#!/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.server import HomeServer
from synapse.config._base import ConfigError
from synapse.config.workers import clobber_with_worker_config
from synapse.config.logger import setup_logging
from synapse.config.homeserver import HomeServerConfig
from synapse.http.site import SynapseSite
from synapse.metrics.resource import MetricsResource, METRICS_PREFIX
from synapse.storage.roommember import RoomMemberStore
from synapse.replication.slave.storage.events import SlavedEventStore
from synapse.replication.slave.storage.pushers import SlavedPusherStore
from synapse.replication.slave.storage.receipts import SlavedReceiptsStore
from synapse.replication.slave.storage.account_data import SlavedAccountDataStore
from synapse.storage.engines import create_engine
from synapse.storage import DataStore
from synapse.util.async import sleep
from synapse.util.httpresourcetree import create_resource_tree
from synapse.util.logcontext import LoggingContext, preserve_fn
from synapse.util.manhole import manhole
from synapse.util.rlimit import change_resource_limit
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

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


class PusherSlaveStore(
    SlavedEventStore, SlavedPusherStore, SlavedReceiptsStore,
    SlavedAccountDataStore
):
    update_pusher_last_stream_ordering_and_success = (
        DataStore.update_pusher_last_stream_ordering_and_success.__func__
    )

    update_pusher_failing_since = (
        DataStore.update_pusher_failing_since.__func__
    )

    update_pusher_last_stream_ordering = (
        DataStore.update_pusher_last_stream_ordering.__func__
    )

    get_throttle_params_by_room = (
        DataStore.get_throttle_params_by_room.__func__
    )

    set_throttle_params = (
        DataStore.set_throttle_params.__func__
    )

    get_time_of_last_push_action_before = (
        DataStore.get_time_of_last_push_action_before.__func__
    )

    get_profile_displayname = (
        DataStore.get_profile_displayname.__func__
    )

    # XXX: This is a bit broken because we don't persist forgotten rooms
    # in a way that they can be streamed. This means that we don't have a
    # way to invalidate the forgotten rooms cache correctly.
    # For now we expire the cache every 10 minutes.
    BROKEN_CACHE_EXPIRY_MS = 60 * 60 * 1000
    who_forgot_in_room = (
        RoomMemberStore.__dict__["who_forgot_in_room"]
    )


class PusherServer(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 = PusherSlaveStore(self.get_db_conn(), self)
        logger.info("Finished setting up.")

    def remove_pusher(self, app_id, push_key, user_id):
        http_client = self.get_simple_http_client()
        replication_url = self.worker_config.replication_url
        url = replication_url + "/remove_pushers"
        return http_client.post_json_get_json(url, {
            "remove": [{
                "app_id": app_id,
                "push_key": push_key,
                "user_id": user_id,
            }]
        })

    def _listen_http(self, listener_config):
        port = listener_config["port"]
        bind_address = listener_config.get("bind_address", "")
        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)

        root_resource = create_resource_tree(resources, Resource())
        reactor.listenTCP(
            port,
            SynapseSite(
                "synapse.access.http.%s" % (site_tag,),
                site_tag,
                listener_config,
                root_resource,
            ),
            interface=bind_address
        )
        logger.info("Synapse pusher 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":
                reactor.listenTCP(
                    listener["port"],
                    manhole(
                        username="matrix",
                        password="rabbithole",
                        globals={"hs": self},
                    ),
                    interface=listener.get("bind_address", '127.0.0.1')
                )
            else:
                logger.warn("Unrecognized listener type: %s", listener["type"])

    @defer.inlineCallbacks
    def replicate(self):
        http_client = self.get_simple_http_client()
        store = self.get_datastore()
        replication_url = self.worker_config.replication_url
        pusher_pool = self.get_pusherpool()
        clock = self.get_clock()

        def stop_pusher(user_id, app_id, pushkey):
            key = "%s:%s" % (app_id, pushkey)
            pushers_for_user = pusher_pool.pushers.get(user_id, {})
            pusher = pushers_for_user.pop(key, None)
            if pusher is None:
                return
            logger.info("Stopping pusher %r / %r", user_id, key)
            pusher.on_stop()

        def start_pusher(user_id, app_id, pushkey):
            key = "%s:%s" % (app_id, pushkey)
            logger.info("Starting pusher %r / %r", user_id, key)
            return pusher_pool._refresh_pusher(app_id, pushkey, user_id)

