# -*- coding: utf-8 -*-
# Copyright 2017 Vector Creations 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
import re

from six import iteritems

from twisted.internet import defer

from synapse.api.constants import EventTypes, JoinRules
from synapse.storage.engines import PostgresEngine, Sqlite3Engine
from synapse.storage.state import StateFilter
from synapse.types import get_domain_from_id, get_localpart_from_id
from synapse.util.caches.descriptors import cached, cachedInlineCallbacks

from ._base import SQLBaseStore

logger = logging.getLogger(__name__)


class UserDirectoryStore(SQLBaseStore):
    @defer.inlineCallbacks
    def is_room_world_readable_or_publicly_joinable(self, room_id):
        """Check if the room is either world_readable or publically joinable
        """

        # Create a state filter that only queries join and history state event
        types_to_filter = (
            (EventTypes.JoinRules, ""),
            (EventTypes.RoomHistoryVisibility, ""),
        )

        current_state_ids = yield self.get_filtered_current_state_ids(
            room_id, StateFilter.from_types(types_to_filter)
        )

        join_rules_id = current_state_ids.get((EventTypes.JoinRules, ""))
        if join_rules_id:
            join_rule_ev = yield self.get_event(join_rules_id, allow_none=True)
            if join_rule_ev:
                if join_rule_ev.content.get("join_rule") == JoinRules.PUBLIC:
                    defer.returnValue(True)

        hist_vis_id = current_state_ids.get((EventTypes.RoomHistoryVisibility, ""))
        if hist_vis_id:
            hist_vis_ev = yield self.get_event(hist_vis_id, allow_none=True)
            if hist_vis_ev:
                if hist_vis_ev.content.get("history_visibility") == "world_readable":
                    defer.returnValue(True)

        defer.returnValue(False)

    def add_profiles_to_user_dir(self, users_with_profile):
        """Add profiles to the user directory

        Args:
            users_with_profile (dict): Users to add to directory in the form of
                mapping of user_id -> ProfileInfo
        """

        if isinstance(self.database_engine, PostgresEngine):
            # We weight the loclpart most highly, then display name and finally
            # server name
            sql = """
                INSERT INTO user_directory_search(user_id, vector)
                VALUES (?,
                    setweight(to_tsvector('english', ?), 'A')
                    || setweight(to_tsvector('english', ?), 'D')
                    || setweight(to_tsvector('english', COALESCE(?, '')), 'B')
                )
            """
            args = (
                (
                    user_id,
                    get_localpart_from_id(user_id),
                    get_domain_from_id(user_id),
                    profile.display_name,
                )
                for user_id, profile in iteritems(users_with_profile)
            )
        elif isinstance(self.database_engine, Sqlite3Engine):
            sql = """
                INSERT INTO user_directory_search(user_id, value)
                VALUES (?,?)
            """
            args = tuple(
                (
                    user_id,
                    "%s %s" % (user_id, p.display_name) if p.display_name else user_id,
                )
                for user_id, p in iteritems(users_with_profile)
            )
        else:
            # This should be unreachable.
            raise Exception("Unrecognized database engine")

        def _add_profiles_to_user_dir_txn(txn):
            txn.executemany(sql, args)
            self._simple_insert_many_txn(
                txn,
                table="user_directory",
                values=[
                    {
                        "user_id": user_id,
                        "room_id": None,
                        "display_name": profile.display_name,
                        "avatar_url": profile.avatar_url,
                    }
                    for user_id, profile in iteritems(users_with_profile)
                ],
            )
            for user_id in users_with_profile:
                txn.call_after(self.get_user_in_directory.invalidate, (user_id,))

        return self.runInteraction(
            "add_profiles_to_user_dir", _add_profiles_to_user_dir_txn
        )

