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package org.fxmisc.richtext.demo;

import javafx.application.Application;
import javafx.event.ActionEvent;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.TextField;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;

import org.fxmisc.flowless.VirtualizedScrollPane;
import org.fxmisc.richtext.InlineCssTextArea;

import java.util.function.Consumer;
import java.util.function.Function;

/**
 * Name: ShowLineDemo
 * Description: .
 * 
 * Comment: ...
 * 
 * Copyright: Copyright (c) 2016-2019
 * Company: >StA-Soft<
 * @author StA
 * @version 1.0
 */

public class ShowLineDemo extends Application
{

  public static final int MIN_LINE_INDEX = 0;

  private class NumbersOnlyField extends TextField
  {

    NumbersOnlyField()
    {
      super();
      setOnKeyTyped(ke ->
      {
        String keyEventText = ke.getCharacter();
        if (Character.isDigit(keyEventText.charAt(0)))
        {
          if (getSelectedText().isEmpty())
          {
            appendText(keyEventText);
          }
          else
          {
            replaceText(getSelection(), keyEventText);
          }
        }
        ke.consume();
      });
    }

    public int getTextAsInt()
    {
      String text = getText();
      if (text.isEmpty())
      {
        setText(String.valueOf(MIN_LINE_INDEX));
        return MIN_LINE_INDEX;
      }
      else
      {
        return Integer.parseInt(text);
      }
    }

  }

  private final NumbersOnlyField field = new NumbersOnlyField();

  {
    field.setPromptText("Input a number to indicate which line you want to show");
  }

  @Override
  public void start(Stage primaryStage) throws Exception
  {
    StringBuilder sb = new StringBuilder();
    int max = 100;
    for (int i = 0; i < max; i++)
    {
      sb.append("Line Index: ").append(i).append("\n");
    }
    sb.append("Line Index: ").append(max);
    InlineCssTextArea area = new InlineCssTextArea(sb.toString());
    VirtualizedScrollPane vsPane = new VirtualizedScrollPane<>(area);

    Function clamp = i -> Math.max(0, Math.min(i, area.getLength() - 1));
    Button showInViewportButton = createButton("Show line somewhere in Viewport", ae ->
    {
      area.showParagraphInViewport(clamp.apply(field.getTextAsInt()));
    });
    Button showAtViewportTopButton = createButton("Show line at top of viewport", ae ->
    {
      area.showParagraphAtTop(clamp.apply(field.getTextAsInt()));
    });
    Button showAtViewportBottomButton = createButton("Show line at bottom of viewport", ae ->
    {
      area.showParagraphAtBottom(clamp.apply(field.getTextAsInt()));
    });

    VBox vbox = new VBox(field, showInViewportButton, showAtViewportTopButton, showAtViewportBottomButton);
    vbox.setAlignment(Pos.CENTER);

    BorderPane root = new BorderPane();
    root.setCenter(vsPane);
    root.setBottom(vbox);

    Scene scene = new Scene(root, 700, 500);
    primaryStage.setScene(scene);
    primaryStage.show();

  }

  private Button createButton(String text, Consumer handler)
  {
    Button b = new Button(text);
    b.setOnAction(ae ->
    {
      handler.accept(ae);
      field.requestFocus();
    });
    return b;
  }

}