from optparse import make_option

from django.conf import settings

from django.db import connections, transaction, models, DEFAULT_DB_ALIAS

from django.core.management import call_command

from django.core.management.base import NoArgsCommand, CommandError

from django.core.management.color import no_style

from django.core.management.sql import sql_flush, emit_post_sync_signal

from django.utils.importlib import import_module

class Command(NoArgsCommand):

    option_list = NoArgsCommand.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('--database', action='store', dest='database',

            default=DEFAULT_DB_ALIAS, help='Nominates a database to flush. '

                'Defaults to the "default" database.'),

    )

    help = "Executes ``sqlflush`` on the current database."

    def handle_noargs(self, **options):

        db = options.get('database', DEFAULT_DB_ALIAS)

        connection = connections[db]

        verbosity = int(options.get('verbosity', 1))

        interactive = options.get('interactive')

        self.style = no_style()

        # Import the 'management' module within each installed app, to register

        # dispatcher events.

        for app_name in settings.INSTALLED_APPS:

            try:

                import_module('.management', app_name)

            except ImportError:

                pass

        sql_list = sql_flush(self.style, connection, only_django=True)

        if interactive:

            confirm = raw_input("""You have requested a flush of the database.

This will IRREVERSIBLY DESTROY all data currently in the %r database,

and return each table to the state it was in after syncdb.

Are you sure you want to do this?

    Type 'yes' to continue, or 'no' to cancel: """ % connection.settings_dict['NAME'])

        else:

            confirm = 'yes'

        if confirm == 'yes':

            try:

                cursor = connection.cursor()

                for sql in sql_list:

                    cursor.execute(sql)

            except Exception, e:

                transaction.rollback_unless_managed(using=db)

                raise CommandError("""Database %s couldn't be flushed. Possible reasons:

  * The database isn't running or isn't configured correctly.

  * At least one of the expected database tables doesn't exist.

  * The SQL was invalid.

Hint: Look at the output of 'django-admin.py sqlflush'. That's the SQL this command wasn't able to run.

The full error: %s""" % (connection.settings_dict['NAME'], e))

            transaction.commit_unless_managed(using=db)

            # Emit the post sync signal. This allows individual

            # applications to respond as if the database had been

            # sync'd from scratch.

            emit_post_sync_signal(models.get_models(), verbosity, interactive, db)

            # Reinstall the initial_data fixture.

            kwargs = options.copy()

            kwargs['database'] = db

            call_command('loaddata', 'initial_data', **kwargs)

        else:

            print "Flush cancelled."