"""장르별 음악 파라미터 랜덤 풀 — 음악적으로 어울리는 결과 유도."""
import random

POOLS = {
    "lo-fi": {
        "moods": ["chill", "relaxing", "dreamy", "melancholic", "mellow", "nostalgic", "peaceful"],
        "instruments_pool": ["piano", "synth", "drums", "vinyl", "rhodes", "soft bass", "ambient pads"],
        "instruments_count": (3, 4),
        "bpm": (70, 90),
        "keys": ["C", "D", "F", "G", "A"],
        "scales": ["minor", "major"],
        "prompt_modifiers": ["cozy bedroom vibes", "rainy night", "late night study", "cafe ambience"],
    },
    "phonk": {
        "moods": ["dark", "aggressive", "moody", "intense", "hypnotic"],
        "instruments_pool": ["808 bass", "hi-hat", "synth lead", "vocal chops", "bass drops", "trap drums"],
        "instruments_count": (3, 4),
        "bpm": (130, 160),
        "keys": ["C", "D", "F", "G"],
        "scales": ["minor"],
        "prompt_modifiers": ["drift atmosphere", "dark neon", "midnight drive"],
    },
    "ambient": {
        "moods": ["peaceful", "meditative", "ethereal", "spacious", "dreamy"],
        "instruments_pool": ["pad synths", "atmospheric guitar", "soft strings", "field recordings", "drone bass"],
        "instruments_count": (2, 3),
        "bpm": (50, 75),
        "keys": ["C", "D", "E", "G", "A"],
        "scales": ["major", "minor"],
        "prompt_modifiers": ["misty mountain morning", "deep space", "still water", "forest dawn"],
    },
    "pop": {
        "moods": ["uplifting", "happy", "energetic", "romantic", "catchy"],
        "instruments_pool": ["acoustic guitar", "piano", "drums", "bass", "synth", "vocals harmonies"],
        "instruments_count": (3, 5),
        "bpm": (95, 130),
        "keys": ["C", "D", "E", "F", "G", "A"],
        "scales": ["major"],
        "prompt_modifiers": ["radio-ready", "summer vibe", "feel-good"],
    },
    "default": {
        "moods": ["chill", "relaxing", "uplifting", "mellow"],
        "instruments_pool": ["piano", "synth", "drums", "guitar", "bass", "strings"],
        "instruments_count": (3, 4),
        "bpm": (80, 110),
        "keys": ["C", "D", "F", "G", "A"],
        "scales": ["minor", "major"],
        "prompt_modifiers": [""],
    },
}


def randomize(genre: str, rng=None) -> dict:
    """장르 → 랜덤 음악 파라미터 1세트.

    반환: {moods, instruments, bpm, key, scale, prompt_modifier}
    """
    rng = rng or random.Random()
    pool = POOLS.get(genre.lower(), POOLS["default"])
    n_instr = rng.randint(*pool["instruments_count"])
    instruments = rng.sample(pool["instruments_pool"], min(n_instr, len(pool["instruments_pool"])))
    return {
        "moods": [rng.choice(pool["moods"])],
        "instruments": instruments,
        "bpm": rng.randint(*pool["bpm"]),
        "key": rng.choice(pool["keys"]),
        "scale": rng.choice(pool["scales"]),
        "prompt_modifier": rng.choice(pool["prompt_modifiers"]),
    }