from __future__ import absolute_import
from __future__ import print_function

from typing import Any, Iterable

import logging
import sys

from django.core.management.base import CommandParser

from zerver.lib import utils
from zerver.lib.management import ZulipBaseCommand
from zerver.models import UserMessage
from django.db import models


class Command(ZulipBaseCommand):
    help = """Sets user message flags. Used internally by actions.py. Marks all
    Expects a comma-delimited list of user message ids via stdin, and an EOF to terminate."""

    def add_arguments(self, parser):
        # type: (CommandParser) -> None
        parser.add_argument('-l', '--for-real',
                            dest='for_real',
                            action='store_true',
                            default=False,
                            help="Actually change message flags. Default is a dry run.")

        parser.add_argument('-f', '--flag',
                            dest='flag',
                            type=str,
                            help="The flag to add of remove")

        parser.add_argument('-o', '--op',
                            dest='op',
                            type=str,
                            help="The operation to do: 'add' or 'remove'")

        parser.add_argument('-u', '--until',
                            dest='all_until',
                            type=str,
                            help="Mark all messages <= specific usermessage id")

        parser.add_argument('-m', '--email',
                            dest='email',
                            type=str,
                            help="Email to set messages for")
        self.add_realm_args(parser)

    def handle(self, *args, **options):
        # type: (*Any, **Any) -> None
        if not options["flag"] or not options["op"] or not options["email"]:
            print("Please specify an operation, a flag and an email")
            exit(1)

        op = options['op']
        flag = getattr(UserMessage.flags, options['flag'])
        all_until = options['all_until']
        email = options['email']

        realm = self.get_realm(options)
        user_profile = self.get_user(email, realm)

        if all_until:
            filt = models.Q(id__lte=all_until)
        else:
            filt = models.Q(message__id__in=[mid.strip() for mid in sys.stdin.read().split(',')])
        mids = [m.id for m in
                UserMessage.objects.filter(filt, user_profile=user_profile).order_by('-id')]

        if options["for_real"]:
            sys.stdin.close()
            sys.stdout.close()
            sys.stderr.close()

        def do_update(batch):
            # type: (Iterable[int]) -> None
            msgs = UserMessage.objects.filter(id__in=batch)
            if op == 'add':
                msgs.update(flags=models.F('flags').bitor(flag))
            elif op == 'remove':
                msgs.update(flags=models.F('flags').bitand(~flag))

        if not options["for_real"]:
            logging.info("Updating %s by %s %s" % (mids, op, flag))
            logging.info("Dry run completed. Run with --for-real to change message flags.")
            exit(1)

        utils.run_in_batches(mids, 400, do_update, sleep_time=3)
        exit(0)