#!/usr/bin/env python3
"""La musica delle bocce al pallaio (assets/audio/bocce.mp3), sintetizzata da zero come il valzer delle carte: una
polka da circolo in do maggiore, in due quarti. Basso «um-pa» sui due movimenti, fisarmonica a contrattempo e una
melodia originale di clarinetto, con un filo di vibrato. Trentadue battute che chiudono sul sol settima: il loop non
si sente. (Andrea, 26 ottobre: «anche le bocce avrebbero bisogno di un sound suo».)
    python3 tools/polka_bocce.py      # scrive assets/audio/bocce.mp3 (serve ffmpeg)
"""
import math
import random
import subprocess
import tempfile
import wave
from array import array
from pathlib import Path

SR = 22050
BPM = 116
BEAT = 60 / BPM
OUT = Path(__file__).resolve().parent.parent / "assets" / "audio" / "bocce.mp3"

HARMONY = {"C": ["E4", "G4", "C5"], "G7": ["F4", "G4", "B4"], "F": ["F4", "A4", "C5"], "A7": ["E4", "G4", "C#5"],
           "Dm": ["F4", "A4", "D5"]}
BASS = {"C": ("C2", "G2"), "G7": ("G1", "D2"), "F": ("F1", "C2"), "A7": ("A1", "E2"), "Dm": ("D2", "A1")}
CHORDS = ("C C G7 G7 G7 G7 C C C C F F C G7 C C "
          "F F C C G7 G7 C C F F C A7 Dm G7 C G7").split()
h = 0.5
MELODY = [
    [("E5", h), ("G5", h), ("C6", 1)], [("B5", h), ("A5", h), ("G5", 1)], [("F5", h), ("G5", h), ("A5", h), ("B5", h)], [("D6", 1), ("B5", 1)],
    [("A5", h), ("B5", h), ("A5", h), ("G5", h)], [("F5", 1), ("D5", 1)], [("E5", h), ("F5", h), ("G5", 1)], [("C5", 2)],
    [("E5", h), ("G5", h), ("C6", 1)], [("E6", h), ("D6", h), ("C6", 1)], [("A5", h), ("C6", h), ("A5", h), ("F5", h)], [("A5", 1.5), ("G5", h)],
    [("G5", h), ("E5", h), ("C5", h), ("E5", h)], [("D5", h), ("F5", h), ("B5", 1)], [("C6", 1), ("G5", 1)], [("C6", 1), (None, 1)],
    [("C6", h), ("A5", h), ("F5", 1)], [("A5", h), ("G5", h), ("F5", 1)], [("G5", h), ("E5", h), ("C5", 1)], [("E5", h), ("G5", h), ("C6", 1)],
    [("B5", h), ("A5", h), ("G5", h), ("F5", h)], [("D5", 1), ("G5", 1)], [("E5", h), ("G5", h), ("E5", h), ("C5", h)], [("G4", 2)],
    [("A4", h), ("C5", h), ("F5", 1)], [("A5", 1), ("F5", 1)], [("E5", h), ("G5", h), ("C6", 1)], [("C#6", 1), ("A5", 1)],
    [("D6", h), ("C6", h), ("A5", 1)], [("B5", h), ("A5", h), ("G5", h), ("F5", h)], [("E5", 1), ("C5", 1)], [("D5", h), ("E5", h), ("F5", h), ("G5", h)],
]
assert len(MELODY) == len(CHORDS) and all(sum(d for _, d in bar) == 2 for bar in MELODY)
DUR = len(CHORDS) * 2 * BEAT
buf = [0.0] * int(SR * DUR)
rng = random.Random(11)


def midi(note: str) -> int:
    names = {"C": 0, "D": 2, "E": 4, "F": 5, "G": 7, "A": 9, "B": 11}
    semis = names[note[0]] + (1 if "#" in note else -1 if len(note) > 2 and note[1] == "b" else 0)
    return semis + 12 * (int(note[-1]) + 1)


