(() => {
  const blockedMarker = 'data-im-overlay-blocked';
  const ownSurfaceIds = new Set([
    'im-cookie-banner',
    'im-cookie-settings-modal',
    'im-cookie-settings-launcher',
  ]);
  const knownExternalSelectors = [
    '#ccm',
    '.ccm-root',
    '.ccm-widget',
    '#cookie-consent',
    '.cookie-consent',
    '.cookie-banner',
    '.cookie-notice',
    '#cookieNotice',
    '.eu-cookie-compliance-banner',
  ];

  const normalize = (value) => String(value || '').replace(/\s+/g, ' ').trim().toLowerCase();

  const looksLikeExternalCookieOverlay = (text) => {
    const normalized = normalize(text);
    if (normalized === '') {
      return false;
    }

    const hasCookieLanguage =
      normalized.includes('we use cookies')
      || normalized.includes('cookie settings')
      || normalized.includes('cookie policy');
    if (!hasCookieLanguage) {
      return false;
    }

    const hasAgree = normalized.includes('agree');
    const hasSettings = normalized.includes('cookie settings');
    const hasPolicyFooter = normalized.includes('imprint') || normalized.includes('privacy policy');
    const hasConsentWords = normalized.includes('consent') || normalized.includes('allow');
    return (hasAgree && (hasSettings || hasPolicyFooter)) || (hasConsentWords && hasSettings);
  };

  const elementArea = (node) => {
    if (!(node instanceof HTMLElement)) {
      return 0;
    }

    const rect = node.getBoundingClientRect();
    return Math.max(0, rect.width) * Math.max(0, rect.height);
  };

  const isViewportOverlay = (node, keywordMatch = false) => {
    if (!(node instanceof HTMLElement)) {
      return false;
    }

    if (ownSurfaceIds.has(node.id)) {
      return false;
    }

    const style = window.getComputedStyle(node);
    if (style.display === 'none' || style.visibility === 'hidden') {
      return false;
    }

    const position = style.position;
    if (!['fixed', 'absolute', 'sticky'].includes(position)) {
      return false;
    }

    const viewportArea = Math.max(window.innerWidth * window.innerHeight, 1);
    const coverage = elementArea(node) / viewportArea;
    const zIndex = Number.parseInt(style.zIndex || '0', 10);
    return coverage >= 0.25 || zIndex >= 900 || (keywordMatch && (coverage >= 0.1 || zIndex >= 100));
  };

  const markHidden = (node) => {
    if (!(node instanceof HTMLElement)) {
      return;
    }

    if (node.getAttribute(blockedMarker) === '1') {
      return;
    }

    node.setAttribute(blockedMarker, '1');
    node.style.setProperty('display', 'none', 'important');
    node.style.setProperty('visibility', 'hidden', 'important');
    node.style.setProperty('pointer-events', 'none', 'important');
    node.setAttribute('aria-hidden', 'true');
  };

  const findOverlayRoot = (node) => {
    if (!(node instanceof HTMLElement)) {
      return null;
    }

    let candidate = node;
    while (candidate.parentElement instanceof HTMLElement) {
      const keywordMatch = looksLikeExternalCookieOverlay(candidate.textContent || '');
      if (isViewportOverlay(candidate, keywordMatch)) {
        return candidate;
      }
      candidate = candidate.parentElement;
      if (candidate === document.body || candidate === document.documentElement) {
        break;
      }
    }

    const keywordMatch = looksLikeExternalCookieOverlay(node.textContent || '');
    return isViewportOverlay(node, keywordMatch) ? node : null;
  };

  const unblockScroll = () => {
    if (document.body instanceof HTMLElement) {
      document.body.style.removeProperty('overflow');
      document.body.style.removeProperty('position');
      document.body.style.removeProperty('height');
    }
    document.documentElement.style.removeProperty('overflow');
  };

  const runGuard = () => {
    const nodes = document.querySelectorAll('div, section, aside, dialog');
    let removed = 0;

    knownExternalSelectors.forEach((selector) => {
      document.querySelectorAll(selector).forEach((node) => {
        if (!(node instanceof HTMLElement)) {
          return;
        }
        if (ownSurfaceIds.has(node.id)) {
          return;
        }
        const root = findOverlayRoot(node) ?? node;
        markHidden(root);
        removed += 1;
      });
    });

    nodes.forEach((node) => {
      if (!(node instanceof HTMLElement)) {
        return;
      }

      if (node.id && ownSurfaceIds.has(node.id)) {
        return;
      }

      if (!looksLikeExternalCookieOverlay(node.textContent || '')) {
        return;
      }

      const root = findOverlayRoot(node) ?? node;
      if (root instanceof HTMLElement && !ownSurfaceIds.has(root.id)) {
        markHidden(root);
        removed += 1;
      }
    });

    document.querySelectorAll('iframe').forEach((frame) => {
      if (!(frame instanceof HTMLIFrameElement)) {
        return;
      }
      const src = normalize(frame.src || '');
      const title = normalize(frame.title || '');
      const marker = `${src} ${title}`;
      const cookieHint =
        marker.includes('cookie')
        || marker.includes('consent')
        || marker.includes('privacy');
      if (!cookieHint) {
        return;
      }
      const root = findOverlayRoot(frame) ?? frame.parentElement;
      if (root instanceof HTMLElement && !ownSurfaceIds.has(root.id)) {
        markHidden(root);
        removed += 1;
      }
    });

    if (removed > 0) {
      unblockScroll();
    }
  };

  let scheduled = false;
  const scheduleGuard = () => {
    if (scheduled) {
      return;
    }
    scheduled = true;
    window.requestAnimationFrame(() => {
      scheduled = false;
      runGuard();
    });
  };

  if (document.readyState === 'loading') {
    document.addEventListener('DOMContentLoaded', scheduleGuard, { once: true });
  } else {
    scheduleGuard();
  }

  window.addEventListener('load', scheduleGuard);

  const observer = new MutationObserver(scheduleGuard);
  observer.observe(document.documentElement, {
    childList: true,
    subtree: true,
  });
})();