# -*- coding: utf-8 -*-
# Copyright 2020 The Matrix.org Foundation C.I.C.
#
# 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 typing import Optional

from synapse.config._base import Config
from synapse.config._util import validate_config


class FederationConfig(Config):
    section = "federation"

    def read_config(self, config, **kwargs):
        # FIXME: federation_domain_whitelist needs sytests
        self.federation_domain_whitelist = None  # type: Optional[dict]
        federation_domain_whitelist = config.get("federation_domain_whitelist", None)

        if federation_domain_whitelist is not None:
            # turn the whitelist into a hash for speed of lookup
            self.federation_domain_whitelist = {}

            for domain in federation_domain_whitelist:
                self.federation_domain_whitelist[domain] = True

        federation_metrics_domains = config.get("federation_metrics_domains") or []
        validate_config(
            _METRICS_FOR_DOMAINS_SCHEMA,
            federation_metrics_domains,
            ("federation_metrics_domains",),
        )
        self.federation_metrics_domains = set(federation_metrics_domains)

    def generate_config_section(self, config_dir_path, server_name, **kwargs):
        return """\
        ## Federation ##

        # Restrict federation to the following whitelist of domains.
        # N.B. we recommend also firewalling your federation listener to limit
        # inbound federation traffic as early as possible, rather than relying
        # purely on this application-layer restriction.  If not specified, the
        # default is to whitelist everything.
        #
        #federation_domain_whitelist:
        #  - lon.example.com
        #  - nyc.example.com
        #  - syd.example.com

        # List of IP address CIDR ranges that should be allowed for federation,
        # identity servers, push servers, and for checking key validity for
        # third-party invite events. This is useful for specifying exceptions to
        # wide-ranging blacklisted target IP ranges - e.g. for communication with
        # a push server only visible in your network.
        #
        # This whitelist overrides ip_range_blacklist and defaults to an empty
        # list.
        #
        #ip_range_whitelist:
        #   - '192.168.1.1'

        # Report prometheus metrics on the age of PDUs being sent to and received from
        # the following domains. This can be used to give an idea of "delay" on inbound
        # and outbound federation, though be aware that any delay can be due to problems
        # at either end or with the intermediate network.
        #
        # By default, no domains are monitored in this way.
        #
        #federation_metrics_domains:
        #  - matrix.org
        #  - example.com
        """


_METRICS_FOR_DOMAINS_SCHEMA = {"type": "array", "items": {"type": "string"}}