envoy/client/src/main/java/envoy/client/ui/controller/LoginScene.java

package envoy.client.ui.controller;

import java.io.FileNotFoundException;
import java.io.IOException;
import java.time.Instant;
import java.util.concurrent.TimeoutException;
import java.util.logging.Level;
import java.util.logging.Logger;

import javafx.application.Platform;
import javafx.fxml.FXML;
import javafx.scene.control.*;
import javafx.scene.control.Alert.AlertType;

import envoy.client.data.*;
import envoy.client.net.Client;
import envoy.client.net.WriteProxy;
import envoy.client.ui.*;
import envoy.data.LoginCredentials;
import envoy.data.User;
import envoy.data.User.UserStatus;
import envoy.event.EventBus;
import envoy.event.HandshakeRejection;
import envoy.exception.EnvoyException;
import envoy.util.Bounds;
import envoy.util.EnvoyLog;

/**
 * Project: <strong>envoy-client</strong><br>
 * File: <strong>LoginDialog.java</strong><br>
 * Created: <strong>03.04.2020</strong><br>
 *
 * @author Kai S. K. Engelbart
 * @author Maximilian K&auml;fer
 * @since Envoy Client v0.1-beta
 */
public final class LoginScene {

	@FXML
	private ClearableTextField userTextField;

	@FXML
	private PasswordField passwordField;

	@FXML
	private PasswordField repeatPasswordField;

	@FXML
	private Label repeatPasswordLabel;

	@FXML
	private CheckBox registerCheckBox;

	@FXML
	private Label connectionLabel;

	private Client			client;
	private LocalDB			localDB;
	private CacheMap		cacheMap;
	private SceneContext	sceneContext;

	private static final Logger			logger		= EnvoyLog.getLogger(LoginScene.class);
	private static final EventBus		eventBus	= EventBus.getInstance();
	private static final ClientConfig	config		= ClientConfig.getInstance();
	private static final Settings		settings	= Settings.getInstance();

	@FXML
	private void initialize() {
		connectionLabel.setText("Server: " + config.getServer() + ":" + config.getPort());

		// Show an alert after an unsuccessful handshake
		eventBus.register(HandshakeRejection.class, e -> Platform.runLater(() -> { new Alert(AlertType.ERROR, e.get()).showAndWait(); }));
	}

	/**
	 * Loads the login dialog using the FXML file {@code LoginDialog.fxml}.
	 *
	 * @param client       the client used to perform the handshake
	 * @param localDB      the local database used for offline login
	 * @param cacheMap     the map of all caches needed
	 * @param sceneContext the scene context used to initialize the chat scene
	 * @since Envoy Client v0.1-beta
	 */
	public void initializeData(Client client, LocalDB localDB, CacheMap cacheMap, SceneContext sceneContext) {
		this.client			= client;
		this.localDB		= localDB;
		this.cacheMap		= cacheMap;
		this.sceneContext	= sceneContext;

		// Prepare handshake
		localDB.loadIDGenerator();

		// Set initial cursor
		userTextField.requestFocus();

		// Perform automatic login if configured
		if (config.hasLoginCredentials())
			performHandshake(new LoginCredentials(config.getUser(), config.getPassword(), false, Startup.VERSION, loadLastSync(config.getUser())));
	}

	@FXML
	private void loginButtonPressed() {

		// Prevent registration with unequal passwords
		if (registerCheckBox.isSelected() && !passwordField.getText().equals(repeatPasswordField.getText())) {
			new Alert(AlertType.ERROR, "The entered password is unequal to the repeated one").showAndWait();
			repeatPasswordField.clear();
		} else if (!Bounds.isValidContactName(userTextField.getTextField().getText())) {
			new Alert(AlertType.ERROR, "The entered user name is not valid (" + Bounds.CONTACT_NAME_PATTERN + ")").showAndWait();
			userTextField.getTextField().clear();
		} else performHandshake(new LoginCredentials(userTextField.getTextField().getText(), passwordField.getText(), registerCheckBox.isSelected(),
				Startup.VERSION, loadLastSync(userTextField.getTextField().getText())));
	}

