/* =========================================================
   video-carousels.js
   Карусели с видео: «Видео отзывы учеников», «СМИ и партнеры».
   Подключать после main.js на главной (GetCourse: отдельный <script>).
   ========================================================= */

(function () {
  function initVideoCarousel(options) {
    var slider = document.querySelector(options.sliderSelector);
    if (!slider) return;

    var section = slider.closest(options.sectionSelector);
    var track = slider.querySelector(options.trackSelector);
    var cards = track ? track.querySelectorAll(options.cardSelector) : [];
    var pagination = section ? section.querySelector(options.paginationSelector) : null;
    var prevBtn = section ? section.querySelector(options.prevSelector) : null;
    var nextBtn = section ? section.querySelector(options.nextSelector) : null;

    if (!track || !cards.length || !pagination) return;

    var dots = [];
    var current = 0;

    function pauseVideos(exceptVideo) {
      cards.forEach(function (card) {
        var video = card.querySelector("video");
        if (video && video !== exceptVideo && !video.paused) {
          video.pause();
        }
      });
    }

    function getStep() {
      if (cards.length < 2) return track.clientWidth;
      return cards[1].offsetLeft - cards[0].offsetLeft;
    }

    function goTo(index, smooth) {
      current = Math.max(0, Math.min(index, cards.length - 1));
      track.scrollTo({
        left: getStep() * current,
        behavior: smooth ? "smooth" : "auto",
      });
      sync();
    }

    function sync() {
      if (prevBtn) prevBtn.disabled = current <= 0;
      if (nextBtn) nextBtn.disabled = current >= cards.length - 1;
      dots.forEach(function (dot, idx) {
        dot.classList.toggle("is-active", idx === current);
        dot.setAttribute("aria-current", idx === current ? "true" : "false");
      });
    }

    function updateByScroll() {
      var step = getStep() || 1;
      var idx = Math.round(track.scrollLeft / step);
      current = Math.max(0, Math.min(idx, cards.length - 1));
      sync();
    }

    cards.forEach(function (card, idx) {
      var dot = document.createElement("button");
      dot.className = options.dotClass;
      dot.type = "button";
      dot.setAttribute("aria-label", options.dotLabel + " " + (idx + 1));
      dot.addEventListener("click", function () {
        goTo(idx, true);
      });
      pagination.appendChild(dot);
      dots.push(dot);

      var video = card.querySelector("video");
      if (video) {
        video.addEventListener("play", function () {
          pauseVideos(video);
        });
      }
    });

    if (prevBtn) {
      prevBtn.addEventListener("click", function () {
        goTo(current - 1, true);
      });
    }

    if (nextBtn) {
      nextBtn.addEventListener("click", function () {
        goTo(current + 1, true);
      });
    }

    track.addEventListener("scroll", function () {
      window.requestAnimationFrame(updateByScroll);
    });

    window.addEventListener("resize", function () {
      goTo(current, false);
    });

    goTo(0, false);
  }

  initVideoCarousel({
    sliderSelector: "[data-media-partners-slider]",
    sectionSelector: ".media-partners",
    trackSelector: "[data-media-partners-track]",
    cardSelector: ".media-partners-card",
    paginationSelector: "[data-media-partners-pagination]",
    prevSelector: ".media-partners__nav--prev",
    nextSelector: ".media-partners__nav--next",
    dotClass: "media-partners__dot",
    dotLabel: "Видео",
  });

  initVideoCarousel({
    sliderSelector: "[data-video-reviews-slider]",
    sectionSelector: ".video-reviews",
    trackSelector: "[data-video-reviews-track]",
    cardSelector: ".video-reviews-card",
    paginationSelector: "[data-video-reviews-pagination]",
    prevSelector: ".video-reviews__nav--prev",
    nextSelector: ".video-reviews__nav--next",
    dotClass: "video-reviews__dot",
    dotLabel: "Видеоотзыв",
  });
})();