/*
 * 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.
 *
 * 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
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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 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.errors.MissingObjectException;
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.revwalk.RevCommit;
import org.eclipse.jgit.revwalk.RevWalk;
import org.eclipse.jgit.treewalk.FileTreeIterator;

A class used to execute a cherry-pick 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 cherry-pick/**
 * A class used to execute a {@code cherry-pick} 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-cherry-pick.html"
 *      >Git documentation about cherry-pick</a>
 */
public class CherryPickCommand extends GitCommand<CherryPickResult> {
	private String reflogPrefix = "cherry-pick:"; //$NON-NLS-1$

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

	private String ourCommitName = null;

	private MergeStrategy strategy = MergeStrategy.RECURSIVE;

	private Integer mainlineParentNumber;

	private boolean noCommit = false;

	private ProgressMonitor monitor = NullProgressMonitor.INSTANCE;

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

	
{@inheritDoc}
 Executes the Cherry-Pick 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 Cherry-Pick} 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 CherryPickResult call() throws GitAPIException, NoMessageException,
			UnmergedPathsException, ConcurrentRefUpdateException,
			WrongRepositoryStateException, NoHeadException {
		RevCommit newHead = null;
		List<Ref> cherryPickedRefs = new LinkedList<>();
		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);

			newHead = revWalk.parseCommit(headRef.getObjectId());

			// loop through all refs to be cherry-picked
			for (Ref src : commits) {
				// get the commit to be cherry-picked
				// 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 cherry-pick
				final RevCommit srcParent = getParentCommit(srcCommit, revWalk);

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

				ResolveMerger merger = (ResolveMerger) strategy.newMerger(repo);
				merger.setWorkingTreeIterator(new FileTreeIterator(repo));
				merger.setBase(srcParent.getTree());
				merger.setCommitNames(new String[] { "BASE", ourName, //$NON-NLS-1$
						cherryPickName });
				if (merger.merge(newHead, srcCommit)) {
					if (AnyObjectId.isEqual(newHead.getTree().getId(),
							merger.getResultTreeId()))
						continue;
					DirCacheCheckout dco = new DirCacheCheckout(repo,
							newHead.getTree(), repo.lockDirCache(),
							merger.getResultTreeId());
					dco.setFailOnConflict(true);
					dco.setProgressMonitor(monitor);
					dco.checkout();
					if (!noCommit)
						newHead = new Git(getRepository()).commit()
								.setMessage(srcCommit.getFullMessage())
								.setReflogComment(reflogPrefix + " " //$NON-NLS-1$
										+ srcCommit.getShortMessage())
								.setAuthor(srcCommit.getAuthorIdent())
								.setNoVerify(true).call();
					cherryPickedRefs.add(src);
				} else {
					if (merger.failed())
						return new CherryPickResult(merger.getFailingPaths());

					// there are merge conflicts

					String message = new MergeMessageFormatter()
							.formatWithConflicts(srcCommit.getFullMessage(),
									merger.getUnmergedPaths());

					if (!noCommit)
						repo.writeCherryPickHead(srcCommit.getId());
					repo.writeMergeCommitMsg(message);

					return CherryPickResult.CONFLICT;
				}
			}
		} catch (IOException e) {
			throw new JGitInternalException(
					MessageFormat.format(
							JGitText.get().exceptionCaughtDuringExecutionOfCherryPickCommand,
							e), e);
		}
		return new CherryPickResult(newHead, cherryPickedRefs);
	}

	private RevCommit getParentCommit(RevCommit srcCommit, RevWalk revWalk)
			throws MultipleParentsNotAllowedException, MissingObjectException,
			IOException {
		final RevCommit srcParent;
		if (mainlineParentNumber == null) {
			if (srcCommit.getParentCount() != 1)
				throw new MultipleParentsNotAllowedException(
						MessageFormat.format(
								JGitText.get().canOnlyCherryPickCommitsWithOneParent,
								srcCommit.name(),
								Integer.valueOf(srcCommit.getParentCount())));
			srcParent = srcCommit.getParent(0);
		} else {
			if (mainlineParentNumber.intValue() > srcCommit.getParentCount())
				throw new JGitInternalException(MessageFormat.format(
						JGitText.get().commitDoesNotHaveGivenParent, srcCommit,
						mainlineParentNumber));
			srcParent = srcCommit
					.getParent(mainlineParentNumber.intValue() - 1);
		}

		revWalk.parseHeaders(srcParent);
		return srcParent;
	}

	
Include a reference to a commit
Params:
commit – 
           a reference to a commit which is cherry-picked to the current
           head
Returns:
this/**
	 * Include a reference to a commit
	 *
	 * @param commit
	 *            a reference to a commit which is cherry-picked to the current
	 *            head
	 * @return {@code this}
	 */
	public CherryPickCommand include(Ref commit) {
		checkCallable();
		commits.add(commit);
		return this;
	}

