#!/usr/bin/env node
/**
 * Header chrome WCAG 2.2 contrast audit + optional Lighthouse accessibility run.
 * Usage: node scripts/a11y/audit-header-wcag.mjs [--lighthouse] [--url=https://mim4u.org]
 */
import { spawnSync } from 'node:child_process'
import { mkdirSync, readFileSync, writeFileSync } from 'node:fs'
import { dirname, join } from 'node:path'
import { fileURLToPath } from 'node:url'

const __dirname = dirname(fileURLToPath(import.meta.url))
const repoRoot = join(__dirname, '../..')
const outDir = join(repoRoot, 'reports/status')

const args = process.argv.slice(2)
const runLighthouse = args.includes('--lighthouse')
const urlArg = args.find((a) => a.startsWith('--url='))
const url = urlArg ? urlArg.split('=')[1] : 'https://mim4u.org'

function relLuminance(hex) {
  const h = hex.replace('#', '')
  const channels = [h.slice(0, 2), h.slice(2, 4), h.slice(4, 6)].map((pair) => {
    const c = parseInt(pair, 16) / 255
    return c <= 0.03928 ? c / 12.92 : ((c + 0.055) / 1.055) ** 2.4
  })
  return 0.2126 * channels[0] + 0.7152 * channels[1] + 0.0722 * channels[2]
}

function contrastRatio(fg, bg) {
  const l1 = relLuminance(fg)
  const l2 = relLuminance(bg)
  const lighter = Math.max(l1, l2)
  const darker = Math.min(l1, l2)
  return (lighter + 0.05) / (darker + 0.05)
}

function gradePair(ratio, { largeText = false, uiComponent = false, decorative = false } = {}) {
  if (decorative) return { pass: true, level: 'exempt', note: 'Decorative; accessible name on parent link' }
  const aa = largeText || uiComponent ? 3 : 4.5
  const aaa = largeText || uiComponent ? 4.5 : 7
  if (ratio >= aaa) return { pass: true, level: 'AAA' }
  if (ratio >= aa) return { pass: true, level: 'AA' }
  return { pass: false, level: 'fail', required: aa }
}

const tokens = {
  headerBgLight: '#fffefb',
  headerBgDark: '#000000',
  navLinkLight: '#52525b',
  navLinkDark: '#d4d4d8',
  navLinkHoverLight: '#1a3c34',
  navLinkHoverDark: '#d4af37',
  logoGold: '#c5a059',
  focusGreenDeep: '#0f2922',
  focusPrimary500: '#2d6b5c',
  eyebrowLight: '#7d6232',
  eyebrowDark: '#d4af37',
  eyebrowBgLight: '#fafafa',
  eyebrowBgDark: '#111827',
  donateBtnText: '#ffffff',
  donateBtnGreen: '#1a3c34',
}

const headerPairs = [
  { id: 'nav-link-light', fg: tokens.navLinkLight, bg: tokens.headerBgLight, context: 'Desktop nav links (light)' },
  { id: 'nav-link-dark', fg: tokens.navLinkDark, bg: tokens.headerBgDark, context: 'Desktop nav links (dark)' },
  { id: 'nav-link-hover-light', fg: tokens.navLinkHoverLight, bg: tokens.headerBgLight, context: 'Nav hover (light)' },
  { id: 'nav-link-hover-dark', fg: tokens.navLinkHoverDark, bg: tokens.headerBgDark, context: 'Nav hover (dark)' },
  {
    id: 'logo-gold-light',
    fg: tokens.logoGold,
    bg: tokens.headerBgLight,
    context: 'Nav logo artwork (light)',
    decorative: true,
  },
  {
    id: 'logo-gold-dark',
    fg: tokens.logoGold,
    bg: tokens.headerBgDark,
    context: 'Nav logo artwork (dark)',
    decorative: true,
  },
  {
    id: 'brand-link-focus-light',
    fg: tokens.focusGreenDeep,
    bg: tokens.headerBgLight,
    context: 'Home logo focus ring (light)',
    uiComponent: true,
  },
  {
    id: 'brand-link-focus-dark',
    fg: tokens.eyebrowDark,
    bg: tokens.headerBgDark,
    context: 'Home logo focus ring (dark)',
    uiComponent: true,
  },
  {
    id: 'nav-focus-ring-light',
    fg: tokens.focusPrimary500,
    bg: tokens.headerBgLight,
    context: 'Nav control focus ring (light)',
    uiComponent: true,
  },
  {
    id: 'donate-btn-text',
    fg: tokens.donateBtnText,
    bg: tokens.donateBtnGreen,
    context: 'Header Donate CTA text',
    largeText: true,
  },
  {
    id: 'section-eyebrow-light',
    fg: tokens.eyebrowLight,
    bg: tokens.eyebrowBgLight,
    context: 'Section eyebrow near hero (light)',
  },
  {
    id: 'section-eyebrow-dark',
    fg: tokens.eyebrowDark,
    bg: tokens.eyebrowBgDark,
    context: 'Section eyebrow (dark)',
  },
]

