# -*- coding: utf-8 -*-
# Copyright 2014-2016 OpenMarket Ltd
# 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 collections import namedtuple

from six import iteritems, itervalues

from canonicaljson import json

from twisted.internet import defer

from synapse.api.constants import EventTypes, Membership
from synapse.storage.events import EventsWorkerStore
from synapse.types import get_domain_from_id
from synapse.util.async import Linearizer
from synapse.util.caches import intern_string
from synapse.util.caches.descriptors import cached, cachedInlineCallbacks
from synapse.util.stringutils import to_ascii

logger = logging.getLogger(__name__)


RoomsForUser = namedtuple(
    "RoomsForUser",
    ("room_id", "sender", "membership", "event_id", "stream_ordering")
)

GetRoomsForUserWithStreamOrdering = namedtuple(
    "_GetRoomsForUserWithStreamOrdering",
    ("room_id", "stream_ordering",)
)


# We store this using a namedtuple so that we save about 3x space over using a
# dict.
ProfileInfo = namedtuple(
    "ProfileInfo", ("avatar_url", "display_name")
)


_MEMBERSHIP_PROFILE_UPDATE_NAME = "room_membership_profile_update"


class RoomMemberWorkerStore(EventsWorkerStore):
    @cachedInlineCallbacks(max_entries=100000, iterable=True, cache_context=True)
    def get_hosts_in_room(self, room_id, cache_context):
        """Returns the set of all hosts currently in the room
        """
        user_ids = yield self.get_users_in_room(
            room_id, on_invalidate=cache_context.invalidate,
        )
        hosts = frozenset(get_domain_from_id(user_id) for user_id in user_ids)
        defer.returnValue(hosts)

    @cached(max_entries=100000, iterable=True)
    def get_users_in_room(self, room_id):
        def f(txn):
            sql = (
                "SELECT m.user_id FROM room_memberships as m"
                " INNER JOIN current_state_events as c"
                " ON m.event_id = c.event_id "
                " AND m.room_id = c.room_id "
                " AND m.user_id = c.state_key"
                " WHERE c.type = 'm.room.member' AND c.room_id = ? AND m.membership = ?"
            )

            txn.execute(sql, (room_id, Membership.JOIN,))
            return [to_ascii(r[0]) for r in txn]
        return self.runInteraction("get_users_in_room", f)

    @cached()
    def get_invited_rooms_for_user(self, user_id):
        """ Get all the rooms the user is invited to
        Args:
            user_id (str): The user ID.
        Returns:
            A deferred list of RoomsForUser.
        """

        return self.get_rooms_for_user_where_membership_is(
            user_id, [Membership.INVITE]
        )

    @defer.inlineCallbacks
    def get_invite_for_user_in_room(self, user_id, room_id):
        """Gets the invite for the given user and room

        Args:
            user_id (str)
            room_id (str)

        Returns:
            Deferred: Resolves to either a RoomsForUser or None if no invite was
                found.
        """
        invites = yield self.get_invited_rooms_for_user(user_id)
        for invite in invites:
            if invite.room_id == room_id:
                defer.returnValue(invite)
        defer.returnValue(None)

    def get_rooms_for_user_where_membership_is(self, user_id, membership_list):
        """ Get all the rooms for this user where the membership for this user
        matches one in the membership list.

        Args:
            user_id (str): The user ID.
            membership_list (list): A list of synapse.api.constants.Membership
            values which the user must be in.
        Returns:
            A list of dictionary objects, with room_id, membership and sender
            defined.
        """
        if not membership_list:
            return defer.succeed(None)

        return self.runInteraction(
            "get_rooms_for_user_where_membership_is",
            self._get_rooms_for_user_where_membership_is_txn,
            user_id, membership_list
        )

    def _get_rooms_for_user_where_membership_is_txn(self, txn, user_id,
                                                    membership_list):

        do_invite = Membership.INVITE in membership_list
        membership_list = [m for m in membership_list if m != Membership.INVITE]