    @defer.inlineCallbacks
    def update_user_in_user_dir(self, user_id, room_id):
        yield self._simple_update_one(
            table="user_directory",
            keyvalues={"user_id": user_id},
            updatevalues={"room_id": room_id},
            desc="update_user_in_user_dir",
        )
        self.get_user_in_directory.invalidate((user_id,))

    def update_profile_in_user_dir(self, user_id, display_name, avatar_url, room_id):
        def _update_profile_in_user_dir_txn(txn):
            new_entry = self._simple_upsert_txn(
                txn,
                table="user_directory",
                keyvalues={"user_id": user_id},
                insertion_values={"room_id": room_id},
                values={"display_name": display_name, "avatar_url": avatar_url},
                lock=False,  # We're only inserter
            )

            if isinstance(self.database_engine, PostgresEngine):
                # We weight the localpart most highly, then display name and finally
                # server name
                if self.database_engine.can_native_upsert:
                    sql = """
                        INSERT INTO user_directory_search(user_id, vector)
                        VALUES (?,
                            setweight(to_tsvector('english', ?), 'A')
                            || setweight(to_tsvector('english', ?), 'D')
                            || setweight(to_tsvector('english', COALESCE(?, '')), 'B')
                        ) ON CONFLICT (user_id) DO UPDATE SET vector=EXCLUDED.vector
                    """
                    txn.execute(
                        sql,
                        (
                            user_id,
                            get_localpart_from_id(user_id),
                            get_domain_from_id(user_id),
                            display_name,
                        ),
                    )
                else:
                    # TODO: Remove this code after we've bumped the minimum version
                    # of postgres to always support upserts, so we can get rid of
                    # `new_entry` usage
                    if new_entry is True:
                        sql = """
                            INSERT INTO user_directory_search(user_id, vector)
                            VALUES (?,
                                setweight(to_tsvector('english', ?), 'A')
                                || setweight(to_tsvector('english', ?), 'D')
                                || setweight(to_tsvector('english', COALESCE(?, '')), 'B')
                            )
                        """
                        txn.execute(
                            sql,
                            (
                                user_id,
                                get_localpart_from_id(user_id),
                                get_domain_from_id(user_id),
                                display_name,
                            ),
                        )
                    elif new_entry is False:
                        sql = """
                            UPDATE user_directory_search
                            SET vector = setweight(to_tsvector('english', ?), 'A')
                                || setweight(to_tsvector('english', ?), 'D')
                                || setweight(to_tsvector('english', COALESCE(?, '')), 'B')
                            WHERE user_id = ?
                        """
                        txn.execute(
                            sql,
                            (
                                get_localpart_from_id(user_id),
                                get_domain_from_id(user_id),
                                display_name,
                                user_id,
                            ),
                        )
                    else:
                        raise RuntimeError(
                            "upsert returned None when 'can_native_upsert' is False"
                        )
            elif isinstance(self.database_engine, Sqlite3Engine):
                value = "%s %s" % (user_id, display_name) if display_name else user_id
                self._simple_upsert_txn(
                    txn,
                    table="user_directory_search",
                    keyvalues={"user_id": user_id},
                    values={"value": value},
                    lock=False,  # We're only inserter
                )
            else:
                # This should be unreachable.
                raise Exception("Unrecognized database engine")

            txn.call_after(self.get_user_in_directory.invalidate, (user_id,))

        return self.runInteraction(
            "update_profile_in_user_dir", _update_profile_in_user_dir_txn
        )

    def remove_from_user_dir(self, user_id):
        def _remove_from_user_dir_txn(txn):
            self._simple_delete_txn(
                txn, table="user_directory", keyvalues={"user_id": user_id}
            )
            self._simple_delete_txn(
                txn, table="user_directory_search", keyvalues={"user_id": user_id}
            )
            self._simple_delete_txn(
                txn,
                table="users_who_share_public_rooms",
                keyvalues={"user_id": user_id},
            )
            self._simple_delete_txn(
                txn,
                table="users_who_share_public_rooms",
                keyvalues={"other_user_id": user_id},
            )
            self._simple_delete_txn(
                txn,
                table="users_who_share_private_rooms",
                keyvalues={"user_id": user_id},
            )
            self._simple_delete_txn(
                txn,
                table="users_who_share_private_rooms",
                keyvalues={"other_user_id": user_id},
            )
            txn.call_after(self.get_user_in_directory.invalidate, (user_id,))

        return self.runInteraction("remove_from_user_dir", _remove_from_user_dir_txn)

