#!/usr/bin/env python
# -*- coding: utf-8 -*-
# Copyright 2019 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.

import argparse
import logging
import sys

import yaml

from twisted.internet import defer, reactor

from synapse.config.homeserver import HomeServerConfig
from synapse.metrics.background_process_metrics import run_as_background_process
from synapse.server import HomeServer
from synapse.storage import DataStore
from synapse.storage.engines import create_engine
from synapse.storage.prepare_database import prepare_database

logger = logging.getLogger("update_database")


class MockHomeserver(HomeServer):
    DATASTORE_CLASS = DataStore

    def __init__(self, config, database_engine, db_conn, **kwargs):
        super(MockHomeserver, self).__init__(
            config.server_name,
            reactor=reactor,
            config=config,
            database_engine=database_engine,
            **kwargs
        )

        self.database_engine = database_engine
        self.db_conn = db_conn

    def get_db_conn(self):
        return self.db_conn


if __name__ == "__main__":
    parser = argparse.ArgumentParser(
        description=(
            "Updates a synapse database to the latest schema and runs background updates"
            " on it."
        )
    )
    parser.add_argument("-v", action="store_true")
    parser.add_argument(
        "--database-config",
        type=argparse.FileType("r"),
        required=True,
        help="A database config file for either a SQLite3 database or a PostgreSQL one.",
    )

    args = parser.parse_args()

    logging_config = {
        "level": logging.DEBUG if args.v else logging.INFO,
        "format": "%(asctime)s - %(name)s - %(lineno)d - %(levelname)s - %(message)s",
    }

    logging.basicConfig(**logging_config)

    # Load, process and sanity-check the config.
    hs_config = yaml.safe_load(args.database_config)

    if "database" not in hs_config:
        sys.stderr.write("The configuration file must have a 'database' section.\n")
        sys.exit(4)

    config = HomeServerConfig()
    config.parse_config_dict(hs_config, "", "")

    # Create the database engine and a connection to it.
    database_engine = create_engine(config.database_config)
    db_conn = database_engine.module.connect(
        **{
            k: v
            for k, v in config.database_config.get("args", {}).items()
            if not k.startswith("cp_")
        }
    )

    # Update the database to the latest schema.
    prepare_database(db_conn, database_engine, config=config)
    db_conn.commit()

    # Instantiate and initialise the homeserver object.
    hs = MockHomeserver(
        config, database_engine, db_conn, db_config=config.database_config,
    )
    # setup instantiates the store within the homeserver object.
    hs.setup()
    store = hs.get_datastore()

    @defer.inlineCallbacks
    def run_background_updates():
        yield store.db.updates.run_background_updates(sleep=False)
        # Stop the reactor to exit the script once every background update is run.
        reactor.stop()

    # Apply all background updates on the database.
    reactor.callWhenRunning(
        lambda: run_as_background_process("background_updates", run_background_updates)
    )

    reactor.run()