/*
 * Copyright 2014 The gRPC 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 io.grpc.internal;

import static com.google.common.truth.Truth.assertThat;
import static io.grpc.internal.GrpcUtil.DEFAULT_MAX_MESSAGE_SIZE;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertNull;
import static org.junit.Assert.assertThrows;
import static org.junit.Assert.assertTrue;
import static org.junit.Assume.assumeTrue;
import static org.mockito.ArgumentMatchers.anyInt;
import static org.mockito.Mockito.atLeast;
import static org.mockito.Mockito.atLeastOnce;
import static org.mockito.Mockito.doAnswer;
import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.times;
import static org.mockito.Mockito.verify;
import static org.mockito.Mockito.verifyNoMoreInteractions;

import com.google.common.io.ByteStreams;
import com.google.common.primitives.Bytes;
import io.grpc.Codec;
import io.grpc.InternalChannelz.TransportStats;
import io.grpc.StatusRuntimeException;
import io.grpc.StreamTracer;
import io.grpc.internal.MessageDeframer.Listener;
import io.grpc.internal.MessageDeframer.SizeEnforcingInputStream;
import io.grpc.internal.testing.TestStreamTracer.TestBaseStreamTracer;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.charset.StandardCharsets;
import java.util.Arrays;
import java.util.Collection;
import java.util.List;
import java.util.Locale;
import java.util.concurrent.TimeUnit;
import java.util.zip.GZIPOutputStream;
import org.junit.Before;
import org.junit.Test;
import org.junit.experimental.runners.Enclosed;
import org.junit.runner.RunWith;
import org.junit.runners.JUnit4;
import org.junit.runners.Parameterized;
import org.junit.runners.Parameterized.Parameter;
import org.junit.runners.Parameterized.Parameters;
import org.mockito.ArgumentCaptor;
import org.mockito.ArgumentMatchers;
import org.mockito.invocation.InvocationOnMock;
import org.mockito.stubbing.Answer;

/**
 * Tests for {@link MessageDeframer}.
 */
@RunWith(Enclosed.class)
public class MessageDeframerTest {

  @RunWith(Parameterized.class)
  public static class WithAndWithoutFullStreamCompressionTests {

    /**
     * Auto called by test.
     */
    @Parameters(name = "{index}: useGzipInflatingBuffer={0}")
    public static Collection<Object[]> data() {
      return Arrays.asList(new Object[][]{
              {false}, {true}
      });
    }

    private final FakeClock fakeClock = new FakeClock();

    @Parameter // Automatically set by test runner, must be public
    public boolean useGzipInflatingBuffer;

    private Listener listener = mock(Listener.class);
    private TestBaseStreamTracer tracer = new TestBaseStreamTracer();
    private StatsTraceContext statsTraceCtx = new StatsTraceContext(new StreamTracer[]{tracer});
    private TransportTracer transportTracer =
        new TransportTracer.Factory(fakeClock.getTimeProvider()).create();

    private MessageDeframer deframer = new MessageDeframer(listener, Codec.Identity.NONE,
            DEFAULT_MAX_MESSAGE_SIZE, statsTraceCtx, transportTracer);

    private ArgumentCaptor<StreamListener.MessageProducer> producer =
            ArgumentCaptor.forClass(StreamListener.MessageProducer.class);

    @Before
    public void setUp() {
      if (useGzipInflatingBuffer) {
        deframer.setFullStreamDecompressor(new GzipInflatingBuffer() {
          @Override
          public void addGzippedBytes(ReadableBuffer buffer) {
            try {
              ByteArrayOutputStream gzippedOutputStream = new ByteArrayOutputStream();
              OutputStream gzipCompressingStream = new GZIPOutputStream(
                      gzippedOutputStream);
              buffer.readBytes(gzipCompressingStream, buffer.readableBytes());
              gzipCompressingStream.close();
              super.addGzippedBytes(ReadableBuffers.wrap(gzippedOutputStream.toByteArray()));
            } catch (IOException e) {
              throw new RuntimeException(e);
            }
          }
        });
      }
    }

