import json
import os
import time
import uuid
from typing import Any

from config.default import CACHE_DIR  # overridden by app config after import


def _cache_path(key: str) -> str:
    safe_key = key.replace("/", "_").replace(" ", "_")
    return os.path.join(CACHE_DIR, f"{safe_key}.json")


def get_cached(key: str, ttl: int | None = None) -> Any:
    """Return cached data, or None if missing or older than ttl seconds."""
    path = _cache_path(key)
    try:
        if not os.path.exists(path):
            return None
        if ttl is not None and time.time() - os.path.getmtime(path) > ttl:
            return None
        with open(path) as f:
            return json.load(f)
    except (OSError, json.JSONDecodeError):
        return None


def set_cached(key: str, data: Any) -> None:
    os.makedirs(CACHE_DIR, exist_ok=True)
    path = _cache_path(key)
    tmp_path = f"{path}.{os.getpid()}.{uuid.uuid4().hex}.tmp"
    with open(tmp_path, "w") as f:
        json.dump(data, f, indent=2)
    os.replace(tmp_path, path)