package envoy.server.net;

import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.*;

import com.jenkov.nioserver.*;

import envoy.util.SerializationUtils;

/**
 * This {@link IMessageReader} decodes serialized Java objects.
 *
 * @author Kai S. K. Engelbart
 * @since Envoy Server Standalone v0.1-alpha
 */
public final class ObjectMessageReader implements IMessageReader {

	private final List<Message>	completeMessages	= new ArrayList<>();
	private Message				nextMessage;
	private MessageBuffer		messageBuffer;

	@Override
	public List<Message> getMessages() { return completeMessages; }

	@Override
	public void init(MessageBuffer messageBuffer) {
		this.messageBuffer	= messageBuffer;
		nextMessage			= messageBuffer.getMessage();
	}

	@Override
	public void read(Socket socket, ByteBuffer buffer) throws IOException {
		socket.read(buffer);
		buffer.flip();

		if (!buffer.hasRemaining()) {
			buffer.clear();
			return;
		}

		nextMessage.writeToMessage(buffer);
		buffer.clear();

		// Get message length
		if (nextMessage.length < 4)
			return;
		int length = SerializationUtils.bytesToInt(nextMessage.sharedArray, nextMessage.offset) + 4;
		do {

			// Separate first complete message
			if (nextMessage.length >= length) {
				Message message = messageBuffer.getMessage();
				message.writePartialMessageToMessage(nextMessage, length);
				message.length		= nextMessage.length - length;
				nextMessage.length	= length;
				completeMessages.add(nextMessage);
				nextMessage = message;
			}

			// Get message length
			if (nextMessage.length < 4)
				return;
			length = SerializationUtils.bytesToInt(nextMessage.sharedArray, nextMessage.offset) + 4;

		} while (nextMessage.length >= length);
	}
}