(() => {
  const visiblePanels = (selector, scope = document) =>
    [...scope.querySelectorAll(selector)].filter((panel) => !panel.hidden);

  const armSidebarFilters = () => {
    const sidebar = document.querySelector(".source-filter-sidebar");
    if (!sidebar || !sidebar.matches("form")) return;
    sidebar.querySelectorAll('input[type="checkbox"]').forEach((box) => {
      box.addEventListener("change", () => {
        sidebar.querySelectorAll('input[type="checkbox"]').forEach((other) => {
          if (other.name === box.name && other !== box) other.checked = false;
        });
        sidebar.requestSubmit();
      });
    });
  };

  const activateCollection = (control) => {
    const switcher = control.closest("[data-collection-switcher]");
    if (!switcher) return;
    const target = control.dataset.collectionTarget;
    switcher
      .querySelectorAll('[data-control-action="switch-collection"]')
      .forEach((button) => {
        button.setAttribute(
          "aria-selected",
          String(button.dataset.collectionTarget === target),
        );
      });
    const panelSelector = target.startsWith("career-")
      ? "[data-career-collection-panel]"
      : "[data-collection-panel]";
    switcher.querySelectorAll(panelSelector).forEach((panel) => {
      panel.hidden = panel.dataset.key !== target;
    });
  };

  let promoIndex = 0;
  let promoCount = 0;
  let promoTimer = null;

  const syncPromo = () => {
    const track = document.querySelector("[data-promo-track] .promo-slide-track");
    const panels = [...document.querySelectorAll("[data-promo-panel]")];
    if (!track || !panels.length) return;
    promoCount = panels.length;
    const safe = (promoIndex + promoCount) % promoCount;
    track.style.transform = `translateX(-${safe * 100}%)`;
    document.querySelectorAll("[data-promo-target]").forEach((control) => {
      control.setAttribute(
        "aria-pressed",
        String(control.dataset.promoTarget === panels[safe].dataset.key),
      );
    });
    document.querySelectorAll("[data-promo-panel]").forEach((panel, index) => {
      if (index === safe) panel.setAttribute("data-promo-active", "true");
      else panel.removeAttribute("data-promo-active");
    });
  };

  const armPromoAutoplay = () => {
    if (promoTimer) window.clearInterval(promoTimer);
    promoTimer = window.setInterval(() => {
      promoIndex = (promoIndex + 1) % promoCount;
      syncPromo();
    }, 5000);
  };

  const switchPromo = (direction) => {
    const panels = [...document.querySelectorAll("[data-promo-panel]")];
    if (!panels.length) return;
    promoIndex = (promoIndex + (direction === "previous" ? -1 : 1) + panels.length) % panels.length;
    syncPromo();
    armPromoAutoplay();
  };

  const selectPromo = (control) => {
    const target = control.dataset.promoTarget;
    const panels = [...document.querySelectorAll("[data-promo-panel]")];
    promoIndex = panels.findIndex((panel) => panel.dataset.key === target);
    syncPromo();
    armPromoAutoplay();
  };

  const expandableContainer = (panel) => {
    let current = panel;
    while (current && current !== document.body) {
      if (current.style.visibility === "hidden") return current;
      current = current.parentElement;
    }
    return null;
  };

  const toggleFaq = (control) => {
    const panelId = control.getAttribute("aria-controls");
    const panel = panelId ? document.getElementById(panelId) : null;
    if (!panel) return;
    const expanded = control.getAttribute("aria-expanded") === "true";
    control.setAttribute("aria-expanded", String(!expanded));
    const capturedContainer = expandableContainer(panel);
    if (capturedContainer) {
      capturedContainer.style.minHeight = "0px";
      capturedContainer.style.height = expanded ? "0px" : "auto";
      capturedContainer.style.overflow = "hidden";
      capturedContainer.style.visibility = expanded ? "hidden" : "visible";
    } else {
      panel.hidden = expanded;
    }
  };

