# Copyright 2014-2016 OpenMarket Ltd
# Copyright 2019 New Vector 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 os
import sys
from typing import Dict, Iterable, List

from matrix_common.versionstring import get_distribution_version_string

from twisted.internet.tcp import Port
from twisted.web.resource import EncodingResourceWrapper, Resource
from twisted.web.server import GzipEncoderFactory

import synapse
import synapse.config.logger
from synapse import events
from synapse.api.urls import (
    CLIENT_API_PREFIX,
    FEDERATION_PREFIX,
    LEGACY_MEDIA_PREFIX,
    MEDIA_R0_PREFIX,
    MEDIA_V3_PREFIX,
    SERVER_KEY_V2_PREFIX,
    STATIC_PREFIX,
)
from synapse.app import _base
from synapse.app._base import (
    handle_startup_exception,
    listen_ssl,
    listen_tcp,
    max_request_body_size,
    redirect_stdio_to_logs,
    register_start,
)
from synapse.config._base import ConfigError, format_config_error
from synapse.config.emailconfig import ThreepidBehaviour
from synapse.config.homeserver import HomeServerConfig
from synapse.config.server import ListenerConfig
from synapse.federation.transport.server import TransportLayerServer
from synapse.http.additional_resource import AdditionalResource
from synapse.http.server import (
    OptionsResource,
    RootOptionsRedirectResource,
    StaticResource,
)
from synapse.http.site import SynapseSite
from synapse.logging.context import LoggingContext
from synapse.metrics import METRICS_PREFIX, MetricsResource, RegistryProxy
from synapse.replication.http import REPLICATION_PREFIX, ReplicationRestResource
from synapse.replication.tcp.resource import ReplicationStreamProtocolFactory
from synapse.rest import ClientRestResource
from synapse.rest.admin import AdminRestResource
from synapse.rest.health import HealthResource
from synapse.rest.key.v2 import KeyApiV2Resource
from synapse.rest.synapse.client import build_synapse_client_resource_tree
from synapse.rest.well_known import well_known_resource
from synapse.server import HomeServer
from synapse.storage import DataStore
from synapse.util.check_dependencies import check_requirements
from synapse.util.httpresourcetree import create_resource_tree
from synapse.util.module_loader import load_module

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


def gz_wrap(r: Resource) -> Resource:
    return EncodingResourceWrapper(r, [GzipEncoderFactory()])


class SynapseHomeServer(HomeServer):
    DATASTORE_CLASS = DataStore  # type: ignore

    def _listener_http(
        self, config: HomeServerConfig, listener_config: ListenerConfig
    ) -> Iterable[Port]:
        port = listener_config.port
        bind_addresses = listener_config.bind_addresses
        tls = listener_config.tls
        # Must exist since this is an HTTP listener.
        assert listener_config.http_options is not None
        site_tag = listener_config.http_options.tag
        if site_tag is None:
            site_tag = str(port)

        # We always include a health resource.
        resources: Dict[str, Resource] = {"/health": HealthResource()}

        for res in listener_config.http_options.resources:
            for name in res.names:
                if name == "openid" and "federation" in res.names:
                    # Skip loading openid resource if federation is defined
                    # since federation resource will include openid
                    continue
                resources.update(self._configure_named_resource(name, res.compress))

        additional_resources = listener_config.http_options.additional_resources
        logger.debug("Configuring additional resources: %r", additional_resources)
        module_api = self.get_module_api()
        for path, resmodule in additional_resources.items():
            handler_cls, config = load_module(
                resmodule,
                ("listeners", site_tag, "additional_resources", "<%s>" % (path,)),
            )
            handler = handler_cls(config, module_api)
            if isinstance(handler, Resource):
                resource = handler
            elif hasattr(handler, "handle_request"):
                resource = AdditionalResource(self, handler.handle_request)
            else:
                raise ConfigError(
                    "additional_resource %s does not implement a known interface"
                    % (resmodule["module"],)
                )
            resources[path] = resource

        # Attach additional resources registered by modules.
        resources.update(self._module_web_resources)
        self._module_web_resources_consumed = True

