#!/usr/bin/env python
# -*- coding: utf-8 -*-
# Copyright 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.

import synapse

from synapse.api.constants import EventTypes
from synapse.config._base import ConfigError
from synapse.config.homeserver import HomeServerConfig
from synapse.config.logger import setup_logging
from synapse.handlers.presence import PresenceHandler, get_interested_parties
from synapse.http.site import SynapseSite
from synapse.http.server import JsonResource
from synapse.metrics.resource import MetricsResource, METRICS_PREFIX
from synapse.rest.client.v2_alpha import sync
from synapse.rest.client.v1 import events
from synapse.rest.client.v1.room import RoomInitialSyncRestServlet
from synapse.rest.client.v1.initial_sync import InitialSyncRestServlet
from synapse.replication.slave.storage._base import BaseSlavedStore
from synapse.replication.slave.storage.events import SlavedEventStore
from synapse.replication.slave.storage.receipts import SlavedReceiptsStore
from synapse.replication.slave.storage.account_data import SlavedAccountDataStore
from synapse.replication.slave.storage.appservice import SlavedApplicationServiceStore
from synapse.replication.slave.storage.registration import SlavedRegistrationStore
from synapse.replication.slave.storage.filtering import SlavedFilteringStore
from synapse.replication.slave.storage.push_rule import SlavedPushRuleStore
from synapse.replication.slave.storage.presence import SlavedPresenceStore
from synapse.replication.slave.storage.deviceinbox import SlavedDeviceInboxStore
from synapse.replication.slave.storage.devices import SlavedDeviceStore
from synapse.replication.slave.storage.room import RoomStore
from synapse.replication.tcp.client import ReplicationClientHandler
from synapse.server import HomeServer
from synapse.storage.client_ips import ClientIpStore
from synapse.storage.engines import create_engine
from synapse.storage.presence import UserPresenceState
from synapse.storage.roommember import RoomMemberStore
from synapse.util.httpresourcetree import create_resource_tree
from synapse.util.logcontext import LoggingContext, PreserveLoggingContext, preserve_fn
from synapse.util.manhole import manhole
from synapse.util.rlimit import change_resource_limit
from synapse.util.stringutils import random_string
from synapse.util.versionstring import get_version_string

from twisted.internet import reactor, defer
from twisted.web.resource import Resource

from daemonize import Daemonize

import sys
import logging
import contextlib
import gc

logger = logging.getLogger("synapse.app.synchrotron")


class SynchrotronSlavedStore(
    SlavedPushRuleStore,
    SlavedEventStore,
    SlavedReceiptsStore,
    SlavedAccountDataStore,
    SlavedApplicationServiceStore,
    SlavedRegistrationStore,
    SlavedFilteringStore,
    SlavedPresenceStore,
    SlavedDeviceInboxStore,
    SlavedDeviceStore,
    RoomStore,
    BaseSlavedStore,
    ClientIpStore,  # After BaseSlavedStore because the constructor is different
):
    who_forgot_in_room = (
        RoomMemberStore.__dict__["who_forgot_in_room"]
    )

    did_forget = (
        RoomMemberStore.__dict__["did_forget"]
    )


UPDATE_SYNCING_USERS_MS = 10 * 1000


class SynchrotronPresence(object):
    def __init__(self, hs):
        self.hs = hs
        self.is_mine_id = hs.is_mine_id
        self.http_client = hs.get_simple_http_client()
        self.store = hs.get_datastore()
        self.user_to_num_current_syncs = {}
        self.clock = hs.get_clock()
        self.notifier = hs.get_notifier()

        active_presence = self.store.take_presence_startup_info()
        self.user_to_current_state = {
            state.user_id: state
            for state in active_presence
        }

        # user_id -> last_sync_ms. Lists the users that have stopped syncing
        # but we haven't notified the master of that yet
        self.users_going_offline = {}

        self._send_stop_syncing_loop = self.clock.looping_call(
            self.send_stop_syncing, 10 * 1000
        )

        self.process_id = random_string(16)
        logger.info("Presence process_id is %r", self.process_id)

    def send_user_sync(self, user_id, is_syncing, last_sync_ms):
        self.hs.get_tcp_replication().send_user_sync(user_id, is_syncing, last_sync_ms)

    def mark_as_coming_online(self, user_id):
        """A user has started syncing. Send a UserSync to the master, unless they
        had recently stopped syncing.

