#!/usr/bin/env bash
set -euo pipefail

DEMO_DIR="${1:-muse-midi-episode00}"

command -v muse >/dev/null 2>&1 || { echo "error: muse not found on PATH" >&2; exit 1; }
command -v python3 >/dev/null 2>&1 || { echo "error: python3 not found on PATH" >&2; exit 1; }

python3 - <<'PY' >/dev/null 2>&1 || {
import mido
PY
  echo "error: Python package 'mido' is not importable by this python3." >&2
  echo "Run from your Muse development environment / venv, where mido is installed." >&2
  exit 1
}

rm -rf "$DEMO_DIR"
mkdir -p "$DEMO_DIR"
cd "$DEMO_DIR"

cat > make_phrase.py <<'PY'
#!/usr/bin/env python3
from pathlib import Path
import argparse
import mido

TPB = 480

BASE = [
    (0, 60, 80, 360),      # C4
    (480, 64, 80, 360),    # E4
    (960, 67, 80, 360),    # G4
    (1440, 72, 80, 360),   # C5
]

SOL = [
    (0, 60, 80, 360),      # unchanged
    (480, 65, 80, 360),    # E4 -> F4: pitch
    (1080, 67, 80, 360),   # moved later: position
    (1440, 72, 108, 360),  # velocity 80 -> 108
]

def build(path: Path, bpm: int, notes):
    mid = mido.MidiFile(type=0, ticks_per_beat=TPB)
    track = mido.MidiTrack()
    mid.tracks.append(track)

    events = [
        (0, mido.MetaMessage("track_name", name="Episode 00 phrase", time=0)),
        (0, mido.MetaMessage("set_tempo", tempo=mido.bpm2tempo(bpm), time=0)),
        (0, mido.MetaMessage(
            "time_signature",
            numerator=4,
            denominator=4,
            clocks_per_click=24,
            notated_32nd_notes_per_beat=8,
            time=0,
        )),
    ]

    for start, pitch, velocity, duration in notes:
        events.append((start, mido.Message("note_on", channel=0, note=pitch, velocity=velocity, time=0)))
        events.append((start + duration, mido.Message("note_off", channel=0, note=pitch, velocity=0, time=0)))

    order = {"track_name": 0, "set_tempo": 1, "time_signature": 2, "note_off": 3, "note_on": 4}
    events.sort(key=lambda item: (item[0], order.get(item[1].type, 99)))

    previous = 0
    for tick, msg in events:
        track.append(msg.copy(time=tick - previous))
        previous = tick

    track.append(mido.MetaMessage("end_of_track", time=0))
    mid.save(path)

parser = argparse.ArgumentParser()
parser.add_argument("variant", choices=["base", "tempo", "sol"])
parser.add_argument("--out", default="phrase.mid")
args = parser.parse_args()

if args.variant == "base":
    build(Path(args.out), 120, BASE)
elif args.variant == "tempo":
    build(Path(args.out), 100, BASE)
else:
    build(Path(args.out), 120, SOL)
PY

echo
echo "==> Initializing Muse MIDI repo"
muse init --domain midi

echo
echo "==> Baseline: 4-note phrase at 120 BPM"
python3 make_phrase.py base
muse commit -m "Base: four-note phrase at 120 BPM"

echo
echo "==> Gabriel branch: tempo only"
muse checkout -b gabriel-tempo
python3 make_phrase.py tempo
muse commit -m "Gabriel: slow tempo to 100 BPM"

echo
echo "==> Sol branch: note semantics only"
muse checkout main
muse checkout -b sol-notes
python3 make_phrase.py sol
muse commit -m "Sol: reshape phrase notes"

echo
echo "==> Return to main"
muse checkout main

cat <<'EOF'

Ready.

Suggested shots:

  muse branch
  muse log --oneline

  muse diff main gabriel-tempo
  muse diff main sol-notes
  muse diff main sol-notes --format json

  muse checkout main
  muse merge gabriel-tempo
  muse merge sol-notes

  muse log --oneline
  muse status

EOF