/* SPDX-License-Identifier: GPL-2.0-or-later */

/** \file
 * \ingroup spoutliner
 */

#pragma once

#include <memory>

struct ListBase;
struct SpaceOutliner;
struct TreeElement;

namespace blender::ed::outliner {

/* -------------------------------------------------------------------- */
/* Tree-Display Interface */

class AbstractTreeElement {
 protected:
  /**
   * Reference back to the owning legacy TreeElement.
   * Most concrete types need access to this, so storing here. Eventually the type should be
   * replaced by AbstractTreeElement and derived types.
   */
  TreeElement &legacy_te_;

 public:
  virtual ~AbstractTreeElement() = default;

  static std::unique_ptr<AbstractTreeElement> createFromType(int type,
                                                             TreeElement &legacy_te,
                                                             void *idv);

  /**
   * Check if the type is expandable in current context.
   */
  virtual bool expandPoll(const SpaceOutliner &) const
  {
    return true;
  }
  virtual void postExpand(SpaceOutliner &) const
  {
  }

  /**
   * Just while transitioning to the new tree-element design: Some types are only partially ported,
   * and the expanding isn't done yet.
   */
  virtual bool isExpandValid() const
  {
    return true;
  }

  friend void tree_element_expand(const AbstractTreeElement &tree_element,
                                  SpaceOutliner &space_outliner);

 protected:
  /* Pseudo-abstract: Only allow creation through derived types. */
  AbstractTreeElement(TreeElement &legacy_te) : legacy_te_(legacy_te)
  {
  }

  /**
   * Let the type add its own children.
   */
  virtual void expand(SpaceOutliner &) const
  {
  }
};

/**
 * TODO: this function needs to be split up! It's getting a bit too large...
 *
 * \note "ID" is not always a real ID.
 * \note If child items are only added to the tree if the item is open,
 * the `TSE_` type _must_ be added to #outliner_element_needs_rebuild_on_open_change().
 */
struct TreeElement *outliner_add_element(SpaceOutliner *space_outliner,
                                         ListBase *lb,
                                         void *idv,
                                         struct TreeElement *parent,
                                         short type,
                                         short index);

void tree_element_expand(const AbstractTreeElement &tree_element, SpaceOutliner &space_outliner);

/**
 * Get actual warning data of a tree element, if any.
 *
 * \param r_icon: The icon to display as warning.
 * \param r_message: The message to display as warning.
 * \return true if there is a warning, false otherwise.
 */
bool tree_element_warnings_get(struct TreeElement *te, int *r_icon, const char **r_message);

}  // namespace blender::ed::outliner