/*
    *  Copyright 2006 Simon Raess
    *
    *  Licensed under the Apache License, Version 2.0 (the "License");
    *  you may not use this file except in compliance with the License.
    *  You may obtain a copy of the License at
    *
    *      http://www.apache.org/licenses/LICENSE-2.0
    * 
   *  Unless required by applicable law or agreed to in writing, software
   *  distributed under the License is distributed on an "AS IS" BASIS,
   *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   *  See the License for the specific language governing permissions and
   *  limitations under the License.
   */
  package net.sf.beep4j.internal.tcp;
  
  import java.nio.ByteBuffer;
  import java.nio.charset.Charset;
  
  import junit.framework.TestCase;
  import net.sf.beep4j.Message;
  import net.sf.beep4j.internal.Constants;
  import net.sf.beep4j.internal.DataHeader;
  import net.sf.beep4j.internal.MessageType;
  import net.sf.beep4j.internal.message.DefaultMessage;
  import net.sf.beep4j.internal.message.MessageHeader;
  import net.sf.beep4j.transport.Transport;
  
  import org.easymock.MockControl;
  
  public class DefaultChannelControllerTest extends TestCase {
  	
  	private MockControl transportCtrl;
  	
  	private Transport transport;
  	
  	private ByteBuffer createFrame(int channel, boolean intermediate, 
  			long seqno, int start, int size, MessageHeader messageHeader) {
  		ByteBuffer headerBuffer = messageHeader.asByteBuffer();
  		
  		ByteBuffer header = new DataHeader(
  				MessageType.MSG, channel, 1, intermediate, 
  				seqno, size + headerBuffer.remaining()).asByteBuffer();
  		
  		ByteBuffer buffer = ByteBuffer.allocate(header.remaining() 
  				+ headerBuffer.remaining() + size + 5);
  		buffer.put(header);
  		buffer.put(createPayload(headerBuffer, start, size));
  		buffer.put(Constants.TRAILER_BYTES);
  		buffer.flip();
  		
  		return buffer;
  	}
  	
  	private ByteBuffer createFrame(int channel, boolean intermediate, long seqno, int start, int size) {
  		ByteBuffer header = new DataHeader(
  				MessageType.MSG, channel, 1, intermediate, 
  				seqno, size).asByteBuffer();
  		
  		ByteBuffer buffer = ByteBuffer.allocate(header.remaining() + size + 5);
  		buffer.put(header);
  		buffer.put(createPayload(start, size));
  		buffer.put(Constants.TRAILER_BYTES);
  		buffer.flip();
  		
  		return buffer;
  	}
  	
  	private Message createMessage(int start, int length) {
  		MessageHeader header = new MessageHeader();
  		header.addHeader("content-type", "application/beep+xml");
  		return new DefaultMessage(header, createPayload(start, length));
  	}
  
  	private ByteBuffer createPayload(int start, int size) {
  		ByteBuffer buffer = ByteBuffer.allocate(size);
  		fill(buffer, start, size);
  		buffer.flip();
  		return buffer;
  	}
  	
  	private ByteBuffer createPayload(ByteBuffer header, int start, int size) {
  		ByteBuffer result = ByteBuffer.allocate(header.capacity() + size);
  		result.put(header);
  		fill(result, start, size);
  		result.flip();
  		return result;
  	}
  	
  	private void fill(ByteBuffer buffer, int start, int size) {
  		for (int i = start; i < start + size; i++) {
  			buffer.put((byte) (i % 128));
  		}
  	}
  	
  	@Override
  	protected void setUp() throws Exception {
  		transportCtrl = MockControl.createStrictControl(Transport.class);
 		transportCtrl.setDefaultMatcher(MockControl.ARRAY_MATCHER);
 		transport = (Transport) transportCtrl.getMock();
 	}
 	
 	/* 
 	 * Tests that sending a message equal to the remaining window size
 	 * is sent unfragmented.
 	 */
 	public void testSendNonFragmented() throws Exception {
 		ChannelController target = new DefaultChannelController(transport, 0, 88);
 		MessageHeader header = new MessageHeader();
 		header.addHeader("content-type", "application/beep+xml");
 		
