import fcntl
import json
from collections.abc import Generator
from contextlib import contextmanager
from pathlib import Path
from typing import Any

from clan_cli.jsonrpc import ClanJSONEncoder

from .dirs import user_history_file


@contextmanager
def locked_open(filename: str | Path, mode: str = "r") -> Generator:
    """
    This is a context manager that provides an advisory write lock on the file specified by `filename` when entering the context, and releases the lock when leaving the context. The lock is acquired using the `fcntl` module's `LOCK_EX` flag, which applies an exclusive write lock to the file.
    """
    with open(filename, mode) as fd:
        fcntl.flock(fd, fcntl.LOCK_EX)
        yield fd
        fcntl.flock(fd, fcntl.LOCK_UN)


def write_history_file(data: Any) -> None:
    with locked_open(user_history_file(), "w+") as f:
        f.write(json.dumps(data, cls=ClanJSONEncoder, indent=4))


def read_history_file() -> list[dict]:
    with locked_open(user_history_file(), "r") as f:
        content: str = f.read()
        parsed: list[dict] = json.loads(content)
        return parsed