# -*- coding: utf-8 -*-
# Copyright 2018 New Vector Ltd
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import logging

from twisted.internet import defer

from synapse.api.constants import EventTypes
from synapse.api.errors import AuthError, SynapseError

logger = logging.getLogger(__name__)


class ResourceLimitsServerNotices(object):
    """
    """
    def __init__(self, hs):
        """

        Args:
            hs (synapse.server.HomeServer):
        """
        self._server_notices_manager = hs.get_server_notices_manager()
        self._store = hs.get_datastore()
        self.auth = hs.get_auth()
        self._server_notice_content = hs.config.user_consent_server_notice_content
        self._admin_uri = hs.config.admin_uri
        self._limit_usage_by_mau = hs.config.limit_usage_by_mau
        self._hs_disabled = hs.config.hs_disabled

        self._resouce_limited = False
        self._message_handler = hs.get_message_handler()
        self._state = hs.get_state_handler()
        # Config checks?

    @defer.inlineCallbacks
    def maybe_send_server_notice_to_user(self, user_id):
        """Check if we need to send a notice to this user, and does so if so

        Args:
            user_id (str): user to check

        Returns:
            Deferred
        """
        if self._hs_disabled is True:
            return

        if self._limit_usage_by_mau is True:
            timestamp = yield self._store.user_last_seen_monthly_active(user_id)
            if timestamp is None:
                # This user will be blocked from receiving the notice anyway.
                # In practice, not sure we can ever get here
                return

            room_id = yield self._server_notices_manager.get_notice_room_for_user(user_id)

            # Need to set tag here because room may have been created prior to
            # tagging being set on creation. Ideally would set something to read
            # room tags first, and cache that aggressively/
            yield self._store.add_tag_to_room(user_id, room_id, 'm.server_notice', None)

            currently_blocked = False
            pinned_state_event = None
            try:
                pinned_state_event = yield self._state.get_current_state(
                    room_id, event_type=EventTypes.Pinned
                )
            except AuthError as e:
                # The user has yet to join the server notices room
                pass

            referenced_events = []
            if pinned_state_event is not None:
                referenced_events = pinned_state_event.content.get('pinned')

            events = yield self._store.get_events(referenced_events)
            for event_id, event in events.items():
                if event.type == EventTypes.ServerNoticeLimitReached:
                    currently_blocked = True
            try:
                # Normally should always pass in user_id if you have it, but in
                # this case are checking what would happen to other users if they
                # were to arrive.
                yield self.auth.check_auth_blocking()

                # Need to start removing notices
                # if user_id in self._notified_of_blocking:
                if currently_blocked:
                    # Send message to remove warning
                    # send state event here
                    # How do I do this? if drop the id, how to refer to it?
                    content = {
                        "pinned": []
                    }
                    yield self._server_notices_manager.send_notice(
                        user_id, content, EventTypes.Pinned, '',
                    )

            except AuthError as e:
                # Need to start notifying of blocking
                try:
                    if not currently_blocked:
                        # TODO use admin email contained in error once PR lands
                        content = {
                            'body': e.msg,
                            'admin_uri': self._admin_uri,
                        }
                        event = yield self._server_notices_manager.send_notice(
                            user_id, content, EventTypes.ServerNoticeLimitReached
                        )

                        # send server notices state event here
                        # TODO Over writing pinned events
                        content = {
                            "pinned": [
                                event.event_id,
                            ]
                        }
                        yield self._server_notices_manager.send_notice(
                            user_id, content, EventTypes.Pinned, '',
                        )

                except SynapseError as e:
                    logger.error("Error sending resource limits server notice: %s", e)