/**
 * Composes the final multi-theme `unity.css` by concatenating the formatted
 * outputs from three SD instances into a single file.
 */
import fs from 'fs'
import path from 'path'

import prettier from 'prettier'

export interface ComposeInput {
  /** css/variables output for legacy (:root selector) */
  legacyCss: string
  /** css/variables output for rebrand ([data-uy-theme="rebrand"] selector) */
  rebrandCss: string
  /** css/unity-theme output (@theme block + grid/typography utilities) */
  themeCss: string
  /** File header + imports */
  header: string
  /** Custom variant declarations */
  customVariants: string
  /** Output path for the composed CSS */
  outputPath: string
}

export async function composeMultiThemeCss(input: ComposeInput): Promise<void> {
  const {
    legacyCss,
    rebrandCss,
    themeCss,
    header,
    customVariants,
    outputPath,
  } = input

  const css = `${header}

@layer base {
${legacyCss}

${rebrandCss}
}

${themeCss}

${customVariants}
`

  console.log('  \x1b[2m→\x1b[0m Formatting with Prettier...')
  const formatted = await prettier.format(css, {
    parser: 'css',
    printWidth: 120,
    tabWidth: 2,
    useTabs: false,
  })

  fs.mkdirSync(path.dirname(outputPath), { recursive: true })
  fs.writeFileSync(outputPath, formatted)
  console.log(`  \x1b[2m→\x1b[0m Written to \x1b[33m${outputPath}\x1b[0m`)
}