    @defer.inlineCallbacks
    def get_users_in_dir_due_to_room(self, room_id):
        """Get all user_ids that are in the room directory because they're
        in the given room_id
        """
        user_ids_share_pub = yield self._simple_select_onecol(
            table="users_who_share_public_rooms",
            keyvalues={"room_id": room_id},
            retcol="other_user_id",
            desc="get_users_in_dir_due_to_room",
        )

        user_ids_share_priv = yield self._simple_select_onecol(
            table="users_who_share_private_rooms",
            keyvalues={"room_id": room_id},
            retcol="other_user_id",
            desc="get_users_in_dir_due_to_room",
        )

        user_ids = set(user_ids_share_pub)
        user_ids.update(user_ids_share_priv)

        defer.returnValue(user_ids)

    @defer.inlineCallbacks
    def get_all_rooms(self):
        """Get all room_ids we've ever known about, in ascending order of "size"
        """
        sql = """
            SELECT room_id FROM current_state_events
            GROUP BY room_id
            ORDER BY count(*) ASC
        """
        rows = yield self._execute("get_all_rooms", None, sql)
        defer.returnValue([room_id for room_id, in rows])

    @defer.inlineCallbacks
    def get_all_local_users(self):
        """Get all local users
        """
        sql = """
            SELECT name FROM users
        """
        rows = yield self._execute("get_all_local_users", None, sql)
        defer.returnValue([name for name, in rows])

    def add_users_who_share_room(self, room_id, share_private, user_id_tuples):
        """Insert entries into the users_who_share_*_rooms table. The first
        user should be a local user.

        Args:
            room_id (str)
            share_private (bool): Is the room private
            user_id_tuples([(str, str)]): iterable of 2-tuple of user IDs.
        """

        def _add_users_who_share_room_txn(txn):

            if share_private:
                tbl = "users_who_share_private_rooms"
            else:
                tbl = "users_who_share_public_rooms"

            self._simple_upsert_many_txn(
                txn,
                table=tbl,
                key_names=["user_id", "other_user_id", "room_id"],
                key_values=[
                    (user_id, other_user_id, room_id)
                    for user_id, other_user_id in user_id_tuples
                ],
                value_names=(),
                value_values=None,
            )
            for user_id, other_user_id in user_id_tuples:
                txn.call_after(
                    self.get_users_who_share_room_from_dir.invalidate, (user_id,)
                )

        return self.runInteraction(
            "add_users_who_share_room", _add_users_who_share_room_txn
        )

    def remove_user_who_share_room(self, user_id, room_id):
        """
        Deletes entries in the users_who_share_*_rooms table. The first
        user should be a local user.

        Args:
            user_id (str)
            room_id (str)
        """

        def _remove_user_who_share_room_txn(txn):
            self._simple_delete_txn(
                txn,
                table="users_who_share_private_rooms",
                keyvalues={"user_id": user_id, "room_id": room_id},
            )
            self._simple_delete_txn(
                txn,
                table="users_who_share_private_rooms",
                keyvalues={"other_user_id": user_id, "room_id": room_id},
            )
            self._simple_delete_txn(
                txn,
                table="users_who_share_public_rooms",
                keyvalues={"user_id": user_id, "room_id": room_id},
            )
            self._simple_delete_txn(
                txn,
                table="users_who_share_public_rooms",
                keyvalues={"other_user_id": user_id, "room_id": room_id},
            )
            txn.call_after(
                self.get_users_who_share_room_from_dir.invalidate, (user_id,)
            )

        return self.runInteraction(
            "remove_user_who_share_room", _remove_user_who_share_room_txn
        )

    @cachedInlineCallbacks(max_entries=500000, iterable=True)
    def get_users_who_share_room_from_dir(self, user_id):
        """Returns the set of users who share a room with `user_id`

        Args:
            user_id(str): Must be a local user

        Returns:
            list: user_id
        """
        rows = yield self._simple_select_onecol(
            table="users_who_share_private_rooms",
            keyvalues={"user_id": user_id},
            retcol="other_user_id",
            desc="get_users_who_share_room_with_user",
        )

        pub_rows = yield self._simple_select_onecol(
            table="users_who_share_public_rooms",
            keyvalues={"user_id": user_id},
            retcol="other_user_id",
            desc="get_users_who_share_room_with_user",
        )

        users = set(pub_rows)
        users.update(rows)

        # Remove the user themselves from this list.
        users.discard(user_id)

        defer.returnValue(list(users))

