// node --require regenerator-runtime/runtime --require ./babel-local --require isomorphic-fetch index.js ..\out

import {createWriteStream, promises} from 'fs';
import {resolve} from 'path';

const {access, rename} = promises;

async function work (prefix) {
    console.info(`Output directory: ${prefix}`);
    let rootUri = 'https://data.gov.sk/api/3/action/package_search?fq=%2btitle:Vestn%C3%ADk%20verejn%C3%A9ho%20obstar%C3%A1vania*&rows=9999&sort=metadata_created_date%20asc';
    const datasetsRaw = await fetch(rootUri);
    const {result: {count, results}} = await datasetsRaw.json();
    console.info(`Datasets: ${count}`);
    for (let {title, num_resources, resources} of results) {
        console.info(`Fetching: ${title}, ${num_resources} files`);
        const saves = [];
        for (let {name, description, url} of resources) {
            const [, issue, year] = name.match(/(\d+)\/(\d+)/);
            const target = `${prefix}/${year}.${issue}.xml`;
            if (await access(target).then(() => true, () => false))
                continue;
            console.info(`File ${year} / ${issue}: ${description}`);
            const xmlRaw = await fetch(url);
            saves.push((async () => {
                const temporary = `${prefix}/${year}.${issue}.xml.download`;
                await xmlRaw.body.pipe(createWriteStream(temporary));
                await rename(temporary, target);
            })());
        }
        await Promise.all(saves);
    }
    return results;
}

work(resolve(process.argv[2] || ''))
    .catch(error => console.error(error));