/*
    * Copyright (C) 2011, GitHub 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.api;
  
  import java.io.File;
  import java.io.IOException;
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.List;
  
  import org.eclipse.jgit.api.errors.CheckoutConflictException;
  import org.eclipse.jgit.api.errors.ConcurrentRefUpdateException;
  import org.eclipse.jgit.api.errors.GitAPIException;
  import org.eclipse.jgit.api.errors.InvalidConfigurationException;
  import org.eclipse.jgit.api.errors.InvalidMergeHeadsException;
  import org.eclipse.jgit.api.errors.JGitInternalException;
  import org.eclipse.jgit.api.errors.NoHeadException;
  import org.eclipse.jgit.api.errors.NoMessageException;
  import org.eclipse.jgit.api.errors.RefNotFoundException;
  import org.eclipse.jgit.api.errors.WrongRepositoryStateException;
  import org.eclipse.jgit.dircache.DirCacheCheckout;
  import org.eclipse.jgit.errors.ConfigInvalidException;
  import org.eclipse.jgit.lib.ConfigConstants;
  import org.eclipse.jgit.lib.Constants;
  import org.eclipse.jgit.lib.NullProgressMonitor;
  import org.eclipse.jgit.lib.ProgressMonitor;
  import org.eclipse.jgit.lib.RefUpdate;
  import org.eclipse.jgit.lib.Repository;
  import org.eclipse.jgit.merge.MergeStrategy;
  import org.eclipse.jgit.revwalk.RevCommit;
  import org.eclipse.jgit.revwalk.RevWalk;
  import org.eclipse.jgit.submodule.SubmoduleWalk;
  import org.eclipse.jgit.treewalk.filter.PathFilterGroup;
  
  /**
   * A class used to execute a submodule update command.
   *
   * @see <a
   *      href="http://www.kernel.org/pub/software/scm/git/docs/git-submodule.html"
   *      >Git documentation about submodules</a>
   */
  public class SubmoduleUpdateCommand extends
  		TransportCommand<SubmoduleUpdateCommand, Collection<String>> {
  
  	private ProgressMonitor monitor;
  
  	private final Collection<String> paths;
  
  	private MergeStrategy strategy = MergeStrategy.RECURSIVE;
  
  	/**
  	 * @param repo
  	 */
  	public SubmoduleUpdateCommand(final Repository repo) {
  		super(repo);
  		paths = new ArrayList<String>();
  	}
  
  	/**
 	 * The progress monitor associated with the clone operation. By default,
 	 * this is set to <code>NullProgressMonitor</code>
 	 *
 	 * @see NullProgressMonitor
 	 * @param monitor
 	 * @return this command
 	 */
 	public SubmoduleUpdateCommand setProgressMonitor(
 			final ProgressMonitor monitor) {
 		this.monitor = monitor;
 		return this;
 	}
 
 	/**
 	 * Add repository-relative submodule path to initialize
 	 *
 	 * @param path
 	 *            (with <code>/</code> as separator)
 	 * @return this command
 	 */
 	public SubmoduleUpdateCommand addPath(final String path) {
 		paths.add(path);
 		return this;
 	}
 
 	/**
 	 * Execute the SubmoduleUpdateCommand command.
 	 *
 	 * @return a collection of updated submodule paths
 	 * @throws ConcurrentRefUpdateException
 	 * @throws CheckoutConflictException
 	 * @throws InvalidMergeHeadsException
 	 * @throws InvalidConfigurationException
 	 * @throws NoHeadException
 	 * @throws NoMessageException
 	 * @throws RefNotFoundException
 	 * @throws WrongRepositoryStateException
 	 * @throws GitAPIException
 	 */
 	public Collection<String> call() throws InvalidConfigurationException,
 			NoHeadException, ConcurrentRefUpdateException,
 			CheckoutConflictException, InvalidMergeHeadsException,
 			WrongRepositoryStateException, NoMessageException, NoHeadException,
 			RefNotFoundException, GitAPIException {
 		checkCallable();
 
 		try (SubmoduleWalk generator = SubmoduleWalk.forIndex(repo)) {
 			if (!paths.isEmpty())
 				generator.setFilter(PathFilterGroup.createFromStrings(paths));
 			List<String> updated = new ArrayList<String>();
 			while (generator.next()) {
 				// Skip submodules not registered in .gitmodules file
 				if (generator.getModulesPath() == null)
 					continue;
 				// Skip submodules not registered in parent repository's config
 				String url = generator.getConfigUrl();
 				if (url == null)
 					continue;
 
 				Repository submoduleRepo = generator.getRepository();
 				// Clone repository is not present
 				if (submoduleRepo == null) {
 					CloneCommand clone = Git.cloneRepository();
 					configure(clone);
 					clone.setURI(url);
 					clone.setDirectory(generator.getDirectory());
 					clone.setGitDir(new File(new File(repo.getDirectory(),
 							Constants.MODULES), generator.getPath()));
 					if (monitor != null)
 						clone.setProgressMonitor(monitor);
 					submoduleRepo = clone.call().getRepository();
 				}
 
 				try (RevWalk walk = new RevWalk(submoduleRepo)) {
 					RevCommit commit = walk
 							.parseCommit(generator.getObjectId());
 
 					String update = generator.getConfigUpdate();
 					if (ConfigConstants.CONFIG_KEY_MERGE.equals(update)) {
 						MergeCommand merge = new MergeCommand(submoduleRepo);
 						merge.include(commit);
 						merge.setStrategy(strategy);
 						merge.call();
 					} else if (ConfigConstants.CONFIG_KEY_REBASE.equals(update)) {
 						RebaseCommand rebase = new RebaseCommand(submoduleRepo);
 						rebase.setUpstream(commit);
 						rebase.setStrategy(strategy);
 						rebase.call();
 					} else {
 						// Checkout commit referenced in parent repository's
 						// index as a detached HEAD
 						DirCacheCheckout co = new DirCacheCheckout(
 								submoduleRepo, submoduleRepo.lockDirCache(),
 								commit.getTree());
 						co.setFailOnConflict(true);
 						co.checkout();
 						RefUpdate refUpdate = submoduleRepo.updateRef(
 								Constants.HEAD, true);
 						refUpdate.setNewObjectId(commit);
 						refUpdate.forceUpdate();
 					}
 				} finally {
 					submoduleRepo.close();
 				}
 				updated.add(generator.getPath());
 			}
 			return updated;
 		} catch (IOException e) {
 			throw new JGitInternalException(e.getMessage(), e);
 		} catch (ConfigInvalidException e) {
 			throw new InvalidConfigurationException(e.getMessage(), e);
 		}
 	}
 
 	/**
 	 * @param strategy
 	 *            The merge strategy to use during this update operation.
 	 * @return {@code this}
 	 * @since 3.4
 	 */
 	public SubmoduleUpdateCommand setStrategy(MergeStrategy strategy) {
 		this.strategy = strategy;
 		return this;
 	}
 }