import time

from django.contrib.auth import REDIRECT_FIELD_NAME
from django.http import HttpResponseRedirect
from django.urls import resolve, reverse
from django.utils.http import urlencode

from allauth.account import app_settings
from allauth.account.adapter import get_adapter
from allauth.account.utils import get_next_redirect_url
from allauth.core.internal.http import deserialize_request, serialize_request
from allauth.utils import import_callable


STATE_SESSION_KEY = "account_reauthentication_state"
AUTHENTICATED_AT_SESSION_KEY = "account_authenticated_at"


def suspend_request(request, redirect_to):
    path = request.get_full_path()
    if request.method == "POST":
        request.session[STATE_SESSION_KEY] = {"request": serialize_request(request)}
    return HttpResponseRedirect(
        redirect_to + "?" + urlencode({REDIRECT_FIELD_NAME: path})
    )


def resume_request(request):
    state = request.session.pop(STATE_SESSION_KEY, None)
    if state and "callback" in state:
        callback = import_callable(state["callback"])
        return callback(request, state["state"])

    url = get_next_redirect_url(request, REDIRECT_FIELD_NAME)
    if not url:
        return None
    if state and "request" in state:
        suspended_request = deserialize_request(state["request"], request)
        if suspended_request.path == url:
            resolved = resolve(suspended_request.path)
            return resolved.func(suspended_request, *resolved.args, **resolved.kwargs)
    return HttpResponseRedirect(url)


def record_authentication(request, user):
    # TODO: This is a different/independent mechanism from
    # ``authentication.record_authentication()``.  We need to unify this.
    request.session[AUTHENTICATED_AT_SESSION_KEY] = time.time()


def reauthenticate_then_callback(request, serialize_state, callback):
    # TODO: Currently, ACCOUNT_REAUTHENTICATION_REQUIRED does not play well with
    # XHR.
    if did_recently_authenticate(request):
        return None
    request.session[STATE_SESSION_KEY] = {
        "state": serialize_state(request),
        "callback": callback,
    }
    return HttpResponseRedirect(reverse("account_reauthenticate"))


def did_recently_authenticate(request):
    if request.user.is_anonymous:
        return False
    if not get_adapter().get_reauthentication_methods(request.user):
        # TODO: This user only has social accounts attached. Now, ideally, you
        # would want to reauthenticate over at the social account provider. For
        # now, this is not implemented. Although definitely suboptimal, this
        # method is currently used for reauthentication checks over at MFA, and,
        # users that delegate the security of their account to an external
        # provider like Google typically use MFA over there anyway.
        return True
    authenticated_at = request.session.get(AUTHENTICATED_AT_SESSION_KEY)
    if not authenticated_at:
        return False
    return time.time() - authenticated_at < app_settings.REAUTHENTICATION_TIMEOUT
