# MySQL Connector/Python - MySQL driver written in Python.
# Copyright (c) 2014, 2018, Oracle and/or its affiliates. All rights reserved.

# MySQL Connector/Python is licensed under the terms of the GPLv2
# <http://www.gnu.org/licenses/old-licenses/gpl-2.0.html>, like most
# MySQL Connectors. There are special exceptions to the terms and
# conditions of the GPLv2 as it is applied to this software, see the
# FOSS License Exception
# <http://www.mysql.com/about/legal/licensing/foss-exception.html>.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA

"""Connection class using the C Extension
"""

# Detection of abstract methods in pylint is not working correctly
#pylint: disable=W0223

from . import errors
from .catch23 import INT_TYPES
from .constants import (
    CharacterSet, FieldFlag, ServerFlag, ShutdownType, ClientFlag
)
from .abstracts import MySQLConnectionAbstract, MySQLCursorAbstract
from .protocol import MySQLProtocol

HAVE_CMYSQL = False
# pylint: disable=F0401,C0413
try:
    import _mysql_connector
    from .cursor_cext import (
        CMySQLCursor, CMySQLCursorRaw,
        CMySQLCursorBuffered, CMySQLCursorBufferedRaw, CMySQLCursorPrepared,
        CMySQLCursorDict, CMySQLCursorBufferedDict, CMySQLCursorNamedTuple,
        CMySQLCursorBufferedNamedTuple)
    from _mysql_connector import MySQLInterfaceError  # pylint: disable=F0401
except ImportError as exc:
    raise ImportError(
        "MySQL Connector/Python C Extension not available ({0})".format(
            str(exc)
        ))
else:
    HAVE_CMYSQL = True
# pylint: enable=F0401,C0413


class CMySQLConnection(MySQLConnectionAbstract):

    """Class initiating a MySQL Connection using Connector/C"""

    def __init__(self, **kwargs):
        """Initialization"""
        if not HAVE_CMYSQL:
            raise RuntimeError(
                "MySQL Connector/Python C Extension not available")
        self._cmysql = None
        self._columns = []
        self.converter = None
        super(CMySQLConnection, self).__init__(**kwargs)

        if kwargs:
            self.connect(**kwargs)

    def _do_handshake(self):
        """Gather information of the MySQL server before authentication"""
        self._handshake = {
            'protocol': self._cmysql.get_proto_info(),
            'server_version_original': self._cmysql.get_server_info(),
            'server_threadid': self._cmysql.thread_id(),
            'charset': None,
            'server_status': None,
            'auth_plugin': None,
            'auth_data': None,
            'capabilities': self._cmysql.st_server_capabilities(),
        }

        self._server_version = self._check_server_version(
            self._handshake['server_version_original']
        )

    @property
    def _server_status(self):
        """Returns the server status attribute of MYSQL structure"""
        return self._cmysql.st_server_status()

    def set_unicode(self, value=True):
        """Toggle unicode mode

        Set whether we return string fields as unicode or not.
        Default is True.
        """
        self._use_unicode = value
        if self._cmysql:
            self._cmysql.use_unicode(value)
        if self.converter:
            self.converter.set_unicode(value)

    @property
    def autocommit(self):
        """Get whether autocommit is on or off"""
        value = self.info_query("SELECT @@session.autocommit")[0]
        return True if value == 1 else False

    @autocommit.setter
    def autocommit(self, value):  # pylint: disable=W0221
        """Toggle autocommit"""
        try:
            self._cmysql.autocommit(value)
            self._autocommit = value
        except MySQLInterfaceError as exc:
            raise errors.get_mysql_exception(msg=exc.msg, errno=exc.errno,
                                             sqlstate=exc.sqlstate)

    @property
    def database(self):
        """Get the current database"""
        return self.info_query("SELECT DATABASE()")[0]

    @database.setter
    def database(self, value):  # pylint: disable=W0221
        """Set the current database"""
        self._cmysql.select_db(value)

