┌─────────────────────────────────────────────────────────────┐
│                    LLM SCREENSHOT INSPECTION                │
├─────────────────────────────────────────────────────────────┤
│                                                             │
│  1. CAPTURE (Playwright)                                    │
│     └─► Wait for React hydration, not just network          │
│                                                             │
│  2. READ (Claude vision)                                    │
│     └─► Pass screenshot to LLM with specific questions      │
│                                                             │
│  3. ANALYZE (Structured response)                           │
│     └─► Extract: content present? theme correct? errors?    │
│                                                             │
│  4. ACT (Conditional logic)                                 │
│     └─► Pass/fail based on semantic understanding           │
│                                                             │
└─────────────────────────────────────────────────────────────┘

# ❌ WRONG - React may not have rendered yet
page.goto(url)
page.wait_for_load_state('networkidle')
page.screenshot(path='broken.png')  # Often blank!

# ✅ CORRECT - Wait for React to mount
page.goto(url, wait_until='domcontentloaded')
page.wait_for_load_state('networkidle')

# Give React time to hydrate
import time
time.sleep(0.5)

# Wait for actual content selector
page.wait_for_selector('.main-content, h1, [data-testid="app"]',
                       state='visible',
                       timeout=10000)

# Verify content exists
body_text = page.locator('body').inner_text()
if len(body_text) < 50:
    time.sleep(2)  # Extra wait for slow hydration

page.screenshot(path='good.png', full_page=True)

def wait_for_react_content(page, selectors, timeout=10000):
    """Wait for React to hydrate by checking for actual content."""
    page.wait_for_load_state('domcontentloaded')
    page.wait_for_load_state('networkidle')
    time.sleep(0.5)  # React hydration buffer

    for selector in selectors.split(','):
        try:
            locator = page.locator(selector.strip())
            if locator.count() > 0:
                locator.first.wait_for(state='visible', timeout=timeout)
                return True
        except:
            continue

    # Fallback: wait for substantial body content
    try:
        page.wait_for_function(
            'document.body.innerText.length > 100',
            timeout=timeout
        )
        return True
    except:
        return False

from playwright.sync_api import sync_playwright

with sync_playwright() as p:
    # CRITICAL: headless=True prevents visible browser windows
    browser = p.chromium.launch(headless=True)

    context = browser.new_context(
        viewport={'width': 1280, 'height': 800},
        color_scheme='dark'  # Initial theme
    )
    page = context.new_page()

    # ... your test logic ...

    browser.close()  # Always clean up

# Dark mode screenshot
page.emulate_media(color_scheme='dark')  # Note: on PAGE, not context
page.goto(url)
wait_for_react_content(page, '.app-container, main, h1')
page.screenshot(path='dark.png', full_page=True)

# Light mode screenshot
page.emulate_media(color_scheme='light')
page.reload()
wait_for_react_content(page, '.app-container, main, h1')
page.screenshot(path='light.png', full_page=True)

Prompt: "Analyze this screenshot. Answer:
1. Is the main content rendered (not blank/loading)?
2. What major UI elements are visible?
3. Are there any error states or broken layouts?
4. Rate content completeness: FULL / PARTIAL / EMPTY"

Prompt: "This is a {dark/light} mode screenshot. Verify:
1. Background color matches expected theme (dark bg for dark mode)
2. Text has sufficient contrast against background
3. Interactive elements are visible and styled correctly
4. No theme leakage (dark elements on light bg or vice versa)"

Prompt: "Compare these two screenshots (before/after). Identify:
1. What changed between them?
2. Are changes intentional (theme switch) or bugs?
3. Is any content missing in the 'after' version?
4. Rate similarity: IDENTICAL / MINOR_DIFF / MAJOR_DIFF / BROKEN"

Prompt: "Evaluate this screenshot for visual accessibility:
1. Is text readable (sufficient size and contrast)?
2. Are interactive elements clearly identifiable?
3. Is there visual hierarchy (headings, sections)?
4. Any elements that would fail WCAG contrast requirements?"