	@FXML
	private void offlineModeButtonPressed() {
		attemptOfflineMode(
				new LoginCredentials(userTextField.getTextField().getText(), passwordField.getText(), false, Startup.VERSION, localDB.getLastSync()));
	}

	@FXML
	private void registerCheckboxChanged() {

		// Make repeat password field and label visible / invisible
		repeatPasswordField.setVisible(registerCheckBox.isSelected());
		repeatPasswordLabel.setVisible(registerCheckBox.isSelected());
	}

	@FXML
	private void abortLogin() {
		logger.log(Level.INFO, "The login process has been cancelled. Exiting...");
		System.exit(0);
	}

	private Instant loadLastSync(String identifier) {
		try {
			localDB.loadUsers();
			localDB.setUser(localDB.getUsers().get(identifier));
			localDB.initializeUserStorage();
			localDB.loadUserData();
		} catch (final Exception e) {
			// User storage empty, wrong user name etc. -> default lastSync
		}
		return localDB.getLastSync();
	}

	private void performHandshake(LoginCredentials credentials) {
		try {
			client.performHandshake(credentials, cacheMap);
			if (client.isOnline()) {
				loadChatScene();
				client.initReceiver(localDB, cacheMap);
			}
		} catch (IOException | InterruptedException | TimeoutException e) {
			logger.log(Level.INFO, "Could not connect to server. Entering offline mode...");
			attemptOfflineMode(credentials);
		}
	}

	private void attemptOfflineMode(LoginCredentials credentials) {
		try {
			// Try entering offline mode
			localDB.loadUsers();
			final User clientUser = localDB.getUsers().get(credentials.getIdentifier());
			if (clientUser == null) throw new EnvoyException("Could not enter offline mode: user name unknown");
			client.setSender(clientUser);
			loadChatScene();
		} catch (final Exception e) {
			new Alert(AlertType.ERROR, "Client error: " + e).showAndWait();
			logger.log(Level.SEVERE, "Offline mode could not be loaded: ", e);
			System.exit(1);
		}
	}

	private void loadChatScene() {

		// Set client user in local database
		localDB.setUser(client.getSender());

		// Initialize chats in local database
		try {
			localDB.initializeUserStorage();
			localDB.loadUserData();
		} catch (final FileNotFoundException e) {
			// The local database file has not yet been created, probably first login
		} catch (final Exception e) {
			new Alert(AlertType.ERROR, "Error while loading local database: " + e + "\nChats will not be stored locally.").showAndWait();
			logger.log(Level.WARNING, "Could not load local database: ", e);
		}

		// Initialize write proxy
		final var writeProxy = new WriteProxy(client, localDB);

		localDB.synchronize();

		if (client.isOnline()) writeProxy.flushCache();
		else
			// Set all contacts to offline mode
			localDB.getChats()
				.stream()
				.map(Chat::getRecipient)
				.filter(User.class::isInstance)
				.map(User.class::cast)
				.forEach(u -> u.setStatus(UserStatus.OFFLINE));

		// Load ChatScene
		sceneContext.pop();
		sceneContext.getStage().setMinHeight(400);
		sceneContext.getStage().setMinWidth(350);
		sceneContext.load(SceneContext.SceneInfo.CHAT_SCENE);
		sceneContext.<ChatScene>getController().initializeData(sceneContext, localDB, client, writeProxy);

		if (StatusTrayIcon.isSupported()) {

			// Configure hide on close
			sceneContext.getStage().setOnCloseRequest(e -> {
				if (settings.isHideOnClose()) {
					sceneContext.getStage().setIconified(true);
					e.consume();
				}
			});

			// Initialize status tray icon
			final var trayIcon = new StatusTrayIcon(sceneContext.getStage());
			settings.getItems().get("hideOnClose").setChangeHandler(c -> {
				if ((Boolean) c) trayIcon.show();
				else trayIcon.hide();
			});
		}
	}
}