        results = []
        if membership_list:
            where_clause = "user_id = ? AND (%s) AND forgotten = 0" % (
                " OR ".join(["membership = ?" for _ in membership_list]),
            )

            args = [user_id]
            args.extend(membership_list)

            sql = (
                "SELECT m.room_id, m.sender, m.membership, m.event_id, e.stream_ordering"
                " FROM current_state_events as c"
                " INNER JOIN room_memberships as m"
                " ON m.event_id = c.event_id"
                " INNER JOIN events as e"
                " ON e.event_id = c.event_id"
                " AND m.room_id = c.room_id"
                " AND m.user_id = c.state_key"
                " WHERE c.type = 'm.room.member' AND %s"
            ) % (where_clause,)

            txn.execute(sql, args)
            results = [
                RoomsForUser(**r) for r in self.cursor_to_dict(txn)
            ]

        if do_invite:
            sql = (
                "SELECT i.room_id, inviter, i.event_id, e.stream_ordering"
                " FROM local_invites as i"
                " INNER JOIN events as e USING (event_id)"
                " WHERE invitee = ? AND locally_rejected is NULL"
                " AND replaced_by is NULL"
            )

            txn.execute(sql, (user_id,))
            results.extend(RoomsForUser(
                room_id=r["room_id"],
                sender=r["inviter"],
                event_id=r["event_id"],
                stream_ordering=r["stream_ordering"],
                membership=Membership.INVITE,
            ) for r in self.cursor_to_dict(txn))

        return results

    @cachedInlineCallbacks(max_entries=500000, iterable=True)
    def get_rooms_for_user_with_stream_ordering(self, user_id):
        """Returns a set of room_ids the user is currently joined to

        Args:
            user_id (str)

        Returns:
            Deferred[frozenset[GetRoomsForUserWithStreamOrdering]]: Returns
            the rooms the user is in currently, along with the stream ordering
            of the most recent join for that user and room.
        """
        rooms = yield self.get_rooms_for_user_where_membership_is(
            user_id, membership_list=[Membership.JOIN],
        )
        defer.returnValue(frozenset(
            GetRoomsForUserWithStreamOrdering(r.room_id, r.stream_ordering)
            for r in rooms
        ))

    @defer.inlineCallbacks
    def get_rooms_for_user(self, user_id, on_invalidate=None):
        """Returns a set of room_ids the user is currently joined to
        """
        rooms = yield self.get_rooms_for_user_with_stream_ordering(
            user_id, on_invalidate=on_invalidate,
        )
        defer.returnValue(frozenset(r.room_id for r in rooms))

    @cachedInlineCallbacks(max_entries=500000, cache_context=True, iterable=True)
    def get_users_who_share_room_with_user(self, user_id, cache_context):
        """Returns the set of users who share a room with `user_id`
        """
        room_ids = yield self.get_rooms_for_user(
            user_id, on_invalidate=cache_context.invalidate,
        )

        user_who_share_room = set()
        for room_id in room_ids:
            user_ids = yield self.get_users_in_room(
                room_id, on_invalidate=cache_context.invalidate,
            )
            user_who_share_room.update(user_ids)

        defer.returnValue(user_who_share_room)

    def get_joined_users_from_context(self, event, context):
        state_group = context.state_group
        if not state_group:
            # If state_group is None it means it has yet to be assigned a
            # state group, i.e. we need to make sure that calls with a state_group
            # of None don't hit previous cached calls with a None state_group.
            # To do this we set the state_group to a new object as object() != object()
            state_group = object()

        return self._get_joined_users_from_context(
            event.room_id, state_group, context.current_state_ids,
            event=event,
            context=context,
        )

    def get_joined_users_from_state(self, room_id, state_entry):
        state_group = state_entry.state_group
        if not state_group:
            # If state_group is None it means it has yet to be assigned a
            # state group, i.e. we need to make sure that calls with a state_group
            # of None don't hit previous cached calls with a None state_group.
            # To do this we set the state_group to a new object as object() != object()
            state_group = object()

        return self._get_joined_users_from_context(
            room_id, state_group, state_entry.state, context=state_entry,
        )

