import asyncio
import requests
import json
from typing import List
import os
import configparser
import aiohttp


async def write_config_files(
    servers: list, path_to_template_file: str, path_for_config: str
) -> None:
    template: str = ""
    with open(path_to_template_file, "r") as file:
        template = file.read()

    config_full_path: str = os.path.abspath(path_for_config)
    if not os.path.isdir(config_full_path):
        os.mkdir(config_full_path)

    for server in servers:

        config_body: str = template.replace(
            "server_name _;", f"server_name {server}.server.com;"
        )
        config_filename: str = f"{server}.conf"

        with open(os.path.join(config_full_path, config_filename), "w") as file:
            file.write(config_body)


async def send_async_request(cfg: dict, columns: list, limit: int = 1) -> None:
    body = {"columns": columns, "limit": 1}
    server = cfg["central_host_url"]
    path_to_template_file = cfg["template"]
    path_for_config = cfg["path_for_config"]

    async with aiohttp.ClientSession() as session:
        tasks = [session.get(server, json=body) for i in range(limit)]
        responses = await asyncio.gather(*tasks)

        for response in responses:
            r = await response.json()
            hosts = [i["hostname"] for i in r.get("result")]

            await write_config_files(hosts, path_to_template_file, path_for_config)


def read_config(path_to_conf_file: str, section: str = "Main") -> dict:
    """
    Считать конфиг с помощью `configparser`.

    Parameters
    ----------
    path_to_conf_file: str
        Путь к файлу конфига. Можно указывать относительный.

    section: str
        Секция в конфиге, которую нужно считывать. По-умолчанию секция [Main].

    Raises
    ------
    KeyError
        Если в конфиге не найдено указанной секции.

    Returns
    -------
    dict
        Словарь, из значений указанной секции.
    """
    config = configparser.ConfigParser()
    config.read(os.path.abspath(path_to_conf_file))

    if section not in config.sections():
        raise KeyError(f"Section {section} not found in config file!")

    return dict(config.items(section))


async def main() -> None:

    cnf = read_config("service.conf")

    wait_sec: int = int(cnf["frequency_sec"])

    while True:
        await send_async_request(cnf, columns=["hostname"], limit=9999)
        await asyncio.sleep(wait_sec)


if __name__ == "__main__":
    asyncio.run(main())