/*
 * Copyright (C) 2010, Christian Halstrick <christian.halstrick@sap.com>
 * 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.
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 * without modification, are permitted provided that the following
 * conditions are met:
 *
 * - Redistributions of source code must retain the above copyright
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package org.eclipse.jgit.api;

import java.io.IOException;
import java.text.MessageFormat;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;

import org.eclipse.jgit.api.MergeResult.MergeStatus;
import org.eclipse.jgit.api.errors.ConcurrentRefUpdateException;
import org.eclipse.jgit.api.errors.GitAPIException;
import org.eclipse.jgit.api.errors.JGitInternalException;
import org.eclipse.jgit.api.errors.MultipleParentsNotAllowedException;
import org.eclipse.jgit.api.errors.NoHeadException;
import org.eclipse.jgit.api.errors.NoMessageException;
import org.eclipse.jgit.api.errors.UnmergedPathsException;
import org.eclipse.jgit.api.errors.WrongRepositoryStateException;
import org.eclipse.jgit.dircache.DirCacheCheckout;
import org.eclipse.jgit.internal.JGitText;
import org.eclipse.jgit.lib.AnyObjectId;
import org.eclipse.jgit.lib.Constants;
import org.eclipse.jgit.lib.NullProgressMonitor;
import org.eclipse.jgit.lib.ObjectId;
import org.eclipse.jgit.lib.ObjectIdRef;
import org.eclipse.jgit.lib.ProgressMonitor;
import org.eclipse.jgit.lib.Ref;
import org.eclipse.jgit.lib.Ref.Storage;
import org.eclipse.jgit.lib.Repository;
import org.eclipse.jgit.merge.MergeMessageFormatter;
import org.eclipse.jgit.merge.MergeStrategy;
import org.eclipse.jgit.merge.ResolveMerger;
import org.eclipse.jgit.merge.ResolveMerger.MergeFailureReason;
import org.eclipse.jgit.revwalk.RevCommit;
import org.eclipse.jgit.revwalk.RevWalk;
import org.eclipse.jgit.treewalk.FileTreeIterator;

A class used to execute a revert command. It has setters for all supported options and arguments of this command and a call() method to finally execute the command. Each instance of this class should only be used for one invocation of the command (means: one call to call()) 
See Also:
Git documentation about revert/**
 * A class used to execute a {@code revert} command. It has setters for all
 * supported options and arguments of this command and a {@link #call()} method
 * to finally execute the command. Each instance of this class should only be
 * used for one invocation of the command (means: one call to {@link #call()})
 *
 * @see <a
 *      href="http://www.kernel.org/pub/software/scm/git/docs/git-revert.html"
 *      >Git documentation about revert</a>
 */
public class RevertCommand extends GitCommand<RevCommit> {
	private List<Ref> commits = new LinkedList<>();

	private String ourCommitName = null;

	private List<Ref> revertedRefs = new LinkedList<>();

	private MergeResult failingResult;

	private List<String> unmergedPaths;

	private MergeStrategy strategy = MergeStrategy.RECURSIVE;

	private ProgressMonitor monitor = NullProgressMonitor.INSTANCE;

	

Constructor for RevertCommand.

Params:
repo –  the Repository/**
	 * <p>
	 * Constructor for RevertCommand.
	 * </p>
	 *
	 * @param repo
	 *            the {@link org.eclipse.jgit.lib.Repository}
	 */
	protected RevertCommand(Repository repo) {
		super(repo);
	}

	
{@inheritDoc}
 Executes the revert command with all the options and parameters collected by the setter methods (e.g. include(Ref) of this class. Each instance of this class should only be used for one invocation of the command. Don't call this method twice on an instance. /**
	 * {@inheritDoc}
	 * <p>
	 * Executes the {@code revert} command with all the options and parameters
	 * collected by the setter methods (e.g. {@link #include(Ref)} of this
	 * class. Each instance of this class should only be used for one invocation
	 * of the command. Don't call this method twice on an instance.
	 */
	@Override
	public RevCommit call() throws NoMessageException, UnmergedPathsException,
			ConcurrentRefUpdateException, WrongRepositoryStateException,
			GitAPIException {
		RevCommit newHead = null;
		checkCallable();

		try (RevWalk revWalk = new RevWalk(repo)) {

			// get the head commit
			Ref headRef = repo.exactRef(Constants.HEAD);
			if (headRef == null)
				throw new NoHeadException(
						JGitText.get().commitOnRepoWithoutHEADCurrentlyNotSupported);
			RevCommit headCommit = revWalk.parseCommit(headRef.getObjectId());

			newHead = headCommit;

