from datetime import datetime, timedelta
from json import dump, load
from pathlib import Path
from typing import Any, Callable, Generic, TypeVar, TypedDict
from requests import RequestException, get


T = TypeVar('T')

class Cached(TypedDict, Generic[T]):
    loaded: int
    data: T


def get_resource(url: str):
    with get(url) as request:
        request.raise_for_status()
        return request.json()


def load_cached(url: str, cache_file: Path, loader: Callable[[str], T] = get_resource, max_age: timedelta = timedelta(hours=1), reload: bool = False, encoding: str = "utf-8") -> T:
    if reload:
        # print(f"Forced cache reload for {cache_file}!")
        pass
    else:
        try:
            with cache_file.open("r", encoding=encoding) as f:
                cached = load(f)
                data: T = cached["data"]
                time = datetime.fromtimestamp(cached["loaded"])
            cache_age = datetime.now() - time
            if cache_age <= max_age:
                # print(f"Loaded cache file with age {cache_age}.")
                return data
            # print(f"Cache is older than {max_age} and will be reloaded.")
        except FileNotFoundError:
            # print(f"File {cache_file} not cached, will be reloaded!")
            pass

    data = loader(url)
    data_dict_tmp: Any = data
    data_dict: dict[str, Any] = data_dict_tmp
    status: None | str = data_dict.get("status", None)
    if status is not None and status.lower() == "error":
        raise RequestException(data_dict.get("message", "No error message!"))

    # Save to cache
    cached: Cached[T] = {"data": data, "loaded": int(
        datetime.now().timestamp())}
    cache_file.parent.mkdir(parents=True, exist_ok=True)
    with cache_file.open("w", encoding=encoding) as f:
        dump(cached, f)

    return data