from functools import lru_cache
from typing import Any, Container, Dict, Iterable, List, Mapping, Optional, Sequence, Tuple, Union

import orjson
import requests
from django.conf import settings
from requests.adapters import ConnectionError, HTTPAdapter
from requests.models import PreparedRequest, Response
from requests.packages.urllib3.util.retry import Retry

from zerver.lib.queue import queue_json_publish
from zerver.models import Client, Realm, UserProfile
from zerver.tornado.event_queue import process_notification
from zerver.tornado.sharding import get_tornado_port, get_tornado_uri, notify_tornado_queue_name


class TornadoAdapter(HTTPAdapter):
    def __init__(self) -> None:
        retry = Retry(total=3, backoff_factor=1)
        super().__init__(max_retries=retry)

    def send(
        self,
        request: PreparedRequest,
        stream: bool = False,
        timeout: Union[None, float, Tuple[float, float], Tuple[float, None]] = 0.5,
        verify: Union[bool, str] = True,
        cert: Union[None, bytes, str, Container[Union[bytes, str]]] = None,
        proxies: Optional[Mapping[str, str]] = None,
    ) -> Response:
        if not proxies:
            proxies = {}
        merged_proxies = {**proxies, "no_proxy": "localhost,127.0.0.1"}
        try:
            resp = super().send(request, stream=stream, timeout=timeout, verify=verify, cert=cert, proxies=merged_proxies)
        except ConnectionError:
            raise ConnectionError(
                f"Django cannot connect to Tornado server ({request.url}); "
                f"check {settings.ERROR_FILE_LOG_PATH} and tornado.log"
            )
        resp.raise_for_status()
        return resp

@lru_cache(None)
def requests_client() -> requests.Session:
    c = requests.Session()
    adapter = TornadoAdapter()
    for scheme in ("https://", "http://"):
        c.mount(scheme, adapter)
    return c

def request_event_queue(user_profile: UserProfile, user_client: Client, apply_markdown: bool,
                        client_gravatar: bool, slim_presence: bool, queue_lifespan_secs: int,
                        event_types: Optional[Iterable[str]]=None,
                        all_public_streams: bool=False,
                        narrow: Iterable[Sequence[str]]=[],
                        bulk_message_deletion: bool=False) -> Optional[str]:

    if not settings.TORNADO_SERVER:
        return None

    tornado_uri = get_tornado_uri(user_profile.realm)
    req = {'dont_block': 'true',
           'apply_markdown': orjson.dumps(apply_markdown),
           'client_gravatar': orjson.dumps(client_gravatar),
           'slim_presence': orjson.dumps(slim_presence),
           'all_public_streams': orjson.dumps(all_public_streams),
           'client': 'internal',
           'user_profile_id': user_profile.id,
           'user_client': user_client.name,
           'narrow': orjson.dumps(narrow),
           'secret': settings.SHARED_SECRET,
           'lifespan_secs': queue_lifespan_secs,
           'bulk_message_deletion': orjson.dumps(bulk_message_deletion)}

    if event_types is not None:
        req['event_types'] = orjson.dumps(event_types)

    resp = requests_client().post(
        tornado_uri + '/api/v1/events/internal',
        data=req
    )
    return resp.json()['queue_id']

def get_user_events(user_profile: UserProfile, queue_id: str, last_event_id: int) -> List[Dict[str, Any]]:
    if not settings.TORNADO_SERVER:
        return []

    tornado_uri = get_tornado_uri(user_profile.realm)
    post_data: Dict[str, Any] = {
        'queue_id': queue_id,
        'last_event_id': last_event_id,
        'dont_block': 'true',
        'user_profile_id': user_profile.id,
        'secret': settings.SHARED_SECRET,
        'client': 'internal',
    }
    resp = requests_client().post(
        tornado_uri + '/api/v1/events/internal',
        data=post_data
    )
    return resp.json()['events']

def send_notification_http(realm: Realm, data: Mapping[str, Any]) -> None:
    if not settings.TORNADO_SERVER or settings.RUNNING_INSIDE_TORNADO:
        process_notification(data)
    else:
        tornado_uri = get_tornado_uri(realm)
        requests_client().post(
            tornado_uri + "/notify_tornado",
            data=dict(data=orjson.dumps(data), secret=settings.SHARED_SECRET),
        )

def send_event(realm: Realm, event: Mapping[str, Any],
               users: Union[Iterable[int], Iterable[Mapping[str, Any]]]) -> None:
    """`users` is a list of user IDs, or in the case of `message` type
    events, a list of dicts describing the users and metadata about
    the user/message pair."""
    port = get_tornado_port(realm)
    queue_json_publish(notify_tornado_queue_name(port),
                       dict(event=event, users=list(users)),
                       lambda *args, **kwargs: send_notification_http(realm, *args, **kwargs))