			// loop through all refs to be reverted
			for (Ref src : commits) {
				// get the commit to be reverted
				// handle annotated tags
				ObjectId srcObjectId = src.getPeeledObjectId();
				if (srcObjectId == null)
					srcObjectId = src.getObjectId();
				RevCommit srcCommit = revWalk.parseCommit(srcObjectId);

				// get the parent of the commit to revert
				if (srcCommit.getParentCount() != 1)
					throw new MultipleParentsNotAllowedException(
							MessageFormat.format(
									JGitText.get().canOnlyRevertCommitsWithOneParent,
									srcCommit.name(),
									Integer.valueOf(srcCommit.getParentCount())));

				RevCommit srcParent = srcCommit.getParent(0);
				revWalk.parseHeaders(srcParent);

				String ourName = calculateOurName(headRef);
				String revertName = srcCommit.getId().abbreviate(7).name()
						+ " " + srcCommit.getShortMessage(); //$NON-NLS-1$

				ResolveMerger merger = (ResolveMerger) strategy.newMerger(repo);
				merger.setWorkingTreeIterator(new FileTreeIterator(repo));
				merger.setBase(srcCommit.getTree());
				merger.setCommitNames(new String[] {
						"BASE", ourName, revertName }); //$NON-NLS-1$

				String shortMessage = "Revert \"" + srcCommit.getShortMessage() //$NON-NLS-1$
						+ "\""; //$NON-NLS-1$
				String newMessage = shortMessage + "\n\n" //$NON-NLS-1$
						+ "This reverts commit " + srcCommit.getId().getName() //$NON-NLS-1$
						+ ".\n"; //$NON-NLS-1$
				if (merger.merge(headCommit, srcParent)) {
					if (AnyObjectId.isEqual(headCommit.getTree().getId(),
							merger.getResultTreeId()))
						continue;
					DirCacheCheckout dco = new DirCacheCheckout(repo,
							headCommit.getTree(), repo.lockDirCache(),
							merger.getResultTreeId());
					dco.setFailOnConflict(true);
					dco.setProgressMonitor(monitor);
					dco.checkout();
					try (Git git = new Git(getRepository())) {
						newHead = git.commit().setMessage(newMessage)
								.setReflogComment("revert: " + shortMessage) //$NON-NLS-1$
								.call();
					}
					revertedRefs.add(src);
					headCommit = newHead;
				} else {
					unmergedPaths = merger.getUnmergedPaths();
					Map<String, MergeFailureReason> failingPaths = merger
							.getFailingPaths();
					if (failingPaths != null)
						failingResult = new MergeResult(null,
								merger.getBaseCommitId(),
								new ObjectId[] { headCommit.getId(),
										srcParent.getId() },
								MergeStatus.FAILED, strategy,
								merger.getMergeResults(), failingPaths, null);
					else
						failingResult = new MergeResult(null,
								merger.getBaseCommitId(),
								new ObjectId[] { headCommit.getId(),
										srcParent.getId() },
								MergeStatus.CONFLICTING, strategy,
								merger.getMergeResults(), failingPaths, null);
					if (!merger.failed() && !unmergedPaths.isEmpty()) {
						String message = new MergeMessageFormatter()
						.formatWithConflicts(newMessage,
								merger.getUnmergedPaths());
						repo.writeRevertHead(srcCommit.getId());
						repo.writeMergeCommitMsg(message);
					}
					return null;
				}
			}
		} catch (IOException e) {
			throw new JGitInternalException(
					MessageFormat.format(
									JGitText.get().exceptionCaughtDuringExecutionOfRevertCommand,
							e), e);
		}
		return newHead;
	}

	
Include a Ref to a commit to be reverted 
Params:
commit – 
           a reference to a commit to be reverted into the current head
Returns:
this/**
	 * Include a {@code Ref} to a commit to be reverted
	 *
	 * @param commit
	 *            a reference to a commit to be reverted into the current head
	 * @return {@code this}
	 */
	public RevertCommand include(Ref commit) {
		checkCallable();
		commits.add(commit);
		return this;
	}

