sclass G22ManagedTextEditor<A extends G22Text> is Swingable {

  settable G22Utils g22utils;

  settable S noScriptSelectedMsg = "Please select or create a text to edit it";

  gettable A script;

  transient SingleComponentPanel scp;

  transient JSyntaxTextFileEditor[] ides;

  transient JExtendedTabbedPane tabs;

  transient JButton btnSave, btnDiscardChanges, btnClearForAutoRun;

  transient CollapsibleLeftPanel collapsibleResultPanel;

  transient G22ScriptResultPanel resultPanel;

  transient Mode lastVisibleMode;

  abstract class Mode {

    G22ScriptMode modeEnum;

    S name;

    gettable bool editable;

    *(G22ScriptMode *modeEnum, S *name, bool *editable) {}

    simplyCached abstract IVarWithNotify<S> scriptVar();

    void addButtons(JPanel panel) {}

    toString { ret name; }

    S tabName() { ret scriptVar().has() ? name : "Not " + firstToLower(name); }

  }

  class ModeClearedForAutoRun > Mode {

    *() { super(G22ScriptMode.autoRunnable, "Cleared for auto-run", false); }

    IVarWithNotify<S> scriptVar_load() {

      var var = new VirtualVar<S>(

        -> script.codeForAutoRun(),

        null /*text -> script.setClearedForAutoRun(text == null ?: new ClearForAutoRun(text))*/);

      addWeakChangeListener(script.varClearedForAutoRun(), var);

      ret var;

    }

    void addButtons(JPanel panel) {

      panel.add(jbutton("Forget auto-run code", rThread forgetAutoRunCode));

    }

  }

  class ModeSaved > Mode {

    *() { super(G22ScriptMode.saved, "Saved", false); }

    IVarWithNotify<S> scriptVar_load() {

      ret getterVarOnly(script.varText());

    }

    void addButtons(JPanel panel) {

      panel.add(btnClearForAutoRun = jbutton("Clear for auto-run", rThread clearForAutoRun));

      panel.add(jbutton("Forget code", rThread forgetSaved));

    }

  }

  class ModeEdit > Mode {

    *() { super(G22ScriptMode.edit, "Edit", true); }

    IVarWithNotify<S> scriptVar_load() {

      var var = new VirtualVar<S>(

        -> script.textForEditing(),

        text -> script.receiveEditingText(text)

      );

      addWeakChangeListener(script, var);

      ret var;

    }

    void addButtons(JPanel panel) {

      panel.add(btnSave = jbutton("Save", rThread saveEdit));

      panel.add(btnDiscardChanges = jbutton("Discard changes", rThread discardEdit));

    }

  }

  transient new ModeEdit modeEdit;

  transient new ModeSaved modeSaved;

  transient L<Mode> modes = ll(

    modeEdit,

    modeSaved

  );

  *(G22Utils *g22utils) {}

  cachedVisualize {

    ides = new JSyntaxTextFileEditor[l(modes)];

    if (scp == null) scp = singleComponentPanel();

    loadScript(script);

    ret scp;

  }

  void setScript(A script) {

    if (this.script != script)

      if (this.script != null)

        fail("Can't set script after initialisation");

      else

        loadScript(script);

  }

  void loadScript(A script) {

    this.script = script;

    if (scp == null) ret;

    if (script == null)

      scp.set(jcenteredlabel(noScriptSelectedMsg()));

    else {

      tabs = jExtendedTabs();

      resultPanel = new G22ScriptResultPanel;

      collapsibleResultPanel = new CollapsibleLeftPanel(false, "Output", resultPanel.visualize(), tabs.visualize());

      collapsibleResultPanel.sidePanelMargins = c -> withTopAndLeftMargin(c);

      // This places tabs vertically at the right hand side...

      // (not what we want)

      //setTabPlacement(JTabbedPane.RIGHT, tabs);

      for (int i, Mode mode : unpair iterateWithIndex(modes)) {

        var ide = ides[i] = new JSyntaxTextFileEditor;

        ide.withResultPanel(false);

        ide.resultPanel = resultPanel;

        ide.collapsibleResultPanel = collapsibleResultPanel;

        ide.wrapSection = c -> wrapEditorSection(mode, c);

        ide.newCompileResult = -> script.newCompileResult();

        ide.makeParser = -> script.makeParser();

        modifyIDE(ide);

        var varScript = mode.scriptVar();

        ide.lvScript(varWithNotifyToLiveValue(S.class, varScript));

        addTab(tabs, str(mode));

        mode.addButtons(ide.buttons());

        ide.visualize();

        ide.setEditable(mode.editable());

        varScript.onChangeAndNow(text ->

          setTab(tabs, i, text == null ? jcenteredlabel("Empty") : wrapIDE(mode, ide)));

        ide.popDownButton.onFillingMenu(menu ->

          addMenuItem(menu, "Show History", rThread showHistory));