#!/usr/bin/env python3
"""
LLM-Powered Screenshot Test Suite
Captures screenshots and uses Claude vision for semantic analysis.
"""

from playwright.sync_api import sync_playwright
import os
import time

PAGES_TO_TEST = [
    # (path, name, content_selectors)
    ('/', 'Home', '.hero, main, h1'),
    ('/about', 'About', '.about-content, main, h1'),
    ('/dashboard', 'Dashboard', '.dashboard, .stats, h1'),
]

BASE_URL = 'http://localhost:5173'
SCREENSHOT_DIR = '/tmp/visual-tests'


def wait_for_content(page, selectors, timeout=10000):
    """Wait for React/Vue/Svelte to hydrate."""
    page.wait_for_load_state('domcontentloaded')
    page.wait_for_load_state('networkidle')
    time.sleep(0.5)

    for selector in selectors.split(','):
        try:
            loc = page.locator(selector.strip())
            if loc.count() > 0:
                loc.first.wait_for(state='visible', timeout=timeout)
                return True
        except:
            continue

    try:
        page.wait_for_function('document.body.innerText.length > 100', timeout=timeout)
        return True
    except:
        return False


def capture_themed_screenshots(page, url, name, selectors):
    """Capture both dark and light mode screenshots."""
    safe_name = name.lower().replace(' ', '-')
    results = {'name': name, 'url': url}

    for theme in ['dark', 'light']:
        page.emulate_media(color_scheme=theme)

        if theme == 'dark':
            page.goto(url, wait_until='domcontentloaded')
        else:
            page.reload(wait_until='domcontentloaded')

        content_loaded = wait_for_content(page, selectors)

        if not content_loaded:
            print(f"  ⚠️  {theme} mode: Content slow to load, waiting...")
            time.sleep(2)

        screenshot_path = f'{SCREENSHOT_DIR}/{safe_name}-{theme}.png'
        page.screenshot(path=screenshot_path, full_page=True)

        # Check content length
        body_text = page.locator('body').inner_text().strip()
        results[f'{theme}_screenshot'] = screenshot_path
        results[f'{theme}_content_length'] = len(body_text)
        results[f'{theme}_has_content'] = len(body_text) > 50

        print(f"  {theme}: {'✅' if results[f'{theme}_has_content'] else '❌'} ({len(body_text)} chars)")

    return results


def run_tests():
    """Run visual tests on all pages."""
    os.makedirs(SCREENSHOT_DIR, exist_ok=True)

    with sync_playwright() as p:
        browser = p.chromium.launch(headless=True)
        context = browser.new_context(
            viewport={'width': 1280, 'height': 800},
            color_scheme='dark'
        )
        page = context.new_page()

        # Capture console errors
        errors = []
        page.on('console', lambda m: errors.append(m.text) if m.type == 'error' else None)

        results = []

        for path, name, selectors in PAGES_TO_TEST:
            print(f"Testing {name}...")
            url = f'{BASE_URL}{path}'
            result = capture_themed_screenshots(page, url, name, selectors)
            result['errors'] = list(errors)
            errors.clear()
            results.append(result)

        browser.close()

        # Summary
        print("\n" + "=" * 50)
        print("VISUAL TEST SUMMARY")
        print("=" * 50)

        passed = sum(1 for r in results
                     if r.get('dark_has_content') and r.get('light_has_content'))
        print(f"\nPassed: {passed}/{len(results)}")
        print(f"Screenshots: {SCREENSHOT_DIR}")

        return results


if __name__ == '__main__':
    run_tests()

What are you doing?
│
├─ Interactive debugging / exploring
│  └─► Playwright MCP (see live browser)
│
├─ Automated test suite
│  └─► Native Python Playwright (headless)
│
├─ CI/CD pipeline
│  └─► Native Python Playwright (headless)
│
├─ Screenshot capture for LLM analysis
│  └─► Native Python Playwright (headless)
│
└─ One-off inspection
   └─► Either works, MCP is convenient