#!/usr/bin/env python
#
# Copyright 2007 Google Inc.
#
# 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.
#


"""Relational database API stub that uses the MySQLdb DB-API library.

Also see the rdbms module.
"""


import logging
import os

_POTENTIAL_SOCKET_LOCATIONS = (
    '/tmp/mysql.sock',
    '/var/run/mysqld/mysqld.sock',
    '/var/lib/mysql/mysql.sock',
    '/var/run/mysql/mysql.sock',
    '/var/mysql/mysql.sock',
    )


_connect_kwargs = {}


_OS_NAME = os.name


def SetConnectKwargs(**kwargs):
  """Sets the keyword args (host, user, etc) to pass to MySQLdb.connect()."""

  global _connect_kwargs
  _connect_kwargs = dict(kwargs)


def FindUnixSocket():
  """Find the Unix socket for MySQL by scanning some known locations.

  Returns:
    If found, the path to the Unix socket, otherwise, None.
  """
  for path in _POTENTIAL_SOCKET_LOCATIONS:
    if os.path.exists(path):
      return path


try:
  import google
  import MySQLdb

  from MySQLdb import *


  __import__('MySQLdb.constants', globals(), locals(), ['*'])
except ImportError:

  def connect(instance=None, database=None):
    logging.error('The rdbms API (Google Cloud SQL) is not available because '
                  'the MySQLdb library could not be loaded. Please see the SDK '
                  'documentation for installation instructions.')

    raise NotImplementedError('Unable to find the MySQLdb library')
else:


  def connect(instance=None, database=None, **kwargs):
    merged_kwargs = _connect_kwargs.copy()
    if database:
      merged_kwargs['db'] = database
    merged_kwargs.update(kwargs)
    if 'password' in merged_kwargs:
      merged_kwargs['passwd'] = merged_kwargs.pop('password')
    host = merged_kwargs.get('host')
    if ((not host or host == 'localhost') and
        not merged_kwargs.get('unix_socket') and
        _OS_NAME == 'posix'):


      socket = FindUnixSocket()
      if socket:
        merged_kwargs['unix_socket'] = socket
      else:
        logging.warning(
            'Unable to find MySQL socket file.  Use --mysql_socket to '
            'specify its location manually.')
    logging.info('Connecting to MySQL with kwargs %r', merged_kwargs)
    try:
      return MySQLdb.connect(**merged_kwargs)
    except MySQLdb.Error:
      logging.critical(
          'MySQL connection failed! Ensure that you have provided correct '
          'values for the --mysql_* flags when running dev_appserver.py')
      raise


def set_instance(instance):
  logging.info('set_instance() is a noop in dev_appserver.')