/*
    * 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.output;
  
  import static org.junit.jupiter.api.Assertions.assertArrayEquals;
  import static org.junit.jupiter.api.Assertions.assertEquals;
  import static org.junit.jupiter.api.Assertions.assertFalse;
  import static org.junit.jupiter.api.Assertions.assertInstanceOf;
  import static org.junit.jupiter.api.Assertions.assertNotNull;
  import static org.junit.jupiter.api.Assertions.assertTrue;
  
  import java.io.IOException;
  import java.util.concurrent.atomic.AtomicBoolean;
  
  import org.junit.jupiter.api.BeforeEach;
  import org.junit.jupiter.api.Test;
  
  /**
   * Tests {@link FlushShieldOutputStream}.
   */
  class FlushShieldOutputStreamTest {
  
      /** Tracks whether the underlying stream's close() was called. */
      private AtomicBoolean closed;
  
      /** Tracks whether the underlying stream's flush() was called. */
      private AtomicBoolean flushed;
  
      /** The stream under test. */
      private FlushShieldOutputStream shielded;
  
      /** The underlying byte-array-backed stream used as the delegate. */
      private ByteArrayOutputStream target;
  
      @BeforeEach
      void setUp() {
          flushed = new AtomicBoolean();
          closed = new AtomicBoolean();
          target = new ByteArrayOutputStream() {
  
              @Override
              public void close() throws IOException {
                  closed.set(true);
                  super.close();
              }
  
              @Override
              public void flush() throws IOException {
                  flushed.set(true);
                  super.flush();
              }
          };
          shielded = new FlushShieldOutputStream(target);
      }
  
      @Test
      void testBuilderGet() throws IOException {
          assertNotNull(FlushShieldOutputStream.builder().setOutputStream(target).get());
      }
  
      @Test
      void testBuilderWithOutputStream() throws IOException {
          try (FlushShieldOutputStream built = FlushShieldOutputStream.builder().setOutputStream(target).get()) {
              assertNotNull(built);
              assertInstanceOf(FlushShieldOutputStream.class, built);
              // flush must be shielded for builder-created instances too
              built.flush();
              assertFalse(flushed.get(), "flush() via builder instance must NOT reach the underlying stream.");
              // writes must still work
              built.write('B');
              assertEquals(1, target.size());
              assertEquals('B', target.toByteArray()[0]);
          }
      }
  
      @Test
      void testCloseReachesUnderlying() throws IOException {
          assertFalse(closed.get(), "close should not have been called yet.");
          shielded.close();
          assertTrue(closed.get(), "close() must reach the underlying stream.");
      }
  
      @Test
      void testFlushCanBeCalledMultipleTimes() throws IOException {
         shielded.flush();
         shielded.flush();
         shielded.flush();
         assertFalse(flushed.get(), "repeated flush() calls must NOT reach the underlying stream.");
     }
 
     @Test
     void testFlushDoesNotDelegateToUnderlying() throws IOException {
         assertFalse(flushed.get(), "flush should not have been called yet.");
         shielded.flush();
         assertFalse(flushed.get(), "flush() must NOT reach the underlying stream.");
     }
 
     @Test
     void testWriteByteArray() throws IOException {
         final byte[] data = { 'H', 'i' };
         shielded.write(data);
         assertEquals(2, target.size());
         assertArrayEquals(data, target.toByteArray());
     }
 
     @Test
     void testWriteByteArrayWithOffset() throws IOException {
         final byte[] data = { 'X', 'Y', 'Z' };
         shielded.write(data, 1, 2);
         assertEquals(2, target.size());
         assertArrayEquals(new byte[] { 'Y', 'Z' }, target.toByteArray());
     }
 
     @Test
     void testWriteInt() throws IOException {
         shielded.write('A');
         assertEquals(1, target.size());
         assertEquals('A', target.toByteArray()[0]);
     }
 }