/*
    * Copyright (C) 2011, GitHub Inc.
    * Copyright (C) 2016, Laurent Delaigue <laurent.delaigue@obeo.fr> and others
    *
    * This program and the accompanying materials are made available under the
    * terms of the Eclipse Distribution License v. 1.0 which is available at
    * https://www.eclipse.org/org/documents/edl-v10.php.
    *
    * SPDX-License-Identifier: BSD-3-Clause
   */
  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;
  
  	private CloneCommand.Callback callback;
  
  	private FetchCommand.Callback fetchCallback;
  
  	private boolean fetch = false;
  
  	/**
  	 * <p>
  	 * Constructor for SubmoduleUpdateCommand.
  	 * </p>
  	 *
  	 * @param repo
  	 *            a {@link org.eclipse.jgit.lib.Repository} object.
  	 */
  	public SubmoduleUpdateCommand(Repository repo) {
  		super(repo);
  		paths = new ArrayList<>();
  	}
  
  	/**
  	 * The progress monitor associated with the clone operation. By default,
  	 * this is set to <code>NullProgressMonitor</code>
  	 *
  	 * @see NullProgressMonitor
  	 * @param monitor
  	 *            a {@link org.eclipse.jgit.lib.ProgressMonitor} object.
  	 * @return this command
  	 */
  	public SubmoduleUpdateCommand setProgressMonitor(
  			final ProgressMonitor monitor) {
  		this.monitor = monitor;
  		return this;
  	}
  
  	/**
  	 * Whether to fetch the submodules before we update them. By default, this
  	 * is set to <code>false</code>
  	 *
  	 * @param fetch
  	 *            whether to fetch the submodules before we update them
  	 * @return this command
 	 * @since 4.9
 	 */
 	public SubmoduleUpdateCommand setFetch(boolean fetch) {
 		this.fetch = fetch;
 		return this;
 	}
 
 	/**
 	 * Add repository-relative submodule path to initialize
 	 *
 	 * @param path
 	 *            (with <code>/</code> as separator)
 	 * @return this command
 	 */
 	public SubmoduleUpdateCommand addPath(String path) {
 		paths.add(path);
 		return this;
 	}
 
 	private Repository getOrCloneSubmodule(SubmoduleWalk generator, String url)
 			throws IOException, GitAPIException {
 		Repository repository = generator.getRepository();
 		if (repository == null) {
 			if (callback != null) {
 				callback.cloningSubmodule(generator.getPath());
 			}
 			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);
 			}
 			repository = clone.call().getRepository();
 		} else if (this.fetch) {
 			if (fetchCallback != null) {
 				fetchCallback.fetchingSubmodule(generator.getPath());
 			}
 			FetchCommand fetchCommand = Git.wrap(repository).fetch();
 			if (monitor != null) {
 				fetchCommand.setProgressMonitor(monitor);
 			}
 			configure(fetchCommand);
 			fetchCommand.call();
 		}
 		return repository;
 	}
 
 	/**
 	 * {@inheritDoc}
 	 *
 	 * Execute the SubmoduleUpdateCommand command.
 	 */
 	@Override
 	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<>();
 			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;
 
 				try (Repository submoduleRepo = getOrCloneSubmodule(generator,
 						url); 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.setProgressMonitor(monitor);
 						merge.setStrategy(strategy);
 						merge.call();
 					} else if (ConfigConstants.CONFIG_KEY_REBASE.equals(update)) {
 						RebaseCommand rebase = new RebaseCommand(submoduleRepo);
 						rebase.setUpstream(commit);
 						rebase.setProgressMonitor(monitor);
 						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.setProgressMonitor(monitor);
 						co.checkout();
 						RefUpdate refUpdate = submoduleRepo.updateRef(
 								Constants.HEAD, true);
 						refUpdate.setNewObjectId(commit);
 						refUpdate.forceUpdate();
 						if (callback != null) {
 							callback.checkingOut(commit,
 									generator.getPath());
 						}
 					}
 				}
 				updated.add(generator.getPath());
 			}
 			return updated;
 		} catch (IOException e) {
 			throw new JGitInternalException(e.getMessage(), e);
 		} catch (ConfigInvalidException e) {
 			throw new InvalidConfigurationException(e.getMessage(), e);
 		}
 	}
 
 	/**
 	 * Setter for the field <code>strategy</code>.
 	 *
 	 * @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;
 	}
 
 	/**
 	 * Set status callback for submodule clone operation.
 	 *
 	 * @param callback
 	 *            the callback
 	 * @return {@code this}
 	 * @since 4.8
 	 */
 	public SubmoduleUpdateCommand setCallback(CloneCommand.Callback callback) {
 		this.callback = callback;
 		return this;
 	}
 
 	/**
 	 * Set status callback for submodule fetch operation.
 	 *
 	 * @param callback
 	 *            the callback
 	 * @return {@code this}
 	 * @since 4.9
 	 */
 	public SubmoduleUpdateCommand setFetchCallback(
 			FetchCommand.Callback callback) {
 		this.fetchCallback = callback;
 		return this;
 	}
 }