/* SPDX-License-Identifier: GPL-2.0-or-later
 * Copyright 2004 Blender Foundation. All rights reserved. */

/** \file
 * \ingroup spoutliner
 */

#include <cstring>

#include "MEM_guardedalloc.h"

#include "DNA_ID.h"
#include "DNA_anim_types.h"
#include "DNA_collection_types.h"
#include "DNA_object_types.h"
#include "DNA_scene_types.h"

#include "BLI_blenlib.h"
#include "BLI_dynstr.h"
#include "BLI_path_util.h"
#include "BLI_utildefines.h"

#include "BLT_translation.h"

#include "BKE_action.h"
#include "BKE_animsys.h"
#include "BKE_appdir.h"
#include "BKE_armature.h"
#include "BKE_blender_copybuffer.h"
#include "BKE_context.h"
#include "BKE_idtype.h"
#include "BKE_layer.h"
#include "BKE_lib_id.h"
#include "BKE_lib_override.h"
#include "BKE_lib_query.h"
#include "BKE_lib_remap.h"
#include "BKE_main.h"
#include "BKE_object.h"
#include "BKE_report.h"
#include "BKE_workspace.h"

#include "DEG_depsgraph.h"
#include "DEG_depsgraph_build.h"

#include "ED_keyframing.h"
#include "ED_outliner.h"
#include "ED_screen.h"
#include "ED_select_utils.h"

#include "WM_api.h"
#include "WM_types.h"

#include "UI_interface.h"
#include "UI_view2d.h"

#include "RNA_access.h"
#include "RNA_define.h"
#include "RNA_enum_types.h"
#include "RNA_path.h"

#include "GPU_material.h"

#include "outliner_intern.hh"
#include "tree/tree_element_rna.hh"
#include "tree/tree_iterator.hh"

using namespace blender::ed::outliner;

namespace blender::ed::outliner {

static void outliner_show_active(SpaceOutliner *space_outliner,
                                 ARegion *region,
                                 TreeElement *te,
                                 ID *id);

/* -------------------------------------------------------------------- */
/** \name Highlight on Cursor Motion Operator
 * \{ */

static int outliner_highlight_update(bContext *C, wmOperator * /*op*/, const wmEvent *event)
{
  /* stop highlighting if out of area */
  if (!ED_screen_area_active(C)) {
    return OPERATOR_PASS_THROUGH;
  }

  /* Drag and drop does own highlighting. */
  wmWindowManager *wm = CTX_wm_manager(C);
  if (wm->drags.first) {
    return OPERATOR_PASS_THROUGH;
  }

  ARegion *region = CTX_wm_region(C);
  SpaceOutliner *space_outliner = CTX_wm_space_outliner(C);

  float view_mval[2];
  UI_view2d_region_to_view(
      &region->v2d, event->mval[0], event->mval[1], &view_mval[0], &view_mval[1]);

  TreeElement *hovered_te = outliner_find_item_at_y(
      space_outliner, &space_outliner->tree, view_mval[1]);

  TreeElement *icon_te = nullptr;
  bool is_over_icon = false;
  if (hovered_te) {
    icon_te = outliner_find_item_at_x_in_row(
        space_outliner, hovered_te, view_mval[0], nullptr, &is_over_icon);
  }

  bool changed = false;

  if (!hovered_te || !is_over_icon || !(hovered_te->store_elem->flag & TSE_HIGHLIGHTED) ||
      !(icon_te->store_elem->flag & TSE_HIGHLIGHTED_ICON)) {
    /* Clear highlights when nothing is hovered or when a new item is hovered. */
    changed = outliner_flag_set(*space_outliner, TSE_HIGHLIGHTED_ANY | TSE_DRAG_ANY, false);
    if (hovered_te) {
      hovered_te->store_elem->flag |= TSE_HIGHLIGHTED;
      changed = true;
    }
    if (is_over_icon) {
      icon_te->store_elem->flag |= TSE_HIGHLIGHTED_ICON;
      changed = true;
    }
  }

  if (changed) {
    ED_region_tag_redraw_no_rebuild(region);
  }

  return OPERATOR_PASS_THROUGH;
}

void OUTLINER_OT_highlight_update(wmOperatorType *ot)
{
  ot->name = "Update Highlight";
  ot->idname = "OUTLINER_OT_highlight_update";
  ot->description = "Update the item highlight based on the current mouse position";

  ot->invoke = outliner_highlight_update;

  ot->poll = ED_operator_outliner_active;
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Toggle Open/Closed Operator
 * \{ */

void outliner_item_openclose(TreeElement *te, bool open, bool toggle_all)
{
  /* Only allow opening elements with children. */
  if (!(te->flag & TE_PRETEND_HAS_CHILDREN) && BLI_listbase_is_empty(&te->subtree)) {
    return;
  }

  /* Don't allow collapsing the scene collection. */
  TreeStoreElem *tselem = TREESTORE(te);
  if (tselem->type == TSE_VIEW_COLLECTION_BASE) {
    return;
  }

  if (open) {
    tselem->flag &= ~TSE_CLOSED;
  }
  else {
    tselem->flag |= TSE_CLOSED;
  }

  if (toggle_all) {
    outliner_flag_set(te->subtree, TSE_CLOSED, !open);
  }
}

struct OpenCloseData {
  TreeStoreElem *prev_tselem;
  bool open;
  int x_location;
};

static int outliner_item_openclose_modal(bContext *C, wmOperator *op, const wmEvent *event)
{
  ARegion *region = CTX_wm_region(C);
  SpaceOutliner *space_outliner = CTX_wm_space_outliner(C);

  float view_mval[2];
  UI_view2d_region_to_view(
      &region->v2d, event->mval[0], event->mval[1], &view_mval[0], &view_mval[1]);

  if (event->type == MOUSEMOVE) {
    TreeElement *te = outliner_find_item_at_y(space_outliner, &space_outliner->tree, view_mval[1]);

    OpenCloseData *data = (OpenCloseData *)op->customdata;

    /* Only openclose if mouse is not over the previously toggled element */
    if (te && TREESTORE(te) != data->prev_tselem) {

      /* Only toggle openclose on the same level as the first clicked element */
      if (te->xs == data->x_location) {
        outliner_item_openclose(te, data->open, false);

        outliner_tag_redraw_avoid_rebuild_on_open_change(space_outliner, region);
      }
    }

    if (te) {
      data->prev_tselem = TREESTORE(te);
    }
    else {
      data->prev_tselem = nullptr;
    }
  }
  else if (event->val == KM_RELEASE) {
    MEM_freeN(op->customdata);

    return OPERATOR_FINISHED;
  }

  return OPERATOR_RUNNING_MODAL;
}

static int outliner_item_openclose_invoke(bContext *C, wmOperator *op, const wmEvent *event)
{
  ARegion *region = CTX_wm_region(C);
  SpaceOutliner *space_outliner = CTX_wm_space_outliner(C);

  const bool toggle_all = RNA_boolean_get(op->ptr, "all");

  float view_mval[2];

  int mval[2];
  WM_event_drag_start_mval(event, region, mval);

  UI_view2d_region_to_view(&region->v2d, mval[0], mval[1], &view_mval[0], &view_mval[1]);

  TreeElement *te = outliner_find_item_at_y(space_outliner, &space_outliner->tree, view_mval[1]);

  if (te && outliner_item_is_co_within_close_toggle(te, view_mval[0])) {
    TreeStoreElem *tselem = TREESTORE(te);

    const bool open = (tselem->flag & TSE_CLOSED) ||
                      (toggle_all && outliner_flag_is_any_test(&te->subtree, TSE_CLOSED, 1));

    outliner_item_openclose(te, open, toggle_all);
    outliner_tag_redraw_avoid_rebuild_on_open_change(space_outliner, region);

    /* Only toggle once for single click toggling */
    if ((event->type == LEFTMOUSE) && (event->val != KM_CLICK_DRAG)) {
      return OPERATOR_FINISHED;
    }

    /* Store last expanded tselem and x coordinate of disclosure triangle */
    OpenCloseData *toggle_data = MEM_cnew<OpenCloseData>("open_close_data");
    toggle_data->prev_tselem = tselem;
    toggle_data->open = open;
    toggle_data->x_location = te->xs;

    /* Store the first clicked on element */
    op->customdata = toggle_data;

    WM_event_add_modal_handler(C, op);
    return OPERATOR_RUNNING_MODAL;
  }

  return OPERATOR_CANCELLED | OPERATOR_PASS_THROUGH;
}

void OUTLINER_OT_item_openclose(wmOperatorType *ot)
{
  ot->name = "Open/Close";
  ot->idname = "OUTLINER_OT_item_openclose";
  ot->description = "Toggle whether item under cursor is enabled or closed";

  ot->invoke = outliner_item_openclose_invoke;
  ot->modal = outliner_item_openclose_modal;

  ot->poll = ED_operator_outliner_active;

  RNA_def_boolean(ot->srna, "all", false, "All", "Close or open all items");
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Rename Operator
 * \{ */

static void do_item_rename(ARegion *region,
                           TreeElement *te,
                           TreeStoreElem *tselem,
                           ReportList *reports)
{
  bool add_textbut = false;