    @Test
    public void simplePayload() {
      deframer.request(1);
      fakeClock.forwardTime(10, TimeUnit.MILLISECONDS);
      deframer.deframe(buffer(new byte[]{0, 0, 0, 0, 2, 3, 14}));
      verify(listener).messagesAvailable(producer.capture());
      assertEquals(Bytes.asList(new byte[]{3, 14}), bytes(producer.getValue().next()));
      verify(listener, atLeastOnce()).bytesRead(anyInt());
      verifyNoMoreInteractions(listener);
      checkStats(tracer, transportTracer.getStats(), fakeClock, useGzipInflatingBuffer, 2, 2);
    }

    @Test
    public void smallCombinedPayloads() {
      deframer.request(2);
      fakeClock.forwardTime(10, TimeUnit.MILLISECONDS);
      deframer.deframe(buffer(new byte[]{0, 0, 0, 0, 1, 3, 0, 0, 0, 0, 2, 14, 15}));
      verify(listener, times(2)).messagesAvailable(producer.capture());
      List<StreamListener.MessageProducer> streams = producer.getAllValues();
      assertEquals(2, streams.size());
      assertEquals(Bytes.asList(new byte[]{3}), bytes(streams.get(0).next()));
      verify(listener, atLeastOnce()).bytesRead(anyInt());
      assertEquals(Bytes.asList(new byte[]{14, 15}), bytes(streams.get(1).next()));
      verifyNoMoreInteractions(listener);
      checkStats(tracer, transportTracer.getStats(), fakeClock, useGzipInflatingBuffer, 1, 1, 2, 2);
    }

    @Test
    public void endOfStreamWithPayloadShouldNotifyEndOfStream() {
      deframer.request(1);
      fakeClock.forwardTime(10, TimeUnit.MILLISECONDS);
      deframer.deframe(buffer(new byte[]{0, 0, 0, 0, 1, 3}));
      deframer.closeWhenComplete();
      verify(listener).messagesAvailable(producer.capture());
      assertEquals(Bytes.asList(new byte[]{3}), bytes(producer.getValue().next()));
      verify(listener).deframerClosed(false);
      verify(listener, atLeastOnce()).bytesRead(anyInt());
      verifyNoMoreInteractions(listener);
      checkStats(tracer, transportTracer.getStats(), fakeClock,  useGzipInflatingBuffer, 1, 1);
    }

    @Test
    public void endOfStreamShouldNotifyEndOfStream() {
      fakeClock.forwardTime(10, TimeUnit.MILLISECONDS);
      deframer.deframe(buffer(new byte[0]));
      deframer.closeWhenComplete();
      deframer.request(1);
      if (useGzipInflatingBuffer) {
        deframer.request(1); // process the 20-byte empty GZIP stream, to get stalled=true
        verify(listener, atLeast(1)).bytesRead(anyInt());
      }
      verify(listener).deframerClosed(false);
      verifyNoMoreInteractions(listener);
      checkStats(tracer, transportTracer.getStats(), fakeClock, false);
    }

    @Test
    public void endOfStreamWithPartialMessageShouldNotifyDeframerClosedWithPartialMessage() {
      deframer.request(1);
      fakeClock.forwardTime(10, TimeUnit.MILLISECONDS);
      deframer.deframe(buffer(new byte[1]));
      deframer.closeWhenComplete();
      verify(listener, atLeastOnce()).bytesRead(anyInt());
      verify(listener).deframerClosed(true);
      verifyNoMoreInteractions(listener);
      checkStats(tracer, transportTracer.getStats(), fakeClock, false);
    }

    @Test
    public void endOfStreamWithInvalidGzipBlockShouldNotifyDeframerClosedWithPartialMessage() {
      assumeTrue("test only valid for full-stream compression", useGzipInflatingBuffer);

