/* weirsoe-ui.js — small, dependency-free UI behaviours for weirsoe-theme.
 *
 *  • Sortable lists: mark a container with [data-wt-sortable] and a
 *    data-order-url; its [data-item-id] children become drag-reorderable, and
 *    on drop the new order is POSTed as urlencoded `order[]=…` to data-order-url.
 *    Add a .drag-handle inside each child as the grab affordance. A clean, solid
 *    drag image is used so translucent/blurred card surfaces don't smear.
 *
 *      <div data-wt-sortable data-order-url="/list/order">
 *        <div data-item-id="1"><span class="drag-handle">⠿</span> …</div>
 *      </div>
 *
 *  • Copy to clipboard: any [data-copy-link] button copies its attribute value
 *    and shows brief "Kopieret ✓" feedback.
 */
(function () {
  function afterElement(container, y) {
    var els = Array.prototype.slice.call(
      container.querySelectorAll('[data-item-id]:not(.wt-dragging)')
    );
    var best = { offset: -Infinity, el: null };
    els.forEach(function (child) {
      var box = child.getBoundingClientRect();
      var offset = y - box.top - box.height / 2;
      if (offset < 0 && offset > best.offset) best = { offset: offset, el: child };
    });
    return best.el;
  }

  function cleanDragImage(el, e) {
    // A solid clone as the drag image — avoids the browser snapshotting the
    // card's translucent/blurred surface + page glow (which looks smeared).
    try {
      var g = el.cloneNode(true);
      g.classList.remove('wt-dragging');
      var cs = getComputedStyle(el);
      var surface = getComputedStyle(document.documentElement)
        .getPropertyValue('--color-surface').trim();
      g.style.position = 'fixed';
      g.style.top = '-9999px';
      g.style.left = '-9999px';
      g.style.width = el.offsetWidth + 'px';
      g.style.margin = '0';
      g.style.opacity = '1';
      g.style.boxShadow = 'none';
      g.style.backdropFilter = 'none';
      g.style.webkitBackdropFilter = 'none';
      g.style.background =
        cs.backgroundColor && cs.backgroundColor !== 'rgba(0, 0, 0, 0)'
          ? cs.backgroundColor
          : surface || '#121a27';
      document.body.appendChild(g);
      e.dataTransfer.setDragImage(g, 16, 16);
      setTimeout(function () { if (g.parentNode) g.parentNode.removeChild(g); }, 0);
    } catch (err) { /* setDragImage unsupported — fall back to default ghost */ }
  }

  function persist(container) {
    var url = container.getAttribute('data-order-url');
    if (!url) return;
    var ids = Array.prototype.slice
      .call(container.querySelectorAll('[data-item-id]'))
      .map(function (el) { return el.getAttribute('data-item-id'); });
    var body = ids.map(function (id) { return 'order[]=' + encodeURIComponent(id); }).join('&');
    fetch(url, {
      method: 'POST',
      headers: { 'Content-Type': 'application/x-www-form-urlencoded' },
      body: body,
      credentials: 'same-origin',
    }).catch(function () { /* non-fatal */ });
  }

  function initSortable(container) {
    // ---- desktop: native HTML5 drag-and-drop ----
    var dragEl = null;
    container.querySelectorAll('[data-item-id]').forEach(function (el) {
      el.setAttribute('draggable', 'true');
      el.addEventListener('dragstart', function (e) {
        dragEl = el;
        el.classList.add('wt-dragging');
        document.body.classList.add('wt-sorting');
        e.dataTransfer.effectAllowed = 'move';
        cleanDragImage(el, e);
      });
      el.addEventListener('dragend', function () {
        el.classList.remove('wt-dragging');
        document.body.classList.remove('wt-sorting');
        dragEl = null;
        persist(container);
      });
    });
    container.addEventListener('dragover', function (e) {
      e.preventDefault();
      if (!dragEl) return;
      var after = afterElement(container, e.clientY);
      if (after == null) container.appendChild(dragEl);
      else container.insertBefore(dragEl, after);
    });