      }

      script.onChangeAndNow(r {

        for (int i, Mode mode : unpair iterateWithIndex(modes))

          setTabTitle(tabs, i, mode.tabName());

        setEnabled(script.isEditing(), btnSave, btnDiscardChanges);

        setEnabled(btnClearForAutoRun, script.isSavedDistinctFromAutoRunVersion());

        for (ide : ides)

          ide.sectionTitle(str(script));

      });

      onTabSelectedAndNow(tabs, -> {

        var mode = visibleMode();

        if (lastVisibleMode != null && lastVisibleMode != mode) {

          // Move selected IDE to same position as previous IDE

          var lastIDE = ide(lastVisibleMode);

          var ide = visibleIDE();

          awtLater(0.5, -> {

            LineAndColumn lac = caretLineAndCol(lastIDE.textArea());

            moveCaretToLineAndCol(ide.textArea(), lac);

            setEnclosingViewPosition(ide.textArea(), enclosingViewPosition(lastIDE.textArea()));

            focus(ide.textArea());

          });

        }

        lastVisibleMode = mode;

        tabs.setComponentBesideTabs(

          mode != modeEdit

            ? jfullcenter(withRightMargin(jbutton("Edit script", -> setMode(modeEdit))))

            : null);

      });

      setMode(script.isEditing() ? modeEdit : modeSaved);

      scp.set(collapsibleResultPanel);

    }

  }

  swappable JComponent wrapEditorSection(Mode mode, JComponent editorSection) {

    /*if (mode != modeEdit)

      ret withTopMargin(northAndCenterWithMargin(

        withRightMargin(jline(jbutton("Edit script", -> setMode(modeEdit)))),

        editorSection));

    else*/

      ret editorSection;

  }

  swappable JComponent wrapIDE(Mode mode, JSyntaxTextFileEditor ide) {

    ret ide.visualize();

  }

  void saveEdit {

    script.completeEdit();

    setMode(modeSaved);

  }

  JSyntaxTextFileEditor ide(Mode mode) {

    if (ides == null) visualize();

    ret _get(ides, indexOf(modes, mode));

  }

  RSyntaxTextArea visibleTextArea() {

    var ide = visibleIDE();

    ret ide?.textArea();

  }

  void setMode(Mode mode) {

    var caretPos = caretLineAndCol(visibleTextArea());

    printVars("setMode", +caretPos);

    selectTab(tabs, indexOf(modes, mode));

    var ide = visibleIDE();

    printVars("setMode", +ide, mode := visibleMode());

    ide.goToPosition_noFocus(caretPos);

    if (mode == modeEdit)

      focus(visibleTextArea());

  }

  // get currently visible mode

  Mode visibleMode() {

    ret _get(modes, indexOfSelectedTab(tabs));

  }

  JSyntaxTextFileEditor visibleIDE() {

    ret ide(visibleMode());

  }

  void discardEdit {

    setMode(modeSaved);

    script.discardEdit();

  }

  void forgetSaved {

    script.setTextWithHistory(null);

  }

  void clearForAutoRun {

    script.clearForAutoRun();

    setMode(modeClearedForAutoRun);

  }

  void forgetAutoRunCode {

    script.forgetAutoRunCode();

  }

  private void selfTest_impl {

    new G22Text script;

    setScript((A) script);

    ide(modeEdit).setText("hello");

    assertEqualsVerbose(null, script.text());

    assertEqualsVerbose("hello", script.editedText());

    saveEdit();

    assertEqualsVerbose("hello", script.text());

    assertEqualsVerbose(null, script.editedText());

  }

  static void selfTest(G22Utils g22utils) {

    new G22ManagedTextEditor(g22utils).selfTest_impl();

  }

  void showHistory {

    showText("Edit history of " + script, loadTextFile(script.historyFile()));

  }

  void goToPositionInAllModes(LineAndColumn lac) {

    for (ide : ides)

      ide?.goToPosition_noFocus(lac);

  }

}