import { HookContext } from '@feathersjs/feathers';
import { Types } from 'mongoose';
import bluebird from 'bluebird';
import _ from 'lodash';
import { Poll, User, Vote } from 'which-types';

import { PollSchema } from '../models/polls/poll.schema';
import VoteModel from '../models/votes/vote.model';


export default async (context: HookContext): Promise<HookContext> => {
  const { app, result, params: { user } } = context;

  const convert = async (poll: PollSchema): Promise<Poll | null> => {
    const author = await app.service('users').get(poll.authorId);

    const contents = await VoteModel.aggregate([
      { $match: { pollId: Types.ObjectId(poll._id) } },
      { $group: { _id: '$which', total: { $sum: 1 } } }
    ]).then(groups => groups.reduce(
      (acc, group) =>  _.set(acc, group._id + '.votes', group.total),
      {}
    ));

    const userChoice = await VoteModel.findOne({ pollId: poll._id, userId: user?._id });

    return _.merge(
      _.omit(poll, ['authorId']),
      { author, contents, userChoice }
    );
  };

  if (Array.isArray(result)) {
    const polls = await bluebird.map(result, (poll: PollSchema) => convert(poll));
    context.result = _.compact(polls);
  } else {
    context.result = await convert(result);
  }
  return context;
};