  /* can't rename rna datablocks entries or listbases */
  if (ELEM(tselem->type,
           TSE_RNA_STRUCT,
           TSE_RNA_PROPERTY,
           TSE_RNA_ARRAY_ELEM,
           TSE_ID_BASE,
           TSE_SCENE_OBJECTS_BASE)) {
    /* do nothing */
  }
  else if (ELEM(tselem->type,
                TSE_ANIM_DATA,
                TSE_NLA,
                TSE_DEFGROUP_BASE,
                TSE_CONSTRAINT_BASE,
                TSE_MODIFIER_BASE,
                TSE_DRIVER_BASE,
                TSE_POSE_BASE,
                TSE_POSEGRP_BASE,
                TSE_R_LAYER_BASE,
                TSE_SCENE_COLLECTION_BASE,
                TSE_VIEW_COLLECTION_BASE,
                TSE_LIBRARY_OVERRIDE_BASE)) {
    BKE_report(reports, RPT_WARNING, "Cannot edit builtin name");
  }
  else if (ELEM(tselem->type, TSE_SEQUENCE, TSE_SEQ_STRIP, TSE_SEQUENCE_DUP)) {
    BKE_report(reports, RPT_WARNING, "Cannot edit sequence name");
  }
  else if (ID_IS_LINKED(tselem->id)) {
    BKE_report(reports, RPT_WARNING, "Cannot edit external library data");
  }
  else if (ID_IS_OVERRIDE_LIBRARY(tselem->id)) {
    BKE_report(reports, RPT_WARNING, "Cannot edit name of an override data-block");
  }
  else if (outliner_is_collection_tree_element(te)) {
    Collection *collection = outliner_collection_from_tree_element(te);

    if (collection->flag & COLLECTION_IS_MASTER) {
      BKE_report(reports, RPT_WARNING, "Cannot edit name of master collection");
    }
    else {
      add_textbut = true;
    }
  }
  else if (te->idcode == ID_LI) {
    if (reinterpret_cast<Library *>(tselem->id)->parent) {
      BKE_report(reports, RPT_WARNING, "Cannot edit the path of an indirectly linked library");
    }
    else {
      BKE_report(
          reports,
          RPT_WARNING,
          "Library path is not editable from here anymore, please use Relocate operation instead");
    }
  }
  else {
    add_textbut = true;
  }

  if (add_textbut) {
    tselem->flag |= TSE_TEXTBUT;
    ED_region_tag_redraw(region);
  }
}

void item_rename_fn(bContext *C,
                    ReportList *reports,
                    Scene * /*scene*/,
                    TreeElement *te,
                    TreeStoreElem * /*tsep*/,
                    TreeStoreElem *tselem,
                    void * /*user_data*/)
{
  ARegion *region = CTX_wm_region(C);
  do_item_rename(region, te, tselem, reports);
}

static TreeElement *outliner_item_rename_find_active(const SpaceOutliner *space_outliner,
                                                     ReportList *reports)
{
  TreeElement *active_element = outliner_find_element_with_flag(&space_outliner->tree, TSE_ACTIVE);

  if (!active_element) {
    BKE_report(reports, RPT_WARNING, "No active item to rename");
    return nullptr;
  }

  return active_element;
}

static TreeElement *outliner_item_rename_find_hovered(const SpaceOutliner *space_outliner,
                                                      ARegion *region,
                                                      const wmEvent *event)
{
  float fmval[2];
  UI_view2d_region_to_view(&region->v2d, event->mval[0], event->mval[1], &fmval[0], &fmval[1]);

  TreeElement *hovered = outliner_find_item_at_y(space_outliner, &space_outliner->tree, fmval[1]);
  if (hovered && outliner_item_is_co_over_name(hovered, fmval[0])) {
    return hovered;
  }

  return nullptr;
}

static int outliner_item_rename(bContext *C, wmOperator *op, const wmEvent *event)
{
  ARegion *region = CTX_wm_region(C);
  View2D *v2d = &region->v2d;
  SpaceOutliner *space_outliner = CTX_wm_space_outliner(C);
  const bool use_active = RNA_boolean_get(op->ptr, "use_active");

  TreeElement *te = use_active ? outliner_item_rename_find_active(space_outliner, op->reports) :
                                 outliner_item_rename_find_hovered(space_outliner, region, event);
  if (!te) {
    return OPERATOR_CANCELLED;
  }

  /* Force element into view. */
  outliner_show_active(space_outliner, region, te, TREESTORE(te)->id);
  int size_y = BLI_rcti_size_y(&v2d->mask) + 1;
  int ytop = (te->ys + (size_y / 2));
  int delta_y = ytop - v2d->cur.ymax;
  outliner_scroll_view(space_outliner, region, delta_y);

  do_item_rename(region, te, TREESTORE(te), op->reports);

  return OPERATOR_FINISHED;
}

void OUTLINER_OT_item_rename(wmOperatorType *ot)
{
  ot->name = "Rename";
  ot->idname = "OUTLINER_OT_item_rename";
  ot->description = "Rename the active element";

  ot->invoke = outliner_item_rename;

  ot->poll = ED_operator_outliner_active;

  /* Flags. */
  ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;

  RNA_def_boolean(ot->srna,
                  "use_active",
                  false,
                  "Use Active",
                  "Rename the active item, rather than the one the mouse is over");
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name ID Delete Operator
 * \{ */

static void id_delete_tag(bContext *C, ReportList *reports, TreeElement *te, TreeStoreElem *tselem)
{
  Main *bmain = CTX_data_main(C);
  ID *id = tselem->id;

  BLI_assert(id != nullptr);
  BLI_assert(((tselem->type == TSE_SOME_ID) && (te->idcode != 0)) ||
             (tselem->type == TSE_LAYER_COLLECTION));
  UNUSED_VARS_NDEBUG(te);

  if (ID_IS_OVERRIDE_LIBRARY(id)) {
    if (!ID_IS_OVERRIDE_LIBRARY_REAL(id) ||
        (id->override_library->flag & IDOVERRIDE_LIBRARY_FLAG_NO_HIERARCHY) == 0) {
      BKE_reportf(reports,
                  RPT_WARNING,
                  "Cannot delete library override id '%s', it is part of an override hierarchy",
                  id->name);
      return;
    }
  }

  if (te->idcode == ID_LI && ((Library *)id)->parent != nullptr) {
    BKE_reportf(reports, RPT_WARNING, "Cannot delete indirectly linked library '%s'", id->name);
    return;
  }
  if (id->tag & LIB_TAG_INDIRECT) {
    BKE_reportf(reports, RPT_WARNING, "Cannot delete indirectly linked id '%s'", id->name);
    return;
  }
  if (ID_REAL_USERS(id) <= 1 && BKE_library_ID_is_indirectly_used(bmain, id)) {
    BKE_reportf(reports,
                RPT_WARNING,
                "Cannot delete id '%s', indirectly used data-blocks need at least one user",
                id->name);
    return;
  }
  if (te->idcode == ID_WS) {
    BKE_workspace_id_tag_all_visible(bmain, LIB_TAG_PRE_EXISTING);
    if (id->tag & LIB_TAG_PRE_EXISTING) {
      BKE_reportf(
          reports, RPT_WARNING, "Cannot delete currently visible workspace id '%s'", id->name);
      BKE_main_id_tag_idcode(bmain, ID_WS, LIB_TAG_PRE_EXISTING, false);
      return;
    }
    BKE_main_id_tag_idcode(bmain, ID_WS, LIB_TAG_PRE_EXISTING, false);
  }

  id->tag |= LIB_TAG_DOIT;

  WM_event_add_notifier(C, NC_WINDOW, nullptr);
}

void id_delete_tag_fn(bContext *C,
                      ReportList *reports,
                      Scene * /*scene*/,
                      TreeElement *te,
                      TreeStoreElem * /*tsep*/,
                      TreeStoreElem *tselem,
                      void * /*user_data*/)
{
  id_delete_tag(C, reports, te, tselem);
}

static int outliner_id_delete_tag(bContext *C,
                                  ReportList *reports,
                                  TreeElement *te,
                                  const float mval[2])
{
  int id_tagged_num = 0;

  if (mval[1] > te->ys && mval[1] < te->ys + UI_UNIT_Y) {
    TreeStoreElem *tselem = TREESTORE(te);

    if (te->idcode != 0 && tselem->id) {
      if (te->idcode == ID_LI && ((Library *)tselem->id)->parent) {
        BKE_reportf(reports,
                    RPT_ERROR_INVALID_INPUT,
                    "Cannot delete indirectly linked library '%s'",
                    ((Library *)tselem->id)->filepath_abs);
      }
      else {
        id_delete_tag(C, reports, te, tselem);
        id_tagged_num++;
      }
    }
  }
  else {
    LISTBASE_FOREACH (TreeElement *, te_sub, &te->subtree) {
      if ((id_tagged_num += outliner_id_delete_tag(C, reports, te_sub, mval)) != 0) {
        break;
      }
    }
  }

  return id_tagged_num;
}

static int outliner_id_delete_invoke(bContext *C, wmOperator *op, const wmEvent *event)
{
  Main *bmain = CTX_data_main(C);
  ARegion *region = CTX_wm_region(C);
  SpaceOutliner *space_outliner = CTX_wm_space_outliner(C);
  float fmval[2];