 		// define expectations
 		transport.sendBytes(createFrame(0, false, 0, 0, 50, header));
 		
 		// replay
 		transportCtrl.replay();
 		
 		// test
 		Message message = createMessage(0, 50);
 		target.sendMSG(1, message);
 		
 		// verify
 		transportCtrl.verify();
 	}
 	
 	/*
 	 * Tests that a message is fragmented and that the first fragment
 	 * is as large as the remaining window size.
 	 */
 	public void testSendFragmented() throws Exception {
 		MessageHeader header = new MessageHeader();
 		header.addHeader("content-type", "application/beep+xml");
 		
 		// define expectations
 		transport.sendBytes(createFrame(0, true, 0, 0, 50, header));
 		
 		// replay
 		transportCtrl.replay();
 		
 		// test
 		ChannelController target = new DefaultChannelController(transport, 0, 88);
 		target.sendMSG(1, createMessage(0, 60));
 		
 		// verify
 		transportCtrl.verify();
 	}
 	
 	/*
 	 * Tests that the updateSendWindow method does what its supposed to do.
 	 * The test scenario includes an initial message of length 65 and a
 	 * window size of 50. 
 	 * 
 	 * - sendMessage of size 65
 	 *   -> first frame (fragment): first 50 bytes of the original message
 	 * - updateSendWindow(10, 50)
 	 *   -> second frame (fragment): bytes 51 - 60 of original message
 	 * - updateSendWindow(15, 50)
 	 *   -> third frame: bytes 61 - 65 of original message
 	 */
 	public void testUpdateSendWindow() throws Exception {
 		ChannelController target = new DefaultChannelController(transport, 0, 88);
 		MessageHeader header = new MessageHeader();
 		header.addHeader("content-type", "application/beep+xml");
 		
 		// define expectations
 		transport.sendBytes(createFrame(0, true, 0, 0, 50, header));
 		transport.sendBytes(createFrame(0, true, 88, 50, 10));
 		transport.sendBytes(createFrame(0, false, 98, 60, 5));
 		
 		// replay
 		transportCtrl.replay();
 		
 		// test
 		target.sendMSG(1, createMessage(0, 65));
 		target.updateSendWindow(10, 88);
 		target.updateSendWindow(15, 88);
 		
 		// verify
 		transportCtrl.verify();
 	}
 	
 	public void testFrameReceived() throws Exception {
 		// define expectations
 		transportCtrl.replay();
 		
 		// test
 		ChannelController controller = new DefaultChannelController(transport, 0, 4096);
 		controller.frameReceived(0, 1024);
 		
 		// verify
 		transportCtrl.verify();
 	}
 	
 	public void testSendUpdateWindow() throws Exception {
 		// define expectations
 		transport.sendBytes(createSEQFrame(0, 4096, 4096));
 		transportCtrl.replay();
 		
 		// test
 		ChannelController controller = new DefaultChannelController(transport, 0, 4096);
 		controller.frameReceived(0, 4096);
 		
 		// verify
 		transportCtrl.verify();
 	}
 	
 	public void testSendMultipleUpdateWindow() throws Exception {
 		// define expectations
 		transport.sendBytes(createSEQFrame(0, 4096, 4096));
 		transport.sendBytes(createSEQFrame(0, 8192, 4096));
 		transport.sendBytes(createSEQFrame(0, 10240, 4096));
 		transportCtrl.replay();
 		
 		// test
 		ChannelController controller = new DefaultChannelController(transport, 0, 4096);
 		controller.frameReceived(0, 4096);
 		controller.frameReceived(4096, 4096);
 		controller.frameReceived(8192, 2048);
 		
 		// verify
 		transportCtrl.verify();
 	}
 	
 	private ByteBuffer createSEQFrame(int channel, long ackno, int window) {
 		StringBuilder buf = new StringBuilder(SEQHeader.TYPE);
 		buf.append(" ");
 		buf.append(channel);
 		buf.append(" ");
 		buf.append(ackno);
 		buf.append(" ");
 		buf.append(window);
 		buf.append("\r\n");
 		return Charset.forName("US-ASCII").encode(buf.toString());
 	}
 
 }