	
Include a commit to be reverted
Params:
commit – 
           the Id of a commit to be reverted into the current head
Returns:
this/**
	 * Include a commit to be reverted
	 *
	 * @param commit
	 *            the Id of a commit to be reverted into the current head
	 * @return {@code this}
	 */
	public RevertCommand include(AnyObjectId commit) {
		return include(commit.getName(), commit);
	}

	
Include a commit to be reverted
Params:
name –  name of a Ref referring to the commit
commit – 
           the Id of a commit which is reverted into the current head
Returns:
this/**
	 * Include a commit to be reverted
	 *
	 * @param name
	 *            name of a {@code Ref} referring to the commit
	 * @param commit
	 *            the Id of a commit which is reverted into the current head
	 * @return {@code this}
	 */
	public RevertCommand include(String name, AnyObjectId commit) {
		return include(new ObjectIdRef.Unpeeled(Storage.LOOSE, name,
				commit.copy()));
	}

	
Set the name to be used in the "OURS" place for conflict markers
Params:
ourCommitName – 
           the name that should be used in the "OURS" place for conflict
           markers
Returns:
this/**
	 * Set the name to be used in the "OURS" place for conflict markers
	 *
	 * @param ourCommitName
	 *            the name that should be used in the "OURS" place for conflict
	 *            markers
	 * @return {@code this}
	 */
	public RevertCommand setOurCommitName(String ourCommitName) {
		this.ourCommitName = ourCommitName;
		return this;
	}

	private String calculateOurName(Ref headRef) {
		if (ourCommitName != null)
			return ourCommitName;

		String targetRefName = headRef.getTarget().getName();
		String headName = Repository.shortenRefName(targetRefName);
		return headName;
	}

	
Get the list of successfully reverted Ref's. 
Returns:
the list of successfully reverted Ref's. Never null but
        maybe an empty list if no commit was successfully cherry-picked/**
	 * Get the list of successfully reverted {@link org.eclipse.jgit.lib.Ref}'s.
	 *
	 * @return the list of successfully reverted
	 *         {@link org.eclipse.jgit.lib.Ref}'s. Never <code>null</code> but
	 *         maybe an empty list if no commit was successfully cherry-picked
	 */
	public List<Ref> getRevertedRefs() {
		return revertedRefs;
	}

	
Get the result of a merge failure
Returns:
the result of a merge failure, null if no merge
        failure occurred during the revert/**
	 * Get the result of a merge failure
	 *
	 * @return the result of a merge failure, <code>null</code> if no merge
	 *         failure occurred during the revert
	 */
	public MergeResult getFailingResult() {
		return failingResult;
	}

	
Get unmerged paths
Returns:
the unmerged paths, will be null if no merge conflicts/**
	 * Get unmerged paths
	 *
	 * @return the unmerged paths, will be null if no merge conflicts
	 */
	public List<String> getUnmergedPaths() {
		return unmergedPaths;
	}

	
Set the merge strategy to use for this revert command
Params:
strategy – 
           The merge strategy to use for this revert command.
Returns:
this
Since:
3.4/**
	 * Set the merge strategy to use for this revert command
	 *
	 * @param strategy
	 *            The merge strategy to use for this revert command.
	 * @return {@code this}
	 * @since 3.4
	 */
	public RevertCommand setStrategy(MergeStrategy strategy) {
		this.strategy = strategy;
		return this;
	}

	
The progress monitor associated with the revert operation. By default,
this is set to NullProgressMonitor
Params:
monitor –  a ProgressMonitor
See Also:
NullProgressMonitor
Returns:
this
Since:
4.11/**
	 * The progress monitor associated with the revert operation. By default,
	 * this is set to <code>NullProgressMonitor</code>
	 *
	 * @see NullProgressMonitor
	 * @param monitor
	 *            a {@link org.eclipse.jgit.lib.ProgressMonitor}
	 * @return {@code this}
	 * @since 4.11
	 */
	public RevertCommand setProgressMonitor(ProgressMonitor monitor) {
		if (monitor == null) {
			monitor = NullProgressMonitor.INSTANCE;
		}
		this.monitor = monitor;
		return this;
	}
}