/*
    * 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.commons.compress.compressors.lz77support;
  
  import static org.junit.jupiter.api.Assertions.assertArrayEquals;
  import static org.junit.jupiter.api.Assertions.assertEquals;
  import static org.junit.jupiter.api.Assertions.assertThrows;
  
  import java.io.ByteArrayInputStream;
  import java.io.IOException;
  import java.io.InputStream;
  
  import org.apache.commons.compress.utils.ByteUtils;
  import org.junit.jupiter.api.Test;
  
  public class AbstractLZ77CompressorInputStreamTest {
  
      private static final class TestStream extends AbstractLZ77CompressorInputStream {
  
          private boolean literal;
  
          TestStream(final InputStream in) {
              super(in, 1024);
          }
  
          void literal(final int len) {
              startLiteral(len);
              literal = true;
          }
  
          @Override
          public int read(final byte[] b, final int off, final int len) throws IOException {
              if (literal) {
                  return readLiteral(b, off, len);
              }
              return readBackReference(b, off, len);
          }
      }
  
      @Test
      public void testCantPrefillAfterDataHasBeenRead() throws IOException {
          final byte[] data = { 1, 2, 3, 4 };
          try (TestStream s = new TestStream(new ByteArrayInputStream(data))) {
              s.literal(3);
              assertEquals(1, s.read());
              assertThrows(IllegalStateException.class, () -> s.prefill(new byte[] { 1, 2, 3 }));
          }
      }
  
      @Test
      public void testIfPrefillExceedsWindowSizeTheLastBytesAreUsed() throws IOException {
          final byte[] data = new byte[2048];
          data[2046] = 3;
          data[2047] = 4;
          try (TestStream s = new TestStream(new ByteArrayInputStream(ByteUtils.EMPTY_BYTE_ARRAY))) {
              s.prefill(data);
              s.startBackReference(2, 4);
              final byte[] r = new byte[4];
              assertEquals(4, s.read(r));
              assertArrayEquals(new byte[] { 3, 4, 3, 4 }, r);
          }
      }
  
      @Test
      public void testPrefillCanBeUsedForBackReferences() throws IOException {
          final byte[] data = { 1, 2, 3, 4 };
          try (TestStream s = new TestStream(new ByteArrayInputStream(ByteUtils.EMPTY_BYTE_ARRAY))) {
              s.prefill(data);
              s.startBackReference(2, 4);
              final byte[] r = new byte[4];
              assertEquals(4, s.read(r));
              assertArrayEquals(new byte[] { 3, 4, 3, 4 }, r);
          }
      }
  }