#!/usr/bin/env bun
 
import plugin from 'bun-plugin-tailwind'
import { existsSync } from 'fs'
import { rm } from 'fs/promises'
import path from 'path'

if (process.argv.includes('--help') || process.argv.includes('-h')) {
  console.log(`
🏗️  Bun Build Script

Usage: bun run build.ts [options]

Common Options:
  --outdir <path>          Output directory (default: "dist")
  --minify                 Enable minification (or --minify.whitespace, --minify.syntax, etc)
  --sourcemap <type>      Sourcemap type: none|linked|inline|external
  --target <target>        Build target: browser|bun|node
  --format <format>        Output format: esm|cjs|iife
  --splitting              Enable code splitting
  --packages <type>        Package handling: bundle|external
  --public-path <path>     Public path for assets
  --env <mode>             Environment handling: inline|disable|prefix*
  --conditions <list>      Package.json export conditions (comma separated)
  --external <list>        External packages (comma separated)
  --banner <text>          Add banner text to output
  --footer <text>          Add footer text to output
  --define <obj>           Define global constants (e.g. --define.VERSION=1.0.0)
  --help, -h               Show this help message

Example:
  bun run build.ts --outdir=dist --minify --sourcemap=linked --external=react,react-dom
`)
  process.exit(0)
}

const toCamelCase = (str: string): string =>
  str.replace(/-([a-z])/g, (g) => g[1].toUpperCase())

const parseValue = (value: string): string | number | boolean | string[] => {
  if (value === 'true') return true
  if (value === 'false') return false

  if (/^\d+$/.test(value)) return parseInt(value, 10)
  if (/^\d*\.\d+$/.test(value)) return parseFloat(value)

  if (value.includes(',')) return value.split(',').map((v) => v.trim())

  return value
}

function parseArgs(): Partial<Bun.BuildConfig> {
  const config: Record<string, unknown> = {}
  const args = process.argv.slice(2)

  for (let i = 0; i < args.length; i++) {
    const arg = args[i]
    if (arg === undefined) continue
    if (!arg.startsWith('--')) continue

    if (arg.startsWith('--no-')) {
      const key = toCamelCase(arg.slice(5))
      config[key] = false
      continue
    }

    if (
      !arg.includes('=') &&
      (i === args.length - 1 || args[i + 1]?.startsWith('--'))
    ) {
      const key = toCamelCase(arg.slice(2))
      config[key] = true
      continue
    }

    let key: string
    let value: string

    if (arg.includes('=')) {
      ;[key, value] = arg.slice(2).split('=', 2) as [string, string]
    } else {
      key = arg.slice(2)
      value = args[++i] ?? ''
    }

    key = toCamelCase(key)

    if (key.includes('.')) {
      const [parentKey, childKey] = key.split('.')
      if (parentKey && childKey) {
        config[parentKey] = config[parentKey] || {}
        config[parentKey][childKey] = parseValue(value)
      }
    } else {
      config[key] = parseValue(value)
    }
  }

  return config as Partial<Bun.BuildConfig>
}

const formatFileSize = (bytes: number): string => {
  const units = ['B', 'KB', 'MB', 'GB']
  let size = bytes
  let unitIndex = 0

  while (size >= 1024 && unitIndex < units.length - 1) {
    size /= 1024
    unitIndex++
  }

  return `${size.toFixed(2)} ${units[unitIndex]}`
}

console.log('\n🚀 Starting build process...\n')

const cliConfig = parseArgs()
const outdir = cliConfig.outdir || path.join(process.cwd(), 'dist')

if (existsSync(outdir)) {
  console.log(`🗑️ Cleaning previous build at ${outdir}`)
  await rm(outdir, { recursive: true, force: true })
}

const start = performance.now()

const entrypoints = [...new Bun.Glob('**.html').scanSync('src')]
  .map((a) => path.resolve('src', a))
  .filter((dir) => !dir.includes('node_modules'))
console.log(
  `📄 Found ${entrypoints.length} HTML ${entrypoints.length === 1 ? 'file' : 'files'} to process\n`,
)

const result = await Bun.build({
  entrypoints,
  outdir,
  plugins: [plugin],
  minify: true,
  target: 'browser',
  sourcemap: 'linked',
  define: {
    'process.env.NODE_ENV': JSON.stringify('production'),
  },
  ...cliConfig,
})

const end = performance.now()

const outputTable = result.outputs.map((output) => ({
  File: path.relative(process.cwd(), output.path),
  Type: output.kind,
  Size: formatFileSize(output.size),
}))

console.table(outputTable)
const buildTime = (end - start).toFixed(2)

console.log(`\n✅ Build completed in ${buildTime}ms\n`)