  BLI_assert(region && space_outliner);

  UI_view2d_region_to_view(&region->v2d, event->mval[0], event->mval[1], &fmval[0], &fmval[1]);

  int id_tagged_num = 0;
  BKE_main_id_tag_all(bmain, LIB_TAG_DOIT, false);
  LISTBASE_FOREACH (TreeElement *, te, &space_outliner->tree) {
    if ((id_tagged_num += outliner_id_delete_tag(C, op->reports, te, fmval)) != 0) {
      break;
    }
  }
  if (id_tagged_num == 0) {
    BKE_main_id_tag_all(bmain, LIB_TAG_DOIT, false);
    return OPERATOR_CANCELLED;
  }

  BKE_id_multi_tagged_delete(bmain);
  BKE_main_id_tag_all(bmain, LIB_TAG_DOIT, false);
  return OPERATOR_FINISHED;
}

void OUTLINER_OT_id_delete(wmOperatorType *ot)
{
  ot->name = "Delete Data-Block";
  ot->idname = "OUTLINER_OT_id_delete";
  ot->description = "Delete the ID under cursor";

  ot->invoke = outliner_id_delete_invoke;
  ot->poll = ED_operator_outliner_active;

  /* Flags. */
  ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name ID Remap Operator
 * \{ */

static int outliner_id_remap_exec(bContext *C, wmOperator *op)
{
  Main *bmain = CTX_data_main(C);
  SpaceOutliner *space_outliner = CTX_wm_space_outliner(C);

  const short id_type = short(RNA_enum_get(op->ptr, "id_type"));
  ID *old_id = static_cast<ID *>(
      BLI_findlink(which_libbase(CTX_data_main(C), id_type), RNA_enum_get(op->ptr, "old_id")));
  ID *new_id = static_cast<ID *>(
      BLI_findlink(which_libbase(CTX_data_main(C), id_type), RNA_enum_get(op->ptr, "new_id")));

  /* check for invalid states */
  if (space_outliner == nullptr) {
    return OPERATOR_CANCELLED;
  }

  if (!(old_id && new_id && (old_id != new_id) && (GS(old_id->name) == GS(new_id->name)))) {
    BKE_reportf(op->reports,
                RPT_ERROR_INVALID_INPUT,
                "Invalid old/new ID pair ('%s' / '%s')",
                old_id ? old_id->name : "Invalid ID",
                new_id ? new_id->name : "Invalid ID");
    return OPERATOR_CANCELLED;
  }

  if (ID_IS_LINKED(old_id)) {
    BKE_reportf(op->reports,
                RPT_WARNING,
                "Old ID '%s' is linked from a library, indirect usages of this data-block will "
                "not be remapped",
                old_id->name);
  }

  BKE_libblock_remap(
      bmain, old_id, new_id, ID_REMAP_SKIP_INDIRECT_USAGE | ID_REMAP_SKIP_NEVER_NULL_USAGE);

  BKE_main_lib_objects_recalc_all(bmain);

  /* recreate dependency graph to include new objects */
  DEG_relations_tag_update(bmain);

  /* Free gpu materials, some materials depend on existing objects,
   * such as lights so freeing correctly refreshes. */
  GPU_materials_free(bmain);

  WM_event_add_notifier(C, NC_WINDOW, nullptr);

  return OPERATOR_FINISHED;
}

static bool outliner_id_remap_find_tree_element(bContext *C,
                                                wmOperator *op,
                                                ListBase *tree,
                                                const float y)
{
  LISTBASE_FOREACH (TreeElement *, te, tree) {
    if (y > te->ys && y < te->ys + UI_UNIT_Y) {
      TreeStoreElem *tselem = TREESTORE(te);

      if ((tselem->type == TSE_SOME_ID) && tselem->id) {
        RNA_enum_set(op->ptr, "id_type", GS(tselem->id->name));
        RNA_enum_set_identifier(C, op->ptr, "new_id", tselem->id->name + 2);
        RNA_enum_set_identifier(C, op->ptr, "old_id", tselem->id->name + 2);
        return true;
      }
    }
    if (outliner_id_remap_find_tree_element(C, op, &te->subtree, y)) {
      return true;
    }
  }
  return false;
}

static int outliner_id_remap_invoke(bContext *C, wmOperator *op, const wmEvent *event)
{
  SpaceOutliner *space_outliner = CTX_wm_space_outliner(C);
  ARegion *region = CTX_wm_region(C);
  float fmval[2];

  if (!RNA_property_is_set(op->ptr, RNA_struct_find_property(op->ptr, "id_type"))) {
    UI_view2d_region_to_view(&region->v2d, event->mval[0], event->mval[1], &fmval[0], &fmval[1]);

    outliner_id_remap_find_tree_element(C, op, &space_outliner->tree, fmval[1]);
  }

  return WM_operator_props_dialog_popup(C, op, 400);
}

static const EnumPropertyItem *outliner_id_itemf(bContext *C,
                                                 PointerRNA *ptr,
                                                 PropertyRNA * /*prop*/,
                                                 bool *r_free)
{
  if (C == nullptr) {
    return DummyRNA_NULL_items;
  }

  EnumPropertyItem item_tmp = {0}, *item = nullptr;
  int totitem = 0;
  int i = 0;

  short id_type = short(RNA_enum_get(ptr, "id_type"));
  ID *id = static_cast<ID *>(which_libbase(CTX_data_main(C), id_type)->first);

  for (; id; id = static_cast<ID *>(id->next)) {
    item_tmp.identifier = item_tmp.name = id->name + 2;
    item_tmp.value = i++;
    RNA_enum_item_add(&item, &totitem, &item_tmp);
  }

  RNA_enum_item_end(&item, &totitem);
  *r_free = true;

  return item;
}

void OUTLINER_OT_id_remap(wmOperatorType *ot)
{
  PropertyRNA *prop;

  /* identifiers */
  ot->name = "Outliner ID Data Remap";
  ot->idname = "OUTLINER_OT_id_remap";

  /* callbacks */
  ot->invoke = outliner_id_remap_invoke;
  ot->exec = outliner_id_remap_exec;
  ot->poll = ED_operator_outliner_active;

  /* Flags. */
  ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;

  prop = RNA_def_enum(ot->srna, "id_type", rna_enum_id_type_items, ID_OB, "ID Type", "");
  RNA_def_property_translation_context(prop, BLT_I18NCONTEXT_ID_ID);
  /* Changing ID type wont make sense, would return early with "Invalid old/new ID pair" anyways.
   */
  RNA_def_property_flag(prop, PROP_HIDDEN);

  prop = RNA_def_enum(ot->srna, "old_id", DummyRNA_NULL_items, 0, "Old ID", "Old ID to replace");
  RNA_def_property_enum_funcs_runtime(prop, nullptr, nullptr, outliner_id_itemf);
  RNA_def_property_flag(prop, (PropertyFlag)(PROP_ENUM_NO_TRANSLATE | PROP_HIDDEN));

  ot->prop = RNA_def_enum(ot->srna,
                          "new_id",
                          DummyRNA_NULL_items,
                          0,
                          "New ID",
                          "New ID to remap all selected IDs' users to");
  RNA_def_property_enum_funcs_runtime(ot->prop, nullptr, nullptr, outliner_id_itemf);
  RNA_def_property_flag(ot->prop, PROP_ENUM_NO_TRANSLATE);
}

void id_remap_fn(bContext *C,
                 ReportList * /*reports*/,
                 Scene * /*scene*/,
                 TreeElement * /*te*/,
                 TreeStoreElem * /*tsep*/,
                 TreeStoreElem *tselem,
                 void * /*user_data*/)
{
  wmOperatorType *ot = WM_operatortype_find("OUTLINER_OT_id_remap", false);
  PointerRNA op_props;

  BLI_assert(tselem->id != nullptr);

  WM_operator_properties_create_ptr(&op_props, ot);

  RNA_enum_set(&op_props, "id_type", GS(tselem->id->name));
  RNA_enum_set_identifier(C, &op_props, "old_id", tselem->id->name + 2);

  WM_operator_name_call_ptr(C, ot, WM_OP_INVOKE_DEFAULT, &op_props, nullptr);

  WM_operator_properties_free(&op_props);
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name ID Copy Operator
 * \{ */

static int outliner_id_copy_tag(SpaceOutliner *space_outliner, ListBase *tree)
{
  int num_ids = 0;

  LISTBASE_FOREACH (TreeElement *, te, tree) {
    TreeStoreElem *tselem = TREESTORE(te);

    /* if item is selected and is an ID, tag it as needing to be copied. */
    if (tselem->flag & TSE_SELECTED && ELEM(tselem->type, TSE_SOME_ID, TSE_LAYER_COLLECTION)) {
      ID *id = tselem->id;
      if (!(id->tag & LIB_TAG_DOIT)) {
        BKE_copybuffer_copy_tag_ID(tselem->id);
        num_ids++;
      }
    }