    @property
    def in_transaction(self):
        """MySQL session has started a transaction"""
        return self._server_status & ServerFlag.STATUS_IN_TRANS

    def _open_connection(self):
        charset_name = CharacterSet.get_info(self._charset_id)[0]
        self._cmysql = _mysql_connector.MySQL(  # pylint: disable=E1101,I1101
            buffered=self._buffered,
            raw=self._raw,
            charset_name=charset_name,
            connection_timeout=(self._connection_timeout or 0),
            use_unicode=self._use_unicode,
            auth_plugin=self._auth_plugin)

        cnx_kwargs = {
            'host': self._host,
            'user': self._user,
            'password': self._password,
            'database': self._database,
            'port': self._port,
            'client_flags': self._client_flags,
            'unix_socket': self._unix_socket,
            'compress': self.isset_client_flag(ClientFlag.COMPRESS)
        }

        if not self._ssl_disabled:
            cnx_kwargs.update({
                'ssl_ca': self._ssl.get('ca'),
                'ssl_cert': self._ssl.get('cert'),
                'ssl_key': self._ssl.get('key'),
                'ssl_verify_cert': self._ssl.get('verify_cert') or False,
                'ssl_disabled': self._ssl_disabled
            })

        try:
            self._cmysql.connect(**cnx_kwargs)
        except MySQLInterfaceError as exc:
            raise errors.get_mysql_exception(msg=exc.msg, errno=exc.errno,
                                             sqlstate=exc.sqlstate)
        self._do_handshake()

    def close(self):
        """Disconnect from the MySQL server"""
        if self._cmysql:
            try:
                self._cmysql.close()
            except MySQLInterfaceError as exc:
                raise errors.get_mysql_exception(msg=exc.msg, errno=exc.errno,
                                                 sqlstate=exc.sqlstate)
            self._cmysql = None
    disconnect = close

    def is_connected(self):
        """Reports whether the connection to MySQL Server is available"""
        if self._cmysql:
            return self._cmysql.ping()

        return False

    def ping(self, reconnect=False, attempts=1, delay=0):
        """Check availability of the MySQL server

        When reconnect is set to True, one or more attempts are made to try
        to reconnect to the MySQL server using the reconnect()-method.

        delay is the number of seconds to wait between each retry.

        When the connection is not available, an InterfaceError is raised. Use
        the is_connected()-method if you just want to check the connection
        without raising an error.

        Raises InterfaceError on errors.
        """
        errmsg = "Connection to MySQL is not available"

        try:
            connected = self._cmysql.ping()
        except AttributeError:
            pass  # Raise or reconnect later
        else:
            if connected:
                return

        if reconnect:
            self.reconnect(attempts=attempts, delay=delay)
        else:
            raise errors.InterfaceError(errmsg)

    def set_character_set_name(self, charset):
        """Sets the default character set name for current connection.
        """
        self._cmysql.set_character_set(charset)

    def info_query(self, query):
        """Send a query which only returns 1 row"""
        self._cmysql.query(query)
        first_row = ()
        if self._cmysql.have_result_set:
            first_row = self._cmysql.fetch_row()
            if self._cmysql.fetch_row():
                self._cmysql.free_result()
                raise errors.InterfaceError(
                    "Query should not return more than 1 row")
        self._cmysql.free_result()

        return first_row

    @property
    def connection_id(self):
        """MySQL connection ID"""
        try:
            return self._cmysql.thread_id()
        except MySQLInterfaceError:
            pass  # Just return None

        return None

    def get_rows(self, count=None, binary=False, columns=None):
        """Get all or a subset of rows returned by the MySQL server"""
        if not (self._cmysql and self.unread_result):
            raise errors.InternalError("No result set available")

        rows = []
        if count is not None and count <= 0:
            raise AttributeError("count should be 1 or higher, or None")

        counter = 0
        try:
            row = self._cmysql.fetch_row()
            while row:
                if self.converter:
                    row = list(row)
                    for i, _ in enumerate(row):
                        row[i] = self.converter.to_python(self._columns[i],
                                                          row[i])
                    row = tuple(row)
                rows.append(row)
                counter += 1
                if count and counter == count:
                    break
                row = self._cmysql.fetch_row()
        except MySQLInterfaceError as exc:
            self.free_result()
            raise errors.get_mysql_exception(msg=exc.msg, errno=exc.errno,
                                             sqlstate=exc.sqlstate)

        return rows

    def get_row(self, binary=False, columns=None):
        """Get the next rows returned by the MySQL server"""
        try:
            return self.get_rows(count=1, binary=binary, columns=columns)[0]
        except IndexError:
            # No row available
            return None

    def next_result(self):
        """Reads the next result"""
        if self._cmysql:
            self._cmysql.consume_result()
            return self._cmysql.next_result()
        return None

    def free_result(self):
        """Frees the result"""
        if self._cmysql:
            self._cmysql.free_result()