const contrastResults = headerPairs.map((pair) => {
  const ratio = contrastRatio(pair.fg, pair.bg)
  const grade = gradePair(ratio, pair)
  return { ...pair, ratio: Number(ratio.toFixed(2)), ...grade }
})

const contrastFailures = contrastResults.filter((r) => !r.pass)

let lighthouse = null
if (runLighthouse) {
  const lhOut = join(outDir, 'lighthouse-a11y-mim4u-latest.json')
  mkdirSync(outDir, { recursive: true })
  const chromePath = process.env.CHROME_PATH || '/usr/bin/google-chrome'
  const result = spawnSync(
    'npx',
    [
      '--yes',
      'lighthouse',
      url,
      '--only-categories=accessibility',
      '--output=json',
      `--output-path=${lhOut}`,
      '--chrome-flags=--headless --no-sandbox',
    ],
    {
      cwd: repoRoot,
      env: { ...process.env, CHROME_PATH: chromePath },
      encoding: 'utf8',
      stdio: ['ignore', 'pipe', 'pipe'],
    }
  )
  if (result.status === 0) {
    const raw = JSON.parse(readFileSync(lhOut, 'utf8'))
    const failing = raw.categories.accessibility.auditRefs
      .filter((ref) => {
        const audit = raw.audits[ref.id]
        return audit && audit.score !== null && audit.score < 1
      })
      .map((ref) => ({
        id: ref.id,
        title: raw.audits[ref.id].title,
        score: raw.audits[ref.id].score,
      }))
    lighthouse = {
      score: Math.round(raw.categories.accessibility.score * 100),
      failingAudits: failing,
      reportPath: lhOut,
    }
  } else {
    lighthouse = {
      error: (result.stderr || result.stdout || 'Lighthouse failed').trim().slice(0, 500),
    }
  }
}

const report = {
  schemaVersion: '1.0.0',
  assessmentDate: new Date().toISOString().slice(0, 10),
  subject: 'mim4u.org header chrome WCAG 2.2 contrast audit',
  standard: 'WCAG 2.2 Level AA (contrast + focus appearance)',
  url,
  summary: {
    headerContrastPairs: contrastResults.length,
    failures: contrastFailures.length,
    pass: contrastFailures.length === 0,
    lighthouseScore: lighthouse?.score ?? null,
  },
  contrastResults,
  lighthouse,
  remediations: [
    'Nav logo marked decorative; home link provides accessible name',
    'Brand link focus ring uses --mim-brand-green-deep (3:1+ UI contrast)',
    'Section eyebrow uses --mim-eyebrow-text (#7d6232) on light backgrounds',
    'Footer Instagram link visible text matches accessible name (no aria-label mismatch)',
  ],
}

mkdirSync(outDir, { recursive: true })
const outPath = join(outDir, 'mim4u-header-wcag-audit-latest.json')
writeFileSync(outPath, `${JSON.stringify(report, null, 2)}\n`)

console.log(`WCAG header audit: ${contrastFailures.length} contrast failure(s)`)
contrastFailures.forEach((f) => {
  console.log(`  FAIL ${f.id}: ${f.ratio}:1 (${f.context})`)
})
if (lighthouse?.score != null) {
  console.log(`Lighthouse accessibility: ${lighthouse.score}/100`)
  lighthouse.failingAudits?.forEach((a) => console.log(`  LH FAIL ${a.id}: ${a.title}`))
}
console.log(`Report: ${outPath}`)

process.exit(contrastFailures.length === 0 ? 0 : 1)