      // Create new deframer to allow writing bytes directly to the GzipInflatingBuffer
      MessageDeframer deframer = new MessageDeframer(listener, Codec.Identity.NONE,
              DEFAULT_MAX_MESSAGE_SIZE, statsTraceCtx, transportTracer);
      deframer.setFullStreamDecompressor(new GzipInflatingBuffer());
      deframer.request(1);
      fakeClock.forwardTime(10, TimeUnit.MILLISECONDS);
      deframer.deframe(buffer(new byte[1]));
      deframer.closeWhenComplete();
      verify(listener).deframerClosed(true);
      verifyNoMoreInteractions(listener);
      checkStats(tracer, transportTracer.getStats(), fakeClock, false);
    }

    @Test
    public void payloadSplitBetweenBuffers() {
      deframer.request(1);
      fakeClock.forwardTime(10, TimeUnit.MILLISECONDS);
      deframer.deframe(buffer(new byte[]{0, 0, 0, 0, 7, 3, 14, 1, 5, 9}));
      verify(listener, atLeastOnce()).bytesRead(anyInt());
      verifyNoMoreInteractions(listener);
      deframer.deframe(buffer(new byte[]{2, 6}));
      verify(listener).messagesAvailable(producer.capture());
      assertEquals(
              Bytes.asList(new byte[]{3, 14, 1, 5, 9, 2, 6}), bytes(producer.getValue().next()));
      verify(listener, atLeastOnce()).bytesRead(anyInt());
      verifyNoMoreInteractions(listener);

      if (useGzipInflatingBuffer) {
        checkStats(
            tracer,
            transportTracer.getStats(),
            fakeClock,
            true,
            7 /* msg size */ + 2 /* second buffer adds two bytes of overhead in deflate block */,
            7);
      } else {
        checkStats(tracer, transportTracer.getStats(), fakeClock, false, 7, 7);
      }
    }

    @Test
    public void frameHeaderSplitBetweenBuffers() {
      deframer.request(1);
      fakeClock.forwardTime(10, TimeUnit.MILLISECONDS);
      deframer.deframe(buffer(new byte[]{0, 0}));
      verify(listener, atLeastOnce()).bytesRead(anyInt());
      verifyNoMoreInteractions(listener);
      fakeClock.forwardTime(10, TimeUnit.MILLISECONDS);
      deframer.deframe(buffer(new byte[]{0, 0, 1, 3}));
      verify(listener).messagesAvailable(producer.capture());
      assertEquals(Bytes.asList(new byte[]{3}), bytes(producer.getValue().next()));
      verify(listener, atLeastOnce()).bytesRead(anyInt());
      verifyNoMoreInteractions(listener);
      checkStats(tracer, transportTracer.getStats(), fakeClock, useGzipInflatingBuffer, 1, 1);
    }

    @Test
    public void emptyPayload() {
      deframer.request(1);
      deframer.deframe(buffer(new byte[]{0, 0, 0, 0, 0}));
      verify(listener).messagesAvailable(producer.capture());
      assertEquals(Bytes.asList(), bytes(producer.getValue().next()));
      verify(listener, atLeastOnce()).bytesRead(anyInt());
      verifyNoMoreInteractions(listener);
      checkStats(tracer, transportTracer.getStats(), fakeClock, useGzipInflatingBuffer, 0, 0);
    }

    @Test
    public void largerFrameSize() {
      deframer.request(1);
      fakeClock.forwardTime(10, TimeUnit.MILLISECONDS);
      deframer.deframe(ReadableBuffers.wrap(
              Bytes.concat(new byte[]{0, 0, 0, 3, (byte) 232}, new byte[1000])));
      verify(listener).messagesAvailable(producer.capture());
      assertEquals(Bytes.asList(new byte[1000]), bytes(producer.getValue().next()));
      verify(listener, atLeastOnce()).bytesRead(anyInt());
      verifyNoMoreInteractions(listener);
      if (useGzipInflatingBuffer) {
        checkStats(tracer, transportTracer.getStats(), fakeClock,true,
            8 /* compressed size */, 1000);
      } else {
        checkStats(tracer, transportTracer.getStats(), fakeClock, false, 1000, 1000);
      }
    }

