package envoy.client.net;

import java.util.logging.*;

import envoy.data.Message;
import envoy.event.MessageStatusChange;
import envoy.util.EnvoyLog;

import envoy.client.data.*;

/**
 * Implements methods to send {@link Message}s and {@link MessageStatusChange}s to the server or
 * cache them inside a {@link LocalDB} depending on the online status.
 *
 * @author Kai S. K. Engelbart
 * @since Envoy Client v0.3-alpha
 */
public final class WriteProxy {

	private final Client	client;
	private final LocalDB	localDB;

	private static final Logger logger = EnvoyLog.getLogger(WriteProxy.class);

	/**
	 * Initializes a write proxy using a client and a local database. The corresponding cache
	 * processors are injected into the caches.
	 *
	 * @param client  the client instance used to send messages and events if online
	 * @param localDB the local database used to cache messages and events if offline
	 * @since Envoy Client v0.3-alpha
	 */
	public WriteProxy(Client client, LocalDB localDB) {
		this.client		= client;
		this.localDB	= localDB;

		// Initialize cache processors for messages and message status change events
		localDB.getCacheMap().get(Message.class).setProcessor(msg -> {
			logger.log(Level.FINER, "Sending cached " + msg);
			client.sendMessage(msg);
		});
		localDB.getCacheMap().get(MessageStatusChange.class).setProcessor(evt -> {
			logger.log(Level.FINER, "Sending cached " + evt);
			client.send(evt);
		});
	}

	/**
	 * Sends cached {@link Message}s and {@link MessageStatusChange}s to the server.
	 *
	 * @since Envoy Client v0.3-alpha
	 */
	public void flushCache() {
		localDB.getCacheMap().getMap().values().forEach(Cache::relay);
	}

	/**
	 * Delivers a message to the server if online. Otherwise the message is cached inside the local
	 * database.
	 *
	 * @param message the message to send
	 * @since Envoy Client v0.3-alpha
	 */
	public void writeMessage(Message message) {
		if (client.isOnline())
			client.sendMessage(message);
		else
			localDB.getCacheMap().getApplicable(Message.class).accept(message);
	}

	/**
	 * Delivers a message status change event to the server if online. Otherwise the event is cached
	 * inside the local database.
	 *
	 * @param evt the event to send
	 * @since Envoy Client v0.3-alpha
	 */
	public void writeMessageStatusChange(MessageStatusChange evt) {
		if (client.isOnline())
			client.send(evt);
		else
			localDB.getCacheMap().getApplicable(MessageStatusChange.class).accept(evt);
	}
}