package envoy.server.data;

import static envoy.data.Message.MessageStatus.*;
import static envoy.server.Startup.config;

import java.time.Instant;

import javax.persistence.*;

import envoy.data.*;
import envoy.data.Attachment.AttachmentType;
import envoy.data.Message.MessageStatus;

/**
 * This JPA entity, which will be referred to as database message, stores the
 * information contained inside a {@link envoy.data.Message} inside the
 * database, while having a slightly different data layout.
 * <p>
 * A message can be converted to a database message by using the
 * {@link Message#Message(envoy.data.Message)} constructor. A database message
 * can be converted to a regular message using the {@link Message#toCommon()}
 * method. In both cases, the objects will not contain references to each other.
 *
 * @author Kai S. K. Engelbart
 * @since Envoy Server Standalone v0.1-alpha
 */
@Entity
@Table(name = "messages")
@Inheritance(strategy = InheritanceType.SINGLE_TABLE)
@NamedQuery(
	name = Message.getPending,
	query = "SELECT m FROM Message m WHERE "
			// Send to or by the user before last seen
			+ "(m.sender = :user OR m.recipient = :user) AND m.creationDate > :lastSeen "
			// SENT to the user
			+ "OR m.recipient = :user AND m.status = envoy.data.Message$MessageStatus.SENT "
			// Sent by the user and RECEIVED / READ after last seen
			+ "OR m.sender = :user AND (m.status = envoy.data.Message$MessageStatus.RECEIVED AND m.receivedDate > :lastSeen "
			+ "OR m.status = envoy.data.Message$MessageStatus.READ AND m.readDate > :lastSeen)"
)
public class Message {

	/**
	 * Named query retrieving pending messages for a user (parameter {@code :user})
	 * which was last seen after a specific date (parameter {@code :lastSeen}).
	 *
	 * @since Envoy Server Standalone v0.1-beta
	 */
	public static final String getPending = "Message.getPending";

	@Id
	protected long id;

	@ManyToOne(cascade = CascadeType.REMOVE)
	@JoinColumn
	protected User sender;

	@ManyToOne(cascade = CascadeType.REMOVE)
	@JoinColumn
	protected Contact recipient;

	@Column(name = "creation_date")
	protected Instant creationDate;

	@Column(name = "received_date")
	protected Instant receivedDate;

	@Column(name = "read_date")
	protected Instant readDate;

	protected String							text;
	protected envoy.data.Message.MessageStatus	status;
	protected AttachmentType					attachmentType;
	protected byte[]							attachment;
	protected String							attachmentName;
	protected boolean							forwarded;

	/**
	 * The constructor for a database object.
	 *
	 * @since Envoy Server Standalone v0.1-alpha
	 */
	public Message() {}

	/**
	 * Constructs a database message from a common message.
	 *
	 * @param message the {@link envoy.data.Message} to convert into a database
	 *                {@link Message}
	 * @since Envoy Server Standalone v0.1-alpha
	 */
	public Message(envoy.data.Message message) {
		final var persistenceManager = PersistenceManager.getInstance();
		id				= message.getID();
		status			= message.getStatus();
		text			= message.getText();
		creationDate	= message.getCreationDate();
		receivedDate	= message.getReceivedDate();
		readDate		= message.getReadDate();
		sender			= persistenceManager.getUserByID(message.getSenderID());
		recipient		= persistenceManager.getContactByID(message.getRecipientID());
		forwarded		= message.isForwarded();
		if (config.isAttachmentSupportEnabled() && message.hasAttachment()) {
			final var messageAttachment = message.getAttachment();
			attachment		= messageAttachment.getData();
			attachmentName	= messageAttachment.getName();
			attachmentType	= messageAttachment.getType();
		}
	}

	/**
	 * Converts this message into an instance of {@link envoy.data.Message}.
	 *
	 * @return a {@link envoy.data.Message} containing the same values as this
	 *         message
	 * @since Envoy Server Standalone v0.1-alpha
	 */
	public envoy.data.Message toCommon() { return prepareBuilder().build(); }

	/**
	 * @return a message builder containing the state of this message
	 * @since Envoy Server Standalone v0.1-beta
	 */
	MessageBuilder prepareBuilder() {
		final var builder = new MessageBuilder(sender.getID(), recipient.getID(), id).setText(text)
			.setCreationDate(creationDate)
			.setReceivedDate(receivedDate)
			.setReadDate(readDate)
			.setStatus(status)
			.setForwarded(forwarded);
		if (attachment != null) builder.setAttachment(new Attachment(attachment, attachmentName, attachmentType));
		return builder;
	}

	/**
	 * Sets the message status to {@link MessageStatus#RECEIVED} and sets the
	 * current time stamp as the received date.
	 *
	 * @since Envoy Server Standalone v0.1-beta
	 */
	public void received() {
		receivedDate	= Instant.now();
		status			= RECEIVED;
	}