    def commit(self):
        """Commit current transaction"""
        if self._cmysql:
            self._cmysql.commit()

    def rollback(self):
        """Rollback current transaction"""
        if self._cmysql:
            self._cmysql.consume_result()
            self._cmysql.rollback()

    def cmd_init_db(self, database):
        """Change the current database"""
        try:
            self._cmysql.select_db(database)
        except MySQLInterfaceError as exc:
            raise errors.get_mysql_exception(msg=exc.msg, errno=exc.errno,
                                             sqlstate=exc.sqlstate)

    def fetch_eof_columns(self):
        """Fetch EOF and column information"""
        if not self._cmysql.have_result_set:
            raise errors.InterfaceError("No result set")

        fields = self._cmysql.fetch_fields()
        self._columns = []
        for col in fields:
            self._columns.append((
                col[4],
                int(col[8]),
                None,
                None,
                None,
                None,
                ~int(col[9]) & FieldFlag.NOT_NULL,
                int(col[9])
            ))

        return {
            'eof': {
                'status_flag': self._server_status,
                'warning_count': self._cmysql.st_warning_count(),
            },
            'columns': self._columns,
        }

    def fetch_eof_status(self):
        """Fetch EOF and status information"""
        if self._cmysql:
            return {
                'warning_count': self._cmysql.st_warning_count(),
                'field_count': self._cmysql.st_field_count(),
                'insert_id': self._cmysql.insert_id(),
                'affected_rows': self._cmysql.affected_rows(),
                'status_flag': self._server_status,
            }

        return None

    def cmd_query(self, query, raw=False, buffered=False, raw_as_string=False):
        """Send a query to the MySQL server"""
        self.handle_unread_result()

        try:
            if not isinstance(query, bytes):
                query = query.encode('utf-8')
            self._cmysql.query(query,
                               raw=raw, buffered=buffered,
                               raw_as_string=raw_as_string)
        except MySQLInterfaceError as exc:
            raise errors.get_mysql_exception(exc.errno, msg=exc.msg,
                                             sqlstate=exc.sqlstate)
        except AttributeError:
            if self._unix_socket:
                addr = self._unix_socket
            else:
                addr = self._host + ':' + str(self._port)
            raise errors.OperationalError(
                errno=2055, values=(addr, 'Connection not available.'))

        self._columns = []
        if not self._cmysql.have_result_set:
            # No result
            return self.fetch_eof_status()

        return self.fetch_eof_columns()
    _execute_query = cmd_query

    def cursor(self, buffered=None, raw=None, prepared=None, cursor_class=None,
               dictionary=None, named_tuple=None):
        """Instantiates and returns a cursor using C Extension

        By default, CMySQLCursor is returned. Depending on the options
        while connecting, a buffered and/or raw cursor is instantiated
        instead. Also depending upon the cursor options, rows can be
        returned as dictionary or named tuple.

        Dictionary and namedtuple based cursors are available with buffered
        output but not raw.

        It is possible to also give a custom cursor through the
        cursor_class parameter, but it needs to be a subclass of
        mysql.connector.cursor_cext.CMySQLCursor.

        Raises ProgrammingError when cursor_class is not a subclass of
        CursorBase. Raises ValueError when cursor is not available.

        Returns instance of CMySQLCursor or subclass.

        :param buffered: Return a buffering cursor
        :param raw: Return a raw cursor
        :param prepared: Return a cursor which uses prepared statements
        :param cursor_class: Use a custom cursor class
        :param dictionary: Rows are returned as dictionary
        :param named_tuple: Rows are returned as named tuple
        :return: Subclass of CMySQLCursor
        :rtype: CMySQLCursor or subclass
        """
        self.handle_unread_result()
        if not self.is_connected():
            raise errors.OperationalError("MySQL Connection not available.")
        if cursor_class is not None:
            if not issubclass(cursor_class, MySQLCursorAbstract):
                raise errors.ProgrammingError(
                    "Cursor class needs be to subclass"
                    " of cursor_cext.CMySQLCursor")
            return (cursor_class)(self)

        buffered = buffered or self._buffered
        raw = raw or self._raw

        cursor_type = 0
        if buffered is True:
            cursor_type |= 1
        if raw is True:
            cursor_type |= 2
        if dictionary is True:
            cursor_type |= 4
        if named_tuple is True:
            cursor_type |= 8
        if prepared is True:
            cursor_type |= 16

