/*
 *  Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  See the NOTICE file distributed with
 *  this work for additional information regarding copyright ownership.
 *  The ASF licenses this file to You 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.apache.coyote.http2;

import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.CompletionHandler;
import java.util.concurrent.Semaphore;
import java.util.concurrent.TimeUnit;

import org.junit.Assert;
import org.junit.Test;

import org.apache.tomcat.util.net.ApplicationBufferHandler;
import org.apache.tomcat.util.net.NioChannel;
import org.apache.tomcat.util.net.NioEndpoint;
import org.apache.tomcat.util.net.SSLSupport;
import org.apache.tomcat.util.net.SendfileDataBase;
import org.apache.tomcat.util.net.SendfileState;
import org.apache.tomcat.util.net.SocketWrapperBase;

/*
 * This tests use A=1, B=2, etc to map stream IDs to the names used in the
 * figures.
 */
public class TestAbstractStream {

    @Test
    public void testDependenciesFig3() {
        // Setup
        Http2UpgradeHandler handler =
                new Http2UpgradeHandler(new Http2Protocol(), null, null, new TesterSocketWrapper());
        Stream a = new Stream(Integer.valueOf(1), handler);
        Stream b = new Stream(Integer.valueOf(2), handler);
        Stream c = new Stream(Integer.valueOf(3), handler);
        Stream d = new Stream(Integer.valueOf(4), handler);
        b.rePrioritise(a, false, 16);
        c.rePrioritise(a, false, 16);

        // Action
        d.rePrioritise(a, false, 16);

        // Check parents
        Assert.assertEquals(handler, a.getParentStream());
        Assert.assertEquals(a, b.getParentStream());
        Assert.assertEquals(a, c.getParentStream());
        Assert.assertEquals(a, d.getParentStream());

        // Check children
        Assert.assertEquals(3,  a.getChildStreams().size());
        Assert.assertTrue(a.getChildStreams().contains(b));
        Assert.assertTrue(a.getChildStreams().contains(c));
        Assert.assertTrue(a.getChildStreams().contains(d));
        Assert.assertEquals(0,  b.getChildStreams().size());
        Assert.assertEquals(0,  c.getChildStreams().size());
        Assert.assertEquals(0,  d.getChildStreams().size());
    }


    @Test
    public void testDependenciesFig4() {
        // Setup
        Http2UpgradeHandler handler =
                new Http2UpgradeHandler(new Http2Protocol(), null, null, new TesterSocketWrapper());
        Stream a = new Stream(Integer.valueOf(1), handler);
        Stream b = new Stream(Integer.valueOf(2), handler);
        Stream c = new Stream(Integer.valueOf(3), handler);
        Stream d = new Stream(Integer.valueOf(4), handler);
        b.rePrioritise(a, false, 16);
        c.rePrioritise(a, false, 16);

        // Action
        d.rePrioritise(a, true, 16);

        // Check parents
        Assert.assertEquals(handler, a.getParentStream());
        Assert.assertEquals(d, b.getParentStream());
        Assert.assertEquals(d, c.getParentStream());
        Assert.assertEquals(a, d.getParentStream());

        // Check children
        Assert.assertEquals(1,  a.getChildStreams().size());
        Assert.assertTrue(a.getChildStreams().contains(d));
        Assert.assertEquals(2,  d.getChildStreams().size());
        Assert.assertTrue(d.getChildStreams().contains(b));
        Assert.assertTrue(d.getChildStreams().contains(c));
        Assert.assertEquals(0,  b.getChildStreams().size());
        Assert.assertEquals(0,  c.getChildStreams().size());
    }


    @Test
    public void testDependenciesFig5NonExclusive() {
        // Setup
        Http2UpgradeHandler handler =
                new Http2UpgradeHandler(new Http2Protocol(), null, null, new TesterSocketWrapper());
        Stream a = new Stream(Integer.valueOf(1), handler);
        Stream b = new Stream(Integer.valueOf(2), handler);
        Stream c = new Stream(Integer.valueOf(3), handler);
        Stream d = new Stream(Integer.valueOf(4), handler);
        Stream e = new Stream(Integer.valueOf(5), handler);
        Stream f = new Stream(Integer.valueOf(6), handler);
        b.rePrioritise(a, false, 16);
        c.rePrioritise(a, false, 16);
        d.rePrioritise(c, false, 16);
        e.rePrioritise(c, false, 16);
        f.rePrioritise(d, false, 16);

        // Action
        a.rePrioritise(d, false, 16);

        // Check parents
        Assert.assertEquals(handler, d.getParentStream());
        Assert.assertEquals(d, f.getParentStream());
        Assert.assertEquals(d, a.getParentStream());
        Assert.assertEquals(a, b.getParentStream());
        Assert.assertEquals(a, c.getParentStream());
        Assert.assertEquals(c, e.getParentStream());

