envoy/src/main/java/envoy/server/processors/LoginCredentialProcessor.java

package envoy.server.processors;

import static envoy.data.User.UserStatus.ONLINE;
import static envoy.event.HandshakeRejection.INTERNAL_ERROR;
import static envoy.event.HandshakeRejection.USERNAME_TAKEN;
import static envoy.event.HandshakeRejection.WRONG_PASSWORD_OR_USER;
import static envoy.event.HandshakeRejection.WRONG_VERSION;

import java.io.IOException;
import java.time.LocalDateTime;
import java.util.Arrays;
import java.util.HashSet;
import java.util.List;
import java.util.logging.Logger;

import javax.persistence.NoResultException;

import enovy.server.util.VersionUtils;
import envoy.data.LoginCredentials;
import envoy.data.Message.MessageStatus;
import envoy.event.HandshakeRejection;
import envoy.event.MessageStatusChange;
import envoy.server.data.GroupMessage;
import envoy.server.data.PersistenceManager;
import envoy.server.data.User;
import envoy.server.net.ConnectionManager;
import envoy.server.net.ObjectWriteProxy;
import envoy.util.Bounds;
import envoy.util.EnvoyLog;

/**
 * This {@link ObjectProcessor} handles {@link LoginCredentials}.<br>
 * <br>
 * Project: <strong>envoy-server-standalone</strong><br>
 * File: <strong>LoginCredentialProcessor.java</strong><br>
 * Created: <strong>30.12.2019</strong><br>
 *
 * @author Kai S. K. Engelbart
 * @author Maximilian K&auml;fer
 * @since Envoy Server Standalone v0.1-alpha
 */
public final class LoginCredentialProcessor implements ObjectProcessor<LoginCredentials> {

	private final PersistenceManager	persistenceManager	= PersistenceManager.getInstance();
	private final ConnectionManager		connectionManager	= ConnectionManager.getInstance();

	private static final Logger logger = EnvoyLog.getLogger(LoginCredentialProcessor.class);

	@Override
	public void process(LoginCredentials credentials, long socketID, ObjectWriteProxy writeProxy) throws IOException {

		// Cache this write proxy for user-independant notifications
		UserStatusChangeProcessor.setWriteProxy(writeProxy);

		if (!VersionUtils.verifyCompatibility(credentials.getClientVersion())) {
			logger.info("The client has the wrong version.");
			writeProxy.write(socketID, new HandshakeRejection(WRONG_VERSION));
			return;
		}

		// Acquire a user object (or reject the handshake if that's impossible)
		User user = null;
		if (!credentials.isRegistration()) {
			try {
				user = persistenceManager.getUserByName(credentials.getIdentifier());

				// Checking if user is already online
				if (connectionManager.isOnline(user.getID())) {
					logger.warning(user + " is already online!");
					writeProxy.write(socketID, new HandshakeRejection(INTERNAL_ERROR));
					return;
				}
				// Evaluating the correctness of the password hash
				if (!Arrays.equals(credentials.getPasswordHash(), user.getPasswordHash())) {
					logger.info(user + " has entered the wrong password.");
					writeProxy.write(socketID, new HandshakeRejection(WRONG_PASSWORD_OR_USER));
					return;
				}
			} catch (NoResultException e) {
				logger.info("The requested user does not exist.");
				writeProxy.write(socketID, new HandshakeRejection(WRONG_PASSWORD_OR_USER));
				return;
			}
		} else {
			// Validate user name
			if (!Bounds.isValidContactName(credentials.getIdentifier())) {
				logger.info("The requested user name is not valid.");
				writeProxy.write(socketID, new HandshakeRejection(INTERNAL_ERROR));
				return;
			}
				try {
					// Checking that no user already has this identifier
					PersistenceManager.getInstance().getUserByName(credentials.getIdentifier());

					// This code only gets executed if this user already exists
					logger.info("The requested user already exists.");
					writeProxy.write(socketID, new HandshakeRejection(USERNAME_TAKEN));
					return;
				} catch (NoResultException e) {
					// Creation of a new user
					user = new User();
					user.setName(credentials.getIdentifier());
					user.setLastSeen(LocalDateTime.now());
					user.setStatus(ONLINE);
					user.setPasswordHash(credentials.getPasswordHash());
					user.setContacts(new HashSet<>());
					persistenceManager.addContact(user);
					logger.info("Registered new " + user);
				}
		}

		logger.info(user + " successfully authenticated.");
		connectionManager.registerUser(user.getID(), socketID);

		// Change status and notify contacts about it
		user.setStatus(ONLINE);
		UserStatusChangeProcessor.updateUserStatus(user);

		// Complete the handshake
		writeProxy.write(socketID, user.toCommon());

		final var pendingMessages = PersistenceManager.getInstance().getPendingMessages(user);
		logger.fine("Sending " + pendingMessages.size() + " pending messages to " + user + "...");

		List<GroupMessage> pendingGroupMessages = PersistenceManager.getInstance().getPendingGroupMessages(user);
		logger.fine("Sending " + pendingGroupMessages.size() + " pending group messages to " + user + "...");

		for (var msg : pendingMessages) {
			final var msgCommon = msg.toCommon();
			if (msg.getStatus() == MessageStatus.SENT) {

				// Send the message
				writeProxy.write(socketID, msgCommon);
				msg.received();
				PersistenceManager.getInstance().updateMessage(msg);

				// Notify the sender about the delivery
				if (connectionManager.isOnline(msg.getSender().getID())) {
					msgCommon.nextStatus();
					writeProxy.write(connectionManager.getSocketID(msg.getSender().getID()), new MessageStatusChange(msgCommon));
				}
			} else writeProxy.write(socketID, new MessageStatusChange(msgCommon));
		}

		for (GroupMessage gmsg : pendingGroupMessages) {
			if (gmsg.getMemberMessageStatus().get(user.getID()) == MessageStatus.SENT) {
				gmsg.getMemberMessageStatus().replace(user.getID(), MessageStatus.RECEIVED);
				envoy.data.GroupMessage groupMessage = gmsg.toCommon();
				logger.info("Sending groupMessage" + groupMessage);
				System.out.println(groupMessage.toString());
				writeProxy.write(socketID, groupMessage);
				// Sending memberStatusEvent to all members (event does not exist yet I think)
				if (!gmsg.getMemberMessageStatus().containsValue(MessageStatus.SENT)) {
					gmsg.setStatus(MessageStatus.RECEIVED);
					// TODO: Sending MessageStatusChangeEvent to all other members
				}
				PersistenceManager.getInstance().updateMessage(gmsg);
			} else {
				// Sending memberStatusEvents and MessageStatusChange Events
			}
		}
	}

	@Override
	public Class<LoginCredentials> getInputClass() { return LoginCredentials.class; }
}