    @cachedInlineCallbacks(num_args=2, cache_context=True, iterable=True,
                           max_entries=100000)
    def _get_joined_users_from_context(self, room_id, state_group, current_state_ids,
                                       cache_context, event=None, context=None):
        # We don't use `state_group`, it's there so that we can cache based
        # on it. However, it's important that it's never None, since two current_states
        # with a state_group of None are likely to be different.
        # See bulk_get_push_rules_for_room for how we work around this.
        assert state_group is not None

        users_in_room = {}
        member_event_ids = [
            e_id
            for key, e_id in iteritems(current_state_ids)
            if key[0] == EventTypes.Member
        ]

        if context is not None:
            # If we have a context with a delta from a previous state group,
            # check if we also have the result from the previous group in cache.
            # If we do then we can reuse that result and simply update it with
            # any membership changes in `delta_ids`
            if context.prev_group and context.delta_ids:
                prev_res = self._get_joined_users_from_context.cache.get(
                    (room_id, context.prev_group), None
                )
                if prev_res and isinstance(prev_res, dict):
                    users_in_room = dict(prev_res)
                    member_event_ids = [
                        e_id
                        for key, e_id in iteritems(context.delta_ids)
                        if key[0] == EventTypes.Member
                    ]
                    for etype, state_key in context.delta_ids:
                        users_in_room.pop(state_key, None)

        # We check if we have any of the member event ids in the event cache
        # before we ask the DB

        # We don't update the event cache hit ratio as it completely throws off
        # the hit ratio counts. After all, we don't populate the cache if we
        # miss it here
        event_map = self._get_events_from_cache(
            member_event_ids,
            allow_rejected=False,
            update_metrics=False,
        )

        missing_member_event_ids = []
        for event_id in member_event_ids:
            ev_entry = event_map.get(event_id)
            if ev_entry:
                if ev_entry.event.membership == Membership.JOIN:
                    users_in_room[to_ascii(ev_entry.event.state_key)] = ProfileInfo(
                        display_name=to_ascii(
                            ev_entry.event.content.get("displayname", None)
                        ),
                        avatar_url=to_ascii(
                            ev_entry.event.content.get("avatar_url", None)
                        ),
                    )
            else:
                missing_member_event_ids.append(event_id)

        if missing_member_event_ids:
            rows = yield self._simple_select_many_batch(
                table="room_memberships",
                column="event_id",
                iterable=missing_member_event_ids,
                retcols=('user_id', 'display_name', 'avatar_url',),
                keyvalues={
                    "membership": Membership.JOIN,
                },
                batch_size=500,
                desc="_get_joined_users_from_context",
            )

            users_in_room.update({
                to_ascii(row["user_id"]): ProfileInfo(
                    avatar_url=to_ascii(row["avatar_url"]),
                    display_name=to_ascii(row["display_name"]),
                )
                for row in rows
            })

        if event is not None and event.type == EventTypes.Member:
            if event.membership == Membership.JOIN:
                if event.event_id in member_event_ids:
                    users_in_room[to_ascii(event.state_key)] = ProfileInfo(
                        display_name=to_ascii(event.content.get("displayname", None)),
                        avatar_url=to_ascii(event.content.get("avatar_url", None)),
                    )

        defer.returnValue(users_in_room)

    @cachedInlineCallbacks(max_entries=10000)
    def is_host_joined(self, room_id, host):
        if '%' in host or '_' in host:
            raise Exception("Invalid host name")

        sql = """
            SELECT state_key FROM current_state_events AS c
            INNER JOIN room_memberships USING (event_id)
            WHERE membership = 'join'
                AND type = 'm.room.member'
                AND c.room_id = ?
                AND state_key LIKE ?
            LIMIT 1
        """

