#!/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.config._base import ConfigError
from synapse.config.homeserver import HomeServerConfig
from synapse.config.logger import setup_logging
from synapse.http.site import SynapseSite
from synapse.http.server import JsonResource
from synapse.metrics.resource import MetricsResource, METRICS_PREFIX
from synapse.replication.slave.storage._base import BaseSlavedStore
from synapse.replication.slave.storage.client_ips import SlavedClientIpStore
from synapse.replication.slave.storage.devices import SlavedDeviceStore
from synapse.replication.tcp.client import ReplicationClientHandler
from synapse.server import HomeServer
from synapse.storage.engines import create_engine
from synapse.util.httpresourcetree import create_resource_tree
from synapse.util.logcontext import LoggingContext, PreserveLoggingContext
from synapse.util.manhole import manhole
from synapse.util.rlimit import change_resource_limit
from synapse.util.versionstring import get_version_string
from synapse.crypto import context_factory
from synapse.api.errors import SynapseError
from synapse.http.servlet import (
    RestServlet, parse_json_object_from_request,
)
from synapse.rest.client.v2_alpha._base import client_v2_patterns

from synapse import events


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

from daemonize import Daemonize

import sys
import logging
import gc


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


class KeyUploadServlet(RestServlet):
    PATTERNS = client_v2_patterns("/keys/upload(/(?P<device_id>[^/]+))?$",
                                  releases=())

    def __init__(self, hs):
        """
        Args:
            hs (synapse.server.HomeServer): server
        """
        super(KeyUploadServlet, self).__init__()
        self.auth = hs.get_auth()
        self.store = hs.get_datastore()
        self.http_client = hs.get_simple_http_client()
        self.main_uri = hs.config.worker_main_http_uri

    @defer.inlineCallbacks
    def on_POST(self, request, device_id):
        requester = yield self.auth.get_user_by_req(request, allow_guest=True)
        user_id = requester.user.to_string()
        body = parse_json_object_from_request(request)

        if device_id is not None:
            # passing the device_id here is deprecated; however, we allow it
            # for now for compatibility with older clients.
            if (requester.device_id is not None and
                    device_id != requester.device_id):
                logger.warning("Client uploading keys for a different device "
                               "(logged in as %s, uploading for %s)",
                               requester.device_id, device_id)
        else:
            device_id = requester.device_id

        if device_id is None:
            raise SynapseError(
                400,
                "To upload keys, you must pass device_id when authenticating"
            )

        if body:
            # They're actually trying to upload something, proxy to main synapse.
            result = yield self.http_client.post_json_get_json(
                self.main_uri + request.uri,
                body,
            )

            defer.returnValue((200, result))
        else:
            # Just interested in counts.
            result = yield self.store.count_e2e_one_time_keys(user_id, device_id)
            defer.returnValue((200, {"one_time_key_counts": result}))


class FrontendProxySlavedStore(
    SlavedDeviceStore,
    SlavedClientIpStore,
    BaseSlavedStore,
):
    pass


class FrontendProxyServer(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 = FrontendProxySlavedStore(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)
                    KeyUploadServlet(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 client reader 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 ReplicationClientHandler(self.get_datastore())


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

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

    assert config.worker_main_http_uri is not None

    setup_logging(config, use_worker_options=True)

    events.USE_FROZEN_DICTS = config.use_frozen_dicts

    database_engine = create_engine(config.database_config)

    tls_server_context_factory = context_factory.ServerContextFactory(config)

    ss = FrontendProxyServer(
        config.server_name,
        db_config=config.database_config,
        tls_server_context_factory=tls_server_context_factory,
        config=config,
        version_string="Synapse/" + get_version_string(synapse),
        database_engine=database_engine,
    )

    ss.setup()
    ss.get_handlers()
    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_state_handler().start_caching()
        ss.get_datastore().start_profiling()

    reactor.callWhenRunning(start)

    if config.worker_daemonize:
        daemon = Daemonize(
            app="synapse-frontend-proxy",
            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:])