"""Module configuring Certbot in a snap environment"""
import logging
import socket
from typing import Iterable
from typing import List
from typing import Optional

from requests import Session
from requests.adapters import HTTPAdapter
from requests.exceptions import HTTPError
from requests.exceptions import RequestException

from certbot.compat import os
from certbot.errors import Error

try:
    from urllib3.connection import HTTPConnection
    from urllib3.connectionpool import HTTPConnectionPool
except ImportError:
    # Stub imports for oldest requirements, that will never be used in snaps.
    HTTPConnection = object
    HTTPConnectionPool = object


_ARCH_TRIPLET_MAP = {
    'arm64': 'aarch64-linux-gnu',
    'armhf': 'arm-linux-gnueabihf',
    'i386': 'i386-linux-gnu',
    'ppc64el': 'powerpc64le-linux-gnu',
    'powerpc': 'powerpc-linux-gnu',
    'amd64': 'x86_64-linux-gnu',
    's390x': 's390x-linux-gnu',
}

LOGGER = logging.getLogger(__name__)


def prepare_env(cli_args: List[str]) -> List[str]:
    """
    Prepare runtime environment for a certbot execution in snap.
    :param list cli_args: List of command line arguments
    :return: Update list of command line arguments
    :rtype: list
    """
    snap_arch = os.environ.get('SNAP_ARCH')

    if snap_arch not in _ARCH_TRIPLET_MAP:
        raise Error('Unrecognized value of SNAP_ARCH: {0}'.format(snap_arch))

    os.environ['CERTBOT_AUGEAS_PATH'] = '{0}/usr/lib/{1}/libaugeas.so.0'.format(
        os.environ.get('SNAP'), _ARCH_TRIPLET_MAP[snap_arch])

    with Session() as session:
        session.mount('http://snapd/', _SnapdAdapter())

        try:
            response = session.get('http://snapd/v2/connections?snap=certbot&interface=content')
            response.raise_for_status()
        except RequestException as e:
            if isinstance(e, HTTPError) and e.response.status_code == 404:
                LOGGER.error('An error occurred while fetching Certbot snap plugins: '
                             'your version of snapd is outdated.')
                LOGGER.error('Please run "sudo snap install core; sudo snap refresh core" '
                             'in your terminal and try again.')
            else:
                LOGGER.error('An error occurred while fetching Certbot snap plugins: '
                             'make sure the snapd service is running.')
            raise e

    data = response.json()
    connections = ['/snap/{0}/current/lib/python3.8/site-packages/'.format(item['slot']['snap'])
                   for item in data.get('result', {}).get('established', [])
                   if item.get('plug', {}).get('plug') == 'plugin'
                   and item.get('plug-attrs', {}).get('content') == 'certbot-1']

    os.environ['CERTBOT_PLUGIN_PATH'] = ':'.join(connections)

    cli_args.append('--preconfigured-renewal')

    return cli_args


class _SnapdConnection(HTTPConnection):
    def __init__(self) -> None:
        super().__init__("localhost")
        self.sock: Optional[socket.socket] = None

    def connect(self) -> None:
        self.sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
        self.sock.connect("/run/snapd.socket")


class _SnapdConnectionPool(HTTPConnectionPool):
    def __init__(self) -> None:
        super().__init__("localhost")

    def _new_conn(self) -> _SnapdConnection:
        return _SnapdConnection()


class _SnapdAdapter(HTTPAdapter):
    def get_connection(self, url: str,
                       proxies: Optional[Iterable[str]] = None) -> _SnapdConnectionPool:
        return _SnapdConnectionPool()
