const got = require("got");
const { createWriteStream, existsSync } = require("fs");
const { pipeline } = require('stream/promises');
const fsp = require('fs').promises;
const { dirname } = require('path');

/**
 * config example: {
 * 		endpoint: "https://bla.com",
 * 		directory: "dir/to/save/to",
 * 		override: true, 	// optional
 * 		extension: "jpg" 	// optional
 * }
 **/
async function getPictures(webmentions, config) {
	const pics = await Promise.all(
		[...new Set(webmentions.filter(wm => wm.author && wm.author.picture).map(wm => wm.author.picture))]
		.map(async picture => {
			let fileName = `${config.directory}/${picture}`
			if(config.extension && !fileName.endsWith(config.extension)) {
				fileName += `.${config.extension}`
			}

			// TODO existsSync does not work, wrapped in Promise.all - does not wait for it!
			if(config.override || !existsSync(fileName)) {
				try {
					await fsp.mkdir(dirname(fileName), { recursive: true }),
					// retry API with streams is ridiculously complicated: https://github.com/sindresorhus/got/blob/main/documentation/7-retry.md
					await pipeline(
						got.stream(`${config.endpoint}/${picture}`),
						createWriteStream(fileName)
					)
				} catch(err) {
					console.log(` !! unable to download ${picture}: ${err.message}`)
					try { await fsp.unlink(fileName) } catch { }
				}
			}
			return fileName
		})
	)
	return pics
}

module.exports = {
	getPictures
}