# -*- coding: utf-8 -*-
# Copyright 2014-2016 OpenMarket 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.

from collections import namedtuple

from twisted.internet import defer

from synapse.api.constants import PresenceState
from synapse.util import batch_iter
from synapse.util.caches.descriptors import cached, cachedList

from ._base import SQLBaseStore


class UserPresenceState(
    namedtuple(
        "UserPresenceState",
        (
            "user_id",
            "state",
            "last_active_ts",
            "last_federation_update_ts",
            "last_user_sync_ts",
            "status_msg",
            "currently_active",
        ),
    )
):
    """Represents the current presence state of the user.

    user_id (str)
    last_active (int): Time in msec that the user last interacted with server.
    last_federation_update (int): Time in msec since either a) we sent a presence
        update to other servers or b) we received a presence update, depending
        on if is a local user or not.
    last_user_sync (int): Time in msec that the user last *completed* a sync
        (or event stream).
    status_msg (str): User set status message.
    """

    def as_dict(self):
        return dict(self._asdict())

    @staticmethod
    def from_dict(d):
        return UserPresenceState(**d)

    def copy_and_replace(self, **kwargs):
        return self._replace(**kwargs)

    @classmethod
    def default(cls, user_id):
        """Returns a default presence state.
        """
        return cls(
            user_id=user_id,
            state=PresenceState.OFFLINE,
            last_active_ts=0,
            last_federation_update_ts=0,
            last_user_sync_ts=0,
            status_msg=None,
            currently_active=False,
        )


class PresenceStore(SQLBaseStore):
    @defer.inlineCallbacks
    def update_presence(self, presence_states):
        stream_ordering_manager = self._presence_id_gen.get_next_mult(
            len(presence_states)
        )

        with stream_ordering_manager as stream_orderings:
            yield self.runInteraction(
                "update_presence",
                self._update_presence_txn,
                stream_orderings,
                presence_states,
            )

        return (stream_orderings[-1], self._presence_id_gen.get_current_token())

    def _update_presence_txn(self, txn, stream_orderings, presence_states):
        for stream_id, state in zip(stream_orderings, presence_states):
            txn.call_after(
                self.presence_stream_cache.entity_has_changed, state.user_id, stream_id
            )
            txn.call_after(self._get_presence_for_user.invalidate, (state.user_id,))

        # Actually insert new rows
        self._simple_insert_many_txn(
            txn,
            table="presence_stream",
            values=[
                {
                    "stream_id": stream_id,
                    "user_id": state.user_id,
                    "state": state.state,
                    "last_active_ts": state.last_active_ts,
                    "last_federation_update_ts": state.last_federation_update_ts,
                    "last_user_sync_ts": state.last_user_sync_ts,
                    "status_msg": state.status_msg,
                    "currently_active": state.currently_active,
                }
                for state in presence_states
            ],
        )

        # Delete old rows to stop database from getting really big
        sql = (
            "DELETE FROM presence_stream WHERE" " stream_id < ?" " AND user_id IN (%s)"
        )

        for states in batch_iter(presence_states, 50):
            args = [stream_id]
            args.extend(s.user_id for s in states)
            txn.execute(sql % (",".join("?" for _ in states),), args)

    def get_all_presence_updates(self, last_id, current_id):
        if last_id == current_id:
            return defer.succeed([])

        def get_all_presence_updates_txn(txn):
            sql = (
                "SELECT stream_id, user_id, state, last_active_ts,"
                " last_federation_update_ts, last_user_sync_ts, status_msg,"
                " currently_active"
                " FROM presence_stream"
                " WHERE ? < stream_id AND stream_id <= ?"
            )
            txn.execute(sql, (last_id, current_id))
            return txn.fetchall()

        return self.runInteraction(
            "get_all_presence_updates", get_all_presence_updates_txn
        )

    @cached()
    def _get_presence_for_user(self, user_id):
        raise NotImplementedError()

    @cachedList(
        cached_method_name="_get_presence_for_user",
        list_name="user_ids",
        num_args=1,
        inlineCallbacks=True,
    )
    def get_presence_for_users(self, user_ids):
        rows = yield self._simple_select_many_batch(
            table="presence_stream",
            column="user_id",
            iterable=user_ids,
            keyvalues={},
            retcols=(
                "user_id",
                "state",
                "last_active_ts",
                "last_federation_update_ts",
                "last_user_sync_ts",
                "status_msg",
                "currently_active",
            ),
            desc="get_presence_for_users",
        )

        for row in rows:
            row["currently_active"] = bool(row["currently_active"])

        return {row["user_id"]: UserPresenceState(**row) for row in rows}

    def get_current_presence_token(self):
        return self._presence_id_gen.get_current_token()

    def allow_presence_visible(self, observed_localpart, observer_userid):
        return self._simple_insert(
            table="presence_allow_inbound",
            values={
                "observed_user_id": observed_localpart,
                "observer_user_id": observer_userid,
            },
            desc="allow_presence_visible",
            or_ignore=True,
        )

    def disallow_presence_visible(self, observed_localpart, observer_userid):
        return self._simple_delete_one(
            table="presence_allow_inbound",
            keyvalues={
                "observed_user_id": observed_localpart,
                "observer_user_id": observer_userid,
            },
            desc="disallow_presence_visible",
        )