#!/usr/bin/env python
# -*- coding: utf-8 -*-
# Copyright 2014, 2015 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.

from synapse.storage import prepare_database, UpgradeDatabaseException

from synapse.server import HomeServer

from synapse.python_dependencies import check_requirements

from twisted.internet import reactor
from twisted.enterprise import adbapi
from twisted.web.resource import Resource
from twisted.web.static import File
from twisted.web.server import Site
from synapse.http.server import JsonResource, RootRedirect
from synapse.rest.media.v0.content_repository import ContentRepoResource
from synapse.rest.media.v1.media_repository import MediaRepositoryResource
from synapse.http.server_key_resource import LocalKey
from synapse.http.matrixfederationclient import MatrixFederationHttpClient
from synapse.api.urls import (
    CLIENT_PREFIX, FEDERATION_PREFIX, WEB_CLIENT_PREFIX, CONTENT_REPO_PREFIX,
    SERVER_KEY_PREFIX, MEDIA_PREFIX, CLIENT_V2_ALPHA_PREFIX,
)
from synapse.config.homeserver import HomeServerConfig
from synapse.crypto import context_factory
from synapse.util.logcontext import LoggingContext
from synapse.rest.client.v1 import ClientV1RestResource
from synapse.rest.client.v2_alpha import ClientV2AlphaRestResource

from daemonize import Daemonize
import twisted.manhole.telnet

import synapse

import logging
import os
import re
import sys
import sqlite3
import syweb

logger = logging.getLogger(__name__)


class SynapseHomeServer(HomeServer):

    def build_http_client(self):
        return MatrixFederationHttpClient(self)

    def build_resource_for_client(self):
        return ClientV1RestResource(self)

    def build_resource_for_client_v2_alpha(self):
        return ClientV2AlphaRestResource(self)

    def build_resource_for_federation(self):
        return JsonResource()

    def build_resource_for_web_client(self):
        syweb_path = os.path.dirname(syweb.__file__)
        webclient_path = os.path.join(syweb_path, "webclient")
        return File(webclient_path)  # TODO configurable?

    def build_resource_for_content_repo(self):
        return ContentRepoResource(
            self, self.upload_dir, self.auth, self.content_addr
        )

    def build_resource_for_media_repository(self):
        return MediaRepositoryResource(self)

    def build_resource_for_server_key(self):
        return LocalKey(self)

    def build_db_pool(self):
        return adbapi.ConnectionPool(
            "sqlite3", self.get_db_name(),
            check_same_thread=False,
            cp_min=1,
            cp_max=1
        )

    def create_resource_tree(self, web_client, redirect_root_to_web_client):
        """Create the resource tree for this Home Server.

        This in unduly complicated because Twisted does not support putting
        child resources more than 1 level deep at a time.

        Args:
            web_client (bool): True to enable the web client.
            redirect_root_to_web_client (bool): True to redirect '/' to the
            location of the web client. This does nothing if web_client is not
            True.
        """
        # list containing (path_str, Resource) e.g:
        # [ ("/aaa/bbb/cc", Resource1), ("/aaa/dummy", Resource2) ]
        desired_tree = [
            (CLIENT_PREFIX, self.get_resource_for_client()),
            (CLIENT_V2_ALPHA_PREFIX, self.get_resource_for_client_v2_alpha()),
            (FEDERATION_PREFIX, self.get_resource_for_federation()),
            (CONTENT_REPO_PREFIX, self.get_resource_for_content_repo()),
            (SERVER_KEY_PREFIX, self.get_resource_for_server_key()),
            (MEDIA_PREFIX, self.get_resource_for_media_repository()),
        ]
        if web_client:
            logger.info("Adding the web client.")
            desired_tree.append((WEB_CLIENT_PREFIX,
                                self.get_resource_for_web_client()))

        if web_client and redirect_root_to_web_client:
            self.root_resource = RootRedirect(WEB_CLIENT_PREFIX)
        else:
            self.root_resource = Resource()

        # ideally we'd just use getChild and putChild but getChild doesn't work
        # unless you give it a Request object IN ADDITION to the name :/ So
        # instead, we'll store a copy of this mapping so we can actually add
        # extra resources to existing nodes. See self._resource_id for the key.
        resource_mappings = {}
        for (full_path, resource) in desired_tree:
            logger.info("Attaching %s to path %s", resource, full_path)
            last_resource = self.root_resource
            for path_seg in full_path.split('/')[1:-1]:
                if not path_seg in last_resource.listNames():
                    # resource doesn't exist, so make a "dummy resource"
                    child_resource = Resource()
                    last_resource.putChild(path_seg, child_resource)
                    res_id = self._resource_id(last_resource, path_seg)
                    resource_mappings[res_id] = child_resource
                    last_resource = child_resource
                else:
                    # we have an existing Resource, use that instead.
                    res_id = self._resource_id(last_resource, path_seg)
                    last_resource = resource_mappings[res_id]