	
Include a commit
Params:
commit – 
           the Id of a commit which is cherry-picked to the current head
Returns:
this/**
	 * Include a commit
	 *
	 * @param commit
	 *            the Id of a commit which is cherry-picked to the current head
	 * @return {@code this}
	 */
	public CherryPickCommand include(AnyObjectId commit) {
		return include(commit.getName(), commit);
	}

	
Include a commit
Params:
name – 
           a name given to the commit
commit – 
           the Id of a commit which is cherry-picked to the current head
Returns:
this/**
	 * Include a commit
	 *
	 * @param name
	 *            a name given to the commit
	 * @param commit
	 *            the Id of a commit which is cherry-picked to the current head
	 * @return {@code this}
	 */
	public CherryPickCommand include(String name, AnyObjectId commit) {
		return include(new ObjectIdRef.Unpeeled(Storage.LOOSE, name,
				commit.copy()));
	}

	
Set the name that should 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 that should 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 CherryPickCommand setOurCommitName(String ourCommitName) {
		this.ourCommitName = ourCommitName;
		return this;
	}

	
Set the prefix to use in the reflog.

This is primarily needed for implementing rebase in terms of
cherry-picking
Params:
prefix – 
           including ":"
Returns:
this
Since:
3.1/**
	 * Set the prefix to use in the reflog.
	 * <p>
	 * This is primarily needed for implementing rebase in terms of
	 * cherry-picking
	 *
	 * @param prefix
	 *            including ":"
	 * @return {@code this}
	 * @since 3.1
	 */
	public CherryPickCommand setReflogPrefix(String prefix) {
		this.reflogPrefix = prefix;
		return this;
	}

	
Set the MergeStrategy 
Params:
strategy – 
           The merge strategy to use during this Cherry-pick.
Returns:
this
Since:
3.4/**
	 * Set the {@code MergeStrategy}
	 *
	 * @param strategy
	 *            The merge strategy to use during this Cherry-pick.
	 * @return {@code this}
	 * @since 3.4
	 */
	public CherryPickCommand setStrategy(MergeStrategy strategy) {
		this.strategy = strategy;
		return this;
	}

	
Set the (1-based) parent number to diff against
Params:
mainlineParentNumber – 
           the (1-based) parent number to diff against. This allows
           cherry-picking of merges.
Returns:
this
Since:
3.4/**
	 * Set the (1-based) parent number to diff against
	 *
	 * @param mainlineParentNumber
	 *            the (1-based) parent number to diff against. This allows
	 *            cherry-picking of merges.
	 * @return {@code this}
	 * @since 3.4
	 */
	public CherryPickCommand setMainlineParentNumber(int mainlineParentNumber) {
		this.mainlineParentNumber = Integer.valueOf(mainlineParentNumber);
		return this;
	}

	
Allows cherry-picking changes without committing them.

NOTE: The behavior of cherry-pick is undefined if you pick multiple
commits or if HEAD does not match the index state before cherry-picking.
Params:
noCommit – 
           true to cherry-pick without committing, false to commit after
           each pick (default)
Returns:
this
Since:
3.5/**
	 * Allows cherry-picking changes without committing them.
	 * <p>
	 * NOTE: The behavior of cherry-pick is undefined if you pick multiple
	 * commits or if HEAD does not match the index state before cherry-picking.
	 *
	 * @param noCommit
	 *            true to cherry-pick without committing, false to commit after
	 *            each pick (default)
	 * @return {@code this}
	 * @since 3.5
	 */
	public CherryPickCommand setNoCommit(boolean noCommit) {
		this.noCommit = noCommit;
		return this;
	}

	
The progress monitor associated with the cherry-pick 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 cherry-pick 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 CherryPickCommand setProgressMonitor(ProgressMonitor monitor) {
		if (monitor == null) {
			monitor = NullProgressMonitor.INSTANCE;
		}
		this.monitor = monitor;
		return this;
	}

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

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

	
{@inheritDoc} /** {@inheritDoc} */
	@SuppressWarnings("nls")
	@Override
	public String toString() {
		return "CherryPickCommand [repo=" + repo + ",\ncommits=" + commits
				+ ",\nmainlineParentNumber=" + mainlineParentNumber
				+ ", noCommit=" + noCommit + ", ourCommitName=" + ourCommitName
				+ ", reflogPrefix=" + reflogPrefix + ", strategy=" + strategy
				+ "]";
	}

}