def hz(note: str) -> float:
    return 440 * 2 ** ((midi(note) - 69) / 12)


def add(start: float, samples) -> None:
    """Somma un suono alla traccia; la coda che esce dalla fine rientra all'inizio (loop continuo)."""
    n0 = int(start * SR)
    for i, v in enumerate(samples):
        buf[(n0 + i) % len(buf)] += v


def tone(freq: float, length: float, vol: float, partials, decay: float, attack: float = 0.006, release: float = 0.06,
         vibrato: float = 0.0):
    n = int((length + release) * SR)
    out, phase = [], 0.0
    for i in range(n):
        t = i / SR
        env = min(1.0, t / attack) * math.exp(-t / decay)
        if t > length:
            env *= max(0.0, 1 - (t - length) / release)
        # Il vibrato arriva dopo l'attacco, come quello di un fiato.
        phase += 2 * math.pi * freq * (1 + vibrato * min(1.0, t / 0.25) * math.sin(2 * math.pi * 5.2 * t)) / SR
        out.append(vol * env * sum(a * math.exp(-t / d) * math.sin(k * phase) for k, a, d in partials))
    return out


at = lambda beat: beat * BEAT  # noqa: E731
LONG = 99
# Fisarmonica: ance ricche di armonici, che non si spengono finché il mantice spinge.
REED = ((1, 1.0, LONG), (2, 0.55, LONG), (3, 0.38, LONG), (4, 0.22, LONG), (5, 0.12, LONG), (6, 0.06, LONG))
# Clarinetto: armonici dispari, il suono di legno.
REEDWOOD = ((1, 1.0, LONG), (3, 0.42, LONG), (5, 0.2, LONG), (7, 0.09, LONG), (2, 0.06, LONG))

for bar, name in enumerate(CHORDS):
    b0 = bar * 2
    # Basso «um-pa»: fondamentale sull'uno, quinta sul due.
    for k, note in enumerate(BASS[name]):
        add(at(b0 + k), tone(hz(note), BEAT * 0.55, 0.32, ((1, 1.0, LONG), (2, 0.5, 0.25), (3, 0.2, 0.12)), decay=0.35))
    # Fisarmonica a contrattempo, corta e frizzante.
    for k in (0.5, 1.5):
        for note in HARMONY[name]:
            for detune, vol in ((1.0, 0.026), (1.004, 0.019)):
                add(at(b0 + k), tone(hz(note) * detune, BEAT * 0.3, vol, REED, decay=LONG, attack=0.012, release=0.04))
    # Un piatto leggero sul due, quello della banda.
    add(at(b0 + 1), [0.03 * math.exp(-i / SR / 0.08) * rng.uniform(-1, 1) for i in range(int(0.2 * SR))])

beat = 0.0
for bar in MELODY:
    for note, length in bar:
        if note:
            add(at(beat), tone(hz(note), BEAT * length * 0.9, 0.09, REEDWOOD, decay=LONG, attack=0.03, release=0.06, vibrato=0.006))
        beat += length

peak = max(abs(x) for x in buf) or 1
with tempfile.TemporaryDirectory() as tmp:
    w = Path(tmp) / "bocce.wav"
    with wave.open(str(w), "wb") as f:
        f.setnchannels(1)
        f.setsampwidth(2)
        f.setframerate(SR)
        f.writeframes(array("h", (int(x / peak * 0.85 * 32767) for x in buf)).tobytes())
    # All'aperto, accanto al campo: poca eco, alti morbidi.
    af = "aecho=0.8:0.5:70|150:0.12|0.07,lowpass=f=8500,volume=1.25"
    subprocess.run(["ffmpeg", "-loglevel", "error", "-y", "-i", str(w), "-af", af, "-c:a", "libmp3lame", "-b:a", "96k", str(OUT)], check=True)
print(f"-> {OUT} ({DUR:.0f} s)")