            # ===========================
            # now attach the actual desired resource
            last_path_seg = full_path.split('/')[-1]

            # if there is already a resource here, thieve its children and
            # replace it
            res_id = self._resource_id(last_resource, last_path_seg)
            if res_id in resource_mappings:
                # there is a dummy resource at this path already, which needs
                # to be replaced with the desired resource.
                existing_dummy_resource = resource_mappings[res_id]
                for child_name in existing_dummy_resource.listNames():
                    child_res_id = self._resource_id(existing_dummy_resource,
                                                     child_name)
                    child_resource = resource_mappings[child_res_id]
                    # steal the children
                    resource.putChild(child_name, child_resource)

            # finally, insert the desired resource in the right place
            last_resource.putChild(last_path_seg, resource)
            res_id = self._resource_id(last_resource, last_path_seg)
            resource_mappings[res_id] = resource

        return self.root_resource

    def _resource_id(self, resource, path_seg):
        """Construct an arbitrary resource ID so you can retrieve the mapping
        later.

        If you want to represent resource A putChild resource B with path C,
        the mapping should looks like _resource_id(A,C) = B.

        Args:
            resource (Resource): The *parent* Resource
            path_seg (str): The name of the child Resource to be attached.
        Returns:
            str: A unique string which can be a key to the child Resource.
        """
        return "%s-%s" % (resource, path_seg)

    def start_listening(self, secure_port, unsecure_port):
        if secure_port is not None:
            reactor.listenSSL(
                secure_port, Site(self.root_resource), self.tls_context_factory
            )
            logger.info("Synapse now listening on port %d", secure_port)
        if unsecure_port is not None:
            reactor.listenTCP(
                unsecure_port, Site(self.root_resource)
            )
            logger.info("Synapse now listening on port %d", unsecure_port)


def setup():
    config = HomeServerConfig.load_config(
        "Synapse Homeserver",
        sys.argv[1:],
        generate_section="Homeserver"
    )

    config.setup_logging()

    check_requirements()

    logger.info("Server hostname: %s", config.server_name)
    logger.info("Server version: %s", synapse.__version__)

    if re.search(":[0-9]+$", config.server_name):
        domain_with_port = config.server_name
    else:
        domain_with_port = "%s:%s" % (config.server_name, config.bind_port)

    tls_context_factory = context_factory.ServerContextFactory(config)

    hs = SynapseHomeServer(
        config.server_name,
        domain_with_port=domain_with_port,
        upload_dir=os.path.abspath("uploads"),
        db_name=config.database_path,
        tls_context_factory=tls_context_factory,
        config=config,
        content_addr=config.content_addr,
    )

    hs.create_resource_tree(
        web_client=config.webclient,
        redirect_root_to_web_client=True,
    )

    db_name = hs.get_db_name()

    logger.info("Preparing database: %s...", db_name)

    try:
        with sqlite3.connect(db_name) as db_conn:
            prepare_database(db_conn)
    except UpgradeDatabaseException:
        sys.stderr.write(
            "\nFailed to upgrade database.\n"
            "Have you checked for version specific instructions in"
            " UPGRADES.rst?\n"
        )
        sys.exit(1)

    logger.info("Database prepared in %s.", db_name)

    db_pool = hs.get_db_pool()

    if db_name == ":memory:":
        # Memory databases will need to be setup each time they are opened.
        reactor.callWhenRunning(
            db_pool.runWithConnection, prepare_database
        )

    if config.manhole:
        f = twisted.manhole.telnet.ShellFactory()
        f.username = "matrix"
        f.password = "rabbithole"
        f.namespace['hs'] = hs
        reactor.listenTCP(config.manhole, f, interface='127.0.0.1')

    bind_port = config.bind_port
    if config.no_tls:
        bind_port = None
    hs.start_listening(bind_port, config.unsecure_port)

    hs.get_pusherpool().start()

    if config.daemonize:
        print config.pid_file
        daemon = Daemonize(
            app="synapse-homeserver",
            pid=config.pid_file,
            action=run,
            auto_close_fds=False,
            verbose=True,
            logger=logger,
        )

        daemon.start()
    else:
        reactor.run()


def run():
    with LoggingContext("run"):
        reactor.run()


def main():
    with LoggingContext("main"):
        check_requirements()
        setup()


if __name__ == '__main__':
    main()