    @Test
    public void endOfStreamCallbackShouldWaitForMessageDelivery() {
      fakeClock.forwardTime(10, TimeUnit.MILLISECONDS);
      deframer.deframe(buffer(new byte[]{0, 0, 0, 0, 1, 3}));
      deframer.closeWhenComplete();
      verifyNoMoreInteractions(listener);

      deframer.request(1);
      verify(listener).messagesAvailable(producer.capture());
      assertEquals(Bytes.asList(new byte[]{3}), bytes(producer.getValue().next()));
      verify(listener).deframerClosed(false);
      verify(listener, atLeastOnce()).bytesRead(anyInt());
      verifyNoMoreInteractions(listener);
      checkStats(tracer, transportTracer.getStats(), fakeClock, useGzipInflatingBuffer, 1, 1);
    }

    @Test
    public void compressed() {
      deframer = new MessageDeframer(listener, new Codec.Gzip(), DEFAULT_MAX_MESSAGE_SIZE,
              statsTraceCtx, transportTracer);
      deframer.request(1);

      byte[] payload = compress(new byte[1000]);
      assertTrue(payload.length < 100);
      byte[] header = new byte[]{1, 0, 0, 0, (byte) payload.length};
      deframer.deframe(buffer(Bytes.concat(header, payload)));
      verify(listener).messagesAvailable(producer.capture());
      assertEquals(Bytes.asList(new byte[1000]), bytes(producer.getValue().next()));
      verify(listener, atLeastOnce()).bytesRead(anyInt());
      checkStats(tracer, transportTracer.getStats(), fakeClock, true, 29, 1000);
      verifyNoMoreInteractions(listener);
    }

    @Test
    public void deliverIsReentrantSafe() {
      doAnswer(
          new Answer<Void>() {
            @Override
            public Void answer(InvocationOnMock invocation) throws Throwable {
              deframer.request(1);
              return null;
            }
          })
          .when(listener)
          .messagesAvailable(ArgumentMatchers.<StreamListener.MessageProducer>any());
      deframer.deframe(buffer(new byte[]{0, 0, 0, 0, 1, 3}));
      deframer.closeWhenComplete();
      verifyNoMoreInteractions(listener);

      deframer.request(1);
      verify(listener).messagesAvailable(producer.capture());
      assertEquals(Bytes.asList(new byte[]{3}), bytes(producer.getValue().next()));
      verify(listener).deframerClosed(false);
      verify(listener, atLeastOnce()).bytesRead(anyInt());
      verifyNoMoreInteractions(listener);
    }
  }

  @RunWith(JUnit4.class)
  public static class SizeEnforcingInputStreamTests {

    private TestBaseStreamTracer tracer = new TestBaseStreamTracer();
    private StatsTraceContext statsTraceCtx = new StatsTraceContext(new StreamTracer[]{tracer});

    @Test
    public void sizeEnforcingInputStream_readByteBelowLimit() throws IOException {
      ByteArrayInputStream in = new ByteArrayInputStream("foo".getBytes(StandardCharsets.UTF_8));
      SizeEnforcingInputStream stream =
              new MessageDeframer.SizeEnforcingInputStream(in, 4, statsTraceCtx);

      while (stream.read() != -1) {
      }

      stream.close();
      checkSizeEnforcingInputStreamStats(tracer, 3);
    }

    @Test
    public void sizeEnforcingInputStream_readByteAtLimit() throws IOException {
      ByteArrayInputStream in = new ByteArrayInputStream("foo".getBytes(StandardCharsets.UTF_8));
      SizeEnforcingInputStream stream =
              new MessageDeframer.SizeEnforcingInputStream(in, 3, statsTraceCtx);

