# -*- coding: utf-8 -*-
'''
Retrieve Pillar data by doing a MySQL query

MariaDB provides Python support through the MySQL Python package.
Therefore, you may use this module with both MySQL or MariaDB.

This module is a concrete implementation of the sql_base ext_pillar for MySQL.

:maturity: new
:depends: python-mysqldb
:platform: all

Configuring the mysql ext_pillar
================================

Use the 'mysql' key under ext_pillar for configuration of queries.

MySQL configuration of the MySQL returner is being used (mysql.db, mysql.user,
mysql.pass, mysql.port, mysql.host) for database connection info.

Required python modules: MySQLdb

Complete example
================

.. code-block:: yaml

    mysql:
      user: 'salt'
      pass: 'super_secret_password'
      db: 'salt_db'
      port: 3306
      ssl:
        cert: /etc/mysql/client-cert.pem
        key: /etc/mysql/client-key.pem

    ext_pillar:
      - mysql:
          fromdb:
            query: 'SELECT col1,col2,col3,col4,col5,col6,col7
                      FROM some_random_table
                     WHERE minion_pattern LIKE %s'
            depth: 5
            as_list: True
            with_lists: [1,3]
'''
from __future__ import absolute_import, print_function, unicode_literals

# Import python libs
from contextlib import contextmanager
import logging

# Import Salt libs
from salt.pillar.sql_base import SqlBaseExtPillar

# Set up logging
log = logging.getLogger(__name__)

# Import third party libs
try:
    # Trying to import MySQLdb
    import MySQLdb
    import MySQLdb.cursors
    import MySQLdb.converters
except ImportError:
    try:
        # MySQLdb import failed, try to import PyMySQL
        import pymysql
        pymysql.install_as_MySQLdb()
        import MySQLdb
        import MySQLdb.cursors
        import MySQLdb.converters
    except ImportError:
        MySQLdb = None


def __virtual__():
    '''
    Confirm that a python mysql client is installed.
    '''
    return bool(MySQLdb), 'No python mysql client installed.' if MySQLdb is None else ''


class MySQLExtPillar(SqlBaseExtPillar):
    '''
    This class receives and processes the database rows from MySQL.
    '''
    @classmethod
    def _db_name(cls):
        return 'MySQL'

    def _get_options(self):
        '''
        Returns options used for the MySQL connection.
        '''
        defaults = {'host': 'localhost',
                    'user': 'salt',
                    'pass': 'salt',
                    'db': 'salt',
                    'port': 3306,
                    'ssl': {}}
        _options = {}
        _opts = __opts__.get('mysql', {})
        for attr in defaults:
            if attr not in _opts:
                log.debug('Using default for MySQL %s', attr)
                _options[attr] = defaults[attr]
                continue
            _options[attr] = _opts[attr]
        return _options

    @contextmanager
    def _get_cursor(self):
        '''
        Yield a MySQL cursor
        '''
        _options = self._get_options()
        conn = MySQLdb.connect(host=_options['host'],
                               user=_options['user'],
                               passwd=_options['pass'],
                               db=_options['db'], port=_options['port'],
                               ssl=_options['ssl'])
        cursor = conn.cursor()
        try:
            yield cursor
        except MySQLdb.DatabaseError as err:
            log.exception('Error in ext_pillar MySQL: %s', err.args)
        finally:
            conn.close()

    def extract_queries(self, args, kwargs):  # pylint: disable=useless-super-delegation
        '''
            This function normalizes the config block into a set of queries we
            can use.  The return is a list of consistently laid out dicts.
        '''
        return super(MySQLExtPillar, self).extract_queries(args, kwargs)


def ext_pillar(minion_id,
               pillar,
               *args,
               **kwargs):
    '''
    Execute queries against MySQL, merge and return as a dict
    '''
    return MySQLExtPillar().fetch(minion_id, pillar, *args, **kwargs)