import javafx.application.Application;
import javafx.application.Platform;
import javafx.stage.Stage;
import javafx.stage.FileChooser;
import javafx.scene.control.TextArea;
import javafx.scene.layout.Pane;
import javafx.scene.Scene;
import javafx.event.EventHandler;
import javafx.scene.input.KeyEvent;

import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;
import java.util.ArrayList;

public class LeetCoder extends Application {

    ArrayList<String> chunks = new ArrayList<>();

    public void start(Stage stage) {
        lesFil(stage);

        TextArea area = new TextArea();
        area.setEditable(false);
        area.setPrefSize(600, 400);
        area.setOnKeyPressed(new EventHandler<KeyEvent>() {
            int i = 0;

            public void handle(KeyEvent e) {
                if (i >= chunks.size()) i = 0;
                String nyTekst = area.getText() + " " + chunks.get(i);
                area.setText(nyTekst);
                area.setScrollTop(Double.MAX_VALUE);
                i++;
            }

        });

        Pane root = new Pane(area);

        stage.setScene(new Scene(root));
        stage.show();
    }

    private void lesFil(Stage stage) {
        FileChooser fs = new FileChooser();
        File fil = fs.showOpenDialog(stage);

        Scanner sc = null;
        try {
            sc = new Scanner(fil);
        } catch (FileNotFoundException fnfe) {
            Platform.exit();
        }

        while (sc.hasNextLine()) {
            String[] biter = sc.nextLine().split(" ");
            for (String bit : biter) chunks.add(bit);
            chunks.add("\n");
        }
    }
}