#!/usr/bin/env node

import path from 'path'

import fs from 'fs'

import zlib from 'zlib'

import walk from 'walk-sync'

const DRY_RUN = Boolean(JSON.parse(process.env.DRY_RUN || 'false'))

// Roughly 100KiB means about 25 files at the moment.

// Set this too low and the overheads will be more than the disk and

// network I/O that this intends to serve.

const MIN_GZIP_SIZE = Number(process.env.MIN_GZIP_SIZE || 1024 * 100)

const BROTLI_OPTIONS = {

params: {

[zlib.constants.BROTLI_PARAM_MODE]: zlib.constants.BROTLI_MODE_TEXT,

[zlib.constants.BROTLI_PARAM_QUALITY]: 6,

},

}

main()

async function main() {

compressFromPattern('lib/**/static/**/*.json')

}

async function compressFromPattern(pattern) {

const glob = pattern.includes('*') ? pattern.split(path.sep).slice(1).join(path.sep) : undefined

const walkOptions = {

globs: glob ? [glob] : undefined,

directories: false,

includeBasePath: true,

}

const root = path.resolve(pattern.includes('*') ? pattern.split(path.sep)[0] : pattern)

const filePaths = walk(root, walkOptions).filter((filePath) => {

return fs.statSync(filePath).size > MIN_GZIP_SIZE

})

if (!DRY_RUN) {

console.time(`Compress ${filePaths.length} files`)

const compressed = await Promise.all(filePaths.map(compressFile))

console.timeEnd(`Compress ${filePaths.length} files`)

console.time(`Delete ${compressed.length} files`)

compressed.forEach((filePath) => fs.unlinkSync(filePath))

console.timeEnd(`Delete ${compressed.length} files`)

}

}

function compressFile(filePath) {

return new Promise((resolve, reject) => {

const contentStream = fs.createReadStream(filePath)

const newFilePath = `${filePath}.br`

const writeStream = fs.createWriteStream(newFilePath)

const compressor = zlib.createBrotliCompress(BROTLI_OPTIONS)

contentStream

.pipe(compressor)

.pipe(writeStream)

.on('finish', (err) => {

if (err) return reject(err)

resolve(filePath)

})

})

}