    @defer.inlineCallbacks
    def get_rooms_in_common_for_users(self, user_id, other_user_id):
        """Given two user_ids find out the list of rooms they share.
        """
        sql = """
            SELECT room_id FROM (
                SELECT c.room_id FROM current_state_events AS c
                INNER JOIN room_memberships USING (event_id)
                WHERE type = 'm.room.member'
                    AND membership = 'join'
                    AND state_key = ?
            ) AS f1 INNER JOIN (
                SELECT c.room_id FROM current_state_events AS c
                INNER JOIN room_memberships USING (event_id)
                WHERE type = 'm.room.member'
                    AND membership = 'join'
                    AND state_key = ?
            ) f2 USING (room_id)
        """

        rows = yield self._execute(
            "get_rooms_in_common_for_users", None, sql, user_id, other_user_id
        )

        defer.returnValue([room_id for room_id, in rows])

    def delete_all_from_user_dir(self):
        """Delete the entire user directory
        """

        def _delete_all_from_user_dir_txn(txn):
            txn.execute("DELETE FROM user_directory")
            txn.execute("DELETE FROM user_directory_search")
            txn.execute("DELETE FROM users_who_share_public_rooms")
            txn.execute("DELETE FROM users_who_share_private_rooms")
            txn.call_after(self.get_user_in_directory.invalidate_all)
            txn.call_after(self.get_users_who_share_room_from_dir.invalidate_all)

        return self.runInteraction(
            "delete_all_from_user_dir", _delete_all_from_user_dir_txn
        )

    @cached()
    def get_user_in_directory(self, user_id):
        return self._simple_select_one(
            table="user_directory",
            keyvalues={"user_id": user_id},
            retcols=("display_name", "avatar_url"),
            allow_none=True,
            desc="get_user_in_directory",
        )

    def get_user_directory_stream_pos(self):
        return self._simple_select_one_onecol(
            table="user_directory_stream_pos",
            keyvalues={},
            retcol="stream_id",
            desc="get_user_directory_stream_pos",
        )

    def update_user_directory_stream_pos(self, stream_id):
        return self._simple_update_one(
            table="user_directory_stream_pos",
            keyvalues={},
            updatevalues={"stream_id": stream_id},
            desc="update_user_directory_stream_pos",
        )

    def get_current_state_deltas(self, prev_stream_id):
        prev_stream_id = int(prev_stream_id)
        if not self._curr_state_delta_stream_cache.has_any_entity_changed(
            prev_stream_id
        ):
            return []

        def get_current_state_deltas_txn(txn):
            # First we calculate the max stream id that will give us less than
            # N results.
            # We arbitarily limit to 100 stream_id entries to ensure we don't
            # select toooo many.
            sql = """
                SELECT stream_id, count(*)
                FROM current_state_delta_stream
                WHERE stream_id > ?
                GROUP BY stream_id
                ORDER BY stream_id ASC
                LIMIT 100
            """
            txn.execute(sql, (prev_stream_id,))

            total = 0
            max_stream_id = prev_stream_id
            for max_stream_id, count in txn:
                total += count
                if total > 100:
                    # We arbitarily limit to 100 entries to ensure we don't
                    # select toooo many.
                    break

            # Now actually get the deltas
            sql = """
                SELECT stream_id, room_id, type, state_key, event_id, prev_event_id
                FROM current_state_delta_stream
                WHERE ? < stream_id AND stream_id <= ?
                ORDER BY stream_id ASC
            """
            txn.execute(sql, (prev_stream_id, max_stream_id))
            return self.cursor_to_dict(txn)

        return self.runInteraction(
            "get_current_state_deltas", get_current_state_deltas_txn
        )

    def get_max_stream_id_in_current_state_deltas(self):
        return self._simple_select_one_onecol(
            table="current_state_delta_stream",
            keyvalues={},
            retcol="COALESCE(MAX(stream_id), -1)",
            desc="get_max_stream_id_in_current_state_deltas",
        )

    @defer.inlineCallbacks
    def search_user_dir(self, user_id, search_term, limit):
        """Searches for users in directory

        Returns:
            dict of the form::

