package envoy.client.data;

import java.io.IOException;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.List;
import java.util.Objects;

import envoy.client.net.WriteProxy;
import envoy.data.*;
import envoy.data.Message.MessageStatus;
import envoy.event.MessageStatusChange;

/**
 * Represents a chat between two {@link User}s
 * as a list of {@link Message} objects.
 * <p>
 * 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 Client v0.1-alpha
 */
public final class Chat implements Serializable {

	private final Contact		recipient;
	private final List<Message>	messages	= new ArrayList<>();

	private static final long serialVersionUID = 1L;

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

	@Override
	public String toString() { return String.format("Chat[recipient=%s,messages=%d]", recipient, messages.size()); }

	/**
	 * Generates a hash code based on the recipient.
	 * 
	 * @since Envoy Client v0.1-beta
	 */
	@Override
	public int hashCode() { return Objects.hash(recipient); }

	/**
	 * Tests equality to another object based on the recipient.
	 * 
	 * @since Envoy Client v0.1-beta
	 */
	@Override
	public boolean equals(Object obj) {
		if (this == obj) return true;
		if (!(obj instanceof Chat)) return false;
		Chat other = (Chat) obj;
		return Objects.equals(recipient, other.recipient);
	}

	/**
	 * 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 writeProxy the write proxy instance used to notify the server about
	 *                   the message status changes
	 * @throws IOException if a {@link MessageStatusChange} could not be
	 *                     delivered to the server
	 * @since Envoy Client v0.3-alpha
	 */
	public void read(WriteProxy writeProxy) throws IOException {
		for (int i = messages.size() - 1; i >= 0; --i) {
			final Message m = messages.get(i);
			if (m.getSenderID() == recipient.getID()) if (m.getStatus() == MessageStatus.READ) break;
			else {
				m.setStatus(MessageStatus.READ);
				writeProxy.writeMessageStatusChange(new MessageStatusChange(m));
			}
		}
	}

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

	/**
	 * @return all messages in the current chat
	 * @since Envoy Client v0.1-beta
	 */
	public List<Message> getMessages() { return messages; }

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

	/**
	 * @return whether this {@link Chat} points at a {@link User}
	 * @since Envoy Client v0.1-beta
	 */
	public boolean isUserChat() { return recipient instanceof User; }

	/**
	 * @return whether this {@link Chat} points at a {@link Group}
	 * @since Envoy Client v0.1-beta
	 */
	public boolean isGroupChat() { return recipient instanceof Group; }
}