#
# Licensed to the Apache Software Foundation (ASF) under one
# or more contributor license agreements.  See the NOTICE file
# distributed with this work for additional information
# regarding copyright ownership.  The ASF licenses this file
# to you 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 time
import traceback

from sqlalchemy import event, exc

from airflow.configuration import conf

log = logging.getLogger(__name__)


def setup_event_handlers(engine):
    """Setups event handlers."""
    # pylint: disable=unused-argument, unused-variable
    @event.listens_for(engine, "connect")
    def connect(dbapi_connection, connection_record):
        connection_record.info['pid'] = os.getpid()

    if engine.dialect.name == "sqlite":

        @event.listens_for(engine, "connect")
        def set_sqlite_pragma(dbapi_connection, connection_record):
            cursor = dbapi_connection.cursor()
            cursor.execute("PRAGMA foreign_keys=ON")
            cursor.close()

    # this ensures sanity in mysql when storing datetimes (not required for postgres)
    if engine.dialect.name == "mysql":

        @event.listens_for(engine, "connect")
        def set_mysql_timezone(dbapi_connection, connection_record):
            cursor = dbapi_connection.cursor()
            cursor.execute("SET time_zone = '+00:00'")
            cursor.close()

    @event.listens_for(engine, "checkout")
    def checkout(dbapi_connection, connection_record, connection_proxy):
        pid = os.getpid()
        if connection_record.info['pid'] != pid:
            connection_record.connection = connection_proxy.connection = None
            raise exc.DisconnectionError(
                "Connection record belongs to pid {}, "
                "attempting to check out in pid {}".format(connection_record.info['pid'], pid)
            )

    if conf.getboolean('debug', 'sqlalchemy_stats', fallback=False):

        @event.listens_for(engine, "before_cursor_execute")
        def before_cursor_execute(conn, cursor, statement, parameters, context, executemany):
            conn.info.setdefault('query_start_time', []).append(time.perf_counter())

        @event.listens_for(engine, "after_cursor_execute")
        def after_cursor_execute(conn, cursor, statement, parameters, context, executemany):
            total = time.perf_counter() - conn.info['query_start_time'].pop()
            file_name = [
                f"'{f.name}':{f.filename}:{f.lineno}"
                for f in traceback.extract_stack()
                if 'sqlalchemy' not in f.filename
            ][-1]
            stack = [f for f in traceback.extract_stack() if 'sqlalchemy' not in f.filename]
            stack_info = ">".join([f"{f.filename.rpartition('/')[-1]}:{f.name}" for f in stack][-3:])
            conn.info.setdefault('query_start_time', []).append(time.monotonic())
            log.info(
                "@SQLALCHEMY %s |$ %s |$ %s |$  %s ",
                total,
                file_name,
                stack_info,
                statement.replace("\n", " "),
            )

    # pylint: enable=unused-argument, unused-variable