"""lib/alarm-sounds.py: put in ~/.local/share/wren by parts/core-commands.sh.
Makes the sounds timer can ring with (timer sound lets you hear and choose them), from
nothing but arithmetic, so each can be read here and nothing comes from anywhere else.
    python3 -I alarm-sounds.py list         their names
    python3 -I alarm-sounds.py make DIR     writes DIR/NAME.wav for each (mono, 16-bit, 8 seconds)"""
import math
import os
import struct
import sys
import tempfile
import wave

RATE = 16000
SECONDS = 8.0
TWO_PI = 2 * math.pi

# A note, in Hz
C5, E5, G5, C6, E6, G6 = 523.25, 659.25, 783.99, 1046.50, 1318.51, 1567.98


def tone(buf, start, length, freq, volume=0.3, decay=3.0, attack=0.01, harmonics=((1, 1.0), (2, 0.2), (3, 0.08)), slide=0.0):
    """Adds one note to buf. decay: how fast it fades. slide: Hz per second it glides by.
    The phase is summed as it goes, so a glide stays smooth."""
    first = int(start * RATE)
    count = min(int(length * RATE), len(buf) - first)
    phase = 0.0
    for i in range(max(0, count)):
        t = i / RATE
        phase += TWO_PI * (freq + slide * t) / RATE
        envelope = min(1.0, t / attack) * math.exp(-decay * t)
        # no click at the end of a note
        envelope *= min(1.0, (length - t) / 0.01)
        buf[first + i] += volume * envelope * sum(a * math.sin(h * phase) for h, a in harmonics)


def chimes(buf):
    """Slow, soft and wide apart, like wind chimes: for waking gently."""
    for start, freq in [(0, C6), (0.9, G5), (1.8, E6), (2.7, C6), (4.2, G6), (5.1, E6), (6.0, C6)]:
        tone(buf, start, 1.9, freq, volume=0.26, decay=1.6, harmonics=((1, 1.0), (2.76, 0.25), (5.4, 0.08)))


def wren(buf):
    """A small bird's quick falling trills, this project's namesake. Not any real recording."""
    for phrase in (0.2, 3.3, 6.0):
        for i in range(9):
            start = phrase + i * 0.11
            tone(buf, start, 0.09, 3400 - 90 * i, volume=0.3, decay=4, attack=0.004,
                 harmonics=((1, 1.0), (2, 0.06)), slide=-3500)
        for i in range(4):
            tone(buf, phrase + 1.05 + i * 0.16, 0.13, 2500 + 500 * (i % 2), volume=0.28, decay=6, attack=0.004,
                 harmonics=((1, 1.0),), slide=2500)


def beeps(buf):
    """The plain alarm clock: four quick beeps and a rest. Hard to sleep through."""
    for group in range(5):
        for i in range(4):
            tone(buf, group * 1.6 + i * 0.2, 0.11, 880, volume=0.3, decay=0, attack=0.003,
                 harmonics=((1, 1.0), (3, 0.15)))


def rising(buf):
    """Starts quiet and climbs, step by step, in pitch and loudness."""
    steps = [C5, E5, G5, C6, E6, G6, C6 * 2]
    for i in range(16):
        tone(buf, i * 0.5, 0.45, steps[min(i // 2, len(steps) - 1)], volume=0.05 + 0.27 * i / 15, decay=2.2)


def gong(buf):
    """Two deep strokes that ring on, with an uneven shimmer."""
    for start in (0.0, 4.0):
        tone(buf, start, 4.0, 110, volume=0.33, decay=0.7, attack=0.008,
             harmonics=((1, 1.0), (2.01, 0.6), (2.97, 0.4), (4.23, 0.25), (5.41, 0.14)))


# (the first is the default: bin/timer lists it first and rings with it)
SOUNDS = {"wren": wren, "chimes": chimes, "beeps": beeps, "rising": rising, "gong": gong}


def render(make):
    """The sound as 16-bit samples, its loudest point brought to one level so that
    no choice is much louder than another."""
    buf = [0.0] * int(SECONDS * RATE)
    make(buf)
    peak = max(abs(x) for x in buf) or 1.0
    return b"".join(struct.pack("<h", int(x / peak * 0.8 * 32767)) for x in buf)


def write(directory):
    os.makedirs(directory, exist_ok=True)
    for name, make in SOUNDS.items():
        fd, tmp = tempfile.mkstemp(dir=directory, suffix=".part")
        os.close(fd)
        with wave.open(tmp, "wb") as out:
            out.setnchannels(1)
            out.setsampwidth(2)
            out.setframerate(RATE)
            out.writeframes(render(make))
        os.chmod(tmp, 0o644)
        os.replace(tmp, os.path.join(directory, name + ".wav"))


def main():
    if len(sys.argv) == 2 and sys.argv[1] == "list":
        print("\n".join(SOUNDS))
    elif len(sys.argv) == 3 and sys.argv[1] == "make":
        write(sys.argv[2])
    else:
        sys.exit(__doc__)


if __name__ == "__main__":
    main()