      while (stream.read() != -1) {
      }

      stream.close();
      checkSizeEnforcingInputStreamStats(tracer, 3);
    }

    @Test
    public void sizeEnforcingInputStream_readByteAboveLimit() throws IOException {
      ByteArrayInputStream in = new ByteArrayInputStream("foo".getBytes(StandardCharsets.UTF_8));
      SizeEnforcingInputStream stream =
              new MessageDeframer.SizeEnforcingInputStream(in, 2, statsTraceCtx);

      try {
        StatusRuntimeException e = assertThrows(StatusRuntimeException.class, () -> {
          while (stream.read() != -1) {
          }
        });
        assertThat(e).hasMessageThat()
            .isEqualTo("RESOURCE_EXHAUSTED: Decompressed gRPC message exceeds maximum size 2");
      } finally {
        stream.close();
      }
    }

    @Test
    public void sizeEnforcingInputStream_readBelowLimit() throws IOException {
      ByteArrayInputStream in = new ByteArrayInputStream("foo".getBytes(StandardCharsets.UTF_8));
      SizeEnforcingInputStream stream =
              new MessageDeframer.SizeEnforcingInputStream(in, 4, statsTraceCtx);
      byte[] buf = new byte[10];

      int read = stream.read(buf, 0, buf.length);

      assertEquals(3, read);
      stream.close();
      checkSizeEnforcingInputStreamStats(tracer, 3);
    }

    @Test
    public void sizeEnforcingInputStream_readAtLimit() throws IOException {
      ByteArrayInputStream in = new ByteArrayInputStream("foo".getBytes(StandardCharsets.UTF_8));
      SizeEnforcingInputStream stream =
              new MessageDeframer.SizeEnforcingInputStream(in, 3, statsTraceCtx);
      byte[] buf = new byte[10];

      int read = stream.read(buf, 0, buf.length);

      assertEquals(3, read);
      stream.close();
      checkSizeEnforcingInputStreamStats(tracer, 3);
    }

    @Test
    public void sizeEnforcingInputStream_readAboveLimit() throws IOException {
      ByteArrayInputStream in = new ByteArrayInputStream("foo".getBytes(StandardCharsets.UTF_8));
      SizeEnforcingInputStream stream =
              new MessageDeframer.SizeEnforcingInputStream(in, 2, statsTraceCtx);
      byte[] buf = new byte[10];

      try {
        StatusRuntimeException e = assertThrows(StatusRuntimeException.class,
            () -> stream.read(buf, 0, buf.length));
        assertThat(e).hasMessageThat()
            .isEqualTo("RESOURCE_EXHAUSTED: Decompressed gRPC message exceeds maximum size 2");
      } finally {
        stream.close();
      }
    }

    @Test
    public void sizeEnforcingInputStream_skipBelowLimit() throws IOException {
      ByteArrayInputStream in = new ByteArrayInputStream("foo".getBytes(StandardCharsets.UTF_8));
      SizeEnforcingInputStream stream =
              new MessageDeframer.SizeEnforcingInputStream(in, 4, statsTraceCtx);

      long skipped = stream.skip(4);

      assertEquals(3, skipped);

      stream.close();
      checkSizeEnforcingInputStreamStats(tracer, 3);
    }

    @Test
    public void sizeEnforcingInputStream_skipAtLimit() throws IOException {
      ByteArrayInputStream in = new ByteArrayInputStream("foo".getBytes(StandardCharsets.UTF_8));
      SizeEnforcingInputStream stream =
              new MessageDeframer.SizeEnforcingInputStream(in, 3, statsTraceCtx);

      long skipped = stream.skip(4);

      assertEquals(3, skipped);
      stream.close();
      checkSizeEnforcingInputStreamStats(tracer, 3);
    }