    // ---- mobile: long-press lifts the card into a floating clone that follows
    // the finger; the list reorders underneath; holding near a screen edge
    // auto-scrolls. (Native DnD doesn't fire on touch.) Hold ~220ms to lift; a
    // scroll-intent move before that cancels the lift so the page scrolls. ----
    var holdTimer = null, lifted = false, touchEl = null, clone = null;
    var startY = 0, offX = 0, offY = 0, scrollSpeed = 0, raf = null;

    function startScroll() {
      if (raf) return;
      var tick = function () {
        if (scrollSpeed !== 0) window.scrollBy(0, scrollSpeed);
        raf = requestAnimationFrame(tick);
      };
      raf = requestAnimationFrame(tick);
    }
    function stopScroll() { if (raf) { cancelAnimationFrame(raf); raf = null; } scrollSpeed = 0; }

    function makeClone(el, x, y) {
      var r = el.getBoundingClientRect();
      offX = x - r.left; offY = y - r.top;
      clone = el.cloneNode(true);
      clone.classList.remove('wt-dragging');
      clone.classList.add('wt-drag-clone');
      clone.style.width = r.width + 'px';
      clone.style.transform = 'translate(' + (x - offX) + 'px,' + (y - offY) + 'px) scale(1.04)';
      document.body.appendChild(clone);
    }
    function moveClone(x, y) {
      if (clone) clone.style.transform = 'translate(' + (x - offX) + 'px,' + (y - offY) + 'px) scale(1.04)';
    }
    function endTouch() {
      if (holdTimer) { clearTimeout(holdTimer); holdTimer = null; }
      if (clone && clone.parentNode) clone.parentNode.removeChild(clone);
      clone = null;
      document.body.classList.remove('wt-sorting');
      if (lifted && touchEl) { touchEl.classList.remove('wt-dragging'); persist(container); }
      lifted = false; touchEl = null; stopScroll();
    }

    container.querySelectorAll('[data-item-id]').forEach(function (el) {
      el.addEventListener('touchstart', function (e) {
        if (e.touches.length !== 1) return;
        if (e.target.closest('a, button, input, select, textarea, summary, label')) return;
        var t = e.touches[0];
        startY = t.clientY;
        holdTimer = setTimeout(function () {
          lifted = true; touchEl = el;
          el.classList.add('wt-dragging');
          document.body.classList.add('wt-sorting');
          makeClone(el, t.clientX, t.clientY);
          if (navigator.vibrate) navigator.vibrate(12);
          startScroll();
        }, 220);
      }, { passive: true });
    });

    container.addEventListener('touchmove', function (e) {
      if (!lifted) {
        if (holdTimer && Math.abs(e.touches[0].clientY - startY) > 12) {
          clearTimeout(holdTimer); holdTimer = null; // moved first → it's a scroll
        }
        return;
      }
      if (!touchEl) return;
      e.preventDefault(); // we own the gesture now
      var t = e.touches[0];
      moveClone(t.clientX, t.clientY);
      var after = afterElement(container, t.clientY);
      if (after == null) container.appendChild(touchEl);
      else container.insertBefore(touchEl, after);
      // edge auto-scroll — generous zone so it triggers well before the edge
      var edge = 130, vh = window.innerHeight;
      if (t.clientY < edge) scrollSpeed = -Math.max(6, Math.ceil((edge - t.clientY) / 4));
      else if (t.clientY > vh - edge) scrollSpeed = Math.max(6, Math.ceil((t.clientY - (vh - edge)) / 4));
      else scrollSpeed = 0;
    }, { passive: false });

    container.addEventListener('touchend', endTouch);
    container.addEventListener('touchcancel', endTouch);
  }

  function wire() {
    document.querySelectorAll('[data-wt-sortable]').forEach(initSortable);
  }

  document.addEventListener('click', function (e) {
    var btn = e.target.closest && e.target.closest('[data-copy-link]');
    if (!btn) return;
    e.preventDefault();
    var text = btn.getAttribute('data-copy-link');
    var done = function () {
      var old = btn.textContent;
      btn.textContent = 'Kopieret ✓';
      setTimeout(function () { btn.textContent = old; }, 1600);
    };
    if (navigator.clipboard && navigator.clipboard.writeText) {
      navigator.clipboard.writeText(text).then(done, function () { window.prompt('Kopiér linket:', text); });
    } else {
      window.prompt('Kopiér linket:', text);
    }
  });

  if (document.readyState === 'loading') document.addEventListener('DOMContentLoaded', wire);
  else wire();
})();