#!/usr/bin/env python
"""Compose a REAPER .rpp project from the sample library.

Single entrypoint: loads sample index, builds a SongDefinition from the selector/composer,
and writes a .rpp file.

Usage:
    python scripts/compose.py --genre reggaeton --bpm 95 --key Am
    python scripts/compose.py --genre trap --bpm 140 --key Cm --output output/my_track.rpp
"""
from __future__ import annotations

import argparse
import sys
from pathlib import Path

# Ensure project root on path
_ROOT = Path(__file__).parent.parent
sys.path.insert(0, str(_ROOT))

from src.core.schema import SongDefinition, SongMeta, TrackDef, ClipDef, MidiNote
from src.composer.rhythm import get_notes
from src.composer.melodic import bass_tresillo, lead_hook, chords_block, pad_sustain
from src.composer.converters import rhythm_to_midi, melodic_to_midi
from src.selector import SampleSelector
from src.reaper_builder import RPPBuilder
from src.reaper_builder.render import render_project


# ---------------------------------------------------------------------------
# Track builders
# ---------------------------------------------------------------------------

def build_drum_track(
    role: str,
    generator_name: str,
    bars: int,
) -> TrackDef:
    """Build a drum MIDI track from a rhythm generator.

    Args:
        role: Track name (e.g. "kick", "snare")
        generator_name: Name from rhythm.GENERATORS (e.g. "kick_main_notes")
        bars: Number of bars
    """
    note_dict = get_notes(generator_name, bars)
    midi_notes = rhythm_to_midi(note_dict)
    clip = ClipDef(
        position=0.0,
        length=bars * 4.0,
        name=f"{role.capitalize()} Pattern",
        midi_notes=midi_notes,
    )
    return TrackDef(name=role.capitalize(), clips=[clip])


def build_melodic_track(
    role: str,
    generator_fn,
    key: str,
    bpm: float,
    bars: int,
    selector: SampleSelector | None = None,
) -> TrackDef:
    """Build a melodic MIDI track from a generator function.

    Args:
        role: Track name (e.g. "bass", "lead")
        generator_fn: Callable from melodic.py (e.g. bass_tresillo)
        key: Musical key (e.g. "Am")
        bpm: Tempo for sample selection
        bars: Number of bars
        selector: Optional SampleSelector; if provided, sets audio_path on ClipDef
    """
    note_list = generator_fn(key=key, bars=bars)
    midi_notes = melodic_to_midi(note_list)

    audio_path: str | None = None
    if selector is not None:
        match = selector.select_one(role=role, key=key, bpm=bpm)
        if match:
            audio_path = match.get("original_path", None)

    clip = ClipDef(
        position=0.0,
        length=bars * 4.0,
        name=f"{role.capitalize()} MIDI",
        audio_path=audio_path,
        midi_notes=midi_notes,
    )
    return TrackDef(name=role.capitalize(), clips=[clip])


# ---------------------------------------------------------------------------
# Main
# ---------------------------------------------------------------------------

def main() -> None:
    parser = argparse.ArgumentParser(
        description="Compose a REAPER .rpp project from the sample library."
    )
    parser.add_argument(
        "--genre",
        default="reggaeton",
        help="Genre (default: reggaeton)",
    )
    parser.add_argument(
        "--bpm",
        type=float,
        default=95.0,
        help="BPM (default: 95)",
    )
    parser.add_argument(
        "--key",
        default="Am",
        help="Musical key (default: Am)",
    )
    parser.add_argument(
        "--output",
        default="output/track.rpp",
        help="Output .rpp path (default: output/track.rpp)",
    )
    parser.add_argument(
        "--render",
        action="store_true",
        help="Render the project to WAV after generating the .rpp file.",
    )
    parser.add_argument(
        "--render-output",
        default=None,
        help="Output WAV path for rendering. Defaults to <output>.wav with .rpp extension replaced.",
    )
    args = parser.parse_args()

    # Validate BPM before any writes
    if args.bpm <= 0:
        raise ValueError(f"bpm must be > 0, got {args.bpm}")

    # Ensure output directory exists
    output_path = Path(args.output)
    output_path.parent.mkdir(parents=True, exist_ok=True)

    # Load sample index (for melodic tracks that use audio samples)
    index_path = _ROOT / "data" / "sample_index.json"
    if not index_path.exists():
        print(f"ERROR: sample index not found at {index_path}", file=sys.stderr)
        sys.exit(1)

    selector = SampleSelector(str(index_path))

    # Determine bar count from genre
    genre_bar_map = {
        "reggaeton": 64,
        "trap": 32,
        "house": 64,
        "drill": 32,
    }
    bar_count = genre_bar_map.get(args.genre.lower(), 48)

    # Build drum tracks (no selector needed)
    drum_tracks = [
        build_drum_track("kick",  "kick_main_notes",   bar_count),
        build_drum_track("snare", "snare_verse_notes",  bar_count),
        build_drum_track("hihat", "hihat_16th_notes",   bar_count),
        build_drum_track("perc",  "perc_combo_notes",   bar_count),
    ]

    # Build melodic tracks (selector passed only to bass)
    melodic_tracks = [
        build_melodic_track("bass",  bass_tresillo,  args.key, args.bpm, bar_count, selector),
        build_melodic_track("lead",  lead_hook,      args.key, args.bpm, bar_count),
        build_melodic_track("chords", chords_block,  args.key, args.bpm, bar_count),
        build_melodic_track("pad",   pad_sustain,   args.key, args.bpm, bar_count),
    ]

    # Assemble full track list
    all_tracks = drum_tracks + melodic_tracks

    # Build SongDefinition
    meta = SongMeta(bpm=args.bpm, key=args.key, title=f"{args.genre.capitalize()} Track")
    song = SongDefinition(meta=meta, tracks=all_tracks)

    # Validate
    errors = song.validate()
    if errors:
        print(f"WARNING: SongDefinition has validation errors:", file=sys.stderr)
        for e in errors:
            print(f"  - {e}", file=sys.stderr)

    # Write .rpp
    builder = RPPBuilder(song)
    builder.write(str(output_path))

    # Render if requested
    if args.render:
        render_output_path = args.render_output
        if render_output_path is None:
            render_output_path = str(output_path).replace('.rpp', '.wav')
        render_project(str(output_path), render_output_path)

    print(str(output_path.resolve()))


if __name__ == "__main__":
    main()