(() => {
  function getSiteBaseUrl() {
    const candidates = [
      ...document.querySelectorAll('link[href*="assets/stylesheets/"]'),
      ...document.querySelectorAll('script[src*="assets/javascripts/"]')
    ];

    for (const el of candidates) {
      const raw = el.getAttribute('href') || el.getAttribute('src');
      if (!raw) continue;

      const absUrl = new URL(raw, window.location.href).href;
      const assetsIndex = absUrl.indexOf('/assets/');
      if (assetsIndex !== -1) {
        return absUrl.slice(0, assetsIndex);
      }
    }

    return window.location.origin;
  }

  function getLogoPath(filename) {
    return `${getSiteBaseUrl()}/assets/branding/${filename}`;
  }

  function getScheme() {
    return (
      document.body?.getAttribute('data-md-color-scheme') ||
      document.documentElement?.getAttribute('data-md-color-scheme') ||
      'default'
    );
  }

  function applyThemeLogo() {
    const logoSrc =
      getScheme() === 'slate' ? getLogoPath('icon-dark.png') : getLogoPath('icon-light.png');
    const logos = document.querySelectorAll('.md-header__button.md-logo img');

    logos.forEach(logo => {
      logo.setAttribute('src', logoSrc);
    });
  }

  function observeThemeChanges() {
    const observer = new MutationObserver(mutations => {
      for (const mutation of mutations) {
        if (mutation.type === 'attributes' && mutation.attributeName === 'data-md-color-scheme') {
          applyThemeLogo();
          break;
        }
      }
    });

    if (document.body) {
      observer.observe(document.body, {
        attributes: true,
        attributeFilter: ['data-md-color-scheme']
      });
    }

    observer.observe(document.documentElement, {
      attributes: true,
      attributeFilter: ['data-md-color-scheme']
    });
  }

  function init() {
    applyThemeLogo();
    observeThemeChanges();
  }

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