package envoy.server.net;

import java.io.IOException;
import java.util.Set;
import java.util.logging.Logger;
import java.util.stream.Stream;

import com.jenkov.nioserver.*;

import envoy.util.*;

import envoy.server.data.Contact;

/**
 * This class defines methods to send an object to a client.
 *
 * @author Kai S. K. Engelbart
 * @since Envoy Server Standalone v0.1-alpha
 */
public final class ObjectWriteProxy {

	private final WriteProxy writeProxy;

	private static final ConnectionManager	connectionManager	= ConnectionManager.getInstance();
	private static final Logger				logger				=
		EnvoyLog.getLogger(ObjectWriteProxy.class);

	/**
	 * Creates an instance of {@link ObjectWriteProxy}.
	 *
	 * @param writeProxy the {@link WriteProxy} to write objects to another client
	 * @since Envoy Server Standalone v0.1-alpha
	 */
	public ObjectWriteProxy(WriteProxy writeProxy) {
		this.writeProxy = writeProxy;
	}

	/**
	 * @param recipientSocketID the socket id of the recipient
	 * @param obj               the object to return to the client
	 * @throws RuntimeException if the serialization of the object failed (this is highly unlikely)
	 * @since Envoy Server Standalone v0.1-alpha
	 */
	public void write(long recipientSocketID, Object obj) {
		// Create message targeted at the client
		final Message response = writeProxy.getMessage();
		response.socketId = recipientSocketID;
		logger.fine("Sending " + obj);

		try {

			// Serialize object to byte array
			final byte[] objBytes = SerializationUtils.writeToByteArray(obj);

			// Acquire object length in bytes
			final byte[] objLen = SerializationUtils.intToBytes(objBytes.length);

			response.writeToMessage(objLen);
			response.writeToMessage(objBytes);
			writeProxy.enqueue(response);
		} catch (IOException e) {
			throw new RuntimeException(e);
		}
	}

	/**
	 * Sends an object to all contacts in a set that are online.
	 *
	 * @param contacts the contacts to send the object to
	 * @param message  the object to send
	 * @since Envoy Server Standalone v0.1-beta
	 */
	public void writeToOnlineContacts(Set<? extends Contact> contacts, Object message) {
		writeToOnlineContacts(contacts.stream(), message);
	}

	/**
	 * Sends an object to all contacts in a set that are online.
	 *
	 * @param contacts the contacts to send the object to
	 * @param message  the object to send
	 * @since Envoy Server Standalone v0.1-beta
	 */
	public void writeToOnlineContacts(Stream<? extends Contact> contacts, Object message) {
		contacts.map(Contact::getID).filter(connectionManager::isOnline)
			.map(connectionManager::getSocketID).forEach(id -> write(id, message));
	}
}