import re
from typing import List, Optional, Sequence, Set

from django.conf import settings
from django.http import HttpRequest, HttpResponse
from django.utils.translation import gettext as _

from confirmation import settings as confirmation_settings
from zerver.actions.invites import (
    do_create_multiuse_invite_link,
    do_get_invites_controlled_by_user,
    do_invite_users,
    do_resend_user_invite_email,
    do_revoke_multi_use_invite,
    do_revoke_user_invite,
)
from zerver.decorator import require_member_or_admin
from zerver.lib.exceptions import JsonableError, OrganizationOwnerRequiredError
from zerver.lib.request import REQ, has_request_variables
from zerver.lib.response import json_success
from zerver.lib.streams import access_stream_by_id
from zerver.lib.validator import check_int, check_int_in, check_list, check_none_or
from zerver.models import MultiuseInvite, PreregistrationUser, Stream, UserProfile

# Convert INVITATION_LINK_VALIDITY_DAYS into minutes.
# Because mypy fails to correctly infer the type of the validator, we want this constant
# to be Optional[int] to avoid a mypy error when using it as the default value.
# https://github.com/python/mypy/issues/13234
INVITATION_LINK_VALIDITY_MINUTES: Optional[int] = 24 * 60 * settings.INVITATION_LINK_VALIDITY_DAYS


def check_role_based_permissions(
    invited_as: int, user_profile: UserProfile, *, require_admin: bool
) -> None:
    if (
        invited_as == PreregistrationUser.INVITE_AS["REALM_OWNER"]
        and not user_profile.is_realm_owner
    ):
        raise OrganizationOwnerRequiredError

    if require_admin and not user_profile.is_realm_admin:
        raise JsonableError(_("Must be an organization administrator"))


@require_member_or_admin
@has_request_variables
def invite_users_backend(
    request: HttpRequest,
    user_profile: UserProfile,
    invitee_emails_raw: str = REQ("invitee_emails"),
    invite_expires_in_minutes: Optional[int] = REQ(
        json_validator=check_none_or(check_int), default=INVITATION_LINK_VALIDITY_MINUTES
    ),
    invite_as: int = REQ(
        json_validator=check_int_in(
            list(PreregistrationUser.INVITE_AS.values()),
        ),
        default=PreregistrationUser.INVITE_AS["MEMBER"],
    ),
    stream_ids: List[int] = REQ(json_validator=check_list(check_int)),
) -> HttpResponse:
    if not user_profile.can_invite_users_by_email():
        # Guest users case will not be handled here as it will
        # be handled by the decorator above.
        raise JsonableError(_("Insufficient permission"))

    require_admin = invite_as in [
        # Owners can only be invited by owners, checked by separate
        # logic in check_role_based_permissions.
        PreregistrationUser.INVITE_AS["REALM_OWNER"],
        PreregistrationUser.INVITE_AS["REALM_ADMIN"],
        PreregistrationUser.INVITE_AS["MODERATOR"],
    ]
    check_role_based_permissions(invite_as, user_profile, require_admin=require_admin)

    if not invitee_emails_raw:
        raise JsonableError(_("You must specify at least one email address."))

    invitee_emails = get_invitee_emails_set(invitee_emails_raw)

    streams: List[Stream] = []
    for stream_id in stream_ids:
        try:
            (stream, sub) = access_stream_by_id(user_profile, stream_id)
        except JsonableError:
            raise JsonableError(
                _("Invalid channel ID {channel_id}. No invites were sent.").format(
                    channel_id=stream_id
                )
            )
        streams.append(stream)

    if len(streams) and not user_profile.can_subscribe_other_users():
        raise JsonableError(_("You do not have permission to subscribe other users to channels."))

    do_invite_users(
        user_profile,
        invitee_emails,
        streams,
        invite_expires_in_minutes=invite_expires_in_minutes,
        invite_as=invite_as,
    )
    return json_success(request)


def get_invitee_emails_set(invitee_emails_raw: str) -> Set[str]:
    invitee_emails_list = set(re.split(r"[,\n]", invitee_emails_raw))
    invitee_emails = set()
    for email in invitee_emails_list:
        is_email_with_name = re.search(r"<(?P<email>.*)>", email)
        if is_email_with_name:
            email = is_email_with_name.group("email")
        invitee_emails.add(email.strip())
    return invitee_emails