        # Try to find something useful to serve at '/':
        #
        # 1. Redirect to the web client if it is an HTTP(S) URL.
        # 2. Redirect to the static "Synapse is running" page.
        # 3. Do not redirect and use a blank resource.
        if self.config.server.web_client_location:
            root_resource: Resource = RootOptionsRedirectResource(
                self.config.server.web_client_location
            )
        elif STATIC_PREFIX in resources:
            root_resource = RootOptionsRedirectResource(STATIC_PREFIX)
        else:
            root_resource = OptionsResource()

        site = SynapseSite(
            "synapse.access.%s.%s" % ("https" if tls else "http", site_tag),
            site_tag,
            listener_config,
            create_resource_tree(resources, root_resource),
            self.version_string,
            max_request_body_size=max_request_body_size(self.config),
            reactor=self.get_reactor(),
        )

        if tls:
            # refresh_certificate should have been called before this.
            assert self.tls_server_context_factory is not None
            ports = listen_ssl(
                bind_addresses,
                port,
                site,
                self.tls_server_context_factory,
                reactor=self.get_reactor(),
            )
            logger.info("Synapse now listening on TCP port %d (TLS)", port)

        else:
            ports = listen_tcp(
                bind_addresses,
                port,
                site,
                reactor=self.get_reactor(),
            )
            logger.info("Synapse now listening on TCP port %d", port)

        return ports

    def _configure_named_resource(
        self, name: str, compress: bool = False
    ) -> Dict[str, Resource]:
        """Build a resource map for a named resource

        Args:
            name: named resource: one of "client", "federation", etc
            compress: whether to enable gzip compression for this resource

        Returns:
            map from path to HTTP resource
        """
        resources: Dict[str, Resource] = {}
        if name == "client":
            client_resource: Resource = ClientRestResource(self)
            if compress:
                client_resource = gz_wrap(client_resource)

            resources.update(
                {
                    CLIENT_API_PREFIX: client_resource,
                    "/.well-known": well_known_resource(self),
                    "/_synapse/admin": AdminRestResource(self),
                    **build_synapse_client_resource_tree(self),
                }
            )

            if self.config.email.threepid_behaviour_email == ThreepidBehaviour.LOCAL:
                from synapse.rest.synapse.client.password_reset import (
                    PasswordResetSubmitTokenResource,
                )

                resources[
                    "/_synapse/client/password_reset/email/submit_token"
                ] = PasswordResetSubmitTokenResource(self)

        if name == "consent":
            from synapse.rest.consent.consent_resource import ConsentResource

            consent_resource: Resource = ConsentResource(self)
            if compress:
                consent_resource = gz_wrap(consent_resource)
            resources.update({"/_matrix/consent": consent_resource})

        if name == "federation":
            resources.update({FEDERATION_PREFIX: TransportLayerServer(self)})

        if name == "openid":
            resources.update(
                {
                    FEDERATION_PREFIX: TransportLayerServer(
                        self, servlet_groups=["openid"]
                    )
                }
            )

        if name in ["static", "client"]:
            resources.update(
                {
                    STATIC_PREFIX: StaticResource(
                        os.path.join(os.path.dirname(synapse.__file__), "static")
                    )
                }
            )

        if name in ["media", "federation", "client"]:
            if self.config.server.enable_media_repo:
                media_repo = self.get_media_repository_resource()
                resources.update(
                    {
                        MEDIA_R0_PREFIX: media_repo,
                        MEDIA_V3_PREFIX: media_repo,
                        LEGACY_MEDIA_PREFIX: media_repo,
                    }
                )
            elif name == "media":
                raise ConfigError(
                    "'media' resource conflicts with enable_media_repo=False"
                )

        if name in ["keys", "federation"]:
            resources[SERVER_KEY_V2_PREFIX] = KeyApiV2Resource(self)

        if name == "metrics" and self.config.metrics.enable_metrics:
            metrics_resource: Resource = MetricsResource(RegistryProxy)
            if compress:
                metrics_resource = gz_wrap(metrics_resource)
            resources[METRICS_PREFIX] = metrics_resource

        if name == "replication":
            resources[REPLICATION_PREFIX] = ReplicationRestResource(self)

        return resources

    def start_listening(self) -> None:
        if self.config.redis.redis_enabled:
            # If redis is enabled we connect via the replication command handler
            # in the same way as the workers (since we're effectively a client
            # rather than a server).
            self.get_replication_command_handler().start_replication(self)

