(function() {
  function isFolder(node) {
    return Array.isArray(node.nodes) && node.nodes.length > 0;
  }

  function renderNode(node, expandedPaths, depth) {
    const li = document.createElement("li");
    li.dataset.id = node.id || "";
    const row = document.createElement("div");
    row.className = "row";
    row.style.paddingLeft = `${(depth + 1) * 1.2}rem`;

    const caret = document.createElement("span");
    caret.className = "caret";
    const folder = isFolder(node);
    const expanded = expandedPaths.has(node.id) || depth === 0;
    caret.textContent = folder ? (expanded ? "▾" : "▸") : "";
    row.appendChild(caret);

    const label = document.createElement("span");
    label.className = "label " + (folder ? "icon-folder" : "icon-file");
    label.textContent = node.text || node.id || "";
    row.appendChild(label);

    if (node.meta) {
      const meta = document.createElement("span");
      meta.className = "meta";
      meta.textContent = node.meta;
      row.appendChild(meta);
    }

    li.appendChild(row);

    if (folder) {
      const ul = document.createElement("ul");
      ul.className = "btv";
      ul.style.display = expanded ? "block" : "none";
      node.nodes.forEach(child => {
        ul.appendChild(renderNode(child, expandedPaths, depth + 1));
      });
      li.appendChild(ul);
    }
    return li;
  }

  function create(container, data, { expandedPaths = new Set(), onClick, onDblClick } = {}) {
    if (!container) return;
    container.innerHTML = "";
    const ul = document.createElement("ul");
    ul.className = "btv";
    data.forEach(node => ul.appendChild(renderNode(node, expandedPaths, 0)));

    ul.addEventListener("click", evt => {
      const row = evt.target.closest(".row");
      const li = evt.target.closest("li");
      if (!li) return;
      const sub = li.querySelector(":scope > ul");
      if (sub) {
        const caret = row?.querySelector(".caret") || li.querySelector(":scope > .row .caret");
        const hidden = sub.style.display === "none";
        sub.style.display = hidden ? "block" : "none";
        if (caret) caret.textContent = hidden ? "▾" : "▸";
        if (hidden) {
          expandedPaths.add(li.dataset.id);
        } else {
          expandedPaths.delete(li.dataset.id);
        }
      }
      onClick?.(li.dataset.id || "");
    });

    ul.addEventListener("dblclick", evt => {
      const li = evt.target.closest("li");
      if (!li) return;
      const sub = li.querySelector(":scope > ul");
      if (!sub) {
        onDblClick?.(li.dataset.id || "");
      }
    });

    container.appendChild(ul);
  }

  window.BootstrapTreeView = { create };
})();