        @defer.inlineCallbacks
        def poke_pushers(results):
            pushers_rows = set(
                map(tuple, results.get("pushers", {}).get("rows", []))
            )
            deleted_pushers_rows = set(
                map(tuple, results.get("deleted_pushers", {}).get("rows", []))
            )
            for row in sorted(pushers_rows | deleted_pushers_rows):
                if row in deleted_pushers_rows:
                    user_id, app_id, pushkey = row[1:4]
                    stop_pusher(user_id, app_id, pushkey)
                elif row in pushers_rows:
                    user_id = row[1]
                    app_id = row[5]
                    pushkey = row[8]
                    yield start_pusher(user_id, app_id, pushkey)

            stream = results.get("events")
            if stream:
                min_stream_id = stream["rows"][0][0]
                max_stream_id = stream["position"]
                preserve_fn(pusher_pool.on_new_notifications)(
                    min_stream_id, max_stream_id
                )

            stream = results.get("receipts")
            if stream:
                rows = stream["rows"]
                affected_room_ids = set(row[1] for row in rows)
                min_stream_id = rows[0][0]
                max_stream_id = stream["position"]
                preserve_fn(pusher_pool.on_new_receipts)(
                    min_stream_id, max_stream_id, affected_room_ids
                )

        def expire_broken_caches():
            store.who_forgot_in_room.invalidate_all()

        next_expire_broken_caches_ms = 0
        while True:
            try:
                args = store.stream_positions()
                args["timeout"] = 30000
                result = yield http_client.get_json(replication_url, args=args)
                now_ms = clock.time_msec()
                if now_ms > next_expire_broken_caches_ms:
                    expire_broken_caches()
                    next_expire_broken_caches_ms = (
                        now_ms + store.BROKEN_CACHE_EXPIRY_MS
                    )
                yield store.process_replication(result)
                poke_pushers(result)
            except:
                logger.exception("Error replicating from %r", replication_url)
                yield sleep(30)


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

    worker_config = config.workers[worker_name]

    setup_logging(worker_config.log_config, worker_config.log_file)

    clobber_with_worker_config(config, worker_config)

    if config.start_pushers:
        sys.stderr.write(
            "\nThe pushers must be disabled in the main synapse process"
            "\nbefore they can be run in a separate worker."
            "\nPlease add ``start_pushers: false`` to the main config"
            "\n"
        )
        sys.exit(1)

    # Force the pushers to start since they will be disabled in the main config
    config.start_pushers = True

    database_engine = create_engine(config.database_config)

    ps = PusherServer(
        config.server_name,
        db_config=config.database_config,
        config=config,
        worker_config=worker_config,
        version_string=get_version_string("Synapse", synapse),
        database_engine=database_engine,
    )

    ps.setup()
    ps.start_listening(worker_config.listeners)

    def run():
        with LoggingContext("run"):
            logger.info("Running")
            change_resource_limit(worker_config.soft_file_limit)
            if worker_config.gc_thresholds:
                ps.set_threshold(worker_config.gc_thresholds)
            reactor.run()

    def start():
        ps.replicate()
        ps.get_pusherpool().start()
        ps.get_datastore().start_profiling()

    reactor.callWhenRunning(start)

    if worker_config.daemonize:
        daemon = Daemonize(
            app="synapse-pusher",
            pid=worker_config.pid_file,
            action=run,
            auto_close_fds=False,
            verbose=True,
            logger=logger,
        )
        daemon.start()
    else:
        run()


if __name__ == '__main__':
    with LoggingContext("main"):
        worker_name = sys.argv[1]
        ps = setup(worker_name, sys.argv[2:])