dbmedialab/reader-critics

//
// LESERKRITIKK v2 (aka Reader Critics)
// Copyright (C) 2017 DB Medialab/Aller Media AS, Oslo, Norway
// https://github.com/dbmedialab/reader-critics/
//
// This program is free software: you can redistribute it and/or modify it under
// the terms of the GNU General Public License as published by the Free Software
// Foundation, either version 3 of the License, or (at your option) any later
// version.
//
// This program is distributed in the hope that it will be useful, but WITHOUT
// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
// FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License along with
// this program. If not, see <http://www.gnu.org/licenses/>.
//

import {
    ArticleDocument,
    ArticleModel
} from 'app/db/models';

import { PollUpdateData } from 'app/services/article/ArticleService';

import emptyCheck from 'app/util/emptyCheck';

export function getIDsToPullUpdates (
    latestCreated : Date,
    earliestCreated : Date,
    latestPoll : Date
) : Promise <PollUpdateData[]>
{
    emptyCheck(latestCreated, earliestCreated, latestPoll);
    // Returning the promise from Mongoose directly will, once again, make
    // TypeScript cry. So we wrap this thing, old style.
    return new Promise((resolve, reject) => {
        // This is a rather complex query, but its parts are explained
        ArticleModel.find({
            // Only a certain timespan will be checked
            'date.created': {
                '$gt': earliestCreated,
                '$lte': latestCreated,
            },
            // Only articles that have received feedback
            'feedbacks': {
                $exists: true,
                $not: {
                    '$size': 0,
                },
            },
            // Only those where the "newerVersion" field does not exist yet, meaning
            // those which haven't been already outdated by an updated version that
            // exists here in the database
            'newerVersion': {
                '$exists': false,
            },
            // Only those which either haven't been polled yet, or whose last time to
            // poll has passed a timeout.
            $or: [
                {
                    'date.lastPoll': {
                        '$exists': false,
                    },
                },
                {
                    'date.lastPoll': {
                        $lt: latestPoll,
                    },
                },
            ],
        })
        .lean().exec()
        .then((docs : ArticleDocument[]) => resolve(docs.map(doc => ({
            ID: doc._id,
            url: doc.url.toString(),
            version: doc.version,
        }))))  // That is a lot of brackets! Are we doing LISP here or what? :D
        .catch(error => reject(error));
    });
}