#!/usr/bin/env node

import finder from 'find-package-json'
import { readdirSync, writeFile } from 'fs'
import * as path from 'path/posix'
import { exit } from 'process'

const packageInfo = finder().next().value

if (packageInfo === undefined) {
  console.error('Failed to get package information. Are you in project directory root-path?')
  exit()
}

const config = packageInfo['css-import-generator']

if (config === undefined) {
  console.error('Please provide value for "css-import-generator" in package.json field')
  exit()
}

const cssRoot = config['css-root']

if (cssRoot === undefined) {
  console.error(
    'Please provide value for "css-root" under "css-import-generator" field of "package.json". It\'s necessary',
  )
  exit()
}

const destination = config['destination'] ?? path.resolve(cssRoot, 'index.js')

if (config['destination'] === undefined) {
  console.log(destination)
  console.warn(
    `"destination" field is missing. It's okay but we will generate output js file at ${destination}\nyou can override this behavior by providing value for "destination" under "css-import-generator" field of "package.json"`,
  )
}

const newLine = '\n'
const extensions = new Set(['css', 'scss', 'sass'])

/**
 * content to write into {destination}
 */
let content = ''

const makeEmptyLine = () => {
  return newLine
}

const makeImport = ({ relativePath }: { relativePath: string }) => {
  return `import './${relativePath}'${newLine}`
}

const makeComment = ({ comment }: { comment: string }) => {
  return `// ${comment}${newLine}`
}

const generateImport = ({ root, currentDirectory }: { root: string; currentDirectory: string }) => {
  const dirents = readdirSync(currentDirectory, { withFileTypes: true })
  const destinationDirectory = path.dirname(destination)

  const directories = dirents.filter((dirent) => dirent.isDirectory())
  const files = dirents.filter((dirent) => dirent.isFile())

  let hasCssFiles = false
  let currentDirectoryImportContent = ''

  // files
  files.forEach((file) => {
    const extension = file.name.split('.').pop()

    if (extension && extensions.has(extension)) {
      hasCssFiles = true
      currentDirectoryImportContent += makeImport({
        relativePath: path.join(path.relative(destinationDirectory, currentDirectory), file.name),
      })
    }
  })

  // comment directory
  if (currentDirectoryImportContent.length > 0 && hasCssFiles) {
    currentDirectoryImportContent =
      makeEmptyLine() +
      makeComment({
        comment: `in directory ${path.relative(destinationDirectory, currentDirectory)}`,
      }) +
      currentDirectoryImportContent
  }

  content += currentDirectoryImportContent

  // call for sub-directories
  directories.forEach((directory) => {
    generateImport({
      root,
      currentDirectory: path.resolve(currentDirectory, directory.name),
    })
  })
}

// main-logic
generateImport({ root: cssRoot, currentDirectory: cssRoot })

writeFile(destination, content, (err) => {
  if (err) {
    console.error(err)
  }
})

console.log('\n')
console.log(`successfully generated "${destination}"`)