                {
                    "limited": <bool>,  # whether there were more results or not
                    "results": [  # Ordered by best match first
                        {
                            "user_id": <user_id>,
                            "display_name": <display_name>,
                            "avatar_url": <avatar_url>
                        }
                    ]
                }
        """

        if self.hs.config.user_directory_search_all_users:
            # make s.user_id null to keep the ordering algorithm happy
            join_clause = """
                CROSS JOIN (SELECT NULL as user_id) AS s
            """
            join_args = ()
            where_clause = "1=1"
        else:
            join_clause = """
                LEFT JOIN (
                    SELECT other_user_id AS user_id FROM users_who_share_public_rooms
                    UNION
                    SELECT other_user_id AS user_id FROM users_who_share_private_rooms
                    WHERE user_id = ?
                ) AS p USING (user_id)
            """
            join_args = (user_id,)
            where_clause = "p.user_id IS NOT NULL"

        if isinstance(self.database_engine, PostgresEngine):
            full_query, exact_query, prefix_query = _parse_query_postgres(search_term)

            # We order by rank and then if they have profile info
            # The ranking algorithm is hand tweaked for "best" results. Broadly
            # the idea is we give a higher weight to exact matches.
            # The array of numbers are the weights for the various part of the
            # search: (domain, _, display name, localpart)
            sql = """
                SELECT d.user_id AS user_id, display_name, avatar_url
                FROM user_directory_search
                INNER JOIN user_directory AS d USING (user_id)
                %s
                WHERE
                    %s
                    AND vector @@ to_tsquery('english', ?)
                ORDER BY
                    (CASE WHEN d.user_id IS NOT NULL THEN 4.0 ELSE 1.0 END)
                    * (CASE WHEN display_name IS NOT NULL THEN 1.2 ELSE 1.0 END)
                    * (CASE WHEN avatar_url IS NOT NULL THEN 1.2 ELSE 1.0 END)
                    * (
                        3 * ts_rank_cd(
                            '{0.1, 0.1, 0.9, 1.0}',
                            vector,
                            to_tsquery('english', ?),
                            8
                        )
                        + ts_rank_cd(
                            '{0.1, 0.1, 0.9, 1.0}',
                            vector,
                            to_tsquery('english', ?),
                            8
                        )
                    )
                    DESC,
                    display_name IS NULL,
                    avatar_url IS NULL
                LIMIT ?
            """ % (
                join_clause,
                where_clause,
            )
            args = join_args + (full_query, exact_query, prefix_query, limit + 1)
        elif isinstance(self.database_engine, Sqlite3Engine):
            search_query = _parse_query_sqlite(search_term)

            sql = """
                SELECT d.user_id AS user_id, display_name, avatar_url
                FROM user_directory_search
                INNER JOIN user_directory AS d USING (user_id)
                %s
                WHERE
                    %s
                    AND value MATCH ?
                ORDER BY
                    rank(matchinfo(user_directory_search)) DESC,
                    display_name IS NULL,
                    avatar_url IS NULL
                LIMIT ?
            """ % (
                join_clause,
                where_clause,
            )
            args = join_args + (search_query, limit + 1)
        else:
            # This should be unreachable.
            raise Exception("Unrecognized database engine")

        results = yield self._execute(
            "search_user_dir", self.cursor_to_dict, sql, *args
        )

        limited = len(results) > limit

        defer.returnValue({"limited": limited, "results": results})


def _parse_query_sqlite(search_term):
    """Takes a plain unicode string from the user and converts it into a form
    that can be passed to database.
    We use this so that we can add prefix matching, which isn't something
    that is supported by default.

    We specifically add both a prefix and non prefix matching term so that
    exact matches get ranked higher.
    """

    # Pull out the individual words, discarding any non-word characters.
    results = re.findall(r"([\w\-]+)", search_term, re.UNICODE)
    return " & ".join("(%s* OR %s)" % (result, result) for result in results)


def _parse_query_postgres(search_term):
    """Takes a plain unicode string from the user and converts it into a form
    that can be passed to database.
    We use this so that we can add prefix matching, which isn't something
    that is supported by default.
    """

    # Pull out the individual words, discarding any non-word characters.
    results = re.findall(r"([\w\-]+)", search_term, re.UNICODE)

    both = " & ".join("(%s:* | %s)" % (result, result) for result in results)
    exact = " & ".join("%s" % (result,) for result in results)
    prefix = " & ".join("%s:*" % (result,) for result in results)

    return both, exact, prefix
