#!/usr/bin/python
# -*- coding: utf-8 -*-

"""

Ansible module to manage mysql variables
(c) 2013, Balazs Pocze <banyek@gawker.com>
Certain parts are taken from Mark Theunissen's mysqldb module

This file is part of Ansible

Ansible 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, either version 3 of the License, or
(at your option) any later version.

Ansible 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 Ansible.  If not, see <http://www.gnu.org/licenses/>.
"""

DOCUMENTATION = '''
---
module: mysql_variables

short_description: Manage MySQL global variables
description:
    - Query / Set MySQL variables
version_added: 1.3
author: "Balazs Pocze (@banyek)"
options:
    variable:
        description:
            - Variable name to operate
        required: True
    value:
        description:
            - If set, then sets variable value to this
        required: False
extends_documentation_fragment: mysql
'''
EXAMPLES = '''
# Check for sync_binlog setting
- mysql_variables: variable=sync_binlog

# Set read_only variable to 1
- mysql_variables: variable=read_only value=1
'''


import os
import warnings
from re import match

try:
    import MySQLdb
except ImportError:
    mysqldb_found = False
else:
    mysqldb_found = True


def typedvalue(value):
    """
    Convert value to number whenever possible, return same value
    otherwise.

    >>> typedvalue('3')
    3
    >>> typedvalue('3.0')
    3.0
    >>> typedvalue('foobar')
    'foobar'

    """
    try:
        return int(value)
    except ValueError:
        pass

    try:
        return float(value)
    except ValueError:
        pass

    return value


def getvariable(cursor, mysqlvar):
    cursor.execute("SHOW VARIABLES WHERE Variable_name = %s", (mysqlvar,))
    mysqlvar_val = cursor.fetchall()
    if len(mysqlvar_val) is 1:
        return mysqlvar_val[0][1]
    else:
        return None

def setvariable(cursor, mysqlvar, value):
    """ Set a global mysql variable to a given value

    The DB driver will handle quoting of the given value based on its
    type, thus numeric strings like '3.0' or '8' are illegal, they
    should be passed as numeric literals.

    """
    query = "SET GLOBAL %s = " % mysql_quote_identifier(mysqlvar, 'vars')
    try:
        cursor.execute(query + "%s", (value,))
        cursor.fetchall()
        result = True
    except Exception, e:
        result = str(e)
    return result

def main():
    module = AnsibleModule(
            argument_spec = dict(
            login_user=dict(default=None),
            login_password=dict(default=None),
            login_host=dict(default="127.0.0.1"),
            login_port=dict(default="3306", type='int'),
            login_unix_socket=dict(default=None),
            variable=dict(default=None),
            value=dict(default=None),
            ssl_cert=dict(default=None),
            ssl_key=dict(default=None),
            ssl_ca=dict(default=None),
            config_file=dict(default="~/.my.cnf")
        )
    )
    user = module.params["login_user"]
    password = module.params["login_password"]
    host = module.params["login_host"]
    port = module.params["login_port"]
    ssl_cert = module.params["ssl_cert"]
    ssl_key = module.params["ssl_key"]
    ssl_ca = module.params["ssl_ca"]
    config_file = module.params['config_file']
    config_file = os.path.expanduser(os.path.expandvars(config_file))
    db = 'mysql'

    mysqlvar = module.params["variable"]
    value = module.params["value"]
    if mysqlvar is None:
        module.fail_json(msg="Cannot run without variable to operate with")
    if match('^[0-9a-z_]+$', mysqlvar) is None:
	    module.fail_json(msg="invalid variable name \"%s\"" % mysqlvar)
    if not mysqldb_found:
        module.fail_json(msg="the python mysqldb module is required")
    else:
        warnings.filterwarnings('error', category=MySQLdb.Warning)

    try:
        cursor = mysql_connect(module, user, password, config_file, ssl_cert, ssl_key, ssl_ca, db)
    except Exception, e:
        if os.path.exists(config_file):
            module.fail_json(msg="unable to connect to database, check login_user and login_password are correct or %s has the credentials. Exception message: %s" % (config_file, e))
        else:
            module.fail_json(msg="unable to find %s. Exception message: %s" % (config_file, e))

    mysqlvar_val = getvariable(cursor, mysqlvar)
    if mysqlvar_val is None:
        module.fail_json(msg="Variable not available \"%s\"" % mysqlvar, changed=False)
    if value is None:
        module.exit_json(msg=mysqlvar_val)
    else:
        # Type values before using them
        value_wanted = typedvalue(value)
        value_actual = typedvalue(mysqlvar_val)
        if value_wanted == value_actual:
            module.exit_json(msg="Variable already set to requested value", changed=False)
        try:
            result = setvariable(cursor, mysqlvar, value_wanted)
        except SQLParseError, e:
            result = str(e)
        if result is True:
            module.exit_json(msg="Variable change succeeded prev_value=%s" % value_actual, changed=True)
        else:
            module.fail_json(msg=result, changed=False)

# import module snippets
from ansible.module_utils.basic import *
from ansible.module_utils.database import *
from ansible.module_utils.mysql import *
main()