/*
 * Copyright 2012-2016 the original author or authors.
 *
 * 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 org.springframework.boot.devtools.tunnel.payload;

import java.io.ByteArrayOutputStream;
import java.nio.ByteBuffer;
import java.nio.channels.Channels;
import java.nio.channels.WritableByteChannel;

import org.junit.Rule;
import org.junit.Test;
import org.junit.rules.ExpectedException;

import static org.assertj.core.api.Assertions.assertThat;

/**
 * Tests for {@link HttpTunnelPayloadForwarder}.
 *
 * @author Phillip Webb
 */
public class HttpTunnelPayloadForwarderTests {

	@Rule
	public ExpectedException thrown = ExpectedException.none();

	@Test
	public void targetChannelMustNotBeNull() throws Exception {
		this.thrown.expect(IllegalArgumentException.class);
		this.thrown.expectMessage("TargetChannel must not be null");
		new HttpTunnelPayloadForwarder(null);
	}

	@Test
	public void forwardInSequence() throws Exception {
		ByteArrayOutputStream out = new ByteArrayOutputStream();
		WritableByteChannel channel = Channels.newChannel(out);
		HttpTunnelPayloadForwarder forwarder = new HttpTunnelPayloadForwarder(channel);
		forwarder.forward(payload(1, "he"));
		forwarder.forward(payload(2, "ll"));
		forwarder.forward(payload(3, "o"));
		assertThat(out.toByteArray()).isEqualTo("hello".getBytes());
	}

	@Test
	public void forwardOutOfSequence() throws Exception {
		ByteArrayOutputStream out = new ByteArrayOutputStream();
		WritableByteChannel channel = Channels.newChannel(out);
		HttpTunnelPayloadForwarder forwarder = new HttpTunnelPayloadForwarder(channel);
		forwarder.forward(payload(3, "o"));
		forwarder.forward(payload(2, "ll"));
		forwarder.forward(payload(1, "he"));
		assertThat(out.toByteArray()).isEqualTo("hello".getBytes());
	}

	@Test
	public void overflow() throws Exception {
		WritableByteChannel channel = Channels.newChannel(new ByteArrayOutputStream());
		HttpTunnelPayloadForwarder forwarder = new HttpTunnelPayloadForwarder(channel);
		this.thrown.expect(IllegalStateException.class);
		this.thrown.expectMessage("Too many messages queued");
		for (int i = 2; i < 130; i++) {
			forwarder.forward(payload(i, "data" + i));
		}
	}

	private HttpTunnelPayload payload(long sequence, String data) {
		return new HttpTunnelPayload(sequence, ByteBuffer.wrap(data.getBytes()));
	}

}
