package envoy.data;

import java.io.Serializable;
import java.text.SimpleDateFormat;
import java.util.Date;

/**
 * Represents a unique message with a unique, numeric ID. Further metadata
 * includes the sender and recipient {@link User}s, as well as the creation
 * date and the current {@link MessageStatus}.<br>
 * <br>
 * Project: <strong>envoy-common</strong><br>
 * File: <strong>Message.java</strong><br>
 * Created: <strong>28.12.2019</strong><br>
 *
 * @author Kai S. K. Engelbart
 * @author Leon Hofmeister
 * @since Envoy Common v0.2-alpha
 */
public class Message implements Serializable {

	/**
	 * This enumeration defines all possible statuses a {link Message} can have.
	 *
	 * @since Envoy Common v0.2-alpha
	 */
	public static enum MessageStatus {

		/**
		 * is selected, if a message was sent but not received by the server yet.
		 */
		WAITING,

		/**
		 * is selected, if a sent message was received by the server.
		 */
		SENT,

		/**
		 * is selected, if a message was delivered from the server to the recipient, but
		 * has not been read yet.
		 */
		RECEIVED,

		/**
		 * is selected, if a recipient opened the corresponding chat of said message.
		 */
		READ
	}

	private final long					id, senderId, recipientId;
	private final Date					creationDate;
	private final String				text;
	private final MessageAttachment<?>	attachment;

	private Date			receivedDate, readDate;
	private MessageStatus	status;

	private static final long serialVersionUID = -4393477412979594435L;

	/**
	 * Initializes a {@link Message} with values for all of its properties. The use
	 * of this constructor is only intended for the {@link MessageBuilder} class, as
	 * this class provides {@code null} checks and default values for all
	 * properties.
	 *
	 * @param id          unique ID
	 * @param senderId    the ID of the user who sends the message
	 * @param recipientId the ID of the user who receives the message
	 * @param date        the creation date of the message
	 * @param text        the text content of the message
	 * @param attachment  the attachment of the message, if present
	 * @param status      the current {@link MessageStatus} of the message
	 * @since Envoy Common v0.2-alpha
	 */
	Message(long id, long senderId, long recipientId, Date date, String text, MessageAttachment<?> attachment, MessageStatus status) {
		this.id				= id;
		this.senderId		= senderId;
		this.recipientId	= recipientId;
		this.creationDate	= date;
		this.text			= text;
		this.attachment		= attachment;
		this.status			= status;
	}

	/**
	 * Changes the current {@link MessageStatus} to the next logical status.<br>
	 * <br>
	 * The underlying order is as follows:
	 * <ol>
	 * <li>{@link MessageStatus#WAITING}
	 * <li>{@link MessageStatus#SENT}
	 * <li>{@link MessageStatus#RECEIVED}
	 * <li>{@link MessageStatus#READ}
	 * </ol>
	 *
	 * @since Envoy Common v0.2-alpha
	 */
	public void nextStatus() {
		if (status == MessageStatus.READ) throw new IllegalStateException("Message status READ is already reached");
		status = MessageStatus.values()[status.ordinal() + 1];
	}

	@Override
	public String toString() {
		return String.format("TextMessage[id=%d,sender=%s,recipient=%s,date=%s,status=%s,text=%s,hasAttachment=%b]",
				id,
				senderId,
				recipientId,
				new SimpleDateFormat("dd.MM.yyyy HH:mm:ss").format(creationDate),
				status,
				text,
				attachment != null);
	}

	/**
	 * @return the ID of this message
	 * @since Envoy Common v0.2-alpha
	 */
	public long getId() { return id; }

	/**
	 * @return the sender ID of this message
	 * @since Envoy Common v0.2-alpha
	 */
	public long getSenderId() { return senderId; }

	/**
	 * @return the recipient ID of this message
	 * @since Envoy Common v0.2-alpha
	 */
	public long getRecipientId() { return recipientId; }

	/**
	 * @return the date at which this message was created
	 * @since Envoy Common v0.2-alpha
	 */
	public Date getCreationDate() { return creationDate; }

	/**
	 * @return the date at which the message has been received by the sender
	 * @since Envoy Common v0.2-alpha
	 */
	public Date getReceivedDate() { return receivedDate; }

	/**
	 * @param receivedDate the date at which the message has been received by the
	 *                     sender
	 * @since Envoy Common v0.2-alpha
	 */
	public void setReceivedDate(Date receivedDate) { this.receivedDate = receivedDate; }

	/**
	 * @return the date at which the message has been read by the sender
	 * @since Envoy Common v0.2-alpha
	 */
	public Date getReadDate() { return readDate; }

	/**
	 * @param readDate at which the message has been read by the sender
	 * @since Envoy Common v0.2-alpha
	 */
	public void setReadDate(Date readDate) { this.readDate = readDate; }

	/**
	 * @return the text content of this message
	 * @since Envoy Common v0.2-alpha
	 */
	public String getText() { return text; }

	/**
	 * @return the messageAttachment
	 * @since Envoy Common v0.2-alpha
	 */
	public MessageAttachment<?> getAttachment() { return attachment; }

	/**
	 * @return the current status of this message
	 * @since Envoy Common v0.2-alpha
	 */
	public MessageStatus getStatus() { return status; }

	/**
	 * @param status the new {@link MessageStatus}, if permitted
	 * @since Envoy Common v0.2-alpha
	 */
	public void setStatus(MessageStatus status) {
		if (status.ordinal() < this.status.ordinal()) throw new IllegalStateException("This message is moving backwards in time");
		else this.status = status;
	}
}