'use strict';

const config = require('config');
const fs = require('fs');
const fsPromises = require('fs').promises;
const Promise = require('bluebird');
const blake2 = require('blake2');
const sharp = require('sharp');
const nanoid = require('nanoid');
const { PassThrough } = require('stream');

const http = require('./http');

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

let peakMemoryUsage = getMemoryUsage();

async function fetchSource(link) {
	const id = nanoid();

	const hasher = new blake2.Hash('blake2b');
	hasher.setEncoding('hex');

	const tempFilePath = `/home/niels/Pictures/thumbs/temp/${id}.jpeg`;
	const tempFileStream = fs.createWriteStream(tempFilePath);
	const hashStream = new PassThrough();

	hashStream.on('data', (chunk) => hasher.write(chunk));

	try {
		const res = await http.get(link, null, {
			stream: true,
			transforms: [hashStream],
			destination: tempFileStream,
			timeout: 5000,
		});

		if (!res.ok) {
			throw new Error(res.status);
		}

		hasher.end();
		const hash = hasher.read();

		const memoryUsage = getMemoryUsage();
		peakMemoryUsage = Math.max(memoryUsage, peakMemoryUsage);

		console.log(`Stored ${tempFilePath}, memory usage: ${memoryUsage.toFixed(2)} MB`);

		return {
			id,
			path: tempFilePath,
			hash,
		};
	} catch (error) {
		await fsPromises.unlink(tempFilePath);

		throw error;
	}
}

async function init() {
	const linksFile = await fsPromises.readFile('/home/niels/Pictures/photos', 'utf8');
	const links = linksFile.split('\n').filter(Boolean);

	await fsPromises.mkdir('/home/niels/Pictures/thumbs/temp', { recursive: true });

	console.time('thumbs');

	const files = await Promise.map(links, async (link) => {
		try {
			return await fetchSource(link);
		} catch (error) {
			console.log(`Failed to fetch ${link}: ${error.message}`);
			return null;
		}
	});

	await Promise.map(files.filter(Boolean), async (file) => {
		const image = sharp(file.path).jpeg();

		const [{ width, height }, { size }] = await Promise.all([
			image.metadata(),
			fsPromises.stat(file.path),
		]);

		await Promise.all([
			image
				.toFile(`/home/niels/Pictures/thumbs/${file.hash}.jpeg`),
			image
				.resize({
					height: config.media.thumbnailSize,
					withoutEnlargement: true,
				})
				.toFile(`/home/niels/Pictures/thumbs/${file.hash}_thumb.jpeg`),
		]);

		const memoryUsage = getMemoryUsage();
		peakMemoryUsage = Math.max(memoryUsage, peakMemoryUsage);

		console.log(`Resized ${file.id} (${width}, ${height}, ${size}), memory usage: ${memoryUsage.toFixed(2)} MB`);
	}, { concurrency: 10 });

	console.log(`Peak memory usage: ${peakMemoryUsage.toFixed(2)} MB`);
	console.timeEnd('thumbs');
}

init();