import json
import os
import time

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):
    """Return cached data, or None if missing or older than ttl seconds."""
    path = _cache_path(key)
    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)


def set_cached(key: str, data) -> None:
    os.makedirs(CACHE_DIR, exist_ok=True)
    with open(_cache_path(key), 'w') as f:
        json.dump(data, f, indent=2)