannels(1)
        w.setsampwidth(2)
        w.setframerate(RATE)
        w.writeframes(b"".join(struct.pack("<h", int(max(-1.0, min(1.0, x / peak * 0.85)) * 32767)) for x in samples))


def lowpass(xs, k):
    out, y = [], 0.0
    for x in xs:
        y += k * (x - y)
        out.append(y)
    return out


def explosion():
    rng = random.Random(1)
    n = int(RATE * 2.0)
    noise = [rng.uniform(-1, 1) for _ in range(n)]
    low = lowpass(lowpass(noise, 0.10), 0.20)
    mid = lowpass(noise, 0.45)
    out = []
    for i in range(n):
        t = i / RATE
        env = math.exp(-t * 2.6) * min(1.0, t * 400)
        thump = math.sin(2 * math.pi * (55 * math.exp(-t * 1.5)) * t) * math.exp(-t * 3.0)
        out.append((low[i] * 3.5 + mid[i] * 0.6 * math.exp(-t * 7)) * env + thump * 0.6)
    return out


def sonar_ping():
    n = int(RATE * 1.4)
    out = []
    for i in range(n):
        t = i / RATE
        s = 0.0
        for delay, gain in ((0.0, 1.0), (0.55, 0.35)):
            u = t - delay
            if u >= 0:
                s += gain * math.sin(2 * math.pi * 1250 * u) * math.exp(-u * 9) * min(1.0, u * 300)
        out.append(s)
    return out


def torpedo_launch():
    rng = random.Random(3)
    n = int(RATE * 1.6)
    noise = [rng.uniform(-1, 1) for _ in range(n)]
    out = []
    y = 0.0
    for i in range(n):
        t = i / RATE
        k = 0.04 + 0.30 * min(1.0, t / 0.5) * math.exp(-max(0.0, t - 0.5) * 1.5)
        y += k * (noise[i] - y)
        env = min(1.0, t * 60) * math.exp(-max(0.0, t - 0.35) * 2.2)
        thump = math.sin(2 * math.pi * 70 * t) * math.exp(-t * 14) * 1.2
        out.append(y * 3.0 * env + thump)
    return out


if __name__ == "__main__":
    d = sys.argv[1]
    write(d + "/explosion.wav", explosion())
    write(d + "/sonar-ping.wav", sonar_ping())
    write(d + "/torpedo-launch.wav", torpedo_launch())