    @Test
    public void sizeEnforcingInputStream_skipAboveLimit() throws IOException {
      ByteArrayInputStream in = new ByteArrayInputStream("foo".getBytes(StandardCharsets.UTF_8));
      SizeEnforcingInputStream stream =
              new MessageDeframer.SizeEnforcingInputStream(in, 2, statsTraceCtx);

      try {
        StatusRuntimeException e = assertThrows(StatusRuntimeException.class, () -> stream.skip(4));
        assertThat(e).hasMessageThat()
            .isEqualTo("RESOURCE_EXHAUSTED: Decompressed gRPC message exceeds maximum size 2");
      } finally {
        stream.close();
      }
    }

    @Test
    public void sizeEnforcingInputStream_markReset() throws IOException {
      ByteArrayInputStream in = new ByteArrayInputStream("foo".getBytes(StandardCharsets.UTF_8));
      SizeEnforcingInputStream stream =
              new MessageDeframer.SizeEnforcingInputStream(in, 3, statsTraceCtx);
      // stream currently looks like: |foo
      stream.skip(1); // f|oo
      stream.mark(10); // any large number will work.
      stream.skip(2); // foo|
      stream.reset(); // f|oo
      long skipped = stream.skip(2); // foo|

      assertEquals(2, skipped);
      stream.close();
      checkSizeEnforcingInputStreamStats(tracer, 3);
    }
  }

  /**
   * Verify stats were published through the tracer.
   *
   * @param transportStats the transport level stats counters
   * @param clock the fakeClock to verify timestamp
   * @param sizes in the format {wire0, uncompressed0, wire1, uncompressed1, ...}
   */
  private static void checkStats(
      TestBaseStreamTracer tracer, TransportStats transportStats, FakeClock clock,
      boolean compressed, long... sizes) {
    assertEquals(0, sizes.length % 2);
    int count = sizes.length / 2;
    long expectedWireSize = 0;
    long expectedUncompressedSize = 0;
    for (int i = 0; i < count; i++) {
      assertEquals("inboundMessage(" + i + ")", tracer.nextInboundEvent());
      assertEquals(
          String.format(Locale.US, "inboundMessageRead(%d, %d, %d)", i, sizes[i * 2],
              compressed ? -1 : sizes[i * 2 + 1]),
          tracer.nextInboundEvent());
      expectedWireSize += sizes[i * 2];
      expectedUncompressedSize += sizes[i * 2 + 1];
    }
    assertNull(tracer.nextInboundEvent());
    assertNull(tracer.nextOutboundEvent());
    assertEquals(expectedWireSize, tracer.getInboundWireSize());
    assertEquals(expectedUncompressedSize, tracer.getInboundUncompressedSize());

    assertEquals(count, transportStats.messagesReceived);
    if (count > 0) {
      assertThat(transportStats.lastMessageReceivedTimeNanos)
          .isEqualTo(clock.getTimeProvider().currentTimeNanos());
    } else {
      assertEquals(0L, transportStats.lastMessageReceivedTimeNanos);
    }
  }

  private static void checkSizeEnforcingInputStreamStats(
      TestBaseStreamTracer tracer, long uncompressedSize) {
    assertNull(tracer.nextInboundEvent());
    assertNull(tracer.nextOutboundEvent());
    assertEquals(0, tracer.getInboundWireSize());
    // SizeEnforcingInputStream only reports uncompressed bytes
    assertEquals(uncompressedSize, tracer.getInboundUncompressedSize());
  }

  private static List<Byte> bytes(InputStream in) {
    try {
      return Bytes.asList(ByteStreams.toByteArray(in));
    } catch (IOException ex) {
      throw new AssertionError(ex);
    }
  }

  private static ReadableBuffer buffer(byte[] bytes) {
    return ReadableBuffers.wrap(bytes);
  }

  private static byte[] compress(byte[] bytes) {
    try {
      ByteArrayOutputStream baos = new ByteArrayOutputStream();
      GZIPOutputStream zip = new GZIPOutputStream(baos);
      zip.write(bytes);
      zip.close();
      return baos.toByteArray();
    } catch (IOException ex) {
      throw new RuntimeException(ex);
    }
  }
}