    /* go over sub-tree */
    num_ids += outliner_id_copy_tag(space_outliner, &te->subtree);
  }

  return num_ids;
}

static int outliner_id_copy_exec(bContext *C, wmOperator *op)
{
  Main *bmain = CTX_data_main(C);
  SpaceOutliner *space_outliner = CTX_wm_space_outliner(C);
  char str[FILE_MAX];

  BKE_copybuffer_copy_begin(bmain);

  const int num_ids = outliner_id_copy_tag(space_outliner, &space_outliner->tree);
  if (num_ids == 0) {
    BKE_report(op->reports, RPT_INFO, "No selected data-blocks to copy");
    return OPERATOR_CANCELLED;
  }

  BLI_path_join(str, sizeof(str), BKE_tempdir_base(), "copybuffer.blend");
  BKE_copybuffer_copy_end(bmain, str, op->reports);

  BKE_reportf(op->reports, RPT_INFO, "Copied %d selected data-block(s)", num_ids);

  return OPERATOR_FINISHED;
}

void OUTLINER_OT_id_copy(wmOperatorType *ot)
{
  /* identifiers */
  ot->name = "Outliner ID Data Copy";
  ot->idname = "OUTLINER_OT_id_copy";
  ot->description = "Selected data-blocks are copied to the clipboard";

  /* callbacks */
  ot->exec = outliner_id_copy_exec;
  ot->poll = ED_operator_outliner_active;

  /* Flags, don't need any undo here (this operator does not change anything in Blender data). */
  ot->flag = 0;
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name ID Paste Operator
 * \{ */

static int outliner_id_paste_exec(bContext *C, wmOperator *op)
{
  char str[FILE_MAX];
  const short flag = FILE_AUTOSELECT | FILE_ACTIVE_COLLECTION;

  BLI_path_join(str, sizeof(str), BKE_tempdir_base(), "copybuffer.blend");

  const int num_pasted = BKE_copybuffer_paste(C, str, flag, op->reports, 0);
  if (num_pasted == 0) {
    BKE_report(op->reports, RPT_INFO, "No data to paste");
    return OPERATOR_CANCELLED;
  }

  WM_event_add_notifier(C, NC_WINDOW, nullptr);

  BKE_reportf(op->reports, RPT_INFO, "%d data-block(s) pasted", num_pasted);

  return OPERATOR_FINISHED;
}

void OUTLINER_OT_id_paste(wmOperatorType *ot)
{
  /* identifiers */
  ot->name = "Outliner ID Data Paste";
  ot->idname = "OUTLINER_OT_id_paste";
  ot->description = "Data-blocks from the clipboard are pasted";

  /* callbacks */
  ot->exec = outliner_id_paste_exec;
  ot->poll = ED_operator_outliner_active;

  /* flags */
  ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Library Relocate Operator
 * \{ */

static int lib_relocate(
    bContext *C, TreeElement *te, TreeStoreElem *tselem, wmOperatorType *ot, const bool reload)
{
  PointerRNA op_props;
  int ret = 0;

  BLI_assert(te->idcode == ID_LI && tselem->id != nullptr);
  UNUSED_VARS_NDEBUG(te);

  WM_operator_properties_create_ptr(&op_props, ot);

  RNA_string_set(&op_props, "library", tselem->id->name + 2);

  if (reload) {
    Library *lib = (Library *)tselem->id;
    char dir[FILE_MAXDIR], filename[FILE_MAX];

    BLI_split_dirfile(lib->filepath_abs, dir, filename, sizeof(dir), sizeof(filename));

    printf("%s, %s\n", tselem->id->name, lib->filepath_abs);

    /* We assume if both paths in lib are not the same then `lib->filepath` was relative. */
    RNA_boolean_set(
        &op_props, "relative_path", BLI_path_cmp(lib->filepath_abs, lib->filepath) != 0);

    RNA_string_set(&op_props, "directory", dir);
    RNA_string_set(&op_props, "filename", filename);

    ret = WM_operator_name_call_ptr(C, ot, WM_OP_EXEC_DEFAULT, &op_props, nullptr);
  }
  else {
    ret = WM_operator_name_call_ptr(C, ot, WM_OP_INVOKE_DEFAULT, &op_props, nullptr);
  }

  WM_operator_properties_free(&op_props);

  return ret;
}

static int outliner_lib_relocate_invoke_do(
    bContext *C, ReportList *reports, TreeElement *te, const float mval[2], const bool reload)
{
  if (mval[1] > te->ys && mval[1] < te->ys + UI_UNIT_Y) {
    TreeStoreElem *tselem = TREESTORE(te);

    if (te->idcode == ID_LI && tselem->id) {
      if (((Library *)tselem->id)->parent && !reload) {
        BKE_reportf(reports,
                    RPT_ERROR_INVALID_INPUT,
                    "Cannot relocate indirectly linked library '%s'",
                    ((Library *)tselem->id)->filepath_abs);
        return OPERATOR_CANCELLED;
      }

      wmOperatorType *ot = WM_operatortype_find(reload ? "WM_OT_lib_reload" : "WM_OT_lib_relocate",
                                                false);
      return lib_relocate(C, te, tselem, ot, reload);
    }
  }
  else {
    LISTBASE_FOREACH (TreeElement *, te_sub, &te->subtree) {
      int ret;
      if ((ret = outliner_lib_relocate_invoke_do(C, reports, te_sub, mval, reload))) {
        return ret;
      }
    }
  }

  return 0;
}

static int outliner_lib_relocate_invoke(bContext *C, wmOperator *op, const wmEvent *event)
{
  ARegion *region = CTX_wm_region(C);
  SpaceOutliner *space_outliner = CTX_wm_space_outliner(C);
  float fmval[2];

  BLI_assert(region && space_outliner);

  UI_view2d_region_to_view(&region->v2d, event->mval[0], event->mval[1], &fmval[0], &fmval[1]);

  LISTBASE_FOREACH (TreeElement *, te, &space_outliner->tree) {
    int ret;

    if ((ret = outliner_lib_relocate_invoke_do(C, op->reports, te, fmval, false))) {
      return ret;
    }
  }

  return OPERATOR_CANCELLED;
}

void OUTLINER_OT_lib_relocate(wmOperatorType *ot)
{
  ot->name = "Relocate Library";
  ot->idname = "OUTLINER_OT_lib_relocate";
  ot->description = "Relocate the library under cursor";

  ot->invoke = outliner_lib_relocate_invoke;
  ot->poll = ED_operator_outliner_active;

  /* Flags. */
  ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
}

void lib_relocate_fn(bContext *C,
                     ReportList * /*reports*/,
                     Scene * /*scene*/,
                     TreeElement *te,
                     TreeStoreElem * /*tsep*/,
                     TreeStoreElem *tselem,
                     void * /*user_data*/)
{
  /* XXX: This does not work with several items
   * (it is only called once in the end, due to the 'deferred'
   * file-browser invocation through event system...). */

  wmOperatorType *ot = WM_operatortype_find("WM_OT_lib_relocate", false);

  lib_relocate(C, te, tselem, ot, false);
}

static int outliner_lib_reload_invoke(bContext *C, wmOperator *op, const wmEvent *event)
{
  ARegion *region = CTX_wm_region(C);
  SpaceOutliner *space_outliner = CTX_wm_space_outliner(C);
  float fmval[2];

  BLI_assert(region && space_outliner);

  UI_view2d_region_to_view(&region->v2d, event->mval[0], event->mval[1], &fmval[0], &fmval[1]);

  LISTBASE_FOREACH (TreeElement *, te, &space_outliner->tree) {
    int ret;

    if ((ret = outliner_lib_relocate_invoke_do(C, op->reports, te, fmval, true))) {
      return ret;
    }
  }

  return OPERATOR_CANCELLED;
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Library Reload Operator
 * \{ */

void OUTLINER_OT_lib_reload(wmOperatorType *ot)
{
  ot->name = "Reload Library";
  ot->idname = "OUTLINER_OT_lib_reload";
  ot->description = "Reload the library under cursor";

  ot->invoke = outliner_lib_reload_invoke;
  ot->poll = ED_operator_outliner_active;

  /* Flags. */
  ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
}

void lib_reload_fn(bContext *C,
                   ReportList * /*reports*/,
                   Scene * /*scene*/,
                   TreeElement *te,
                   TreeStoreElem * /*tsep*/,
                   TreeStoreElem *tselem,
                   void * /*user_data*/)
{
  wmOperatorType *ot = WM_operatortype_find("WM_OT_lib_reload", false);

  lib_relocate(C, te, tselem, ot, true);
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Apply Settings Utilities
 * \{ */

static int outliner_count_levels(ListBase *lb, const int curlevel)
{
  int level = curlevel;