  const openLogin = () => {
    const dialog = document.querySelector("[data-login-dialog]");
    if (dialog instanceof HTMLDialogElement) {
      if (!dialog.open) dialog.showModal();
      return;
    }
    const overlay = document.querySelector("[data-business-login-overlay]");
    if (overlay) overlay.style.display = "flex";
  };

  const toggleControlledPanel = (control) => {
    const panelId = control.getAttribute("aria-controls");
    const panel = panelId ? document.getElementById(panelId) : null;
    if (!panel) return;
    const expanded = control.getAttribute("aria-expanded") === "true";
    control.setAttribute("aria-expanded", String(!expanded));
    panel.hidden = expanded;
  };

  const togglePlayer = (control) => {
    const playing = control.getAttribute("aria-pressed") === "true";
    control.setAttribute("aria-pressed", String(!playing));
    control.setAttribute("aria-label", playing ? "Play" : "Pause");
    control.textContent = playing ? "▶" : "❚❚";
    const status = control.parentElement?.querySelector("[data-player-status]");
    if (status) {
      status.textContent = playing
        ? "Paused at 0:00. The source video is not streamed; this local player preserves the observed controls."
        : "Playing the deterministic local lesson timeline at 0:00.";
    }
  };

  const switchLessonTab = (control) => {
    const target = control.dataset.lessonTarget;
    const shell = control.closest(".course-learning-content") || document;
    shell.querySelectorAll('[data-control-action="switch-lesson-tab"]').forEach((tab) => {
      tab.setAttribute("aria-selected", String(tab === control));
    });
    shell.querySelectorAll("[data-lesson-panel]").forEach((panel) => {
      panel.hidden = panel.dataset.lessonPanel !== target;
    });
  };

  const toggleCourseDetails = (control) => {
    const course = control.closest(".source-specialization-course");
    if (!course) return;
    const expanded = control.getAttribute("aria-expanded") === "true";
    control.setAttribute("aria-expanded", String(!expanded));
    const arrow = control.querySelector("[aria-hidden]");
    if (arrow) arrow.textContent = expanded ? "⌄" : "⌃";
  };

  const toggleFaqAll = (control) => {
    const section = control.closest(".source-specialization-faq");
    if (!section) return;
    const expanded = control.getAttribute("aria-expanded") === "true";
    control.setAttribute("aria-expanded", String(!expanded));
    section.querySelectorAll("details").forEach((details) => {
      details.open = !expanded;
    });
  };

  const openFaqPanel = (control) => {
    const target = control.dataset.faqTarget;
    const panel = document.getElementById(target);
    if (!panel) return;
    panel.hidden = panel.hidden === undefined ? false : !panel.hidden;
  };

  document.addEventListener("click", (event) => {
    const control = event.target.closest("[data-control-action]");
    if (!control) return;
    switch (control.dataset.controlAction) {
      case "switch-collection":
        activateCollection(control);
        break;
      case "switch-promo":
        switchPromo(control.dataset.promoDirection);
        break;
      case "switch-promo-choice":
        selectPromo(control);
        break;
      case "toggle-faq":
        toggleFaq(control);
        break;
      case "open-login":
        openLogin();
        break;
      case "toggle-course-details":
        toggleCourseDetails(control);
        break;
      case "toggle-faq-all":
        toggleFaqAll(control);
        break;
      case "open-faq-panel":
        openFaqPanel(control);
        break;
      case "toggle-objectives":
        toggleControlledPanel(control);
        break;
      case "toggle-player":
        togglePlayer(control);
        break;
      case "switch-lesson-tab":
        switchLessonTab(control);
        break;
    }
  });

  document.addEventListener("click", (event) => {
    const card = event.target.closest("[data-card-href]");
    if (card && !event.target.closest("a")) {
      window.location.href = card.dataset.cardHref;
    }
  });
  document.addEventListener("keydown", (event) => {
    if (event.key !== "Enter" && event.key !== " ") return;
    const card = event.target.closest("[data-card-href]");
    if (card && event.target === card) {
      event.preventDefault();
      window.location.href = card.dataset.cardHref;
    }
  });

  syncPromo();
  armPromoAutoplay();
  armSidebarFilters();
})();