/*
    * 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
    *
    *      https://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.io.input;
  
  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 static org.junit.jupiter.api.Assertions.assertTrue;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.util.Arrays;
  
  import org.apache.commons.io.IOUtils;
  import org.junit.jupiter.api.Test;
  
  /**
   * Tests {@link CircularInputStream}.
   */
  class CircularInputStreamTest {
  
      private void assertStreamOutput(final byte[] toCycle, final byte[] expected) throws IOException {
          final byte[] actual = new byte[expected.length];
  
          try (InputStream inputStream = createInputStream(toCycle, -1)) {
              final int actualReadBytes = inputStream.read(actual);
              assertArrayEquals(expected, actual);
              assertEquals(expected.length, actualReadBytes);
          }
      }
  
      private InputStream createInputStream(final byte[] repeatContent, final long targetByteCount) {
          return new CircularInputStream(repeatContent, targetByteCount);
      }
  
      @SuppressWarnings("resource")
      @Test
      void testAvailableAfterClose() throws Exception {
          final InputStream shadow;
          try (InputStream in = createInputStream(new byte[] { 1, 2 }, 4)) {
              assertTrue(in.available() > 0);
              assertEquals(1, in.read());
              assertEquals(2, in.read());
              assertEquals(1, in.read());
              shadow = in;
          }
          assertEquals(0, shadow.available());
      }
  
      @Test
      void testAvailableAfterOpen() throws Exception {
          try (InputStream in = createInputStream(new byte[] { 1, 2 }, 1)) {
              assertTrue(in.available() > 0);
              assertEquals(1, in.read());
              assertTrue(in.available() > 0);
          }
      }
  
      @Test
      void testContainsEofInputSize0() {
          assertThrows(IllegalArgumentException.class, () -> createInputStream(new byte[] { -1 }, 0));
      }
  
      @Test
      void testCount0() throws IOException {
          try (InputStream in = createInputStream(new byte[] { 1, 2 }, 0)) {
              assertEquals(IOUtils.EOF, in.read());
          }
      }
  
      @Test
      void testCount0InputSize0() {
          assertThrows(IllegalArgumentException.class, () -> createInputStream(new byte[] {}, 0));
      }
  
      @Test
      void testCount0InputSize1() throws IOException {
          try (InputStream in = createInputStream(new byte[] { 1 }, 0)) {
              assertEquals(IOUtils.EOF, in.read());
          }
      }
  
      @Test
      void testCount1InputSize1() throws IOException {
          try (InputStream in = createInputStream(new byte[] { 1 }, 1)) {
             assertEquals(1, in.read());
             assertEquals(IOUtils.EOF, in.read());
         }
     }
 
     @Test
     void testCycleBytes() throws IOException {
         final byte[] input = { 1, 2 };
         final byte[] expected = { 1, 2, 1, 2, 1 };
         assertStreamOutput(input, expected);
     }
 
     @Test
     void testNullInputSize0() {
         assertThrows(NullPointerException.class, () -> createInputStream(null, 0));
     }
 
     @SuppressWarnings("resource")
     @Test
     void testReaderAfterClose() throws Exception {
         final InputStream shadow;
         try (InputStream in = createInputStream(new byte[] { 1, 2 }, 4)) {
             assertTrue(in.available() > 0);
             assertEquals(1, in.read());
             assertEquals(2, in.read());
             assertEquals(1, in.read());
             shadow = in;
         }
         assertEquals(IOUtils.EOF, shadow.read());
     }
 
     @Test
     void testWholeRangeOfBytes() throws IOException {
         final int size = Byte.MAX_VALUE - Byte.MIN_VALUE + 1;
         final byte[] contentToCycle = new byte[size];
         byte value = Byte.MIN_VALUE;
         for (int i = 0; i < contentToCycle.length; i++) {
             contentToCycle[i] = value == IOUtils.EOF ? 0 : value;
             value++;
         }
         final byte[] expectedOutput = Arrays.copyOf(contentToCycle, size);
         assertStreamOutput(contentToCycle, expectedOutput);
     }
 
 }