  LISTBASE_FOREACH (TreeElement *, te, lb) {
    int lev = outliner_count_levels(&te->subtree, curlevel + 1);
    if (lev > level) {
      level = lev;
    }
  }
  return level;
}

int outliner_flag_is_any_test(ListBase *lb, short flag, const int curlevel)
{
  LISTBASE_FOREACH (TreeElement *, te, lb) {
    TreeStoreElem *tselem = TREESTORE(te);
    if (tselem->flag & flag) {
      return curlevel;
    }

    int level = outliner_flag_is_any_test(&te->subtree, flag, curlevel + 1);
    if (level) {
      return level;
    }
  }
  return 0;
}

bool outliner_flag_set(const SpaceOutliner &space_outliner, const short flag, const short set)
{
  return outliner_flag_set(space_outliner.tree, flag, set);
}

bool outliner_flag_set(const ListBase &lb, const short flag, const short set)
{
  bool changed = false;

  tree_iterator::all(lb, [&](TreeElement *te) {
    TreeStoreElem *tselem = TREESTORE(te);
    bool has_flag = (tselem->flag & flag);
    if (set == 0) {
      if (has_flag) {
        tselem->flag &= ~flag;
        changed = true;
      }
    }
    else if (!has_flag) {
      tselem->flag |= flag;
      changed = true;
    }
  });

  return changed;
}

bool outliner_flag_flip(const SpaceOutliner &space_outliner, const short flag)
{
  return outliner_flag_flip(space_outliner.tree, flag);
}

bool outliner_flag_flip(const ListBase &lb, const short flag)
{
  bool changed = false;

  tree_iterator::all(lb, [&](TreeElement *te) {
    TreeStoreElem *tselem = TREESTORE(te);
    tselem->flag ^= flag;
  });

  return changed;
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Toggle Expanded (Outliner) Operator
 * \{ */

static int outliner_toggle_expanded_exec(bContext *C, wmOperator * /*op*/)
{
  SpaceOutliner *space_outliner = CTX_wm_space_outliner(C);
  ARegion *region = CTX_wm_region(C);

  if (outliner_flag_is_any_test(&space_outliner->tree, TSE_CLOSED, 1)) {
    outliner_flag_set(*space_outliner, TSE_CLOSED, 0);
  }
  else {
    outliner_flag_set(*space_outliner, TSE_CLOSED, 1);
  }

  ED_region_tag_redraw(region);

  return OPERATOR_FINISHED;
}

void OUTLINER_OT_expanded_toggle(wmOperatorType *ot)
{
  /* identifiers */
  ot->name = "Expand/Collapse All";
  ot->idname = "OUTLINER_OT_expanded_toggle";
  ot->description = "Expand/Collapse all items";

  /* callbacks */
  ot->exec = outliner_toggle_expanded_exec;
  ot->poll = ED_operator_outliner_active;

  /* no undo or registry, UI option */
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Toggle Selected (Outliner) Operator
 * \{ */

static int outliner_select_all_exec(bContext *C, wmOperator *op)
{
  SpaceOutliner *space_outliner = CTX_wm_space_outliner(C);
  ARegion *region = CTX_wm_region(C);
  Scene *scene = CTX_data_scene(C);
  int action = RNA_enum_get(op->ptr, "action");
  if (action == SEL_TOGGLE) {
    action = outliner_flag_is_any_test(&space_outliner->tree, TSE_SELECTED, 1) ? SEL_DESELECT :
                                                                                 SEL_SELECT;
  }

  switch (action) {
    case SEL_SELECT:
      outliner_flag_set(*space_outliner, TSE_SELECTED, 1);
      break;
    case SEL_DESELECT:
      outliner_flag_set(*space_outliner, TSE_SELECTED, 0);
      break;
    case SEL_INVERT:
      outliner_flag_flip(*space_outliner, TSE_SELECTED);
      break;
  }

  ED_outliner_select_sync_from_outliner(C, space_outliner);

  DEG_id_tag_update(&scene->id, ID_RECALC_SELECT);
  WM_event_add_notifier(C, NC_SCENE | ND_OB_SELECT, scene);
  ED_region_tag_redraw_no_rebuild(region);

  return OPERATOR_FINISHED;
}

void OUTLINER_OT_select_all(wmOperatorType *ot)
{
  /* identifiers */
  ot->name = "Toggle Selected";
  ot->idname = "OUTLINER_OT_select_all";
  ot->description = "Toggle the Outliner selection of items";

  /* callbacks */
  ot->exec = outliner_select_all_exec;
  ot->poll = ED_operator_outliner_active;

  /* no undo or registry */

  /* rna */
  WM_operator_properties_select_all(ot);
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name View Show Active (Outliner) Operator
 * \{ */

void outliner_set_coordinates(const ARegion *region, const SpaceOutliner *space_outliner)
{
  int starty = int(region->v2d.tot.ymax) - UI_UNIT_Y;

  tree_iterator::all_open(*space_outliner, [&](TreeElement *te) {
    /* store coord and continue, we need coordinates for elements outside view too */
    te->xs = 0;
    te->ys = float(starty);
    starty -= UI_UNIT_Y;
  });
}

/* return 1 when levels were opened */
static int outliner_open_back(TreeElement *te)
{
  TreeStoreElem *tselem;
  int retval = 0;

  for (te = te->parent; te; te = te->parent) {
    tselem = TREESTORE(te);
    if (tselem->flag & TSE_CLOSED) {
      tselem->flag &= ~TSE_CLOSED;
      retval = 1;
    }
  }
  return retval;
}

/* Return element representing the active base or bone in the outliner, or NULL if none exists */
static TreeElement *outliner_show_active_get_element(bContext *C,
                                                     SpaceOutliner *space_outliner,
                                                     const Scene *scene,
                                                     ViewLayer *view_layer)
{
  TreeElement *te;

  BKE_view_layer_synced_ensure(scene, view_layer);
  Object *obact = BKE_view_layer_active_object_get(view_layer);

  if (!obact) {
    return nullptr;
  }

  te = outliner_find_id(space_outliner, &space_outliner->tree, &obact->id);

  if (te != nullptr && obact->type == OB_ARMATURE) {
    /* traverse down the bone hierarchy in case of armature */
    TreeElement *te_obact = te;

    if (obact->mode & OB_MODE_POSE) {
      Object *obpose = BKE_object_pose_armature_get(obact);
      bPoseChannel *pchan = BKE_pose_channel_active(obpose, false);
      if (pchan) {
        te = outliner_find_posechannel(&te_obact->subtree, pchan);
      }
    }
    else if (obact->mode & OB_MODE_EDIT) {
      EditBone *ebone = CTX_data_active_bone(C);
      if (ebone) {
        te = outliner_find_editbone(&te_obact->subtree, ebone);
      }
    }
  }

  return te;
}

static void outliner_show_active(SpaceOutliner *space_outliner,
                                 ARegion *region,
                                 TreeElement *te,
                                 ID *id)
{
  /* open up tree to active object/bone */
  if (TREESTORE(te)->id == id) {
    if (outliner_open_back(te)) {
      outliner_set_coordinates(region, space_outliner);
    }
    return;
  }

  LISTBASE_FOREACH (TreeElement *, ten, &te->subtree) {
    outliner_show_active(space_outliner, region, ten, id);
  }
}

static int outliner_show_active_exec(bContext *C, wmOperator * /*op*/)
{
  SpaceOutliner *space_outliner = CTX_wm_space_outliner(C);
  const Scene *scene = CTX_data_scene(C);
  ViewLayer *view_layer = CTX_data_view_layer(C);
  ARegion *region = CTX_wm_region(C);
  View2D *v2d = &region->v2d;

  TreeElement *active_element = outliner_show_active_get_element(
      C, space_outliner, scene, view_layer);

  if (active_element) {
    ID *id = TREESTORE(active_element)->id;

    /* Expand all elements in the outliner with matching ID */
    LISTBASE_FOREACH (TreeElement *, te, &space_outliner->tree) {
      outliner_show_active(space_outliner, region, te, id);
    }

    /* Also open back from the active_element (only done for the first found occurrence of ID
     * though). */
    outliner_show_active(space_outliner, region, active_element, id);

    /* Center view on first element found */
    int size_y = BLI_rcti_size_y(&v2d->mask) + 1;
    int ytop = (active_element->ys + (size_y / 2));
    int delta_y = ytop - v2d->cur.ymax;

    outliner_scroll_view(space_outliner, region, delta_y);
  }
  else {
    return OPERATOR_CANCELLED;
  }

  ED_region_tag_redraw_no_rebuild(region);

  return OPERATOR_FINISHED;
}

void OUTLINER_OT_show_active(wmOperatorType *ot)
{
  /* identifiers */
  ot->name = "Show Active";
  ot->idname = "OUTLINER_OT_show_active";
  ot->description =
      "Open up the tree and adjust the view so that the active object is shown centered";

  /* callbacks */
  ot->exec = outliner_show_active_exec;
  ot->poll = ED_operator_outliner_active;
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name View Panning (Outliner) Operator
 * \{ */

static int outliner_scroll_page_exec(bContext *C, wmOperator *op)
{
  SpaceOutliner *space_outliner = CTX_wm_space_outliner(C);
  ARegion *region = CTX_wm_region(C);
  int size_y = BLI_rcti_size_y(&region->v2d.mask) + 1;

  bool up = RNA_boolean_get(op->ptr, "up");

  if (!up) {
    size_y = -size_y;
  }

  outliner_scroll_view(space_outliner, region, size_y);

  ED_region_tag_redraw_no_rebuild(region);

  return OPERATOR_FINISHED;
}

void OUTLINER_OT_scroll_page(wmOperatorType *ot)
{
  PropertyRNA *prop;

