package envoy.client.data;

import java.io.IOException;
import java.io.Serializable;

import envoy.client.net.Client;
import envoy.client.ui.list.ComponentListModel;
import envoy.data.Message;
import envoy.data.Message.MessageStatus;
import envoy.data.User;
import envoy.event.MessageStatusChangeEvent;

/**
 * Represents a chat between two {@link User}s <br>
 * as a list of {@link Message} objects.
 * <br>
 * Project: <strong>envoy-client</strong><br>
 * File: <strong>Chat.java</strong><br>
 * Created: <strong>19 Oct 2019</strong><br>
 *
 * @author Maximilian K&auml;fer
 * @author Leon Hofmeister
 * @author Kai S. K. Engelbart
 * @since Envoy v0.1-alpha
 */
public class Chat implements Serializable {

	private static final long serialVersionUID = -7751248474547242056L;

	private final User							recipient;
	private final ComponentListModel<Message>	model	= new ComponentListModel<>();

	/**
	 * Provides the list of messages that the recipient receives.<br>
	 * Saves the Messages in the corresponding chat at that Point.
	 *
	 * @param recipient the user who receives the messages
	 * @since Envoy v0.1-alpha
	 */
	public Chat(User recipient) { this.recipient = recipient; }

	/**
	 * Appends a message to the bottom of this chat
	 *
	 * @param message the message to append
	 * @since Envoy v0.1-alpha
	 */
	public void appendMessage(Message message) { model.add(message); }

	/**
	 * Sets the status of all chat messages received from the recipient to
	 * {@code READ} starting from the bottom and stopping once a read message is
	 * found.
	 *
	 * @param client the client instance used to notify the server about the message
	 *               status changes
	 * @throws IOException if a {@link MessageStatusChangeEvent} could not be
	 *                     delivered to the server
	 * @since Envoy v0.3-alpha
	 */
	public void read(Client client) throws IOException {
		for (int i = model.size() - 1; i >= 0; --i) {
			final Message m = model.get(i);
			if (m.getSenderId() == recipient.getId()) {
				if (m.getStatus() == MessageStatus.READ) break;
				else {
					m.setStatus(MessageStatus.READ);

					// TODO: Cache events in offline mode
					client.sendEvent(new MessageStatusChangeEvent(m));
				}
			}
		}
	}

	/**
	 * @return {@code true} if the newest message received in the chat doesn't have
	 *         the status {@code READ}
	 * @since Envoy v0.3-alpha
	 */
	public boolean isUnread() { return !model.isEmpty() && model.get(model.size() - 1).getStatus() != MessageStatus.READ; }

	/**
	 * @return all messages in the current chat
	 * @since Envoy v0.1-alpha
	 */
	public ComponentListModel<Message> getModel() { return model; }

	/**
	 * @return the recipient of a message
	 * @since Envoy v0.1-alpha
	 */
	public User getRecipient() { return recipient; }
}