/**
 * Module dependencies
 */
import $ from 'cafy';
import Vote from '../../../models/poll-vote';
import Post from '../../../models/post';
import serialize from '../../../serializers/post';

/**
 * Get recommended polls
 *
 * @param {any} params
 * @param {any} user
 * @return {Promise<any>}
 */
module.exports = (params, user) => new Promise(async (res, rej) => {
	// Get 'limit' parameter
	const [limit = 10, limitErr] = $(params.limit).optional.number().range(1, 100).$;
	if (limitErr) return rej('invalid limit param');

	// Get 'offset' parameter
	const [offset = 0, offsetErr] = $(params.offset).optional.number().min(0).$;
	if (offsetErr) return rej('invalid offset param');

	// Get votes
	const votes = await Vote.find({
		user_id: user._id
	}, {
		fields: {
			_id: false,
			post_id: true
		}
	});

	const nin = votes && votes.length != 0 ? votes.map(v => v.post_id) : [];

	const posts = await Post
		.find({
			_id: {
				$nin: nin
			},
			user_id: {
				$ne: user._id
			},
			poll: {
				$exists: true,
				$ne: null
			}
		}, {
			limit: limit,
			skip: offset,
			sort: {
				_id: -1
			}
		});

	// Serialize
	res(await Promise.all(posts.map(async post =>
		await serialize(post, user, { detail: true }))));
});