        # We do need to be careful to ensure that host doesn't have any wild cards
        # in it, but we checked above for known ones and we'll check below that
        # the returned user actually has the correct domain.
        like_clause = "%:" + host

        rows = yield self._execute("is_host_joined", None, sql, room_id, like_clause)

        if not rows:
            defer.returnValue(False)

        user_id = rows[0][0]
        if get_domain_from_id(user_id) != host:
            # This can only happen if the host name has something funky in it
            raise Exception("Invalid host name")

        defer.returnValue(True)

    @cachedInlineCallbacks()
    def was_host_joined(self, room_id, host):
        """Check whether the server is or ever was in the room.

        Args:
            room_id (str)
            host (str)

        Returns:
            Deferred: Resolves to True if the host is/was in the room, otherwise
            False.
        """
        if '%' in host or '_' in host:
            raise Exception("Invalid host name")

        sql = """
            SELECT user_id FROM room_memberships
            WHERE room_id = ?
                AND user_id LIKE ?
                AND membership = 'join'
            LIMIT 1
        """

        # We do need to be careful to ensure that host doesn't have any wild cards
        # in it, but we checked above for known ones and we'll check below that
        # the returned user actually has the correct domain.
        like_clause = "%:" + host

        rows = yield self._execute("was_host_joined", None, sql, room_id, like_clause)

        if not rows:
            defer.returnValue(False)

        user_id = rows[0][0]
        if get_domain_from_id(user_id) != host:
            # This can only happen if the host name has something funky in it
            raise Exception("Invalid host name")

        defer.returnValue(True)

    def get_joined_hosts(self, room_id, state_entry):
        state_group = state_entry.state_group
        if not state_group:
            # If state_group is None it means it has yet to be assigned a
            # state group, i.e. we need to make sure that calls with a state_group
            # of None don't hit previous cached calls with a None state_group.
            # To do this we set the state_group to a new object as object() != object()
            state_group = object()

        return self._get_joined_hosts(
            room_id, state_group, state_entry.state, state_entry=state_entry,
        )

    @cachedInlineCallbacks(num_args=2, max_entries=10000, iterable=True)
    # @defer.inlineCallbacks
    def _get_joined_hosts(self, room_id, state_group, current_state_ids, state_entry):
        # We don't use `state_group`, its there so that we can cache based
        # on it. However, its important that its never None, since two current_state's
        # with a state_group of None are likely to be different.
        # See bulk_get_push_rules_for_room for how we work around this.
        assert state_group is not None

        cache = self._get_joined_hosts_cache(room_id)
        joined_hosts = yield cache.get_destinations(state_entry)

        defer.returnValue(joined_hosts)

    @cached(max_entries=10000)
    def _get_joined_hosts_cache(self, room_id):
        return _JoinedHostsCache(self, room_id)

    @cached()
    def who_forgot_in_room(self, room_id):
        return self._simple_select_list(
            table="room_memberships",
            retcols=("user_id", "event_id"),
            keyvalues={
                "room_id": room_id,
                "forgotten": 1,
            },
            desc="who_forgot"
        )


class RoomMemberStore(RoomMemberWorkerStore):
    def __init__(self, db_conn, hs):
        super(RoomMemberStore, self).__init__(db_conn, hs)
        self.register_background_update_handler(
            _MEMBERSHIP_PROFILE_UPDATE_NAME, self._background_add_membership_profile
        )

    def _store_room_members_txn(self, txn, events, backfilled):
        """Store a room member in the database.
        """
        self._simple_insert_many_txn(
            txn,
            table="room_memberships",
            values=[
                {
                    "event_id": event.event_id,
                    "user_id": event.state_key,
                    "sender": event.user_id,
                    "room_id": event.room_id,
                    "membership": event.membership,
                    "display_name": event.content.get("displayname", None),
                    "avatar_url": event.content.get("avatar_url", None),
                }
                for event in events
            ]
        )

        for event in events:
            txn.call_after(
                self._membership_stream_cache.entity_has_changed,
                event.state_key, event.internal_metadata.stream_ordering
            )
            txn.call_after(
                self.get_invited_rooms_for_user.invalidate, (event.state_key,)
            )

