// now a concept to allow for persistence of selected item

abstract concept G22CRUDAndDetailPanel<A extends ConceptWithChangeListeners> extends ConceptWithChangeListeners is Swingable, IUnstructured {

  new Ref<A> selected;

  CollapsibleNorthPanel collapsiblePanel = new(true);

  transient settable G22Utils g22utils;

  transient SimpleCRUD_v2<A> crud;

  transient SingleComponentPanel scpDetail;

  abstract SimpleCRUD_v2<A> makeCRUD();

  // create detail view in background thread

  transient RSTVar<A> handleSelectionVar = new(l1 handleSelection_impl);

  // a is not null

  // override me

  JComponent makeDetailView(A a) {

    ret jTodo();

  }

  { _doneLoading2(); }

  public void _doneLoading2 :: after {

    // Save vertical space

    collapsiblePanel.wrappedSideComponent = -> centerAndEastWithMargin(collapsiblePanel.sideComponent(), vstack(collapsiblePanel.collapseButton()));

  }

  cachedVisualize {

    crud = makeCRUD();

    putCRUDButtonsNextToSearchBar(crud);

    scpDetail = singleComponentPanel();

    if (collapsiblePanel.expanded)

      selectAfterUpdate(selected!);

    var crudVis = crud.visualize();

    crudVisualized();

    handleSelectionVar.forceUpdate();

    crud.onSelectionChanged(-> {

      var selected = crud.selected();

      this.selected.set(selected);

      handleSelectionVar.set(selected);

    });

    /*ret jvsplit(

      jCenteredSection(crud.entityNamePlural(), crudVis),

      scpDetail);*/

    collapsiblePanel.defaultSplitPoint(0.3);

    collapsiblePanel.init(

      crud.entityName() + " List",

      jCenteredSection(crud.entityNamePlural(), crudVis),

      scpDetail);

    collapsiblePanel.onChange(l0 change);

    ret collapsiblePanel.visualize();

  }

  void handleSelection_impl(A selected) {

    if (selected == null)

      scpDetail.set(emptyDetailView());

    else {

      var view = makeDetailView(selected);

      var lvTitle = liveValue_hasChangeListeners(

        selected,

        -> detailTitle(selected));

      scpDetail.set(jCenteredRaisedBoldLiveValueSection(lvTitle, view));

    }

  }

  // item is not null

  swappable S detailTitle(A item) {

    ret appendPrefix(crud.entityName() + " " + item.id + ": ", str(item));

  }

  JComponent emptyDetailView() {

    ret jGazelleLogo();

  }

  // override me

  void crudVisualized {}

  void addCountToEnclosingTab(bool b) {

    crud.addCountToEnclosingTab(b);

  }

  void updateCount {

    crud.update();

  }

  void edit aka setSelected(A A) {

    var searcher = crud().tableSearcher();

    searcher?.clearSearchField();

    crud().setSelected(A);

  }

  void selectAfterUpdate(A A) {

    crud.selectAfterUpdate(A);

  }

  SimpleCRUD_v2<A> crud() {

    visualize();

    ret crud;

  }

}