from __future__ import absolute_import
from __future__ import print_function

from django.core.management.base import BaseCommand

from zerver.lib.actions import do_rename_stream
from zerver.models import Realm, get_realm

import sys

class Command(BaseCommand):
    help = """Change the stream name for a realm."""

    def add_arguments(self, parser):
        parser.add_argument('domain', metavar='<domain>', type=str,
                            help="domain to operate on")
        parser.add_argument('old_name', metavar='<old name>', type=str,
                            help='name of stream to be renamed')
        parser.add_argument('new_name', metavar='<new name>', type=str,
                            help='new name to rename the stream to')

    def handle(self, *args, **options):
        domain = options['domain']
        old_name = options['old_name']
        new_name = options['new_name']
        encoding = sys.getfilesystemencoding()

        try:
            realm = get_realm(domain)
        except Realm.DoesNotExist:
            print("Unknown domain %s" % (domain,))
            exit(1)

        do_rename_stream(realm, old_name.decode(encoding),
                         new_name.decode(encoding))