        Args:
            user_id (str)
        """
        going_offline = self.users_going_offline.pop(user_id, None)
        if not going_offline:
            # Safe to skip because we haven't yet told the master they were offline
            self.send_user_sync(user_id, True, self.clock.time_msec())

    def mark_as_going_offline(self, user_id):
        """A user has stopped syncing. We wait before notifying the master as
        its likely they'll come back soon. This allows us to avoid sending
        a stopped syncing immediately followed by a started syncing notification
        to the master

        Args:
            user_id (str)
        """
        self.users_going_offline[user_id] = self.clock.time_msec()

    def send_stop_syncing(self):
        """Check if there are any users who have stopped syncing a while ago
        and haven't come back yet. If there are poke the master about them.
        """
        now = self.clock.time_msec()
        for user_id, last_sync_ms in self.users_going_offline.items():
            if now - last_sync_ms > 10 * 1000:
                self.users_going_offline.pop(user_id, None)
                self.send_user_sync(user_id, False, last_sync_ms)

    def set_state(self, user, state, ignore_status_msg=False):
        # TODO Hows this supposed to work?
        pass

    get_states = PresenceHandler.get_states.__func__
    get_state = PresenceHandler.get_state.__func__
    current_state_for_users = PresenceHandler.current_state_for_users.__func__

    def user_syncing(self, user_id, affect_presence):
        if affect_presence:
            curr_sync = self.user_to_num_current_syncs.get(user_id, 0)
            self.user_to_num_current_syncs[user_id] = curr_sync + 1

            # If we went from no in flight sync to some, notify replication
            if self.user_to_num_current_syncs[user_id] == 1:
                self.mark_as_coming_online(user_id)

        def _end():
            # We check that the user_id is in user_to_num_current_syncs because
            # user_to_num_current_syncs may have been cleared if we are
            # shutting down.
            if affect_presence and user_id in self.user_to_num_current_syncs:
                self.user_to_num_current_syncs[user_id] -= 1

                # If we went from one in flight sync to non, notify replication
                if self.user_to_num_current_syncs[user_id] == 0:
                    self.mark_as_going_offline(user_id)

        @contextlib.contextmanager
        def _user_syncing():
            try:
                yield
            finally:
                _end()

        return defer.succeed(_user_syncing())

    @defer.inlineCallbacks
    def notify_from_replication(self, states, stream_id):
        parties = yield get_interested_parties(self.store, states)
        room_ids_to_states, users_to_states = parties

        self.notifier.on_new_event(
            "presence_key", stream_id, rooms=room_ids_to_states.keys(),
            users=users_to_states.keys()
        )

    @defer.inlineCallbacks
    def process_replication_rows(self, token, rows):
        states = [UserPresenceState(
            row.user_id, row.state, row.last_active_ts,
            row.last_federation_update_ts, row.last_user_sync_ts, row.status_msg,
            row.currently_active
        ) for row in rows]

        for state in states:
            self.user_to_current_state[row.user_id] = state

        stream_id = token
        yield self.notify_from_replication(states, stream_id)

    def get_currently_syncing_users(self):
        return [
            user_id for user_id, count in self.user_to_num_current_syncs.iteritems()
            if count > 0
        ]


class SynchrotronTyping(object):
    def __init__(self, hs):
        self._latest_room_serial = 0
        self._room_serials = {}
        self._room_typing = {}

    def stream_positions(self):
        # We must update this typing token from the response of the previous
        # sync. In particular, the stream id may "reset" back to zero/a low
        # value which we *must* use for the next replication request.
        return {"typing": self._latest_room_serial}

    def process_replication_rows(self, token, rows):
        self._latest_room_serial = token

        for row in rows:
            self._room_serials[row.room_id] = token
            self._room_typing[row.room_id] = row.user_ids


class SynchrotronApplicationService(object):
    def notify_interested_services(self, event):
        pass


class SynchrotronServer(HomeServer):
    def get_db_conn(self, run_new_connection=True):
        # Any param beginning with cp_ is a parameter for adbapi, and should
        # not be passed to the database engine.
        db_params = {
            k: v for k, v in self.db_config.get("args", {}).items()
            if not k.startswith("cp_")
        }
        db_conn = self.database_engine.module.connect(**db_params)

        if run_new_connection:
            self.database_engine.on_new_connection(db_conn)
        return db_conn

    def setup(self):
        logger.info("Setting up.")
        self.datastore = SynchrotronSlavedStore(self.get_db_conn(), self)
        logger.info("Finished setting up.")

    def _listen_http(self, listener_config):
        port = listener_config["port"]
        bind_addresses = listener_config["bind_addresses"]
        site_tag = listener_config.get("tag", port)
        resources = {}
        for res in listener_config["resources"]:
            for name in res["names"]:
                if name == "metrics":
                    resources[METRICS_PREFIX] = MetricsResource(self)
                elif name == "client":
                    resource = JsonResource(self, canonical_json=False)
                    sync.register_servlets(self, resource)
                    events.register_servlets(self, resource)
                    InitialSyncRestServlet(self).register(resource)
                    RoomInitialSyncRestServlet(self).register(resource)
                    resources.update({
                        "/_matrix/client/r0": resource,
                        "/_matrix/client/unstable": resource,
                        "/_matrix/client/v2_alpha": resource,
                        "/_matrix/client/api/v1": resource,
                    })

        root_resource = create_resource_tree(resources, Resource())

        for address in bind_addresses:
            reactor.listenTCP(
                port,
                SynapseSite(
                    "synapse.access.http.%s" % (site_tag,),
                    site_tag,
                    listener_config,
                    root_resource,
                ),
                interface=address
            )

        logger.info("Synapse synchrotron now listening on port %d", port)

