/*
    * 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.lang3.concurrent;
  
  import static org.junit.jupiter.api.Assertions.assertEquals;
  import static org.junit.jupiter.api.Assertions.assertInstanceOf;
  import static org.junit.jupiter.api.Assertions.assertThrows;
  import static org.junit.jupiter.api.Assertions.assertTrue;
  
  import java.util.Arrays;
  import java.util.List;
  import java.util.concurrent.CountDownLatch;
  import java.util.concurrent.ExecutionException;
  import java.util.concurrent.Future;
  import java.util.concurrent.TimeUnit;
  import java.util.concurrent.TimeoutException;
  import java.util.concurrent.atomic.AtomicBoolean;
  import java.util.concurrent.atomic.AtomicReference;
  import java.util.function.Consumer;
  import java.util.stream.Collectors;
  
  import org.apache.commons.lang3.AbstractLangTest;
  import org.apache.commons.lang3.exception.UncheckedInterruptedException;
  import org.junit.jupiter.api.Test;
  
  /**
   * Tests {@link UncheckedFuture}.
   */
  class UncheckedFutureTest extends AbstractLangTest {
  
      private static final class TestFuture<V> extends AbstractFutureProxy<V> {
  
          private final Exception exception;
  
          TestFuture(final Exception throwable) {
              super(ConcurrentUtils.constantFuture(null));
              this.exception = throwable;
          }
  
          TestFuture(final V value) {
              super(ConcurrentUtils.constantFuture(value));
              this.exception = null;
          }
  
          @SuppressWarnings("unchecked") // Programming error if call site blows up at runtime.
          private <T extends Exception> void checkException() throws T {
              if (exception != null) {
                  throw (T) exception;
              }
          }
  
          @Override
          public V get() throws InterruptedException, ExecutionException {
              checkException();
              return super.get();
          }
  
          @Override
          public V get(final long timeout, final TimeUnit unit) throws InterruptedException, ExecutionException, TimeoutException {
              checkException();
              return super.get(timeout, unit);
          }
  
      }
  
      private static void assertInterruptPreserved(final Consumer<UncheckedFuture<Integer>> call) throws Exception {
          final CountDownLatch enteredGet = new CountDownLatch(1);
          final Future<Integer> blockingFuture = new AbstractFutureProxy<Integer>(ConcurrentUtils.constantFuture(42)) {
  
              private final CountDownLatch neverRelease = new CountDownLatch(1);
  
              @Override
              public Integer get() throws InterruptedException {
                  enteredGet.countDown();
                  neverRelease.await();
                  throw new AssertionError("We should not get here");
              }
  
              @Override
              public Integer get(final long timeout, final TimeUnit unit) throws InterruptedException {
                  enteredGet.countDown();
                  neverRelease.await();
                  throw new AssertionError("We should not get here");
              }
 
             @Override
             public boolean isDone() {
                 return false;
             }
         };
         final UncheckedFuture<Integer> uf = UncheckedFuture.on(blockingFuture);
         final AtomicReference<Throwable> thrown = new AtomicReference<>();
         final AtomicBoolean interruptObserved = new AtomicBoolean(false);
         final Thread worker = new Thread(() -> {
             try {
                 call.accept(uf);
                 thrown.set(new AssertionError("We should not get here"));
             } catch (final Throwable e) {
                 interruptObserved.set(Thread.currentThread().isInterrupted());
                 thrown.set(e);
             }
         }, "unchecked-future-test-worker");
         worker.start();
         assertTrue(enteredGet.await(2, TimeUnit.SECONDS), "Worker did not enter Future.get() in time");
         worker.interrupt();
         worker.join();
         final Throwable t = thrown.get();
         assertInstanceOf(UncheckedInterruptedException.class, t, "Unexpected exception: " + t);
         assertInstanceOf(InterruptedException.class, t.getCause(), "Cause should be InterruptedException");
         assertTrue(interruptObserved.get(), "Interrupt flag was not restored by the wrapper");
     }
 
     @Test
     void interruptFlagIsPreservedOnGet() throws Exception {
         assertInterruptPreserved(UncheckedFuture::get);
     }
 
     @Test
     void interruptFlagIsPreservedOnGetWithTimeout() throws Exception {
         assertInterruptPreserved(uf -> uf.get(1, TimeUnit.DAYS));
     }
 
     @Test
     void testGetExecutionException() {
         final ExecutionException e = new ExecutionException(new Exception());
         assertThrows(UncheckedExecutionException.class, () -> UncheckedFuture.on(new TestFuture<>(e)).get());
     }
 
     @Test
     void testGetInterruptedException() {
         final InterruptedException e = new InterruptedException();
         assertThrows(UncheckedInterruptedException.class, () -> UncheckedFuture.on(new TestFuture<>(e)).get());
     }
 
     @Test
     void testGetLongExecutionException() {
         final ExecutionException e = new ExecutionException(new Exception());
         assertThrows(UncheckedExecutionException.class, () -> UncheckedFuture.on(new TestFuture<>(e)).get(1, TimeUnit.MICROSECONDS));
     }
 
     @Test
     void testGetLongInterruptedException() {
         final InterruptedException e = new InterruptedException();
         assertThrows(UncheckedInterruptedException.class, () -> UncheckedFuture.on(new TestFuture<>(e)).get(1, TimeUnit.MICROSECONDS));
     }
 
     @Test
     void testGetLongTimeoutException() {
         final TimeoutException e = new TimeoutException();
         assertThrows(UncheckedTimeoutException.class, () -> UncheckedFuture.on(new TestFuture<>(e)).get(1, TimeUnit.MICROSECONDS));
     }
 
     @Test
     void testMap() {
         final List<String> expected = Arrays.asList("Y", "Z");
         final List<Future<String>> input = Arrays.asList(new TestFuture<>("Y"), new TestFuture<>("Z"));
         assertEquals(expected, UncheckedFuture.map(input).map(UncheckedFuture::get).collect(Collectors.toList()));
     }
 
     @Test
     void testOnCollection() {
         final List<String> expected = Arrays.asList("Y", "Z");
         final List<Future<String>> input = Arrays.asList(new TestFuture<>("Y"), new TestFuture<>("Z"));
         assertEquals(expected, UncheckedFuture.on(input).stream().map(UncheckedFuture::get).collect(Collectors.toList()));
     }
 
     @Test
     void testOnFuture() {
         assertEquals("Z", UncheckedFuture.on(new TestFuture<>("Z")).get());
     }
 }