        // Check children
        Assert.assertEquals(2,  d.getChildStreams().size());
        Assert.assertTrue(d.getChildStreams().contains(a));
        Assert.assertTrue(d.getChildStreams().contains(f));
        Assert.assertEquals(0,  f.getChildStreams().size());
        Assert.assertEquals(2,  a.getChildStreams().size());
        Assert.assertTrue(a.getChildStreams().contains(b));
        Assert.assertTrue(a.getChildStreams().contains(c));
        Assert.assertEquals(0,  b.getChildStreams().size());
        Assert.assertEquals(1,  c.getChildStreams().size());
        Assert.assertTrue(c.getChildStreams().contains(e));
        Assert.assertEquals(0,  e.getChildStreams().size());
    }


    @Test
    public void testDependenciesFig5Exclusive() {
        // Setup
        Http2UpgradeHandler handler =
                new Http2UpgradeHandler(new Http2Protocol(), null, null, new TesterSocketWrapper());
        Stream a = new Stream(Integer.valueOf(1), handler);
        Stream b = new Stream(Integer.valueOf(2), handler);
        Stream c = new Stream(Integer.valueOf(3), handler);
        Stream d = new Stream(Integer.valueOf(4), handler);
        Stream e = new Stream(Integer.valueOf(5), handler);
        Stream f = new Stream(Integer.valueOf(6), handler);
        b.rePrioritise(a, false, 16);
        c.rePrioritise(a, false, 16);
        d.rePrioritise(c, false, 16);
        e.rePrioritise(c, false, 16);
        f.rePrioritise(d, false, 16);

        // Action
        a.rePrioritise(d, true, 16);

        // Check parents
        Assert.assertEquals(handler, d.getParentStream());
        Assert.assertEquals(d, a.getParentStream());
        Assert.assertEquals(a, b.getParentStream());
        Assert.assertEquals(a, c.getParentStream());
        Assert.assertEquals(a, f.getParentStream());
        Assert.assertEquals(c, e.getParentStream());

        // Check children
        Assert.assertEquals(1,  d.getChildStreams().size());
        Assert.assertTrue(d.getChildStreams().contains(a));
        Assert.assertEquals(3,  a.getChildStreams().size());
        Assert.assertTrue(a.getChildStreams().contains(b));
        Assert.assertTrue(a.getChildStreams().contains(c));
        Assert.assertTrue(a.getChildStreams().contains(f));
        Assert.assertEquals(0,  b.getChildStreams().size());
        Assert.assertEquals(0,  f.getChildStreams().size());
        Assert.assertEquals(1,  c.getChildStreams().size());
        Assert.assertTrue(c.getChildStreams().contains(e));
        Assert.assertEquals(0,  e.getChildStreams().size());
    }


    @Test
    public void testCircular01() {
        // Setup
        Http2UpgradeHandler handler =
                new Http2UpgradeHandler(new Http2Protocol(), null, null, new TesterSocketWrapper());
        Stream a = new Stream(Integer.valueOf(1), handler);
        Stream b = new Stream(Integer.valueOf(2), handler);
        Stream c = new Stream(Integer.valueOf(3), handler);

        b.rePrioritise(a, false, 16);
        c.rePrioritise(b, false, 16);

        // Action
        a.rePrioritise(c, false, 16);

        // Check parents
        Assert.assertEquals(c, a.getParentStream());
        Assert.assertEquals(a, b.getParentStream());
        Assert.assertEquals(handler, c.getParentStream());

        // Check children
        Assert.assertEquals(1,  handler.getChildStreams().size());
        Assert.assertTrue(handler.getChildStreams().contains(c));
        Assert.assertEquals(1,  a.getChildStreams().size());
        Assert.assertTrue(a.getChildStreams().contains(b));
        Assert.assertEquals(0,  b.getChildStreams().size());
        Assert.assertEquals(1,  c.getChildStreams().size());
        Assert.assertTrue(c.getChildStreams().contains(a));
    }


    @Test
    public void testCircular02() {
        // Setup
        Http2UpgradeHandler handler =
                new Http2UpgradeHandler(new Http2Protocol(), null, null, new TesterSocketWrapper());
        Stream a = new Stream(Integer.valueOf(1), handler);
        Stream b = new Stream(Integer.valueOf(2), handler);
        Stream c = new Stream(Integer.valueOf(3), handler);
        Stream d = new Stream(Integer.valueOf(4), handler);
        Stream e = new Stream(Integer.valueOf(5), handler);
        Stream f = new Stream(Integer.valueOf(6), handler);

        b.rePrioritise(a, false, 16);
        c.rePrioritise(b, false, 16);
        e.rePrioritise(d, false, 16);
        f.rePrioritise(e, false, 16);

        // Action
        a.rePrioritise(f, false, 16);
        d.rePrioritise(c, false, 16);

