#!/usr/bin/env node
//
// Render the site in a real browser at real viewports and MEASURE it.
//
//   node scripts/qa-browser.mjs                          # production, default widths
//   node scripts/qa-browser.mjs --url http://localhost:3001
//   node scripts/qa-browser.mjs --viewports 320,768
//   node scripts/qa-browser.mjs --paths / /about /contact
//   node scripts/qa-browser.mjs --shots /tmp/qa           # also write screenshots
//
// Exit codes: 0 nothing found. 1 findings, each named. 2 NOTHING WAS CHECKED —
// playwright missing or the site unreachable. Two is not a pass.
//
// ## Which incident motivated it
//
// Batches 10 and 11 were twenty-ish UI and accessibility defects filed from
// reading markup. **Seven of ten misstated their own evidence.** Two contrast
// figures were simply wrong when computed; one proposed a colour measuring
// 1.96:1 against the background it would sit on, which would have made the
// footer materially worse; one asked for aria-labels whose existing versions
// were already WCAG 2.5.3 Level A failures, so doing what it said would have
// spread the defect; one described a clipping ancestor that does not exist;
// one described an overlap that is a 12px gap; one described a readOnly
// attribute that is not in the file.
//
// Every one of those took minutes to disprove with a browser and would have
// taken hours to "fix". The cost of not having this script was not the fixes —
// it was very nearly making the site worse, twice, on the strength of a
// confident sentence.
//
// So: numbers, from the thing itself. Contrast is arithmetic, overlap is two
// rectangles, and "does it clip" is a computed style you can read.
//
// ## What it measures
//
//   horizontal scroll   scrollWidth > innerWidth, and which element causes it
//   broken images       after scrolling the whole page, so lazy ones are fair
//   CLS                 cumulative layout shift, good < 0.1
//   LCP                 largest contentful paint, good < 2500ms
//   overflowing nodes   any element whose right edge is past the viewport
//
// ## Why it is not wired into verify.sh
//
// playwright is not a dependency of this project — it is installed globally on
// this machine. Adding ~300MB of browser to every clone to run a check nobody
// runs on every commit is the wrong trade. This is a tool you reach for when a
// UI defect is filed, and `docs/qa/ClaudeQAPlan.md` says to reach for it.
//
// If it is ever made a devDependency, wire it in as scripts/verify.d/40-browser.

import { createRequire } from 'node:module'
import { execSync } from 'node:child_process'
import path from 'node:path'

const args = process.argv.slice(2)
const opt = (name, dflt) => {
  const i = args.indexOf(`--${name}`)
  return i === -1 ? dflt : args[i + 1]
}
const URL_BASE  = (opt('url', 'https://queuenorth.com')).replace(/\/$/, '')
const VIEWPORTS = (opt('viewports', '320,390,768,1024')).split(',').map(Number)
// Stop at the next flag rather than filtering non-flags out of the whole tail:
// `--paths / --viewports 320` otherwise swallowed "320" as a path and then
// tried to navigate to it. Caught by the tool reporting four findings that were
// its own argument handling.
const collect = (name, dflt) => {
  const i = args.indexOf(`--${name}`)
  if (i === -1) return dflt
  const out = []
  for (let j = i + 1; j < args.length && !args[j].startsWith('--'); j++) out.push(args[j])
  return out.length ? out : dflt
}
const PATHS = collect('paths', ['/', '/about', '/services', '/contact', '/support'])
const SHOTS = opt('shots', null)

// playwright is global here. Resolve it explicitly rather than failing with a
// bare MODULE_NOT_FOUND, which reads as "the script is broken" rather than
// "install this".
let chromium
try {
  const require = createRequire(import.meta.url)
  let root
  try { root = require.resolve('playwright') } catch {
    const g = execSync('npm root -g', { encoding: 'utf8' }).trim()
    root = path.join(g, 'playwright', 'index.js')
  }
  ;({ chromium } = require(root))
} catch (e) {
  console.error('qa-browser: playwright is not available, so NOTHING was checked.')
  console.error('            npm i -g playwright && npx playwright install chromium')
  process.exit(2)
}

const findings = []
const say = (...a) => console.log(...a)

const browser = await chromium.launch().catch(e => {
  console.error('qa-browser: could not launch chromium, so nothing was checked:', e.message)
  process.exit(2)
})

for (const p of PATHS) {
  for (const width of VIEWPORTS) {
    const page = await browser.newPage({ viewport: { width, height: 900 } })
    await page.addInitScript(() => {
      window.__cls = 0; window.__lcp = 0
      new PerformanceObserver(l => { for (const e of l.getEntries()) if (!e.hadRecentInput) window.__cls += e.value })
        .observe({ type: 'layout-shift', buffered: true })
      new PerformanceObserver(l => { for (const e of l.getEntries()) window.__lcp = e.startTime })
        .observe({ type: 'largest-contentful-paint', buffered: true })
    })

    const httpFailed = []
    page.on('response', r => {
      if (r.request().resourceType() === 'image' && r.status() >= 400) httpFailed.push(`${r.status()} ${r.url()}`)
    })

    let resp
    try {
      resp = await page.goto(URL_BASE + p, { waitUntil: 'networkidle', timeout: 45000 })
    } catch (e) {
      findings.push(`${p} @${width}: could not load — ${e.message.split('\n')[0]}`)
      await page.close(); continue
    }
    if (!resp || resp.status() >= 400) {
      findings.push(`${p} @${width}: HTTP ${resp ? resp.status() : '?'}`)
      await page.close(); continue
    }

