import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.Control;
import javafx.scene.control.Label;
import javafx.scene.layout.HBox;
import javafx.scene.layout.VBox;
import javafx.scene.paint.Color;
import javafx.scene.shape.Circle;
import javafx.stage.Stage;

public class MultilineLabelInHboxTest extends Application {

  public static final int CIRCLE_RADIUS = 20;

  public static void main(String[] args) {
    Application.launch(args);
  }
  
  @Override
  public void start(Stage primaryStage) {
    primaryStage.setTitle("Multi-line Label in HBox Test");
    
    System.out.println("HBox 1 containing Label 1 is the broken one");

    // create some sample text to display
    final String seed = "Every good boy deserves fruit;";
    final StringBuilder sb = new StringBuilder();
    for (int i = 0; i < 10; i++) sb.append(seed);
    final String testString = sb.toString();

    // create a HBox with a circle and a label inside (will not be sized as expected, label will be sized to the circles height).
    Label brokenLabel = new HeightReportingLabel(testString);
    brokenLabel.setWrapText(true);
    HBox brokenBox = makeBox(brokenLabel, Color.RED);
    brokenBox.setStyle("-fx-background-color: wheat");

    // create a HBox with a circle and a label inside (will be sized as expected, label will be sized to all of it's text is displayed).
    Label okLabel = new HeightReportingLabel(testString);
    okLabel.setWrapText(true);
    HBox okBox = makeBox(okLabel, Color.GREEN);
    okBox.setStyle("-fx-background-color: lightgray");

    // place HBoxes in a VBox so that they get re-sized.
    final VBox vbox = new VBox();
    vbox.getChildren().addAll(brokenBox, okBox);

    Scene scene = new Scene(vbox, 400, 400);

    // manually overriding the label's computed width somewhat strangely allows the layout manager to correctly calculate the label's preferred height.
    okLabel.prefWidthProperty().bind(scene.widthProperty().subtract(CIRCLE_RADIUS * 2).subtract(5));    // subtract the width of the circle and hbox spacing.

    // display the scene.
    primaryStage.setScene(scene);
    primaryStage.show();
  }

  private HBox makeBox(Label label, Color circleColor) {
    final HBox hbox = new HeightReportingHBox();
    hbox.setSpacing(5);
    hbox.setFillHeight(false);  // keep children at their preferred size, don't try to resize them to fill the hbox.
    hbox.getChildren().addAll(
      new Circle(CIRCLE_RADIUS, CIRCLE_RADIUS, CIRCLE_RADIUS, circleColor),
      label
    );
    return hbox;
  }
}

class HeightReportingHBox extends HBox {
  static int nBoxes = 1;
  final int boxNum = nBoxes++;
  double priorPrefHeight = Control.USE_COMPUTED_SIZE;
  @Override
  protected double computePrefHeight(double v) {
    double h =  super.computePrefHeight(v);
    if (h != priorPrefHeight) {
      priorPrefHeight = h;
      System.out.println("HBox " + boxNum + " Computed Pref Height: " + h + " for width " + v);
    }
    return h;
  }
}

class HeightReportingLabel extends Label {
  static int nLabels = 1;
  final int labelNum = nLabels++;
  double priorPrefHeight = Control.USE_COMPUTED_SIZE;

  HeightReportingLabel(String s) {
    super(s);
  }

  @Override
  protected double computePrefHeight(double v) {
    double h =  super.computePrefHeight(v);
    if (h != priorPrefHeight) {
      priorPrefHeight = h;
      System.out.println("Label " + labelNum + " Computed Pref Height: " + h + " for width " + v);
    }
    return h;
  }
}