from __future__ import annotations

import json
import time
from pathlib import Path
from typing import Any


class StickerCache:
    def __init__(self, cache_dir: str | None = None, max_entries: int = 500):
        self._cache_dir = Path(cache_dir or str(Path.home() / ".yuxi" / "imessage" / "stickers"))
        self._max_entries = max_entries
        self._index: dict[str, dict[str, Any]] = {}
        self._cache_dir.mkdir(parents=True, exist_ok=True)
        self._load_index()

    def add(self, sticker_id: str, url: str, metadata: dict[str, Any] | None = None) -> None:
        entry = {
            "sticker_id": sticker_id,
            "url": url,
            "metadata": metadata or {},
            "cached_at": time.time(),
        }
        self._index[sticker_id] = entry
        if len(self._index) > self._max_entries:
            oldest = min(self._index.values(), key=lambda e: e["cached_at"])
            self._index.pop(oldest["sticker_id"], None)
        self._save_index()

    def get(self, sticker_id: str) -> dict[str, Any] | None:
        return self._index.get(sticker_id)

    def get_url(self, sticker_id: str) -> str | None:
        entry = self._index.get(sticker_id)
        return entry["url"] if entry else None

    def clear(self) -> None:
        self._index.clear()
        self._save_index()

    def _load_index(self) -> None:
        index_path = self._cache_dir / "sticker_index.json"
        if index_path.exists():
            try:
                self._index = json.loads(index_path.read_text(encoding="utf-8"))
            except (json.JSONDecodeError, OSError):
                self._index = {}

    def _save_index(self) -> None:
        index_path = self._cache_dir / "sticker_index.json"
        index_path.write_text(json.dumps(self._index, ensure_ascii=False, indent=2), encoding="utf-8")