        // Check parents
        Assert.assertEquals(f, a.getParentStream());
        Assert.assertEquals(a, b.getParentStream());
        Assert.assertEquals(handler, c.getParentStream());
        Assert.assertEquals(c, d.getParentStream());
        Assert.assertEquals(d, e.getParentStream());
        Assert.assertEquals(e, f.getParentStream());

        // Check children
        Assert.assertEquals(1,  handler.getChildStreams().size());
        Assert.assertTrue(handler.getChildStreams().contains(c));
        Assert.assertEquals(1,  a.getChildStreams().size());
        Assert.assertTrue(a.getChildStreams().contains(b));
        Assert.assertEquals(0,  b.getChildStreams().size());
        Assert.assertEquals(1,  c.getChildStreams().size());
        Assert.assertTrue(c.getChildStreams().contains(d));
        Assert.assertEquals(1,  d.getChildStreams().size());
        Assert.assertTrue(d.getChildStreams().contains(e));
        Assert.assertEquals(1,  e.getChildStreams().size());
        Assert.assertTrue(e.getChildStreams().contains(f));
        Assert.assertEquals(1,  f.getChildStreams().size());
        Assert.assertTrue(f.getChildStreams().contains(a));
    }


    // https://bz.apache.org/bugzilla/show_bug.cgi?id=61682
    @Test
    public void testCircular03() {
        // Setup
        Http2UpgradeHandler handler =
                new Http2UpgradeHandler(new Http2Protocol(), null, null, new TesterSocketWrapper());
        Stream a = new Stream(Integer.valueOf(1), handler);
        Stream b = new Stream(Integer.valueOf(3), handler);
        Stream c = new Stream(Integer.valueOf(5), handler);
        Stream d = new Stream(Integer.valueOf(7), handler);

        // Action
        b.rePrioritise(a, false, 16);
        c.rePrioritise(a, false, 16);
        d.rePrioritise(b, false, 16);
        c.rePrioritise(handler, false, 16);
        a.rePrioritise(c, false, 16);

        // Check parents
        Assert.assertEquals(c, a.getParentStream());
        Assert.assertEquals(a, b.getParentStream());
        Assert.assertEquals(handler, c.getParentStream());
        Assert.assertEquals(b, d.getParentStream());

        // This triggers the StackOverflowError
        Assert.assertTrue(c.isDescendant(d));

        // Check children
        Assert.assertEquals(1,  handler.getChildStreams().size());
        Assert.assertTrue(handler.getChildStreams().contains(c));
        Assert.assertEquals(1,  c.getChildStreams().size());
        Assert.assertTrue(c.getChildStreams().contains(a));
        Assert.assertEquals(1,  a.getChildStreams().size());
        Assert.assertTrue(a.getChildStreams().contains(b));
        Assert.assertEquals(1,  b.getChildStreams().size());
        Assert.assertTrue(b.getChildStreams().contains(d));
        Assert.assertEquals(0,  d.getChildStreams().size());
    }


    private static class TesterSocketWrapper extends SocketWrapperBase<NioChannel> {

        public TesterSocketWrapper() {
            super(null, new NioEndpoint());
        }

        @Override
        protected void populateRemoteHost() {
        }

        @Override
        protected void populateRemoteAddr() {
        }

        @Override
        protected void populateRemotePort() {
        }

        @Override
        protected void populateLocalName() {
        }

        @Override
        protected void populateLocalAddr() {
        }

        @Override
        protected void populateLocalPort() {
        }

        @Override
        public int read(boolean block, byte[] b, int off, int len) throws IOException {
            return 0;
        }

        @Override
        public int read(boolean block, ByteBuffer to) throws IOException {
            return 0;
        }

        @Override
        public boolean isReadyForRead() throws IOException {
            return false;
        }

        @Override
        public void setAppReadBufHandler(ApplicationBufferHandler handler) {
        }

        @Override
        protected void doClose() {
        }

        @Override
        protected boolean flushNonBlocking() throws IOException {
            return false;
        }

        @Override
        protected void doWrite(boolean block, ByteBuffer from) throws IOException {
        }

        @Override
        public void registerReadInterest() {
        }

        @Override
        public void registerWriteInterest() {
        }

        @Override
        public SendfileDataBase createSendfileData(String filename, long pos, long length) {
            return null;
        }

        @Override
        public SendfileState processSendfile(SendfileDataBase sendfileData) {
            return null;
        }

        @Override
        public void doClientAuth(SSLSupport sslSupport) throws IOException {
        }

        @Override
        public SSLSupport getSslSupport() {
            return null;
        }

        @Override
        protected <A> SocketWrapperBase<NioChannel>.OperationState<A> newOperationState(
                boolean read, ByteBuffer[] buffers, int offset, int length, BlockingMode block,
                long timeout, TimeUnit unit, A attachment, CompletionCheck check,
                CompletionHandler<Long, ? super A> handler, Semaphore semaphore,
                SocketWrapperBase<NioChannel>.VectoredIOCompletionHandler<A> completion) {
            return null;
        }
    }
}
