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

package envoy.client.ui.controller;

import java.util.function.Consumer;
import java.util.logging.Level;
import java.util.logging.Logger;

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

import envoy.client.data.LocalDB;
import envoy.client.event.SendEvent;
import envoy.client.ui.ClearableTextField;
import envoy.client.ui.SceneContext;
import envoy.client.ui.listcell.ContactControl;
import envoy.client.ui.listcell.ListCellFactory;
import envoy.data.User;
import envoy.event.ElementOperation;
import envoy.event.EventBus;
import envoy.event.contact.ContactOperation;
import envoy.event.contact.UserSearchRequest;
import envoy.event.contact.UserSearchResult;
import envoy.util.EnvoyLog;

/**
 * Provides a search bar in which a user name (substring) can be entered. The
 * users with a matching name are then displayed inside a list view. A
 * {@link UserSearchRequest} is sent on every keystroke.
 * <p>
 * <i>The actual search algorithm is implemented on the server.
 * <p>
 * To create a group, a button is available that loads the
 * {@link GroupCreationScene}.
 * <p>
 * Project: <strong>envoy-client</strong><br>
 * File: <strong>ContactSearchScene.java</strong><br>
 * Created: <strong>07.06.2020</strong><br>
 *
 * @author Leon Hofmeister
 * @since Envoy Client v0.1-beta
 */
public class ContactSearchScene {

	@FXML
	private ClearableTextField searchBar;

	@FXML
	private ListView<User> userList;

	private SceneContext sceneContext;

	private LocalDB localDB;

	private Alert alert = new Alert(AlertType.CONFIRMATION);

	private User currentlySelectedUser;

	private final Consumer<ContactOperation> handler = e -> {
		final var contact = e.get();
		if (e.getOperationType() == ElementOperation.ADD) Platform.runLater(() -> {
			userList.getItems().remove(contact);
			if (currentlySelectedUser != null && currentlySelectedUser.equals(contact) && alert.isShowing()) alert.close();
		});
	};

	private static final EventBus	eventBus	= EventBus.getInstance();
	private static final Logger		logger		= EnvoyLog.getLogger(ChatScene.class);

	/**
	 * @param sceneContext enables the user to return to the chat scene
	 * @param localDB      the local database to which new contacts are added
	 * @since Envoy Client v0.1-beta
	 */
	public void initializeData(SceneContext sceneContext, LocalDB localDB) {
		this.sceneContext	= sceneContext;
		this.localDB		= localDB;
	}

	@FXML
	private void initialize() {
		userList.setCellFactory(new ListCellFactory<>(ContactControl::new));
		searchBar.setClearButtonListener(e -> { searchBar.getTextField().clear(); userList.getItems().clear(); });
		eventBus.register(UserSearchResult.class,
				response -> Platform.runLater(() -> { userList.getItems().clear(); userList.getItems().addAll(response.get()); }));
		eventBus.register(ContactOperation.class, handler);
	}

	/**
	 * Disables the clear and search button if no text is present in the search bar.
	 *
	 * @since Envoy Client v0.1-beta
	 */
	@FXML
	private void sendRequest() {
		final var text = searchBar.getTextField().getText().strip();
		if (!text.isBlank()) eventBus.dispatch(new SendEvent(new UserSearchRequest(text)));
		else userList.getItems().clear();
	}

	/**
	 * Clears the text in the search bar and the items shown in the list.
	 * Additionally disables both clear and search button.
	 *
	 * @since Envoy Client v0.1-beta
	 */
	@FXML
	private void clear() {
		searchBar.getTextField().setText(null);
		userList.getItems().clear();
	}

	/**
	 * Sends an {@link ContactOperation} for the selected user to the
	 * server.
	 *
	 * @since Envoy Client v0.1-beta
	 */
	@FXML
	private void userListClicked() {
		final var user = userList.getSelectionModel().getSelectedItem();
		if (user != null) {
			currentlySelectedUser	= user;
			alert					= new Alert(AlertType.CONFIRMATION);
			alert.setTitle("Add User to Contact List");
			alert.setHeaderText("Add the user " + currentlySelectedUser.getName() + " to your contact list?");
			// Normally, this would be total BS (we are already on the FX Thread), however
			// it could be proven that the creation of this dialog wrapped in
			// Platform.runLater is less error-prone than without it
			Platform.runLater(() -> alert.showAndWait().filter(btn -> btn == ButtonType.OK).ifPresent(btn -> {
				final var event = new ContactOperation(currentlySelectedUser, ElementOperation.ADD);
				// Sends the event to the server
				eventBus.dispatch(new SendEvent(event));
				// Removes the chosen user and updates the UI
				userList.getItems().remove(currentlySelectedUser);
				eventBus.dispatch(event);
				logger.log(Level.INFO, "Added user " + currentlySelectedUser);
			}));
		}
	}

	@FXML
	private void newGroupButtonClicked() {
		sceneContext.load(SceneContext.SceneInfo.GROUP_CREATION_SCENE);
		sceneContext.<GroupCreationScene>getController().initializeData(sceneContext, localDB);
	}

	@FXML
	private void backButtonClicked() { sceneContext.pop(); }
}