            # We update the local_invites table only if the event is "current",
            # i.e., its something that has just happened.
            # The only current event that can also be an outlier is if its an
            # invite that has come in across federation.
            is_new_state = not backfilled and (
                not event.internal_metadata.is_outlier()
                or event.internal_metadata.is_invite_from_remote()
            )
            is_mine = self.hs.is_mine_id(event.state_key)
            if is_new_state and is_mine:
                if event.membership == Membership.INVITE:
                    self._simple_insert_txn(
                        txn,
                        table="local_invites",
                        values={
                            "event_id": event.event_id,
                            "invitee": event.state_key,
                            "inviter": event.sender,
                            "room_id": event.room_id,
                            "stream_id": event.internal_metadata.stream_ordering,
                        }
                    )
                else:
                    sql = (
                        "UPDATE local_invites SET stream_id = ?, replaced_by = ? WHERE"
                        " room_id = ? AND invitee = ? AND locally_rejected is NULL"
                        " AND replaced_by is NULL"
                    )

                    txn.execute(sql, (
                        event.internal_metadata.stream_ordering,
                        event.event_id,
                        event.room_id,
                        event.state_key,
                    ))

    @defer.inlineCallbacks
    def locally_reject_invite(self, user_id, room_id):
        sql = (
            "UPDATE local_invites SET stream_id = ?, locally_rejected = ? WHERE"
            " room_id = ? AND invitee = ? AND locally_rejected is NULL"
            " AND replaced_by is NULL"
        )

        def f(txn, stream_ordering):
            txn.execute(sql, (
                stream_ordering,
                True,
                room_id,
                user_id,
            ))

        with self._stream_id_gen.get_next() as stream_ordering:
            yield self.runInteraction("locally_reject_invite", f, stream_ordering)

    def forget(self, user_id, room_id):
        """Indicate that user_id wishes to discard history for room_id."""
        def f(txn):
            sql = (
                "UPDATE"
                "  room_memberships"
                " SET"
                "  forgotten = 1"
                " WHERE"
                "  user_id = ?"
                " AND"
                "  room_id = ?"
            )
            txn.execute(sql, (user_id, room_id))

            txn.call_after(self.did_forget.invalidate, (user_id, room_id))
            self._invalidate_cache_and_stream(
                txn, self.who_forgot_in_room, (room_id,)
            )
        return self.runInteraction("forget_membership", f)

    @cachedInlineCallbacks(num_args=2)
    def did_forget(self, user_id, room_id):
        """Returns whether user_id has elected to discard history for room_id.

        Returns False if they have since re-joined."""
        def f(txn):
            sql = (
                "SELECT"
                "  COUNT(*)"
                " FROM"
                "  room_memberships"
                " WHERE"
                "  user_id = ?"
                " AND"
                "  room_id = ?"
                " AND"
                "  forgotten = 0"
            )
            txn.execute(sql, (user_id, room_id))
            rows = txn.fetchall()
            return rows[0][0]
        count = yield self.runInteraction("did_forget_membership", f)
        defer.returnValue(count == 0)

    @defer.inlineCallbacks
    def _background_add_membership_profile(self, progress, batch_size):
        target_min_stream_id = progress.get(
            "target_min_stream_id_inclusive", self._min_stream_order_on_start
        )
        max_stream_id = progress.get(
            "max_stream_id_exclusive", self._stream_order_on_start + 1
        )