    def start_listening(self, listeners):
        for listener in listeners:
            if listener["type"] == "http":
                self._listen_http(listener)
            elif listener["type"] == "manhole":
                bind_addresses = listener["bind_addresses"]

                for address in bind_addresses:
                    reactor.listenTCP(
                        listener["port"],
                        manhole(
                            username="matrix",
                            password="rabbithole",
                            globals={"hs": self},
                        ),
                        interface=address
                    )
            else:
                logger.warn("Unrecognized listener type: %s", listener["type"])

        self.get_tcp_replication().start_replication(self)

    def build_tcp_replication(self):
        return SyncReplicationHandler(self)

    def build_presence_handler(self):
        return SynchrotronPresence(self)

    def build_typing_handler(self):
        return SynchrotronTyping(self)


class SyncReplicationHandler(ReplicationClientHandler):
    def __init__(self, hs):
        super(SyncReplicationHandler, self).__init__(hs.get_datastore())

        self.store = hs.get_datastore()
        self.typing_handler = hs.get_typing_handler()
        self.presence_handler = hs.get_presence_handler()
        self.notifier = hs.get_notifier()

        self.presence_handler.sync_callback = self.send_user_sync

    def on_rdata(self, stream_name, token, rows):
        super(SyncReplicationHandler, self).on_rdata(stream_name, token, rows)

        preserve_fn(self.process_and_notify)(stream_name, token, rows)

    def get_streams_to_replicate(self):
        args = super(SyncReplicationHandler, self).get_streams_to_replicate()
        args.update(self.typing_handler.stream_positions())
        return args

    def get_currently_syncing_users(self):
        return self.presence_handler.get_currently_syncing_users()

    @defer.inlineCallbacks
    def process_and_notify(self, stream_name, token, rows):
        if stream_name == "events":
            # We shouldn't get multiple rows per token for events stream, so
            # we don't need to optimise this for multiple rows.
            for row in rows:
                event = yield self.store.get_event(row.event_id)
                extra_users = ()
                if event.type == EventTypes.Member:
                    extra_users = (event.state_key,)
                max_token = self.store.get_room_max_stream_ordering()
                self.notifier.on_new_room_event(
                    event, token, max_token, extra_users
                )
        elif stream_name == "push_rules":
            self.notifier.on_new_event(
                "push_rules_key", token, users=[row.user_id for row in rows],
            )
        elif stream_name in ("account_data", "tag_account_data",):
            self.notifier.on_new_event(
                "account_data_key", token, users=[row.user_id for row in rows],
            )
        elif stream_name == "receipts":
            self.notifier.on_new_event(
                "receipt_key", token, rooms=[row.room_id for row in rows],
            )
        elif stream_name == "typing":
            self.typing_handler.process_replication_rows(token, rows)
            self.notifier.on_new_event(
                "typing_key", token, rooms=[row.room_id for row in rows],
            )
        elif stream_name == "to_device":
            entities = [row.entity for row in rows if row.entity.startswith("@")]
            if entities:
                self.notifier.on_new_event(
                    "to_device_key", token, users=entities,
                )
        elif stream_name == "device_lists":
            all_room_ids = set()
            for row in rows:
                room_ids = yield self.store.get_rooms_for_user(row.user_id)
                all_room_ids.update(room_ids)
            self.notifier.on_new_event(
                "device_list_key", token, rooms=all_room_ids,
            )
        elif stream_name == "presence":
            yield self.presence_handler.process_replication_rows(token, rows)


def start(config_options):
    try:
        config = HomeServerConfig.load_config(
            "Synapse synchrotron", config_options
        )
    except ConfigError as e:
        sys.stderr.write("\n" + e.message + "\n")
        sys.exit(1)

    assert config.worker_app == "synapse.app.synchrotron"

    setup_logging(config, use_worker_options=True)

    synapse.events.USE_FROZEN_DICTS = config.use_frozen_dicts

    database_engine = create_engine(config.database_config)

    ss = SynchrotronServer(
        config.server_name,
        db_config=config.database_config,
        config=config,
        version_string="Synapse/" + get_version_string(synapse),
        database_engine=database_engine,
        application_service_handler=SynchrotronApplicationService(),
    )

    ss.setup()
    ss.start_listening(config.worker_listeners)

    def run():
        # make sure that we run the reactor with the sentinel log context,
        # otherwise other PreserveLoggingContext instances will get confused
        # and complain when they see the logcontext arbitrarily swapping
        # between the sentinel and `run` logcontexts.
        with PreserveLoggingContext():
            logger.info("Running")
            change_resource_limit(config.soft_file_limit)
            if config.gc_thresholds:
                gc.set_threshold(*config.gc_thresholds)
            reactor.run()

    def start():
        ss.get_datastore().start_profiling()
        ss.get_state_handler().start_caching()

    reactor.callWhenRunning(start)

    if config.worker_daemonize:
        daemon = Daemonize(
            app="synapse-synchrotron",
            pid=config.worker_pid_file,
            action=run,
            auto_close_fds=False,
            verbose=True,
            logger=logger,
        )
        daemon.start()
    else:
        run()


if __name__ == '__main__':
    with LoggingContext("main"):
        start(sys.argv[1:])
