#!/usr/bin/env node
const globby = require('globby')
const cssstats = require('cssstats')
const postcss = require('postcss')
const loadConfig = require('postcss-load-config')
const {remove, mkdirp, readFile, writeFile} = require('fs-extra')
const {dirname, basename, join} = require('path')
const {promisify} = require('util')

const inDir = 'src'
const outDir = 'dist'
const statsDir = join(outDir, 'stats')
const encoding = 'utf8'

remove(outDir)
  .then(() => mkdirp(statsDir))
  .then(() => globby([`${inDir}/**/index.scss`]))
  .then(files => {
    return loadConfig().then(({plugins, options}) => {
      const processor = postcss(plugins)

      const inPattern = new RegExp(`^${inDir}/`)
      const names = {
        'index.scss': 'primer'
      }
      const tasks = files.map(from => {
        const path = from.replace(inPattern, '')
        const name = names[path] || dirname(path).replace(/\//g, '-')

        const to = join(outDir, `${name}.css`)
        const info = {
          name,
          source: from,
          sass: `@primer/css/${path}`,
          css: to,
          map: `${to}.map`,
          js: join(outDir, `${name}.js`),
          stats: join(statsDir, `${name}.json`),
          legacy: `primer-${name}/index.scss`
        }

        return readFile(from)
          .then(scss => processor.process(scss, Object.assign({from, to}, options)))
          .then(result => Promise.all([
            writeFile(to, result.css, encoding),
            writeFile(info.stats, JSON.stringify(cssstats(result.css)), encoding),
            writeFile(info.js, `module.exports = {cssstats: require('./stats/${name}.json')}`, encoding),
            result.map ? writeFile(info.map, result.map, encoding) : null
          ]))
          .then(() => info)
      })

      return Promise.all(tasks)
    })
    .then(files => {
      const meta = {files}
      return writeFile(join(outDir, 'meta.json'), JSON.stringify(meta, null, 2), encoding)
    })
  })
  .catch(error => {
    console.error(error)
    process.exitCode = 1
  })