function handleDrop()

in script.js [770:822]
30 lines of code
6 McCabe index (conditional complexity)

  function handleDrop(e) {
    e.stopPropagation(); // Stop redirect
    e.preventDefault();

    // Remove drag-over class from all items
    document.querySelectorAll('.tree-item.drag-over').forEach(item => {
      item.classList.remove('drag-over');
    });

    // Find the tree item element (could be a child element that received the event)
    const dropTarget = e.target.closest('.tree-item');
    if (!dropTarget) {
      return false;
    }

    // Remove highlight from drop target
    dropTarget.classList.remove('drag-over');

    // Get the target management group ID (where we're dropping)
    const dropTargetId = dropTarget.dataset.id;

    // Only process if target has an ID (is a management group)
    if (!dropTargetId) {
      return false;
    }

    // Don't do anything if dropping onto itself
    if (draggedMgId === dropTargetId) {
      return false;
    }

    // Prevent a management group from becoming its own ancestor
    if (wouldCreateCycle(draggedMgId, dropTargetId)) {
      alert("Cannot move a management group to one of its descendants.");
      return false;
    }

    // Change the parent ID of the dragged management group
    updateMgParent(draggedMgId, dropTargetId);

    // Mark the drop as successful
    dropSuccessful = true;

    // Re-render the tree
    renderManagementGroups();

    // Keep the previously selected management group selected
    if (selectedMgId) {
      selectManagementGroup(selectedMgId);
    }

    return false;
  }