import logging
from optparse import make_option

from django.conf import settings
from django.core.management.base import BaseCommand, CommandError
from six.moves import configparser, input

from django_extensions.management.utils import signalcommand

try:
    from django.db.backends.base.creation import TEST_DATABASE_PREFIX
except ImportError:
    # Django < 1.7
    from django.db.backends.creation import TEST_DATABASE_PREFIX


class Command(BaseCommand):
    option_list = BaseCommand.option_list + (
        make_option('--noinput', action='store_false',
                    dest='interactive', default=True,
                    help='Tells Django to NOT prompt the user for input of any kind.'),
        make_option('-U', '--user', action='store',
                    dest='user', default=None,
                    help='Use another user for the database then defined in settings.py'),
        make_option('-P', '--password', action='store',
                    dest='password', default=None,
                    help='Use another password for the database then defined in settings.py'),
        make_option('-D', '--dbname', action='store',
                    dest='dbname', default=None,
                    help='Use another database name then defined in settings.py'),
        make_option('-R', '--router', action='store',
                    dest='router', default='default',
                    help='Use this router-database other then defined in settings.py'),
    )
    help = "Drops test database for this project."

    @signalcommand
    def handle(self, *args, **options):
        """
        Drop test database for this project.
        """

        if args:
            raise CommandError("reset_db takes no arguments")

        router = options.get('router')
        dbinfo = settings.DATABASES.get(router)
        if dbinfo is None:
            raise CommandError("Unknown database router %s" % router)

        engine = dbinfo.get('ENGINE').split('.')[-1]

        user = password = database_name = ''
        if engine == 'mysql':
            read_default_file = dbinfo.get('OPTIONS', {}).get('read_default_file')
            if read_default_file:
                config = configparser.ConfigParser()
                config.read(read_default_file)
                user = config.get('client', 'user')
                password = config.get('client', 'password')
                database_name = config.get('client', 'database')

        user = options.get('user') or dbinfo.get('USER') or user
        password = options.get('password') or dbinfo.get('PASSWORD') or password

        try:
            database_name = dbinfo['TEST']['NAME']
        except KeyError:
            database_name = None

        if database_name is None:
            database_name = TEST_DATABASE_PREFIX + (options.get('dbname') or dbinfo.get('NAME'))

        if database_name is None or database_name == '':
            raise CommandError("You need to specify DATABASE_NAME in your Django settings file.")

        database_host = dbinfo.get('HOST')
        database_port = dbinfo.get('PORT')

        verbosity = int(options.get('verbosity', 1))
        if options.get('interactive'):
            confirm = input("""
You have requested to drop the test database.
This will IRREVERSIBLY DESTROY
ALL data in the database "%s".
Are you sure you want to do this?

Type 'yes' to continue, or 'no' to cancel: """ % (database_name,))
        else:
            confirm = 'yes'

        if confirm != 'yes':
            print("Reset cancelled.")
            return

        if engine in ('sqlite3', 'spatialite'):
            import os
            try:
                logging.info("Unlinking %s database" % engine)
                if os.path.isfile(database_name):
                    os.unlink(database_name)
            except OSError:
                pass
        elif engine in ('mysql',):
            import MySQLdb as Database
            kwargs = {
                'user': user,
                'passwd': password,
            }
            if database_host.startswith('/'):
                kwargs['unix_socket'] = database_host
            else:
                kwargs['host'] = database_host

            if database_port:
                kwargs['port'] = int(database_port)

            connection = Database.connect(**kwargs)
            drop_query = 'DROP DATABASE IF EXISTS `%s`' % database_name
            logging.info('Executing: "' + drop_query + '"')
            connection.query(drop_query)
        elif engine in ('postgresql', 'postgresql_psycopg2', 'postgis'):
            if engine == 'postgresql':
                import psycopg as Database  # NOQA
            elif engine in ('postgresql_psycopg2', 'postgis'):
                import psycopg2 as Database  # NOQA

            conn_string = "dbname=template1"
            if user:
                conn_string += " user=%s" % user
            if password:
                conn_string += " password='%s'" % password
            if database_host:
                conn_string += " host=%s" % database_host
            if database_port:
                conn_string += " port=%s" % database_port

            connection = Database.connect(conn_string)
            connection.set_isolation_level(0)  # autocommit false
            cursor = connection.cursor()
            drop_query = "DROP DATABASE IF EXISTS \"%s\";" % database_name
            logging.info('Executing: "' + drop_query + '"')

            try:
                cursor.execute(drop_query)
            except Database.ProgrammingError as e:
                logging.exception("Error: %s" % str(e))
        else:
            raise CommandError("Unknown database engine %s" % engine)

        if verbosity >= 2 or options.get('interactive'):
            print("Reset successful.")