        INSERT_CLUMP_SIZE = 1000

        def add_membership_profile_txn(txn):
            sql = ("""
                SELECT stream_ordering, event_id, events.room_id, event_json.json
                FROM events
                INNER JOIN event_json USING (event_id)
                INNER JOIN room_memberships USING (event_id)
                WHERE ? <= stream_ordering AND stream_ordering < ?
                AND type = 'm.room.member'
                ORDER BY stream_ordering DESC
                LIMIT ?
            """)

            txn.execute(sql, (target_min_stream_id, max_stream_id, batch_size))

            rows = self.cursor_to_dict(txn)
            if not rows:
                return 0

            min_stream_id = rows[-1]["stream_ordering"]

            to_update = []
            for row in rows:
                event_id = row["event_id"]
                room_id = row["room_id"]
                try:
                    event_json = json.loads(row["json"])
                    content = event_json['content']
                except Exception:
                    continue

                display_name = content.get("displayname", None)
                avatar_url = content.get("avatar_url", None)

                if display_name or avatar_url:
                    to_update.append((
                        display_name, avatar_url, event_id, room_id
                    ))

            to_update_sql = ("""
                UPDATE room_memberships SET display_name = ?, avatar_url = ?
                WHERE event_id = ? AND room_id = ?
            """)
            for index in range(0, len(to_update), INSERT_CLUMP_SIZE):
                clump = to_update[index:index + INSERT_CLUMP_SIZE]
                txn.executemany(to_update_sql, clump)

            progress = {
                "target_min_stream_id_inclusive": target_min_stream_id,
                "max_stream_id_exclusive": min_stream_id,
            }

            self._background_update_progress_txn(
                txn, _MEMBERSHIP_PROFILE_UPDATE_NAME, progress
            )

            return len(rows)

        result = yield self.runInteraction(
            _MEMBERSHIP_PROFILE_UPDATE_NAME, add_membership_profile_txn
        )

        if not result:
            yield self._end_background_update(_MEMBERSHIP_PROFILE_UPDATE_NAME)

        defer.returnValue(result)


class _JoinedHostsCache(object):
    """Cache for joined hosts in a room that is optimised to handle updates
    via state deltas.
    """

    def __init__(self, store, room_id):
        self.store = store
        self.room_id = room_id

        self.hosts_to_joined_users = {}

        self.state_group = object()

        self.linearizer = Linearizer("_JoinedHostsCache")

        self._len = 0

    @defer.inlineCallbacks
    def get_destinations(self, state_entry):
        """Get set of destinations for a state entry

        Args:
            state_entry(synapse.state._StateCacheEntry)
        """
        if state_entry.state_group == self.state_group:
            defer.returnValue(frozenset(self.hosts_to_joined_users))

        with (yield self.linearizer.queue(())):
            if state_entry.state_group == self.state_group:
                pass
            elif state_entry.prev_group == self.state_group:
                for (typ, state_key), event_id in iteritems(state_entry.delta_ids):
                    if typ != EventTypes.Member:
                        continue

                    host = intern_string(get_domain_from_id(state_key))
                    user_id = state_key
                    known_joins = self.hosts_to_joined_users.setdefault(host, set())

                    event = yield self.store.get_event(event_id)
                    if event.membership == Membership.JOIN:
                        known_joins.add(user_id)
                    else:
                        known_joins.discard(user_id)

                        if not known_joins:
                            self.hosts_to_joined_users.pop(host, None)
            else:
                joined_users = yield self.store.get_joined_users_from_state(
                    self.room_id, state_entry,
                )

                self.hosts_to_joined_users = {}
                for user_id in joined_users:
                    host = intern_string(get_domain_from_id(user_id))
                    self.hosts_to_joined_users.setdefault(host, set()).add(user_id)

            if state_entry.state_group:
                self.state_group = state_entry.state_group
            else:
                self.state_group = object()
            self._len = sum(len(v) for v in itervalues(self.hosts_to_joined_users))
        defer.returnValue(frozenset(self.hosts_to_joined_users))

    def __len__(self):
        return self._len