  /* identifiers */
  ot->name = "Scroll Page";
  ot->idname = "OUTLINER_OT_scroll_page";
  ot->description = "Scroll page up or down";

  /* callbacks */
  ot->exec = outliner_scroll_page_exec;
  ot->poll = ED_operator_outliner_active;

  /* properties */
  prop = RNA_def_boolean(ot->srna, "up", false, "Up", "Scroll up one page");
  RNA_def_property_flag(prop, PROP_SKIP_SAVE);
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Show One Level Operator
 * \{ */

/* helper function for Show/Hide one level operator */
static void outliner_openclose_level(ListBase *lb, int curlevel, int level, int open)
{
  LISTBASE_FOREACH (TreeElement *, te, lb) {
    TreeStoreElem *tselem = TREESTORE(te);

    if (open) {
      if (curlevel <= level) {
        tselem->flag &= ~TSE_CLOSED;
      }
    }
    else {
      if (curlevel >= level) {
        tselem->flag |= TSE_CLOSED;
      }
    }

    outliner_openclose_level(&te->subtree, curlevel + 1, level, open);
  }
}

static int outliner_one_level_exec(bContext *C, wmOperator *op)
{
  SpaceOutliner *space_outliner = CTX_wm_space_outliner(C);
  ARegion *region = CTX_wm_region(C);
  const bool add = RNA_boolean_get(op->ptr, "open");
  int level;

  level = outliner_flag_is_any_test(&space_outliner->tree, TSE_CLOSED, 1);
  if (add == 1) {
    if (level) {
      outliner_openclose_level(&space_outliner->tree, 1, level, 1);
    }
  }
  else {
    if (level == 0) {
      level = outliner_count_levels(&space_outliner->tree, 0);
    }
    if (level) {
      outliner_openclose_level(&space_outliner->tree, 1, level - 1, 0);
    }
  }

  ED_region_tag_redraw(region);

  return OPERATOR_FINISHED;
}

void OUTLINER_OT_show_one_level(wmOperatorType *ot)
{
  PropertyRNA *prop;

  /* identifiers */
  ot->name = "Show/Hide One Level";
  ot->idname = "OUTLINER_OT_show_one_level";
  ot->description = "Expand/collapse all entries by one level";

  /* callbacks */
  ot->exec = outliner_one_level_exec;
  ot->poll = ED_operator_outliner_active;

  /* no undo or registry, UI option */

  /* properties */
  prop = RNA_def_boolean(ot->srna, "open", true, "Open", "Expand all entries one level deep");
  RNA_def_property_flag(prop, PROP_SKIP_SAVE);
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Show Hierarchy Operator
 * \{ */

/**
 * Helper function for #tree_element_shwo_hierarchy() -
 * recursively checks whether subtrees have any objects.
 */
static int subtree_has_objects(ListBase *lb)
{
  LISTBASE_FOREACH (TreeElement *, te, lb) {
    TreeStoreElem *tselem = TREESTORE(te);
    if ((tselem->type == TSE_SOME_ID) && (te->idcode == ID_OB)) {
      return 1;
    }
    if (subtree_has_objects(&te->subtree)) {
      return 1;
    }
  }
  return 0;
}

/* Helper function for Show Hierarchy operator */
static void tree_element_show_hierarchy(Scene *scene, SpaceOutliner *space_outliner)
{
  /* open all object elems, close others */
  tree_iterator::all_open(*space_outliner, [&](TreeElement *te) {
    TreeStoreElem *tselem = TREESTORE(te);

    if (ELEM(tselem->type,
             TSE_SOME_ID,
             TSE_SCENE_OBJECTS_BASE,
             TSE_VIEW_COLLECTION_BASE,
             TSE_LAYER_COLLECTION)) {
      if (te->idcode == ID_SCE) {
        if (tselem->id != (ID *)scene) {
          tselem->flag |= TSE_CLOSED;
        }
        else {
          tselem->flag &= ~TSE_CLOSED;
        }
      }
      else if (te->idcode == ID_OB) {
        if (subtree_has_objects(&te->subtree)) {
          tselem->flag &= ~TSE_CLOSED;
        }
        else {
          tselem->flag |= TSE_CLOSED;
        }
      }
    }
    else {
      tselem->flag |= TSE_CLOSED;
    }
  });
}

/* show entire object level hierarchy */
static int outliner_show_hierarchy_exec(bContext *C, wmOperator * /*op*/)
{
  SpaceOutliner *space_outliner = CTX_wm_space_outliner(C);
  ARegion *region = CTX_wm_region(C);
  Scene *scene = CTX_data_scene(C);

  /* recursively open/close levels */
  tree_element_show_hierarchy(scene, space_outliner);

  ED_region_tag_redraw(region);

  return OPERATOR_FINISHED;
}

void OUTLINER_OT_show_hierarchy(wmOperatorType *ot)
{
  /* identifiers */
  ot->name = "Show Hierarchy";
  ot->idname = "OUTLINER_OT_show_hierarchy";
  ot->description = "Open all object entries and close all others";

  /* callbacks */
  ot->exec = outliner_show_hierarchy_exec;
  ot->poll = ED_operator_outliner_active; /* TODO: shouldn't be allowed in RNA views... */

  /* no undo or registry, UI option */
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Animation Internal Utilities
 * \{ */

/**
 * Specialized poll callback for these operators to work in data-blocks view only.
 */
static bool ed_operator_outliner_datablocks_active(bContext *C)
{
  ScrArea *area = CTX_wm_area(C);
  if ((area) && (area->spacetype == SPACE_OUTLINER)) {
    SpaceOutliner *space_outliner = CTX_wm_space_outliner(C);
    return (space_outliner->outlinevis == SO_DATA_API);
  }
  return false;
}

/* Helper func to extract an RNA path from selected tree element
 * NOTE: the caller must zero-out all values of the pointers that it passes here first, as
 * this function does not do that yet
 */
static void tree_element_to_path(TreeElement *te,
                                 TreeStoreElem *tselem,
                                 ID **id,
                                 char **path,
                                 int *array_index,
                                 short *flag,
                                 short * /*groupmode*/)
{
  ListBase hierarchy = {nullptr, nullptr};
  char *newpath = nullptr;

  /* optimize tricks:
   * - Don't do anything if the selected item is a 'struct', but arrays are allowed
   */
  if (tselem->type == TSE_RNA_STRUCT) {
    return;
  }

  /* Overview of Algorithm:
   * 1. Go up the chain of parents until we find the 'root', taking note of the
   *    levels encountered in reverse-order (i.e. items are added to the start of the list
   *    for more convenient looping later)
   * 2. Walk down the chain, adding from the first ID encountered
   *    (which will become the 'ID' for the KeyingSet Path), and build a
   *    path as we step through the chain
   */

  /* step 1: flatten out hierarchy of parents into a flat chain */
  for (TreeElement *tem = te->parent; tem; tem = tem->parent) {
    LinkData *ld = MEM_cnew<LinkData>("LinkData for tree_element_to_path()");
    ld->data = tem;
    BLI_addhead(&hierarchy, ld);
  }

  /* step 2: step down hierarchy building the path
   * (NOTE: addhead in previous loop was needed so that we can loop like this) */
  LISTBASE_FOREACH (LinkData *, ld, &hierarchy) {
    /* get data */
    TreeElement *tem = (TreeElement *)ld->data;
    TreeElementRNACommon *tem_rna = tree_element_cast<TreeElementRNACommon>(tem);
    PointerRNA ptr = tem_rna->getPointerRNA();

    /* check if we're looking for first ID, or appending to path */
    if (*id) {
      /* just 'append' property to path
       * - to prevent memory leaks, we must write to newpath not path,
       *   then free old path + swap them.
       */
      if (TreeElementRNAProperty *tem_rna_prop = tree_element_cast<TreeElementRNAProperty>(tem)) {
        PropertyRNA *prop = tem_rna_prop->getPropertyRNA();

        if (RNA_property_type(prop) == PROP_POINTER) {
          /* for pointer we just append property name */
          newpath = RNA_path_append(*path, &ptr, prop, 0, nullptr);
        }
        else if (RNA_property_type(prop) == PROP_COLLECTION) {
          char buf[128], *name;

          TreeElement *temnext = (TreeElement *)(ld->next->data);
          PointerRNA nextptr = tree_element_cast<TreeElementRNACommon>(temnext)->getPointerRNA();
          name = RNA_struct_name_get_alloc(&nextptr, buf, sizeof(buf), nullptr);

          if (name) {
            /* if possible, use name as a key in the path */
            newpath = RNA_path_append(*path, nullptr, prop, 0, name);

            if (name != buf) {
              MEM_freeN(name);
            }
          }
          else {
            /* otherwise use index */
            int index = 0;

            LISTBASE_FOREACH (TreeElement *, temsub, &tem->subtree) {
              if (temsub == temnext) {
                break;
              }
              index++;
            }
            newpath = RNA_path_append(*path, nullptr, prop, index, nullptr);
          }

          ld = ld->next;
        }
      }

      if (newpath) {
        if (*path) {
          MEM_freeN(*path);
        }
        *path = newpath;
        newpath = nullptr;
      }
    }
    else {
      /* no ID, so check if entry is RNA-struct,
       * and if that RNA-struct is an ID datablock to extract info from. */
      if (tree_element_cast<TreeElementRNAStruct>(tem)) {
        /* ptr->data not ptr->owner_id seems to be the one we want,
         * since ptr->data is sometimes the owner of this ID? */
        if (RNA_struct_is_ID(ptr.type)) {
          *id = static_cast<ID *>(ptr.data);

