TranslateQueueApiService.js

const moment = require('moment');
const Promise = require('bluebird');
const _ = require('underscore');

const {Logger} = require('../logger');

const translator = require('./translators');

let translationQueue = [];
let isProcessing = false;

async function processQueueItem() {
    Logger.info(`TranslateQueueApiService.processQueueItem() translationQueue.length == ${translationQueue.length}`);
    const nextItem = translationQueue.shift();

    if (nextItem) {
        const {entity, args, resolve, reject} = nextItem;

        try {
            const translation = await translator.translate(...args);
            resolve(translation);

            for (const sameEntityItem of translationQueue) {
                if (sameEntityItem.entity
                    && `${entity._id}` === `${sameEntityItem.entity._id}`
                    && entity.updated_at >= sameEntityItem.entity.updated_at) {

                    sameEntityItem.resolve(translation);
                    const indexToRemove = translationQueue.indexOf(sameEntityItem);
                    translationQueue.splice(indexToRemove, 1);

                    Logger.info(`TranslateQueueApiService.processQueueItem() resolved too ${indexToRemove} id: ${sameEntityItem.entity._id}`);
                }
            }

        } catch (error) {
            reject(error);
        }
    }

    if (translationQueue.length) {
        setTimeout(processQueueItem, 5000 + parseInt(Math.random() * 1000 * 5)); // 5 - 10 sec
    } else {
        isProcessing = false;
    }
}

function startQueue() {
    if (isProcessing) {
        return;
    }
    isProcessing = true;
    setTimeout(processQueueItem, 5000);
}

class TranslateQueueApiService {
    static async translate(entity, ...args) {
        const translatePromise = new Promise((resolve, reject) => {
            translationQueue.push({entity, args, resolve, reject});
            startQueue();
        });

        return translatePromise;
    }
}

module.exports = TranslateQueueApiService;