        types = {
            0: CMySQLCursor,  # 0
            1: CMySQLCursorBuffered,
            2: CMySQLCursorRaw,
            3: CMySQLCursorBufferedRaw,
            4: CMySQLCursorDict,
            5: CMySQLCursorBufferedDict,
            8: CMySQLCursorNamedTuple,
            9: CMySQLCursorBufferedNamedTuple,
            16: CMySQLCursorPrepared
        }
        try:
            return (types[cursor_type])(self)
        except KeyError:
            args = ('buffered', 'raw', 'dictionary', 'named_tuple', 'prepared')
            raise ValueError('Cursor not available with given criteria: ' +
                             ', '.join([args[i] for i in range(5)
                                        if cursor_type & (1 << i) != 0]))

    @property
    def num_rows(self):
        """Returns number of rows of current result set"""
        if not self._cmysql.have_result_set:
            raise errors.InterfaceError("No result set")

        return self._cmysql.num_rows()

    @property
    def warning_count(self):
        """Returns number of warnings"""
        if not self._cmysql:
            return 0

        return self._cmysql.warning_count()

    @property
    def result_set_available(self):
        """Check if a result set is available"""
        if not self._cmysql:
            return False

        return self._cmysql.have_result_set

    @property
    def unread_result(self):
        """Check if there are unread results or rows"""
        return self.result_set_available

    @property
    def more_results(self):
        """Check if there are more results"""
        return self._cmysql.more_results()

    def prepare_for_mysql(self, params):
        """Prepare parameters for statements

        This method is use by cursors to prepared parameters found in the
        list (or tuple) params.

        Returns dict.
        """
        if isinstance(params, (list, tuple)):
            result = self._cmysql.convert_to_mysql(*params)
        elif isinstance(params, dict):
            result = {}
            for key, value in params.items():
                result[key] = self._cmysql.convert_to_mysql(value)[0]
        else:
            raise ValueError("Could not process parameters")

        return result

    def consume_results(self):
        """Consume the current result

        This method consume the result by reading (consuming) all rows.
        """
        self._cmysql.consume_result()

    def cmd_change_user(self, username='', password='', database='',
                        charset=33):
        """Change the current logged in user"""
        try:
            self._cmysql.change_user(username, password, database)
        except MySQLInterfaceError as exc:
            raise errors.get_mysql_exception(msg=exc.msg, errno=exc.errno,
                                             sqlstate=exc.sqlstate)

        self._charset_id = charset
        self._post_connection()
        return self.fetch_eof_status()

    def cmd_refresh(self, options):
        """Send the Refresh command to the MySQL server"""
        try:
            self._cmysql.refresh(options)
        except MySQLInterfaceError as exc:
            raise errors.get_mysql_exception(msg=exc.msg, errno=exc.errno,
                                             sqlstate=exc.sqlstate)

        return self.fetch_eof_status()

    def cmd_quit(self):
        """Close the current connection with the server"""
        self.close()

    def cmd_shutdown(self, shutdown_type=None):
        """Shut down the MySQL Server"""
        if not self._cmysql:
            raise errors.OperationalError("MySQL Connection not available")

        if shutdown_type:
            if not ShutdownType.get_info(shutdown_type):
                raise errors.InterfaceError("Invalid shutdown type")
            level = shutdown_type
        else:
            level = ShutdownType.SHUTDOWN_DEFAULT

        try:
            self._cmysql.shutdown(level)
        except MySQLInterfaceError as exc:
            raise errors.get_mysql_exception(msg=exc.msg, errno=exc.errno,
                                             sqlstate=exc.sqlstate)

        self.close()

    def cmd_statistics(self):
        """Return statistics from the MySQL server"""
        self.handle_unread_result()

        try:
            stat = self._cmysql.stat()
            return MySQLProtocol().parse_statistics(stat, with_header=False)
        except (MySQLInterfaceError, errors.InterfaceError) as exc:
            raise errors.get_mysql_exception(msg=exc.msg, errno=exc.errno,
                                             sqlstate=exc.sqlstate)

    def cmd_process_kill(self, mysql_pid):
        """Kill a MySQL process"""
        if not isinstance(mysql_pid, INT_TYPES):
            raise ValueError("MySQL PID must be int")
        self.info_query("KILL {0}".format(mysql_pid))

    def handle_unread_result(self):
        """Check whether there is an unread result"""
        if self.can_consume_results:
            self.consume_results()
        elif self.unread_result:
            raise errors.InternalError("Unread result found")
