/*
    * Copyright (C) 2010, Google Inc.
    * and other copyright owners as documented in the project's IP log.
    *
    * This program and the accompanying materials are made available
    * under the terms of the Eclipse Distribution License v1.0 which
    * accompanies this distribution, is reproduced below, and is
    * available at http://www.eclipse.org/org/documents/edl-v10.php
    *
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or
   * without modification, are permitted provided that the following
   * conditions are met:
   *
   * - Redistributions of source code must retain the above copyright
   *   notice, this list of conditions and the following disclaimer.
   *
   * - Redistributions in binary form must reproduce the above
   *   copyright notice, this list of conditions and the following
   *   disclaimer in the documentation and/or other materials provided
   *   with the distribution.
   *
   * - Neither the name of the Eclipse Foundation, Inc. nor the
   *   names of its contributors may be used to endorse or promote
   *   products derived from this software without specific prior
   *   written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
   * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
   * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
   * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
   * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
   * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
   * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
   * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
   * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   */
  
  package org.eclipse.jgit.lib;
  
  import static org.junit.Assert.assertEquals;
  import static org.junit.Assert.assertFalse;
  import static org.junit.Assert.assertNull;
  import static org.junit.Assert.assertTrue;
  import static org.junit.Assert.fail;
  
  import java.util.concurrent.CountDownLatch;
  import java.util.concurrent.TimeUnit;
  
  import org.junit.Test;
  
  public class ThreadSafeProgressMonitorTest {
  	@Test
  	public void testFailsMethodsOnBackgroundThread()
  			throws InterruptedException {
  		final MockProgressMonitor mock = new MockProgressMonitor();
  		final ThreadSafeProgressMonitor pm = new ThreadSafeProgressMonitor(mock);
  
  		runOnThread(new Runnable() {
  			public void run() {
  				try {
  					pm.start(1);
  					fail("start did not fail on background thread");
  				} catch (IllegalStateException notMainThread) {
  					// Expected result
  				}
  
  				try {
  					pm.beginTask("title", 1);
  					fail("beginTask did not fail on background thread");
  				} catch (IllegalStateException notMainThread) {
  					// Expected result
  				}
  
  				try {
  					pm.endTask();
  					fail("endTask did not fail on background thread");
  				} catch (IllegalStateException notMainThread) {
  					// Expected result
  				}
  			}
  		});
  
  		// Ensure we didn't alter the mock above when checking threads.
  		assertNull(mock.taskTitle);
  		assertEquals(0, mock.value);
  	}
  
  	@Test
  	public void testMethodsOkOnMainThread() {
  		final MockProgressMonitor mock = new MockProgressMonitor();
  		final ThreadSafeProgressMonitor pm = new ThreadSafeProgressMonitor(mock);
  
  		pm.start(1);
 		assertEquals(1, mock.value);
 
 		pm.beginTask("title", 42);
 		assertEquals("title", mock.taskTitle);
 		assertEquals(42, mock.value);
 
 		pm.update(1);
 		pm.pollForUpdates();
 		assertEquals(43, mock.value);
 
 		pm.update(2);
 		pm.pollForUpdates();
 		assertEquals(45, mock.value);
 
 		pm.endTask();
 		assertNull(mock.taskTitle);
 		assertEquals(0, mock.value);
 	}
 
 	@Test
 	public void testUpdateOnBackgroundThreads() throws InterruptedException {
 		final MockProgressMonitor mock = new MockProgressMonitor();
 		final ThreadSafeProgressMonitor pm = new ThreadSafeProgressMonitor(mock);
 
 		pm.startWorker();
 
 		final CountDownLatch doUpdate = new CountDownLatch(1);
 		final CountDownLatch didUpdate = new CountDownLatch(1);
 		final CountDownLatch doEndWorker = new CountDownLatch(1);
 
 		final Thread bg = new Thread() {
 			public void run() {
 				assertFalse(pm.isCancelled());
 
 				await(doUpdate);
 				pm.update(2);
 				didUpdate.countDown();
 
 				await(doEndWorker);
 				pm.update(1);
 				pm.endWorker();
 			}
 		};
 		bg.start();
 
 		pm.pollForUpdates();
 		assertEquals(0, mock.value);
 		doUpdate.countDown();
 
 		await(didUpdate);
 		pm.pollForUpdates();
 		assertEquals(2, mock.value);
 
 		doEndWorker.countDown();
 		pm.waitForCompletion();
 		assertEquals(3, mock.value);
 	}
 
 	private static void await(CountDownLatch cdl) {
 		try {
 			assertTrue("latch released", cdl.await(1000, TimeUnit.MILLISECONDS));
 		} catch (InterruptedException ie) {
 			fail("Did not expect to be interrupted");
 		}
 	}
 
 	private static void runOnThread(Runnable task) throws InterruptedException {
 		Thread t = new Thread(task);
 		t.start();
 		t.join(1000);
 		assertFalse("thread has stopped", t.isAlive());
 	}
 
 	private static class MockProgressMonitor implements ProgressMonitor {
 		String taskTitle;
 
 		int value;
 
 		public void update(int completed) {
 			value += completed;
 		}
 
 		public void start(int totalTasks) {
 			value = totalTasks;
 		}
 
 		public void beginTask(String title, int totalWork) {
 			taskTitle = title;
 			value = totalWork;
 		}
 
 		public void endTask() {
 			taskTitle = null;
 			value = 0;
 		}
 
 		public boolean isCancelled() {
 			return false;
 		}
 	}
 }