"""RemoteWriter which writes BSON to the given HTTP destination."""

import typing as t

import requests

from . import logger

TIMEOUT_SECS = 60


class HTTPWriter(logger.RemoteWriter):

    def __init__(self, url: str, preamble: t.Dict[str, object]):
        self._url = url
        self._session = requests.Session()
        self._session.headers['User-Agent'] = 'weatherlogger/0.0.1'
        self._preamble = logger.bson_encode(preamble)

    def write(self, readings: t.Iterable[t.Dict[str, object]]) -> None:
        try:
            data = b''.join(map(logger.bson_encode, readings))
            response = self._session.post(
                self._url, data=self._preamble + data, timeout=TIMEOUT_SECS)
            response.raise_for_status()
            contents = response.json()
            if contents.get('status') != 'OK':
                raise logger.RemoteWriteError(
                    f'Invalid server response: {contents!r}')
        except requests.exceptions.RequestException as rex:
            raise logger.RemoteWriteError("Coulndn't write values") from rex
        except ValueError as ve:
            raise logger.RemoteWriteError('Invalid JSON response') from ve