from __future__ import annotations

from dataclasses import asdict, dataclass
from datetime import datetime
from pathlib import Path
import json
import re

from .models import PatternParams, SceneState


@dataclass(slots=True)
class PresetRecord:
    name: str
    pattern_id: str
    tempo_bpm: float
    params: dict
    created_at: str

    @classmethod
    def from_scene(cls, name: str, scene: SceneState) -> "PresetRecord":
        return cls(
            name=name,
            pattern_id=scene.pattern_id,
            tempo_bpm=scene.tempo_bpm,
            params=asdict(scene.params),
            created_at=datetime.utcnow().isoformat(timespec="seconds"),
        )


class PresetStore:
    def __init__(self, root: str | Path) -> None:
        self.root = Path(root)
        self.root.mkdir(parents=True, exist_ok=True)

    def save(self, record: PresetRecord) -> Path:
        path = self.root / f"{slugify(record.name)}.json"
        path.write_text(json.dumps(asdict(record), indent=2), encoding="utf-8")
        return path

    def list(self) -> list[PresetRecord]:
        presets: list[PresetRecord] = []
        for path in sorted(self.root.glob("*.json")):
            try:
                payload = json.loads(path.read_text(encoding="utf-8"))
                presets.append(PresetRecord(**payload))
            except (OSError, json.JSONDecodeError, TypeError):
                continue
        return presets

    def load_scene(self, name: str) -> SceneState:
        path = self.root / f"{slugify(name)}.json"
        payload = json.loads(path.read_text(encoding="utf-8"))
        record = PresetRecord(**payload)
        return SceneState(
            pattern_id=record.pattern_id,
            tempo_bpm=float(record.tempo_bpm),
            params=PatternParams(**record.params),
        )


def slugify(value: str) -> str:
    return re.sub(r"[^a-z0-9]+", "-", value.lower()).strip("-") or "preset"