#!/usr/bin/env python3
"""Local synthetic keyboard test. Not an axe scan or screen-reader test.

Run: python lab/run_keyboard_lab.py --browser /usr/bin/chromium
Requires Python 3.10+ and playwright==1.57.0 or another compatible installed version.
The exact tested package and browser versions are written to the results.
"""
from __future__ import annotations
import argparse, hashlib, importlib.metadata, json
from datetime import datetime, timezone
from pathlib import Path
from playwright.sync_api import sync_playwright

ROOT = Path(__file__).resolve().parent.parent

def sha256(path: Path) -> str:
    return hashlib.sha256(path.read_bytes()).hexdigest()

def main() -> None:
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument('--browser', default='/usr/bin/chromium')
    args = parser.parse_args()
    executable = Path(args.browser)
    if not executable.is_file():
        parser.error(f'Browser not found: {executable}')
    results = {
        'schema': 'cometweb.synthetic-keyboard-lab/v1',
        'run_at_utc': datetime.now(timezone.utc).isoformat(),
        'dataset': 'two local, deliberately authored fixtures',
        'document_delivery': 'Playwright page.set_content, no HTTP requests',
        'not_assessed': ['live CometWeb site', 'axe-core', 'screen readers',
                         'WCAG conformance of a page or site', 'legal compliance',
                         'other browser engines', 'usability with disabled people'],
        'python_playwright_version': importlib.metadata.version('playwright'),
        'cases': []
    }
    with sync_playwright() as p:
        browser = p.chromium.launch(executable_path=str(executable), headless=True,
                                    args=['--no-sandbox'])
        results['browser'] = browser.version
        for variant in ('before', 'after'):
            file = ROOT / 'lab' / 'fixtures' / f'{variant}.html'
            page = browser.new_page(viewport={'width': 1280, 'height': 800})
            page.set_content(file.read_text(encoding='utf-8'), wait_until='load')
            button = page.get_by_role('button', name='Zamów', exact=True)
            assert button.count() == 1
            # Chromium's AX tree is not a screen reader or a complete accessibility evaluation.
            cdp = page.context.new_cdp_session(page)
            ax = cdp.send('Accessibility.getFullAXTree')
            ax_buttons = [n for n in ax['nodes'] if n.get('role', {}).get('value') == 'button'
                          and n.get('name', {}).get('value') == 'Zamów']
            assert len(ax_buttons) == 1
            forward, backward = [], []
            for key, trace in [('Tab', forward), ('Shift+Tab', backward)]:
                button.focus()
                for _ in range(3):
                    page.keyboard.press(key)
                    trace.append(page.evaluate('document.activeElement.id || document.activeElement.tagName'))
            expected_first = {'Tab': 'next', 'Shift+Tab': 'previous'}
            observed = {'Tab': forward[0], 'Shift+Tab': backward[0]}
            case = {
                'variant': variant, 'fixture_sha256': sha256(file),
                'computed_accessibility_role': 'button',
                'computed_accessibility_name': 'Zamów',
                'role_and_name_observed': True,
                'tab_trace': forward, 'shift_tab_trace': backward,
                'expected_first_destination': expected_first,
                'observed_first_destination': observed,
                'forward_navigation_matches_expected': forward[0] == 'next',
                'backward_navigation_matches_expected': backward[0] == 'previous'
            }
            if variant == 'before':
                assert forward == ['buy'] * 3 and backward == ['buy'] * 3
                case['interpretation'] = 'Authored Tab trap reproduced; no in-page escape is implemented.'
            else:
                assert forward[0] == 'next' and backward[0] == 'previous'
                case['interpretation'] = 'First forward and backward focus destinations match the fixture contract.'
            results['cases'].append(case)
            page.close()
        browser.close()
    dest = ROOT / 'evidence' / 'keyboard-lab-results.json'
    dest.write_text(json.dumps(results, ensure_ascii=False, indent=2) + '\n', encoding='utf-8')
    print(json.dumps(results, ensure_ascii=False, indent=2))

if __name__ == '__main__':
    main()