/*
    * Copyright (C) 2019, Google LLC.
    * 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.revwalk;
  
  import static org.junit.Assert.assertFalse;
  import static org.junit.Assert.assertTrue;
  
  import java.util.Arrays;
  import java.util.Optional;
  
  import org.eclipse.jgit.internal.storage.file.FileRepository;
  import org.eclipse.jgit.junit.LocalDiskRepositoryTestCase;
  import org.eclipse.jgit.junit.TestRepository;
  import org.junit.Before;
  import org.junit.Test;
  
  public abstract class ReachabilityCheckerTestCase
  		extends LocalDiskRepositoryTestCase {
  
  	protected abstract ReachabilityChecker getChecker(
  			TestRepository<FileRepository> repository) throws Exception;
  
  	TestRepository<FileRepository> repo;
  
  	/** {@inheritDoc} */
  	@Override
  	@Before
  	public void setUp() throws Exception {
  		super.setUp();
  		FileRepository db = createWorkRepository();
  		repo = new TestRepository<>(db);
  	}
  
  	@Test
  	public void reachable() throws Exception {
  		RevCommit a = repo.commit().create();
  		RevCommit b1 = repo.commit(a);
  		RevCommit b2 = repo.commit(b1);
  		RevCommit c1 = repo.commit(a);
  		RevCommit c2 = repo.commit(c1);
  		repo.update("refs/heads/checker", b2);
  
  		ReachabilityChecker checker = getChecker(repo);
  
  		assertReachable("reachable from one tip",
  				checker.areAllReachable(Arrays.asList(a), Arrays.asList(c2)));
  		assertReachable("reachable from another tip",
  				checker.areAllReachable(Arrays.asList(a), Arrays.asList(b2)));
  		assertReachable("reachable from itself",
  				checker.areAllReachable(Arrays.asList(a), Arrays.asList(b2)));
  	}
  
  	@Test
  	public void reachable_merge() throws Exception {
  		RevCommit a = repo.commit().create();
  		RevCommit b1 = repo.commit(a);
  		RevCommit b2 = repo.commit(b1);
  		RevCommit c1 = repo.commit(a);
  		RevCommit c2 = repo.commit(c1);
 		RevCommit merge = repo.commit(c2, b2);
 		repo.update("refs/heads/checker", merge);
 
 		ReachabilityChecker checker = getChecker(repo);
 
 		assertReachable("reachable through one branch",
 				checker.areAllReachable(Arrays.asList(b1),
 						Arrays.asList(merge)));
 		assertReachable("reachable through another branch",
 				checker.areAllReachable(Arrays.asList(c1),
 						Arrays.asList(merge)));
 		assertReachable("reachable, before the branching",
 				checker.areAllReachable(Arrays.asList(a),
 						Arrays.asList(merge)));
 	}
 
 	@Test
 	public void unreachable_isLaterCommit() throws Exception {
 		RevCommit a = repo.commit().create();
 		RevCommit b1 = repo.commit(a);
 		RevCommit b2 = repo.commit(b1);
 		repo.update("refs/heads/checker", b2);
 
 		ReachabilityChecker checker = getChecker(repo);
 
 		assertUnreachable("unreachable from the future",
 				checker.areAllReachable(Arrays.asList(b2), Arrays.asList(b1)));
 	}
 
 	@Test
 	public void unreachable_differentBranch() throws Exception {
 		RevCommit a = repo.commit().create();
 		RevCommit b1 = repo.commit(a);
 		RevCommit b2 = repo.commit(b1);
 		RevCommit c1 = repo.commit(a);
 		repo.update("refs/heads/checker", b2);
 
 		ReachabilityChecker checker = getChecker(repo);
 
 		assertUnreachable("unreachable from different branch",
 				checker.areAllReachable(Arrays.asList(c1), Arrays.asList(b2)));
 	}
 
 	@Test
 	public void reachable_longChain() throws Exception {
 		RevCommit root = repo.commit().create();
 		RevCommit head = root;
 		for (int i = 0; i < 10000; i++) {
 			head = repo.commit(head);
 		}
 		repo.update("refs/heads/master", head);
 
 		ReachabilityChecker checker = getChecker(repo);
 
 		assertReachable("reachable with long chain in the middle", checker
 				.areAllReachable(Arrays.asList(root), Arrays.asList(head)));
 	}
 
 	private static void assertReachable(String msg,
 			Optional<RevCommit> result) {
 		assertFalse(msg, result.isPresent());
 	}
 
 	private static void assertUnreachable(String msg,
 			Optional<RevCommit> result) {
 		assertTrue(msg, result.isPresent());
 	}
 
 }