// The size budget: what does the framework itself cost on the wire?
// Bundles @uhhm/buuh + @uhhm/buuh-html (browser condition) minified via
// the same Vite/Rolldown pipeline apps use, then reports min+gzip and
// min+brotli. CI fails if min+gzip exceeds the budget.
//
//   npm run size

import { build } from 'vite'
import { readFile, readdir, rm, mkdtemp } from 'node:fs/promises'
import { join } from 'node:path'
import { tmpdir } from 'node:os'
import { gzipSync, brotliCompressSync, constants } from 'node:zlib'

// The promise the README makes; raise only with a paper trail.
// Context: v7's "4kb" was choo alone — nanohtml lived in the browserify
// transform. This number is the whole framework: core, html engine,
// morph, hydrate, router, bus. Currently ~7.97 kB gzip; the headroom is
// margin, not license.
const BUDGET_GZIP = 8.5 * 1024

const VIRTUAL = '\0size:entry'

const outDir = await mkdtemp(join(tmpdir(), 'choo-size-'))
await build({
  appType: 'custom',
  logLevel: 'error',
  plugins: [{
    name: 'size-entry',
    resolveId: (id) => id === 'size:entry' ? VIRTUAL : undefined,
    load: (id) => id === VIRTUAL
      ? "import choo, { Choo, lazy } from '@uhhm/buuh'\n" +
        "import html from '@uhhm/buuh-html'\n" +
        "import raw from '@uhhm/buuh-html/raw'\n" +
        'window.__keep = { choo, Choo, lazy, html, raw }\n'
      : undefined
  }],
  build: {
    outDir,
    emptyOutDir: true,
    rollupOptions: { input: { framework: 'size:entry' } }
  }
})

const assets = await readdir(join(outDir, 'assets'))
const file = assets.find((name) => name.endsWith('.js'))
const code = await readFile(join(outDir, 'assets', file))
await rm(outDir, { recursive: true, force: true })

const gz = gzipSync(code, { level: constants.Z_BEST_COMPRESSION }).length
const br = brotliCompressSync(code, {
  params: { [constants.BROTLI_PARAM_QUALITY]: constants.BROTLI_MAX_QUALITY }
}).length

const kb = (n) => (n / 1024).toFixed(2) + ' kB'
console.log(`@uhhm/buuh + @uhhm/buuh-html (browser, minified)`)
console.log(`  raw:     ${kb(code.length)}`)
console.log(`  gzip:    ${kb(gz)}  (budget ${kb(BUDGET_GZIP)})`)
console.log(`  brotli:  ${kb(br)}`)

if (gz > BUDGET_GZIP) {
  console.error(`\nsize budget exceeded: ${kb(gz)} > ${kb(BUDGET_GZIP)} min+gzip`)
  process.exit(1)
}
console.log('\nwithin budget ✔')