@require_member_or_admin
def get_user_invites(request: HttpRequest, user_profile: UserProfile) -> HttpResponse:
    all_users = do_get_invites_controlled_by_user(user_profile)
    return json_success(request, data={"invites": all_users})


@require_member_or_admin
@has_request_variables
def revoke_user_invite(
    request: HttpRequest, user_profile: UserProfile, invite_id: int
) -> HttpResponse:
    try:
        prereg_user = PreregistrationUser.objects.get(id=invite_id)
    except PreregistrationUser.DoesNotExist:
        raise JsonableError(_("No such invitation"))

    if prereg_user.realm != user_profile.realm:
        raise JsonableError(_("No such invitation"))

    if prereg_user.referred_by_id != user_profile.id:
        check_role_based_permissions(prereg_user.invited_as, user_profile, require_admin=True)

    do_revoke_user_invite(prereg_user)
    return json_success(request)


@require_member_or_admin
@has_request_variables
def revoke_multiuse_invite(
    request: HttpRequest, user_profile: UserProfile, invite_id: int
) -> HttpResponse:
    try:
        invite = MultiuseInvite.objects.get(id=invite_id)
    except MultiuseInvite.DoesNotExist:
        raise JsonableError(_("No such invitation"))

    if invite.realm != user_profile.realm:
        raise JsonableError(_("No such invitation"))

    if invite.referred_by_id != user_profile.id:
        check_role_based_permissions(invite.invited_as, user_profile, require_admin=True)

    if invite.status == confirmation_settings.STATUS_REVOKED:
        raise JsonableError(_("Invitation has already been revoked"))

    do_revoke_multi_use_invite(invite)
    return json_success(request)


@require_member_or_admin
@has_request_variables
def resend_user_invite_email(
    request: HttpRequest, user_profile: UserProfile, prereg_id: int
) -> HttpResponse:
    try:
        prereg_user = PreregistrationUser.objects.get(id=prereg_id)
    except PreregistrationUser.DoesNotExist:
        raise JsonableError(_("No such invitation"))

    # Structurally, any invitation the user can actually access should
    # have a referred_by set for the user who created it.
    if prereg_user.referred_by is None or prereg_user.referred_by.realm != user_profile.realm:
        raise JsonableError(_("No such invitation"))

    if prereg_user.referred_by_id != user_profile.id:
        check_role_based_permissions(prereg_user.invited_as, user_profile, require_admin=True)

    timestamp = do_resend_user_invite_email(prereg_user)
    return json_success(request, data={"timestamp": timestamp})


@require_member_or_admin
@has_request_variables
def generate_multiuse_invite_backend(
    request: HttpRequest,
    user_profile: UserProfile,
    invite_expires_in_minutes: Optional[int] = REQ(
        json_validator=check_none_or(check_int), default=INVITATION_LINK_VALIDITY_MINUTES
    ),
    invite_as: int = REQ(
        json_validator=check_int_in(
            list(PreregistrationUser.INVITE_AS.values()),
        ),
        default=PreregistrationUser.INVITE_AS["MEMBER"],
    ),
    stream_ids: Sequence[int] = REQ(json_validator=check_list(check_int), default=[]),
) -> HttpResponse:
    if not user_profile.can_create_multiuse_invite_to_realm():
        # Guest users case will not be handled here as it will
        # be handled by the decorator above.
        raise JsonableError(_("Insufficient permission"))

    require_admin = invite_as in [
        # Owners can only be invited by owners, checked by separate
        # logic in check_role_based_permissions.
        PreregistrationUser.INVITE_AS["REALM_OWNER"],
        PreregistrationUser.INVITE_AS["REALM_ADMIN"],
        PreregistrationUser.INVITE_AS["MODERATOR"],
    ]
    check_role_based_permissions(invite_as, user_profile, require_admin=require_admin)

    streams = []
    for stream_id in stream_ids:
        try:
            (stream, sub) = access_stream_by_id(user_profile, stream_id)
        except JsonableError:
            raise JsonableError(
                _("Invalid channel ID {channel_id}. No invites were sent.").format(
                    channel_id=stream_id
                )
            )
        streams.append(stream)

    if len(streams) and not user_profile.can_subscribe_other_users():
        raise JsonableError(_("You do not have permission to subscribe other users to channels."))

    invite_link = do_create_multiuse_invite_link(
        user_profile, invite_as, invite_expires_in_minutes, streams
    )
    return json_success(request, data={"invite_link": invite_link})