# mysql/mysqldb.py
# Copyright (C) 2005-2015 the SQLAlchemy authors and contributors
# <see AUTHORS file>
#
# This module is part of SQLAlchemy and is released under
# the MIT License: http://www.opensource.org/licenses/mit-license.php

"""

.. dialect:: mysql+mysqldb
    :name: MySQL-Python
    :dbapi: mysqldb
    :connectstring: mysql+mysqldb://<user>:<password>@<host>[:<port>]/<dbname>
    :url: http://sourceforge.net/projects/mysql-python

.. _mysqldb_unicode:

Unicode
-------

Please see :ref:`mysql_unicode` for current recommendations on unicode
handling.

Py3K Support
------------

Currently, MySQLdb only runs on Python 2 and development has been stopped.
`mysqlclient`_ is fork of MySQLdb and provides Python 3 support as well
as some bugfixes.

.. _mysqlclient: https://github.com/PyMySQL/mysqlclient-python

Using MySQLdb with Google Cloud SQL
-----------------------------------

Google Cloud SQL now recommends use of the MySQLdb dialect.  Connect
using a URL like the following::

    mysql+mysqldb://root@/<dbname>?unix_socket=/cloudsql/<projectid>:<instancename>

"""

from .base import (MySQLDialect, MySQLExecutionContext,
                   MySQLCompiler, MySQLIdentifierPreparer)
from ...connectors.mysqldb import (
    MySQLDBExecutionContext,
    MySQLDBCompiler,
    MySQLDBIdentifierPreparer,
    MySQLDBConnector
)
from .base import TEXT
from ... import sql


class MySQLExecutionContext_mysqldb(
        MySQLDBExecutionContext,
        MySQLExecutionContext):
    pass


class MySQLCompiler_mysqldb(MySQLDBCompiler, MySQLCompiler):
    pass


class MySQLIdentifierPreparer_mysqldb(
        MySQLDBIdentifierPreparer,
        MySQLIdentifierPreparer):
    pass


class MySQLDialect_mysqldb(MySQLDBConnector, MySQLDialect):
    execution_ctx_cls = MySQLExecutionContext_mysqldb
    statement_compiler = MySQLCompiler_mysqldb
    preparer = MySQLIdentifierPreparer_mysqldb

    def _check_unicode_returns(self, connection):
        # work around issue fixed in
        # https://github.com/farcepest/MySQLdb1/commit/cd44524fef63bd3fcb71947392326e9742d520e8
        # specific issue w/ the utf8_bin collation and unicode returns

        has_utf8_bin = self.server_version_info > (5, ) and \
            connection.scalar(
                "show collation where %s = 'utf8' and %s = 'utf8_bin'"
                % (
                    self.identifier_preparer.quote("Charset"),
                    self.identifier_preparer.quote("Collation")
                ))
        if has_utf8_bin:
            additional_tests = [
                sql.collate(sql.cast(
                    sql.literal_column(
                            "'test collated returns'"),
                    TEXT(charset='utf8')), "utf8_bin")
            ]
        else:
            additional_tests = []
        return super(MySQLDBConnector, self)._check_unicode_returns(
            connection, additional_tests)

dialect = MySQLDialect_mysqldb