	/**
	 * Sets the message status to {@link MessageStatus#READ} and sets the
	 * current time stamp as the read date.
	 *
	 * @since Envoy Server Standalone v0.1-beta
	 */
	public void read() {
		readDate	= Instant.now();
		status		= READ;
	}

	/**
	 * @return the id of a {link envoy.data.Message}
	 * @since Envoy Server Standalone v0.1-alpha
	 */
	public long getID() { return id; }

	/**
	 * @param id the id to set
	 * @since Envoy Server Standalone v0.1-alpha
	 * @see Message#getID()
	 */
	public void setId(long id) { this.id = id; }

	/**
	 * @return the sender of a {link envoy.data.Message}
	 * @since Envoy Server Standalone v0.1-alpha
	 */
	public User getSender() { return sender; }

	/**
	 * @param sender the sender to set
	 * @since Envoy Server Standalone v0.1-alpha
	 * @see Message#getSender()
	 */
	public void setSender(User sender) { this.sender = sender; }

	/**
	 * @return the recipient of a {link envoy.data.Message}
	 * @since Envoy Server Standalone v0.1-alpha
	 */
	public Contact getRecipient() { return recipient; }

	/**
	 * @param recipient the recipient to set
	 * @since Envoy Server Standalone v0.1-alpha
	 * @see Message#getRecipient()
	 */
	public void setRecipient(User recipient) { this.recipient = recipient; }

	/**
	 * @return the date at which a {link envoy.data.Message} has been created
	 * @since Envoy Server Standalone v0.2-beta
	 */
	public Instant getCreationDate() { return creationDate; }

	/**
	 * @param creationDate the creation date to set
	 * @since Envoy Server Standalone v0.2-beta
	 * @see Message#getCreationDate()
	 */
	public void setCreationDate(Instant creationDate) { this.creationDate = creationDate; }

	/**
	 * @return the date at which a {link envoy.data.Message} has been received by
	 *         the server
	 * @since Envoy Server Standalone v0.2-beta
	 */
	public Instant getReceivedDate() { return receivedDate; }

	/**
	 * @param receivedDate the received date to set
	 * @since Envoy Server Standalone v0.2-beta
	 * @see Message#getReceivedDate()
	 */
	public void setReceivedDate(Instant receivedDate) { this.receivedDate = receivedDate; }

	/**
	 * @return the date at which a {link envoy.data.Message} has been read
	 * @since Envoy Server Standalone v0.2-beta
	 */
	public Instant getReadDate() { return readDate; }

	/**
	 * @param readDate the read date to set
	 * @since Envoy Server Standalone v0.2-beta
	 * @see Message#getReadDate()
	 */
	public void setReadDate(Instant readDate) { this.readDate = readDate; }

	/**
	 * @return the status of a {link envoy.data.Message}
	 * @since Envoy Server Standalone v0.1-alpha
	 */
	public envoy.data.Message.MessageStatus getStatus() { return status; }

	/**
	 * @param status the new status of a {link envoy.data.Message}
	 * @since Envoy Server Standalone v0.1-alpha
	 */
	public void setStatus(envoy.data.Message.MessageStatus status) { this.status = status; }

	/**
	 * @return the text content of a {link envoy.data.Message}
	 * @since Envoy Server Standalone v0.1-alpha
	 */
	public String getText() { return text; }

	/**
	 * @param text the new text content of a {@link envoy.data.Message}
	 * @since Envoy Server Standalone v0.1-alpha
	 */
	public void setText(String text) { this.text = text; }

	/**
	 * @return the attachment of a {@link envoy.data.Message}
	 * @since Envoy Server Standalone v0.1-alpha
	 */
	public byte[] getAttachment() { return attachment; }

	/**
	 * @param attachment the new attachment
	 * @since Envoy Server Standalone v0.1-alpha
	 */
	public void setAttachment(byte[] attachment) { this.attachment = attachment; }

	/**
	 * @return the attachmentType
	 * @since Envoy Server Standalone v0.1-beta
	 */
	public AttachmentType getAttachmentType() { return attachmentType; }

	/**
	 * @param attachmentType the attachmentType to set
	 * @since Envoy Server Standalone v0.1-beta
	 */
	public void setAttachmentType(AttachmentType attachmentType) { this.attachmentType = attachmentType; }

	/**
	 * @return the attachmentName
	 * @since Envoy Server v0.2-beta
	 */
	public String getAttachmentName() { return attachmentName; }

	/**
	 * @param attachmentName the attachmentName to set
	 * @since Envoy Server v0.2-beta
	 */
	public void setAttachmentName(String attachmentName) { this.attachmentName = attachmentName; }

	/**
	 * @return whether this message is a forwarded message
	 * @since Envoy Server Standalone v0.1-alpha
	 */
	public boolean isForwarded() { return forwarded; }

	/**
	 * @param forwarded this message should be a forwarded message.
	 * @since Envoy Server Standalone v0.1-alpha
	 */
	public void setForwarded(boolean forwarded) { this.forwarded = forwarded; }
}