Client.java

package org.discrypto.client;

import javafx.application.Platform;
import javafx.scene.control.ButtonBar;
import javafx.scene.control.ButtonType;
import javafx.scene.control.Dialog;
import lombok.Getter;
import lombok.Setter;
import org.discrypto.client.model.User;
import org.discrypto.client.screens.Screen;
import org.discrypto.client.screens.main.MainScreen;
import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.scene.Scene;
import javafx.stage.Stage;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.net.URL;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;

public class Client extends Application {

    private static final ExecutorService VIRTUAL_EXECUTOR
            = Executors.newVirtualThreadPerTaskExecutor();

    @Setter @Getter private static volatile User user;

    private static final File dataFolder;

    /* Use Main class */
    protected static void main(String[] args) {
        launch();
    }

    @Override
    public void start(Stage stage) throws Exception {
        validateDataFolder();

        MainScreen main = new MainScreen();
        main.stage = stage;
        openScreen(main);
    }

    public static Scene loadScene(String fxmlName) {
        return loadScene(fxmlName, null);
    }

    public static Scene loadScene(String fxmlName, Object controller) {
        try {
            FXMLLoader fxmlLoader = new FXMLLoader(getResource(fxmlName + ".fxml"));
            if(controller != null)
                fxmlLoader.setController(controller);
            return new Scene(fxmlLoader.load());
        } catch(IOException e) {
            throw new RuntimeException(e);
        }
    }

    public static void openScreen(Screen screen) {
        if(screen.stage == null)
            screen.stage = new Stage();

        screen.stage.setTitle(screen.getTitle());
        screen.stage.setScene(loadScene(screen.getFxml(), screen));

        screen.beforeShow();

        screen.stage.show();

        screen.afterShow();
    }

    public static void showMessageDialog(String dialogTitle, String messageText, String buttonText, ButtonBar.ButtonData buttonData) {
        Dialog<String> dialog = new Dialog<>();
        dialog.setTitle(dialogTitle);
        ButtonType type = new ButtonType(buttonText, buttonData);
        dialog.setContentText(messageText);
        dialog.getDialogPane().getButtonTypes().add(type);
        dialog.showAndWait();
    }

    public static URL getResource(String name) {
        return Client.class.getResource(name);
    }

    public static Future<?> submitVirtual(Runnable virtualThreadAction) {
        /* THIS ACTION WILL RUN ASYNCHRONOUSLY ON A NEW VIRTUAL THREAD. */
        return VIRTUAL_EXECUTOR.submit(virtualThreadAction);
    }

    private static void validateDataFolder() {
        try {
            if(!dataFolder.exists())
                throw new FileNotFoundException();
            if(!dataFolder.canRead())
                throw new IOException("read");
            if(!dataFolder.canWrite())
                throw new IOException("write");
        } catch(Exception e) {
            if(e instanceof FileNotFoundException) {
                /* fail-safe code in case user somehow gets here */
                showMessageDialog(
                        "Discrypto Trading Bot | Failed to find required path!",
                        "Please make sure the following path exists:\n\n" + dataFolder.getAbsolutePath(),
                        "OK",
                        ButtonBar.ButtonData.OK_DONE
                );
            } else {
                /* fail-safe code in case user somehow gets here */
                showMessageDialog(
                        "Discrypto Trading Bot | Failed to access required path!",
                        "Please make sure the following path is readable/writeable:\n\n" + dataFolder.getAbsolutePath() + "\n\n" + "You can also try running this program with admin privileges.",
                        "OK",
                        ButtonBar.ButtonData.OK_DONE
                );
            }
        }
    }

    static {
        String userHome = null;
        try {
            userHome = System.getProperty("user.home");
        } catch(Exception e) {
            /* ignored */
        }
        dataFolder = new File((userHome == null ? "~" : userHome) + File.separator + "Discrypto");
        try {
            if(!dataFolder.exists())
                dataFolder.mkdir();
        } catch(Exception e) {
            /* ignored */
        }
    }

}