        for listener in self.config.server.listeners:
            if listener.type == "http":
                self._listening_services.extend(
                    self._listener_http(self.config, listener)
                )
            elif listener.type == "manhole":
                _base.listen_manhole(
                    listener.bind_addresses,
                    listener.port,
                    manhole_settings=self.config.server.manhole_settings,
                    manhole_globals={"hs": self},
                )
            elif listener.type == "replication":
                services = listen_tcp(
                    listener.bind_addresses,
                    listener.port,
                    ReplicationStreamProtocolFactory(self),
                )
                for s in services:
                    self.get_reactor().addSystemEventTrigger(
                        "before", "shutdown", s.stopListening
                    )
            elif listener.type == "metrics":
                if not self.config.metrics.enable_metrics:
                    logger.warning(
                        "Metrics listener configured, but "
                        "enable_metrics is not True!"
                    )
                else:
                    _base.listen_metrics(listener.bind_addresses, listener.port)
            else:
                # this shouldn't happen, as the listener type should have been checked
                # during parsing
                logger.warning("Unrecognized listener type: %s", listener.type)


def setup(config_options: List[str]) -> SynapseHomeServer:
    """
    Args:
        config_options_options: The options passed to Synapse. Usually `sys.argv[1:]`.

    Returns:
        A homeserver instance.
    """
    try:
        config = HomeServerConfig.load_or_generate_config(
            "Synapse Homeserver", config_options
        )
    except ConfigError as e:
        sys.stderr.write("\n")
        for f in format_config_error(e):
            sys.stderr.write(f)
        sys.stderr.write("\n")
        sys.exit(1)

    if not config:
        # If a config isn't returned, and an exception isn't raised, we're just
        # generating config files and shouldn't try to continue.
        sys.exit(0)

    if config.worker.worker_app:
        raise ConfigError(
            "You have specified `worker_app` in the config but are attempting to start a non-worker "
            "instance. Please use `python -m synapse.app.generic_worker` instead (or remove the option if this is the main process)."
        )
        sys.exit(1)

    events.USE_FROZEN_DICTS = config.server.use_frozen_dicts
    synapse.util.caches.TRACK_MEMORY_USAGE = config.caches.track_memory_usage

    if config.server.gc_seconds:
        synapse.metrics.MIN_TIME_BETWEEN_GCS = config.server.gc_seconds

    if (
        config.registration.enable_registration
        and not config.registration.enable_registration_without_verification
    ):
        if (
            not config.captcha.enable_registration_captcha
            and not config.registration.registrations_require_3pid
            and not config.registration.registration_requires_token
        ):

            raise ConfigError(
                "You have enabled open registration without any verification. This is a known vector for "
                "spam and abuse. If you would like to allow public registration, please consider adding email, "
                "captcha, or token-based verification. Otherwise this check can be removed by setting the "
                "`enable_registration_without_verification` config option to `true`."
            )

    hs = SynapseHomeServer(
        config.server.server_name,
        config=config,
        version_string="Synapse/" + get_distribution_version_string("matrix-synapse"),
    )

    synapse.config.logger.setup_logging(hs, config, use_worker_options=False)

    logger.info("Setting up server")

    try:
        hs.setup()
    except Exception as e:
        handle_startup_exception(e)

    async def start() -> None:
        # Load the OIDC provider metadatas, if OIDC is enabled.
        if hs.config.oidc.oidc_enabled:
            oidc = hs.get_oidc_handler()
            # Loading the provider metadata also ensures the provider config is valid.
            await oidc.load_metadata()

        await _base.start(hs)

        hs.get_datastores().main.db_pool.updates.start_doing_background_updates()

    register_start(start)

    return hs


def run(hs: HomeServer) -> None:
    _base.start_reactor(
        "synapse-homeserver",
        soft_file_limit=hs.config.server.soft_file_limit,
        gc_thresholds=hs.config.server.gc_thresholds,
        pid_file=hs.config.server.pid_file,
        daemonize=hs.config.server.daemonize,
        print_pidfile=hs.config.server.print_pidfile,
        logger=logger,
    )


def main() -> None:
    with LoggingContext("main"):
        # check base requirements
        check_requirements()
        hs = setup(sys.argv[1:])

        # redirect stdio to the logs, if configured.
        if not hs.config.logging.no_redirect_stdio:
            redirect_stdio_to_logs()

        run(hs)


if __name__ == "__main__":
    main()