    // Scroll the whole page so lazy images are actually requested, then chase
    // any that still have not loaded by scrolling to each one directly.
    //
    // Both passes are needed and the second is the one that matters. A coarse
    // scroll can outrun the intersection observer, and the first version of
    // this reported a perfectly healthy lazy badge as broken at three
    // viewports — a false positive in the tool, on the very run that was
    // meant to demonstrate the tool. Anything that survives BOTH passes plus
    // an observed HTTP failure is worth reporting; anything less is noise, and
    // noise is how a checker gets ignored.
    await page.evaluate(async () => {
      for (let y = 0; y < document.body.scrollHeight; y += 300) {
        window.scrollTo(0, y); await new Promise(r => setTimeout(r, 80))
      }
      window.scrollTo(0, 0)
    })
    await page.waitForTimeout(800)

    const stragglers = await page.$$('img')
    for (const h of stragglers) {
      const ok = await h.evaluate(i => i.complete && i.naturalWidth > 0)
      if (ok) continue
      await h.scrollIntoViewIfNeeded({ timeout: 3000 }).catch(() => {})
      await page.waitForTimeout(400)
    }
    await page.evaluate(() => window.scrollTo(0, 0))
    await page.waitForTimeout(600)

    const m = await page.evaluate(() => {
      const vw = window.innerWidth
      const over = [...document.querySelectorAll('body *')]
        .filter(e => { const b = e.getBoundingClientRect(); return b.width > 0 && b.right > vw + 1 })
        .slice(0, 5)
        .map(e => `${e.tagName.toLowerCase()}${e.className ? '.' + String(e.className).split(' ')[0] : ''} (right ${Math.round(e.getBoundingClientRect().right)})`)
      return {
        vw,
        scrollWidth: document.documentElement.scrollWidth,
        broken: [...document.images].filter(i => !(i.complete && i.naturalWidth > 0)).map(i => i.getAttribute('src')),
        images: document.images.length,
        cls: +(window.__cls || 0).toFixed(4),
        lcp: Math.round(window.__lcp || 0),
        over,
      }
    })

    const bits = []
    if (m.scrollWidth > m.vw) { bits.push(`H-SCROLL ${m.scrollWidth}>${m.vw}`); findings.push(`${p} @${width}: horizontal scroll ${m.scrollWidth} > ${m.vw}`) }
    if (httpFailed.length)    { bits.push(`HTTP-FAIL ${httpFailed.length}`);    findings.push(`${p} @${width}: image request failed — ${httpFailed.join(', ')}`) }
    if (m.broken.length)      { bits.push(`BROKEN ${m.broken.length}`);        findings.push(`${p} @${width}: image never rendered after being scrolled to — ${m.broken.join(', ')}`) }
    if (m.cls > 0.1)          { bits.push(`CLS ${m.cls}`);                     findings.push(`${p} @${width}: CLS ${m.cls} (>0.1)`) }
    if (m.lcp > 2500)         { bits.push(`LCP ${m.lcp}ms`);                   findings.push(`${p} @${width}: LCP ${m.lcp}ms (>2500)`) }
    if (m.over.length)        { bits.push(`OVERFLOW ${m.over.length}`);        findings.push(`${p} @${width}: past the right edge — ${m.over.join('; ')}`) }

    say(`  ${p.padEnd(12)} @${String(width).padEnd(5)} imgs=${String(m.images).padEnd(3)} cls=${String(m.cls).padEnd(7)} lcp=${String(m.lcp + 'ms').padEnd(8)} ${bits.length ? '‼ ' + bits.join('  ') : 'ok'}`)

    if (SHOTS) await page.screenshot({ path: `${SHOTS}/${p.replace(/\//g, '_') || 'root'}-${width}.png`, fullPage: false })
    await page.close()
  }
}

await browser.close()

say('')
if (findings.length) {
  say(`qa-browser: ${findings.length} finding(s):`)
  for (const f of findings) say(`  - ${f}`)
  process.exit(1)
}
say(`qa-browser: nothing found across ${PATHS.length} path(s) x ${VIEWPORTS.length} viewport(s).`)
say('            That is not "the UI is correct" — it is these five measurements,')
say('            on these pages, at these widths. Nothing here opens a menu or')
say('            uses a keyboard.')