import { readFile, writeFile } from 'node:fs/promises'
import path from 'node:path'
import { fileURLToPath } from 'node:url'

import { build } from 'vite'

const root = path.dirname(path.dirname(fileURLToPath(import.meta.url)))
const result = await build({
  configFile: false,
  logLevel: 'silent',
  build: {
    write: false,
    minify: true,
    lib: {
      entry: path.join(root, 'src/standaloneEngine.entry.ts'),
      formats: ['iife'],
      name: 'AvatarProceduralEngine',
    },
  },
})
const outputs = Array.isArray(result) ? result.flatMap(item => item.output) : result.output
const chunk = outputs.find(item => item.type === 'chunk')
if (!chunk) throw new Error('Standalone avatar engine bundle was not generated.')

const outputPath = path.join(root, 'src/standaloneEngine.generated.ts')
const source = `// Generated by scripts/generate-standalone-engine.mjs. Do not edit.\nexport const standaloneEngineSource = ${JSON.stringify(chunk.code)}\n`

if (process.argv.includes('--check')) {
  const current = await readFile(outputPath, 'utf8').catch(() => '')
  if (current !== source) throw new Error('Standalone avatar engine is stale. Run yarn engine.')
} else {
  await writeFile(outputPath, source)
}