// @flow
import type { GraphQLContext } from '../../';
import UserError from '../../utils/UserError';
import { removeMembersInChannel } from '../../models/usersChannels';
import { getChannelById, deleteChannel } from '../../models/channel';
import { getThreadsByChannelToDelete, deleteThread } from '../../models/thread';
import {
  isAuthedResolver as requireAuth,
  canModerateChannel,
} from '../../utils/permissions';

type Input = {
  channelId: string,
};

export default requireAuth(async (_: any, args: Input, ctx: GraphQLContext) => {
  const { channelId } = args;
  const { user, loaders } = ctx;

  if (!(await canModerateChannel(user.id, channelId, loaders))) {
    return new UserError('You don’t have permission to manage this channel');
  }

  const channel = await getChannelById(channelId);

  if (channel.slug === 'general') {
    return new UserError("The general channel can't be deleted");
  }

  const [allThreadsInChannel] = await Promise.all([
    getThreadsByChannelToDelete(channelId),
    deleteChannel(channelId, user.id),
    removeMembersInChannel(channelId),
  ]);

  if (allThreadsInChannel.length === 0) return true;

  return allThreadsInChannel.map(
    async thread => await deleteThread(thread.id, user.id)
  );
});