          /* clear path */
          if (*path) {
            MEM_freeN(*path);
            path = nullptr;
          }
        }
      }
    }
  }

  /* step 3: if we've got an ID, add the current item to the path */
  if (*id) {
    /* add the active property to the path */
    PropertyRNA *prop = tree_element_cast<TreeElementRNACommon>(te)->getPropertyRNA();

    /* array checks */
    if (tselem->type == TSE_RNA_ARRAY_ELEM) {
      /* item is part of an array, so must set the array_index */
      *array_index = te->index;
    }
    else if (RNA_property_array_check(prop)) {
      /* entire array was selected, so keyframe all */
      *flag |= KSP_FLAG_WHOLE_ARRAY;
    }

    /* path */
    newpath = RNA_path_append(*path, nullptr, prop, 0, nullptr);
    if (*path) {
      MEM_freeN(*path);
    }
    *path = newpath;
  }

  /* free temp data */
  BLI_freelistN(&hierarchy);
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Driver Internal Utilities
 * \{ */

/**
 * Driver Operations
 *
 * These operators are only available in data-browser mode for now,
 * as they depend on having RNA paths and/or hierarchies available.
 */
enum {
  DRIVERS_EDITMODE_ADD = 0,
  DRIVERS_EDITMODE_REMOVE,
} /*eDrivers_EditModes*/;

/* Iterate over tree, finding and working on selected items */
static void do_outliner_drivers_editop(SpaceOutliner *space_outliner,
                                       ReportList *reports,
                                       short mode)
{
  tree_iterator::all_open(*space_outliner, [&](TreeElement *te) {
    TreeStoreElem *tselem = TREESTORE(te);

    /* if item is selected, perform operation */
    if (!(tselem->flag & TSE_SELECTED)) {
      return;
    }

    ID *id = nullptr;
    char *path = nullptr;
    int array_index = 0;
    short flag = 0;
    short groupmode = KSP_GROUP_KSNAME;

    TreeElementRNACommon *te_rna = tree_element_cast<TreeElementRNACommon>(te);
    PointerRNA ptr = te_rna ? te_rna->getPointerRNA() : PointerRNA_NULL;
    PropertyRNA *prop = te_rna ? te_rna->getPropertyRNA() : nullptr;

    /* check if RNA-property described by this selected element is an animatable prop */
    if (prop && RNA_property_animateable(&ptr, prop)) {
      /* get id + path + index info from the selected element */
      tree_element_to_path(te, tselem, &id, &path, &array_index, &flag, &groupmode);
    }

    /* only if ID and path were set, should we perform any actions */
    if (id && path) {
      short dflags = CREATEDRIVER_WITH_DEFAULT_DVAR;
      int arraylen = 1;

      /* array checks */
      if (flag & KSP_FLAG_WHOLE_ARRAY) {
        /* entire array was selected, so add drivers for all */
        arraylen = RNA_property_array_length(&ptr, prop);
      }
      else {
        arraylen = array_index;
      }

      /* we should do at least one step */
      if (arraylen == array_index) {
        arraylen++;
      }

      /* for each array element we should affect, add driver */
      for (; array_index < arraylen; array_index++) {
        /* action depends on mode */
        switch (mode) {
          case DRIVERS_EDITMODE_ADD: {
            /* add a new driver with the information obtained (only if valid) */
            ANIM_add_driver(reports, id, path, array_index, dflags, DRIVER_TYPE_PYTHON);
            break;
          }
          case DRIVERS_EDITMODE_REMOVE: {
            /* remove driver matching the information obtained (only if valid) */
            ANIM_remove_driver(reports, id, path, array_index, dflags);
            break;
          }
        }
      }

      /* free path, since it had to be generated */
      MEM_freeN(path);
    }
  });
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Driver Add Operator
 * \{ */

static int outliner_drivers_addsel_exec(bContext *C, wmOperator *op)
{
  SpaceOutliner *space_outliner = CTX_wm_space_outliner(C);

  /* check for invalid states */
  if (space_outliner == nullptr) {
    return OPERATOR_CANCELLED;
  }

  /* recursively go into tree, adding selected items */
  do_outliner_drivers_editop(space_outliner, op->reports, DRIVERS_EDITMODE_ADD);

  /* send notifiers */
  WM_event_add_notifier(C, NC_ANIMATION | ND_FCURVES_ORDER, nullptr); /* XXX */

  return OPERATOR_FINISHED;
}

void OUTLINER_OT_drivers_add_selected(wmOperatorType *ot)
{
  /* api callbacks */
  ot->idname = "OUTLINER_OT_drivers_add_selected";
  ot->name = "Add Drivers for Selected";
  ot->description = "Add drivers to selected items";

  /* api callbacks */
  ot->exec = outliner_drivers_addsel_exec;
  ot->poll = ed_operator_outliner_datablocks_active;

  /* flags */
  ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Driver Remove Operator
 * \{ */

static int outliner_drivers_deletesel_exec(bContext *C, wmOperator *op)
{
  SpaceOutliner *space_outliner = CTX_wm_space_outliner(C);

  /* check for invalid states */
  if (space_outliner == nullptr) {
    return OPERATOR_CANCELLED;
  }

  /* recursively go into tree, adding selected items */
  do_outliner_drivers_editop(space_outliner, op->reports, DRIVERS_EDITMODE_REMOVE);

  /* send notifiers */
  WM_event_add_notifier(C, ND_KEYS, nullptr); /* XXX */

  return OPERATOR_FINISHED;
}

void OUTLINER_OT_drivers_delete_selected(wmOperatorType *ot)
{
  /* identifiers */
  ot->idname = "OUTLINER_OT_drivers_delete_selected";
  ot->name = "Delete Drivers for Selected";
  ot->description = "Delete drivers assigned to selected items";

  /* api callbacks */
  ot->exec = outliner_drivers_deletesel_exec;
  ot->poll = ed_operator_outliner_datablocks_active;

  /* flags */
  ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Keying-Set Internal Utilities
 * \{ */

/**
 * Keying-Set Operations
 *
 * These operators are only available in data-browser mode for now, as
 * they depend on having RNA paths and/or hierarchies available.
 */
enum {
  KEYINGSET_EDITMODE_ADD = 0,
  KEYINGSET_EDITMODE_REMOVE,
} /*eKeyingSet_EditModes*/;

/* Find the 'active' KeyingSet, and add if not found (if adding is allowed). */
/* TODO: should this be an API func? */
static KeyingSet *verify_active_keyingset(Scene *scene, short add)
{
  KeyingSet *ks = nullptr;

  /* sanity check */
  if (scene == nullptr) {
    return nullptr;
  }

  /* try to find one from scene */
  if (scene->active_keyingset > 0) {
    ks = static_cast<KeyingSet *>(BLI_findlink(&scene->keyingsets, scene->active_keyingset - 1));
  }

  /* Add if none found */
  /* XXX the default settings have yet to evolve. */
  if ((add) && (ks == nullptr)) {
    ks = BKE_keyingset_add(&scene->keyingsets, nullptr, nullptr, KEYINGSET_ABSOLUTE, 0);
    scene->active_keyingset = BLI_listbase_count(&scene->keyingsets);
  }

  return ks;
}

/* Iterate over tree, finding and working on selected items */
static void do_outliner_keyingset_editop(SpaceOutliner *space_outliner,
                                         KeyingSet *ks,
                                         const short mode)
{
  tree_iterator::all_open(*space_outliner, [&](TreeElement *te) {
    TreeStoreElem *tselem = TREESTORE(te);

    /* if item is selected, perform operation */
    if (!(tselem->flag & TSE_SELECTED)) {
      return;
    }

    ID *id = nullptr;
    char *path = nullptr;
    int array_index = 0;
    short flag = 0;
    short groupmode = KSP_GROUP_KSNAME;

    /* check if RNA-property described by this selected element is an animatable prop */
    const TreeElementRNACommon *te_rna = tree_element_cast<TreeElementRNACommon>(te);
    PointerRNA ptr = te_rna->getPointerRNA();
    if (te_rna && te_rna->getPropertyRNA() &&
        RNA_property_animateable(&ptr, te_rna->getPropertyRNA())) {
      /* get id + path + index info from the selected element */
      tree_element_to_path(te, tselem, &id, &path, &array_index, &flag, &groupmode);
    }

