// From the NPM docs:

// "If you need to perform operations on your package before it is used, in a way that is not dependent on the

// operating system or architecture of the target system, use a prepublish script."

// Once this step is complete, a developer should be able to work without an Internet connection.

// See also: https://docs.npmjs.com/cli/using-npm/scripts

import fs from 'fs';

import path from 'path';

import crossFetch from 'cross-fetch';

import yauzl from 'yauzl';

import {fileURLToPath} from 'url';

/** @typedef {import('yauzl').Entry} ZipEntry */

/** @typedef {import('yauzl').ZipFile} ZipFile */

// these aren't set in ESM mode

const __filename = fileURLToPath(import.meta.url);

const __dirname = path.dirname(__filename);

// base/root path for the project

const basePath = path.join(__dirname, '..');

/**

* Extract the first matching file from a zip buffer.

* The path within the zip file is ignored: the destination path is `${destinationDirectory}/${basename(entry.name)}`.

* Prints warnings if more than one matching file is found.

* @param {function(ZipEntry): boolean} filter Returns true if the entry should be extracted.

* @param {string} relativeDestDir The directory to extract to, relative to `basePath`.

* @param {Buffer} zipBuffer A buffer containing the zip file.

* @returns {Promise<string>} A Promise for the base name of the written file (without directory).

*/

const extractFirstMatchingFile = (filter, relativeDestDir, zipBuffer) => new Promise((resolve, reject) => {

try {

let extractedFileName;

yauzl.fromBuffer(zipBuffer, {lazyEntries: true}, (zipError, zipfile) => {

if (zipError) {

throw zipError;

}

zipfile.readEntry();

zipfile.on('end', () => {

resolve(extractedFileName);

});

zipfile.on('entry', entry => {

if (!filter(entry)) {

// ignore non-matching file

return zipfile.readEntry();

}

if (extractedFileName) {

console.warn(`Multiple matching files found. Ignoring: ${entry.fileName}`);

return zipfile.readEntry();

}

extractedFileName = entry.fileName;

console.info(`Found matching file: ${entry.fileName}`);

zipfile.openReadStream(entry, (fileError, readStream) => {

if (fileError) {

throw fileError;

}

const baseName = path.basename(entry.fileName);

const relativeDestFile = path.join(relativeDestDir, baseName);

console.info(`Extracting ${relativeDestFile}`);

const absoluteDestDir = path.join(basePath, relativeDestDir);

fs.mkdirSync(absoluteDestDir, {recursive: true});

const absoluteDestFile = path.join(basePath, relativeDestFile);

const outStream = fs.createWriteStream(absoluteDestFile);

readStream.on('end', () => {

outStream.close();

zipfile.readEntry();

});

readStream.pipe(outStream);

});

});

});

} catch (error) {

reject(error);

}

});

const downloadMicrobitHex = async () => {

const url = 'https://downloads.scratch.mit.edu/microbit/scratch-microbit.hex.zip';

console.info(`Downloading ${url}`);

const response = await crossFetch(url);

const zipBuffer = Buffer.from(await response.arrayBuffer());

const relativeHexDir = path.join('static', 'microbit');

const hexFileName = await extractFirstMatchingFile(

entry => /\.hex$/.test(entry.fileName),

path.join('static', 'microbit'),

zipBuffer

);

const relativeHexFile = path.join(relativeHexDir, hexFileName);

const relativeGeneratedDir = path.join('src', 'generated');

const relativeGeneratedFile = path.join(relativeGeneratedDir, 'microbit-hex-url.cjs');

const absoluteGeneratedDir = path.join(basePath, relativeGeneratedDir);

fs.mkdirSync(absoluteGeneratedDir, {recursive: true});

const absoluteGeneratedFile = path.join(basePath, relativeGeneratedFile);

const requirePath = `./${path

.relative(relativeGeneratedDir, relativeHexFile)

.split(path.win32.sep)

.join(path.posix.sep)}`;

fs.writeFileSync(

absoluteGeneratedFile,

[

'// This file is generated by scripts/prepublish.mjs',

'// Do not edit this file directly',

'// This file relies on a loader to turn this `require` into a URL',

`module.exports = require('${requirePath}');`,

'' // final newline

].join('\n')

);

console.info(`Wrote ${relativeGeneratedFile}`);

};

const prepublish = async () => {

await downloadMicrobitHex();

};

prepublish().then(

() => {

console.info('Prepublish script complete');

process.exit(0);

},

e => {

console.error(e);

process.exit(1);

}

);