private void insertLookupString(LookupElement item, final int prefix) {
    final String lookupString = getCaseCorrectedLookupString(item);

    final Editor hostEditor = InjectedLanguageUtil.getTopLevelEditor(myEditor);
    hostEditor
        .getCaretModel()
        .runForEachCaret(
            new CaretAction() {
              @Override
              public void perform(Caret caret) {
                EditorModificationUtil.deleteSelectedText(hostEditor);
                final int caretOffset = hostEditor.getCaretModel().getOffset();
                int lookupStart = Math.max(caretOffset - prefix, 0);

                int len = hostEditor.getDocument().getTextLength();
                LOG.assertTrue(
                    lookupStart >= 0 && lookupStart <= len,
                    "ls: "
                        + lookupStart
                        + " caret: "
                        + caretOffset
                        + " prefix:"
                        + prefix
                        + " doc: "
                        + len);
                LOG.assertTrue(
                    caretOffset >= 0 && caretOffset <= len, "co: " + caretOffset + " doc: " + len);

                hostEditor.getDocument().replaceString(lookupStart, caretOffset, lookupString);

                int offset = lookupStart + lookupString.length();
                hostEditor.getCaretModel().moveToOffset(offset);
                hostEditor.getSelectionModel().removeSelection();
              }
            });

    myEditor.getScrollingModel().scrollToCaret(ScrollType.RELATIVE);
  }
  public boolean performGuardedChange(Runnable change) {
    checkValid();
    assert !myChangeGuard : "already in change";

    myEditor.getDocument().startGuardedBlockChecking();
    myChangeGuard = true;
    boolean result;
    try {
      result = myOffsets.performGuardedChange(change);
    } finally {
      myEditor.getDocument().stopGuardedBlockChecking();
      myChangeGuard = false;
    }
    if (!result || myDisposed) {
      hide();
      return false;
    }
    if (isVisible()) {
      HintManagerImpl.updateLocation(this, myEditor, myUi.calculatePosition().getLocation());
    }
    checkValid();
    return true;
  }
        @Override
        protected void processKeyEvent(@NotNull final KeyEvent e) {
          final char keyChar = e.getKeyChar();
          if (keyChar == KeyEvent.VK_ENTER || keyChar == KeyEvent.VK_TAB) {
            IdeFocusManager.getInstance(myProject)
                .requestFocus(myEditor.getContentComponent(), true)
                .doWhenDone(
                    new Runnable() {
                      @Override
                      public void run() {
                        IdeEventQueue.getInstance().getKeyEventDispatcher().dispatchKeyEvent(e);
                      }
                    });
            return;
          }

          super.processKeyEvent(e);
        }
  public boolean showLookup() {
    ApplicationManager.getApplication().assertIsDispatchThread();
    checkValid();
    LOG.assertTrue(!myShown);
    myShown = true;
    myStampShown = System.currentTimeMillis();

    if (ApplicationManager.getApplication().isUnitTestMode()) return true;

    if (!myEditor.getContentComponent().isShowing()) {
      hide();
      return false;
    }

    myAdComponent.showRandomText();

    myUi = new LookupUi(this, myAdComponent, myList, myProject);
    myUi.setCalculating(myCalculating);
    Point p = myUi.calculatePosition().getLocation();
    try {
      HintManagerImpl.getInstanceImpl()
          .showEditorHint(
              this,
              myEditor,
              p,
              HintManager.HIDE_BY_ESCAPE | HintManager.UPDATE_BY_SCROLLING,
              0,
              false,
              HintManagerImpl.createHintHint(myEditor, p, this, HintManager.UNDER)
                  .setAwtTooltip(false));
    } catch (Exception e) {
      LOG.error(e);
    }

    if (!isVisible() || !myList.isShowing()) {
      hide();
      return false;
    }

    DaemonCodeAnalyzer.getInstance(myProject).disableUpdateByTimer(this);

    return true;
  }
  private void addListeners() {
    myEditor
        .getDocument()
        .addDocumentListener(
            new DocumentAdapter() {
              @Override
              public void documentChanged(DocumentEvent e) {
                if (!myChangeGuard && !myFinishing) {
                  hide();
                }
              }
            },
            this);

    final CaretListener caretListener =
        new CaretAdapter() {
          @Override
          public void caretPositionChanged(CaretEvent e) {
            if (!myChangeGuard && !myFinishing) {
              hide();
            }
          }
        };
    final SelectionListener selectionListener =
        new SelectionListener() {
          @Override
          public void selectionChanged(final SelectionEvent e) {
            if (!myChangeGuard && !myFinishing) {
              hide();
            }
          }
        };
    final EditorMouseListener mouseListener =
        new EditorMouseAdapter() {
          @Override
          public void mouseClicked(EditorMouseEvent e) {
            e.consume();
            hide();
          }
        };

    myEditor.getCaretModel().addCaretListener(caretListener);
    myEditor.getSelectionModel().addSelectionListener(selectionListener);
    myEditor.addEditorMouseListener(mouseListener);
    Disposer.register(
        this,
        new Disposable() {
          @Override
          public void dispose() {
            myEditor.getCaretModel().removeCaretListener(caretListener);
            myEditor.getSelectionModel().removeSelectionListener(selectionListener);
            myEditor.removeEditorMouseListener(mouseListener);
          }
        });

    JComponent editorComponent = myEditor.getContentComponent();
    if (editorComponent.isShowing()) {
      Disposer.register(
          this,
          new UiNotifyConnector(
              editorComponent,
              new Activatable() {
                @Override
                public void showNotify() {}

                @Override
                public void hideNotify() {
                  hideLookup(false);
                }
              }));
    }

    myList.addListSelectionListener(
        new ListSelectionListener() {
          private LookupElement oldItem = null;

          @Override
          public void valueChanged(@NotNull ListSelectionEvent e) {
            if (!myUpdating) {
              final LookupElement item = getCurrentItem();
              fireCurrentItemChanged(oldItem, item);
              oldItem = item;
            }
          }
        });

    new ClickListener() {
      @Override
      public boolean onClick(@NotNull MouseEvent e, int clickCount) {
        setFocusDegree(FocusDegree.FOCUSED);
        markSelectionTouched();

        if (clickCount == 2) {
          CommandProcessor.getInstance()
              .executeCommand(
                  myProject,
                  new Runnable() {
                    @Override
                    public void run() {
                      finishLookup(NORMAL_SELECT_CHAR);
                    }
                  },
                  "",
                  null);
        }
        return true;
      }
    }.installOn(myList);
  }
 @Override
 @Nullable
 public PsiFile getPsiFile() {
   return PsiDocumentManager.getInstance(myProject).getPsiFile(myEditor.getDocument());
 }