import javafx.application.Application;
import javafx.stage.Stage;
import javafx.scene.Scene;
import javafx.scene.layout.VBox;
import javafx.scene.layout.HBox;
import javafx.scene.text.Font;
import javafx.scene.text.Text;
import javafx.geometry.Pos;
import javafx.scene.control.Button;
import javafx.scene.control.TextField;
import javafx.event.EventHandler;
import javafx.event.ActionEvent;

public class Kalkulator extends Application {

    // trenger tilgang til disse i KnappBehandler
    TextField tall1, tall2; // tallene
    TextField resultat; // svaret


    // indre klasse - handling som skal skje naar vi trykker paa knappene
    class KnappBehandler implements EventHandler<ActionEvent> {
        @Override
        public void handle(ActionEvent e) {
            Button trykket = (Button) e.getSource(); // knappen som ble trykket
            double tallInn1 = 0.0;
            double tallInn2 = 0.0;
            try {
                tallInn1 = Double.parseDouble(tall1.getText()); // leser inn tall
                tallInn2 = Double.parseDouble(tall2.getText()); // leser inn tall
            } catch (NumberFormatException eksept) {
                System.out.println("Ikke tall");
                return;
            }

            String operasjon = trykket.getText(); // hva staar paa knappePane
            double svar = 0.0;
            switch (operasjon) {
                case "+":
                    svar = tallInn1 + tallInn2;
                    break;
                case "-":
                    svar = tallInn1 - tallInn2;
                    break;
                case "x":
                    svar = tallInn1*tallInn2;
                    break;
                case "/":
                    svar = tallInn1/tallInn2;
                    break;
            }
            resultat.setText(" " + svar);
        }
    }

    @Override
    public void start(Stage teater) {
        VBox kulisser = new VBox();

        HBox tekstPane = new HBox();
        tekstPane.setAlignment(Pos.CENTER);

        tall1 = new TextField("tall1");
        tall2 = new TextField("tall2");

        tekstPane.getChildren().addAll(tall1, tall2);

        HBox knappePane = new HBox();
        knappePane.setAlignment(Pos.CENTER);

        Button plussKnapp = new Button("+");
        Button minusKnapp = new Button("-");
        Button gangeKnapp = new Button("x");
        Button deleKnapp = new Button("/");

        knappePane.getChildren().addAll(plussKnapp, minusKnapp,
                                            gangeKnapp, deleKnapp);

        KnappBehandler handling = new KnappBehandler();

        plussKnapp.setOnAction(handling);
        minusKnapp.setOnAction(handling);
        gangeKnapp.setOnAction(handling);
        deleKnapp.setOnAction(handling);

        resultat = new TextField("resultat");

        kulisser.getChildren().addAll(tekstPane, knappePane, resultat);

        teater.setTitle("Kalkulator");
        teater.setScene(new Scene(kulisser, 200, 100));
        teater.show();
    }

    public static void main(String[] args) {
        Application.launch(args);
    }

}