    /* only if ID and path were set, should we perform any actions */
    if (id && path) {
      /* action depends on mode */
      switch (mode) {
        case KEYINGSET_EDITMODE_ADD: {
          /* add a new path with the information obtained (only if valid) */
          /* TODO: what do we do with group name?
           * for now, we don't supply one, and just let this use the KeyingSet name */
          BKE_keyingset_add_path(ks, id, nullptr, path, array_index, flag, groupmode);
          ks->active_path = BLI_listbase_count(&ks->paths);
          break;
        }
        case KEYINGSET_EDITMODE_REMOVE: {
          /* find the relevant path, then remove it from the KeyingSet */
          KS_Path *ksp = BKE_keyingset_find_path(ks, id, nullptr, path, array_index, groupmode);

          if (ksp) {
            /* free path's data */
            BKE_keyingset_free_path(ks, ksp);

            ks->active_path = 0;
          }
          break;
        }
      }

      /* free path, since it had to be generated */
      MEM_freeN(path);
    }
  });
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Keying-Set Add Operator
 * \{ */

static int outliner_keyingset_additems_exec(bContext *C, wmOperator *op)
{
  SpaceOutliner *space_outliner = CTX_wm_space_outliner(C);
  Scene *scene = CTX_data_scene(C);
  KeyingSet *ks = verify_active_keyingset(scene, 1);

  /* check for invalid states */
  if (ks == nullptr) {
    BKE_report(op->reports, RPT_ERROR, "Operation requires an active keying set");
    return OPERATOR_CANCELLED;
  }
  if (space_outliner == nullptr) {
    return OPERATOR_CANCELLED;
  }

  /* recursively go into tree, adding selected items */
  do_outliner_keyingset_editop(space_outliner, ks, KEYINGSET_EDITMODE_ADD);

  /* send notifiers */
  WM_event_add_notifier(C, NC_SCENE | ND_KEYINGSET, nullptr);

  return OPERATOR_FINISHED;
}

void OUTLINER_OT_keyingset_add_selected(wmOperatorType *ot)
{
  /* identifiers */
  ot->idname = "OUTLINER_OT_keyingset_add_selected";
  ot->name = "Keying Set Add Selected";
  ot->description = "Add selected items (blue-gray rows) to active Keying Set";

  /* api callbacks */
  ot->exec = outliner_keyingset_additems_exec;
  ot->poll = ed_operator_outliner_datablocks_active;

  /* flags */
  ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Keying-Set Remove Operator
 * \{ */

static int outliner_keyingset_removeitems_exec(bContext *C, wmOperator * /*op*/)
{
  SpaceOutliner *space_outliner = CTX_wm_space_outliner(C);
  Scene *scene = CTX_data_scene(C);
  KeyingSet *ks = verify_active_keyingset(scene, 1);

  /* check for invalid states */
  if (space_outliner == nullptr) {
    return OPERATOR_CANCELLED;
  }

  /* recursively go into tree, adding selected items */
  do_outliner_keyingset_editop(space_outliner, ks, KEYINGSET_EDITMODE_REMOVE);

  /* send notifiers */
  WM_event_add_notifier(C, NC_SCENE | ND_KEYINGSET, nullptr);

  return OPERATOR_FINISHED;
}

void OUTLINER_OT_keyingset_remove_selected(wmOperatorType *ot)
{
  /* identifiers */
  ot->idname = "OUTLINER_OT_keyingset_remove_selected";
  ot->name = "Keying Set Remove Selected";
  ot->description = "Remove selected items (blue-gray rows) from active Keying Set";

  /* api callbacks */
  ot->exec = outliner_keyingset_removeitems_exec;
  ot->poll = ed_operator_outliner_datablocks_active;

  /* flags */
  ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Purge Orphan Data-Blocks Operator
 * \{ */

static bool ed_operator_outliner_id_orphans_active(bContext *C)
{
  ScrArea *area = CTX_wm_area(C);
  if (area != nullptr && area->spacetype == SPACE_OUTLINER) {
    SpaceOutliner *space_outliner = CTX_wm_space_outliner(C);
    return (space_outliner->outlinevis == SO_ID_ORPHANS);
  }
  return true;
}

static int outliner_orphans_purge_invoke(bContext *C, wmOperator *op, const wmEvent * /*event*/)
{
  Main *bmain = CTX_data_main(C);
  int num_tagged[INDEX_ID_MAX] = {0};

  const bool do_local_ids = RNA_boolean_get(op->ptr, "do_local_ids");
  const bool do_linked_ids = RNA_boolean_get(op->ptr, "do_linked_ids");
  const bool do_recursive_cleanup = RNA_boolean_get(op->ptr, "do_recursive");

  /* Tag all IDs to delete. */
  BKE_lib_query_unused_ids_tag(
      bmain, LIB_TAG_DOIT, do_local_ids, do_linked_ids, do_recursive_cleanup, num_tagged);

  RNA_int_set(op->ptr, "num_deleted", num_tagged[INDEX_ID_NULL]);

  if (num_tagged[INDEX_ID_NULL] == 0) {
    BKE_report(op->reports, RPT_INFO, "No orphaned data-blocks to purge");
    return OPERATOR_CANCELLED;
  }

  DynStr *dyn_str = BLI_dynstr_new();
  BLI_dynstr_appendf(dyn_str, "Purging %d unused data-blocks (", num_tagged[INDEX_ID_NULL]);
  bool is_first = true;
  for (int i = 0; i < INDEX_ID_MAX - 2; i++) {
    if (num_tagged[i] != 0) {
      if (!is_first) {
        BLI_dynstr_append(dyn_str, ", ");
      }
      else {
        is_first = false;
      }
      BLI_dynstr_appendf(dyn_str,
                         "%d %s",
                         num_tagged[i],
                         TIP_(BKE_idtype_idcode_to_name_plural(BKE_idtype_idcode_from_index(i))));
    }
  }
  BLI_dynstr_append(dyn_str, TIP_("). Click here to proceed..."));

  char *message = BLI_dynstr_get_cstring(dyn_str);
  int ret = WM_operator_confirm_message(C, op, message);

  MEM_freeN(message);
  BLI_dynstr_free(dyn_str);
  return ret;
}

static int outliner_orphans_purge_exec(bContext *C, wmOperator *op)
{
  Main *bmain = CTX_data_main(C);
  ScrArea *area = CTX_wm_area(C);
  SpaceOutliner *space_outliner = CTX_wm_space_outliner(C);
  int num_tagged[INDEX_ID_MAX] = {0};

  if ((num_tagged[INDEX_ID_NULL] = RNA_int_get(op->ptr, "num_deleted")) == 0) {
    const bool do_local_ids = RNA_boolean_get(op->ptr, "do_local_ids");
    const bool do_linked_ids = RNA_boolean_get(op->ptr, "do_linked_ids");
    const bool do_recursive_cleanup = RNA_boolean_get(op->ptr, "do_recursive");

    /* Tag all IDs to delete. */
    BKE_lib_query_unused_ids_tag(
        bmain, LIB_TAG_DOIT, do_local_ids, do_linked_ids, do_recursive_cleanup, num_tagged);

    if (num_tagged[INDEX_ID_NULL] == 0) {
      BKE_report(op->reports, RPT_INFO, "No orphaned data-blocks to purge");
      return OPERATOR_CANCELLED;
    }
  }

  BKE_id_multi_tagged_delete(bmain);

  BKE_reportf(op->reports, RPT_INFO, "Deleted %d data-block(s)", num_tagged[INDEX_ID_NULL]);

  /* XXX: tree management normally happens from draw_outliner(), but when
   *      you're clicking to fast on Delete object from context menu in
   *      outliner several mouse events can be handled in one cycle without
   *      handling notifiers/redraw which leads to deleting the same object twice.
   *      cleanup tree here to prevent such cases. */
  if ((area != nullptr) && (area->spacetype == SPACE_OUTLINER)) {
    outliner_cleanup_tree(space_outliner);
  }

  DEG_relations_tag_update(bmain);
  WM_event_add_notifier(C, NC_ID | NA_REMOVED, nullptr);
  /* Force full redraw of the UI. */
  WM_main_add_notifier(NC_WINDOW, nullptr);

  return OPERATOR_FINISHED;
}

void OUTLINER_OT_orphans_purge(wmOperatorType *ot)
{
  /* identifiers */
  ot->idname = "OUTLINER_OT_orphans_purge";
  ot->name = "Purge All";
  ot->description = "Clear all orphaned data-blocks without any users from the file";

  /* callbacks */
  ot->invoke = outliner_orphans_purge_invoke;
  ot->exec = outliner_orphans_purge_exec;
  ot->poll = ed_operator_outliner_id_orphans_active;

  /* flags */
  ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;

  /* properties */
  PropertyRNA *prop = RNA_def_int(ot->srna, "num_deleted", 0, 0, INT_MAX, "", "", 0, INT_MAX);
  RNA_def_property_flag(prop, (PropertyFlag)(PROP_SKIP_SAVE | PROP_HIDDEN));

  RNA_def_boolean(ot->srna,
                  "do_local_ids",
                  true,
                  "Local Data-blocks",
                  "Include unused local data-blocks into deletion");
  RNA_def_boolean(ot->srna,
                  "do_linked_ids",
                  true,
                  "Linked Data-blocks",
                  "Include unused linked data-blocks into deletion");

  RNA_def_boolean(ot->srna,
                  "do_recursive",
                  false,
                  "Recursive Delete",
                  "Recursively check for indirectly unused data-blocks, ensuring that no orphaned "
                  "data-blocks remain after execution");
}

/** \} */

}  // namespace blender::ed::outliner