'use strict';

const bhttp = require('bhttp');
const Promise = require('bluebird');
const fsPromises = require('fs').promises;
const fs = require('fs');
const { PassThrough } = require('stream');
const blake2 = require('blake2');
const argv = require('yargs').argv;

const file = 'https://speed.hetzner.de/100MB.bin';
// const file = 'https://speed.hetzner.de/1GB.bin';
// const file = 'https://speed.hetzner.de/10GB.bin';

function getMemoryUsage() {
	return process.memoryUsage().rss / (10 ** 6);
}

const stats = {
	peakMemoryUsage: getMemoryUsage(),
	done: false,
	downloads: {},
};

function render() {
	const downloads = Object.entries(stats.downloads);

	process.stdout.clearScreenDown();

	process.stdout.write(`peak memory: ${stats.peakMemoryUsage.toFixed(2)} MB\n`);

	downloads.forEach(([download, progress]) => {
		process.stdout.write(`${download}: ${progress}${typeof progress === 'string' ? '' : '%'}\n`);
	});

	process.stdout.moveCursor(0, -(downloads.length + 1));
	process.stdout.cursorTo(0);

	if (downloads.length === 0 || !downloads.every(([_label, download]) => typeof download === 'string')) {
		setTimeout(() => render(), 1000);
		return;
	}

	process.stdout.moveCursor(0, downloads.length + 1);
}

function setProgress(label, completedBytes, totalBytes, hash) {
	const memory = getMemoryUsage();

	stats.peakMemoryUsage = Math.max(memory, stats.peakMemoryUsage);
	stats.downloads[label] = hash || Math.round((completedBytes / totalBytes) * 100);
}

async function buffered(label) {
	const hash = new blake2.Hash('blake2b');

	const imageRes = await bhttp.get(file, {
		onDownloadProgress(completedBytes, totalBytes) {
			setProgress(label, completedBytes, totalBytes);
		},
	});

	hash.update(imageRes.body);
	setProgress(label, null, null, hash.digest('hex'));

	await fsPromises.writeFile(`/mnt/stor/Pictures/traxxx/temp/buffered-${label}.bin`, imageRes.body);
}

async function streamed(label) {
	const hash = new blake2.Hash('blake2b');
	hash.setEncoding('hex');

	const hashStream = new PassThrough();
	const targetStream = fs.createWriteStream(`/mnt/stor/Pictures/traxxx/temp/streamed-${label}.bin`);

	const imageRes = await bhttp.get(file, {
		stream: true,
	});

	const stream = imageRes
		.pipe(hashStream)
		.pipe(targetStream);

	imageRes.on('progress', (completedBytes, totalBytes) => {
		setProgress(label, completedBytes, totalBytes);
	});

	hashStream.on('data', (chunk) => {
		hash.write(chunk);
	});

	stream.on('finish', () => {
		hash.end();
		setProgress(label, null, null, hash.read());
	});
}

async function init() {
	const n = argv.n || 1;

	if (argv._.includes('stream')) {
		console.log('using streams');
		render();

		await Promise.map(Array.from({ length: n }), async (value, index) => streamed(index + 1));

		return;
	}

	if (argv._.includes('buffer')) {
		console.log('using buffers');
		render();

		await Promise.map(Array.from({ length: n }), async (value, index) => buffered(index + 1));
	}
}

init();