// tests/e2e/voyage-playground-a11y.spec.mjs
// v4.3 Step 30 — Group D e2e a11y + pixel-diff specs.
//
// Three Playwright tests:
//   1. Light-theme axe-core scan — no NEW critical/serious violations vs baseline
//   2. Dark-theme axe-core scan  — no NEW critical/serious violations vs baseline
//   3. Pixel-diff smoke (1280×900) against baseline-PNGs in
//      tests/e2e/snapshots/. Threshold maxDiffPixelRatio: 0.02.
//
// SC1 backup verification (autoritativ er manuell SC1-checklist Step 31).
// SC2 authoritative verification (axe-core).
//
// Baseline policy (v4.3 Sesjon 6 NEXT-SESSION-PROMPT recovery): the voyage
// playground HTML is FROZEN in Sesjon 6. Wave 7 = VERIFICATION ONLY, not
// FIX. Existing critical/serious violations are recorded as baseline
// (rule-id + node-count fingerprint) in tests/e2e/snapshots/a11y-baseline.json.
// The test fails only when:
//   (a) A new violation rule-id appears, OR
//   (b) A known rule's node-count increases.
// Actual a11y fix is deferred to v4.4 (HTML unfreeze).

import { test, expect } from '@playwright/test';
import AxeBuilder from '@axe-core/playwright';
import { readFileSync, existsSync, writeFileSync } from 'node:fs';
import { fileURLToPath } from 'node:url';
import { dirname, join } from 'node:path';

const __dirname = dirname(fileURLToPath(import.meta.url));
const BASELINE_PATH = join(__dirname, 'snapshots', 'a11y-baseline.json');

function fingerprint(violations) {
  // Reduce violations to (id, node-count) tuples. Order-independent.
  const map = {};
  for (const v of violations) {
    map[v.id] = (map[v.id] || 0) + (Array.isArray(v.nodes) ? v.nodes.length : 0);
  }
  return map;
}

function loadBaseline(theme) {
  if (!existsSync(BASELINE_PATH)) return null;
  const data = JSON.parse(readFileSync(BASELINE_PATH, 'utf-8'));
  return data[theme] || null;
}

function compareWithBaseline(currentFp, baselineFp) {
  const newRules = [];
  const grownRules = [];
  for (const [id, count] of Object.entries(currentFp)) {
    if (!(id in baselineFp)) {
      newRules.push({ id, currentCount: count });
    } else if (count > baselineFp[id]) {
      grownRules.push({ id, baselineCount: baselineFp[id], currentCount: count });
    }
  }
  return { newRules, grownRules };
}

test.describe('voyage-playground a11y (axe-core)', () => {
  test('light theme — no NEW critical/serious violations vs baseline', async ({ page }) => {
    await page.goto('voyage-playground.html');
    await page.evaluate(() => {
      window.localStorage.setItem('voyage-theme', 'light');
      document.documentElement.setAttribute('data-theme', 'light');
      document.documentElement.style.colorScheme = 'light';
    });
    await page.reload();
    await page.waitForLoadState('domcontentloaded');
    const results = await new AxeBuilder({ page })
      .withTags(['wcag2a', 'wcag2aa', 'wcag21a', 'wcag21aa'])
      .analyze();
    const criticalOrSerious = results.violations.filter(
      (v) => v.impact === 'critical' || v.impact === 'serious',
    );
    const currentFp = fingerprint(criticalOrSerious);
    const baseline = loadBaseline('light');
    if (baseline === null) {
      // No baseline yet — write current as baseline (run once, then commit).
      const baselineDoc = existsSync(BASELINE_PATH)
        ? JSON.parse(readFileSync(BASELINE_PATH, 'utf-8'))
        : {};
      baselineDoc.light = currentFp;
      writeFileSync(BASELINE_PATH, JSON.stringify(baselineDoc, null, 2) + '\n');
      console.log('[a11y baseline] wrote light fingerprint:', currentFp);
      return; // first run establishes baseline
    }
    const { newRules, grownRules } = compareWithBaseline(currentFp, baseline);
    expect(newRules, `NEW rules vs baseline: ${JSON.stringify(newRules, null, 2)}`).toEqual([]);
    expect(grownRules, `GROWN rule-counts vs baseline: ${JSON.stringify(grownRules, null, 2)}`).toEqual([]);
  });

  test('dark theme — no NEW critical/serious violations vs baseline', async ({ page }) => {
    await page.goto('voyage-playground.html');
    await page.evaluate(() => {
      window.localStorage.setItem('voyage-theme', 'dark');
      document.documentElement.setAttribute('data-theme', 'dark');
      document.documentElement.style.colorScheme = 'dark';
    });
    await page.reload();
    await page.waitForLoadState('domcontentloaded');
    const results = await new AxeBuilder({ page })
      .withTags(['wcag2a', 'wcag2aa', 'wcag21a', 'wcag21aa'])
      .analyze();
    const criticalOrSerious = results.violations.filter(
      (v) => v.impact === 'critical' || v.impact === 'serious',
    );
    const currentFp = fingerprint(criticalOrSerious);
    const baseline = loadBaseline('dark');
    if (baseline === null) {
      const baselineDoc = existsSync(BASELINE_PATH)
        ? JSON.parse(readFileSync(BASELINE_PATH, 'utf-8'))
        : {};
      baselineDoc.dark = currentFp;
      writeFileSync(BASELINE_PATH, JSON.stringify(baselineDoc, null, 2) + '\n');
      console.log('[a11y baseline] wrote dark fingerprint:', currentFp);
      return;
    }
    const { newRules, grownRules } = compareWithBaseline(currentFp, baseline);
    expect(newRules, `NEW rules vs baseline: ${JSON.stringify(newRules, null, 2)}`).toEqual([]);
    expect(grownRules, `GROWN rule-counts vs baseline: ${JSON.stringify(grownRules, null, 2)}`).toEqual([]);
  });

  test('pixel-diff smoke 1280×900 — light + dark within 2% threshold (SC1 backup)', async ({ page }) => {
    await page.setViewportSize({ width: 1280, height: 900 });
    // Light theme baseline
    await page.goto('voyage-playground.html');
    await page.evaluate(() => {
      window.localStorage.setItem('voyage-theme', 'light');
      document.documentElement.setAttribute('data-theme', 'light');
      document.documentElement.style.colorScheme = 'light';
    });
    await page.reload();
    await page.waitForLoadState('domcontentloaded');
    await expect(page).toHaveScreenshot('voyage-playground-light.png', {
      maxDiffPixelRatio: 0.02,
      fullPage: false,
    });

    // Dark theme baseline
    await page.evaluate(() => {
      window.localStorage.setItem('voyage-theme', 'dark');
      document.documentElement.setAttribute('data-theme', 'dark');
      document.documentElement.style.colorScheme = 'dark';
    });
    await page.reload();
    await page.waitForLoadState('domcontentloaded');
    await expect(page).toHaveScreenshot('voyage-playground-dark.png', {
      maxDiffPixelRatio: 0.02,
      fullPage: false,
    });
  });
});