/*
 * Copyright (C) 2010, Chris Aniszczyk <caniszczyk@gmail.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
 * 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.IOException;
import java.text.MessageFormat;

import org.eclipse.jgit.api.errors.ConcurrentRefUpdateException;
import org.eclipse.jgit.api.errors.GitAPIException;
import org.eclipse.jgit.api.errors.InvalidTagNameException;
import org.eclipse.jgit.api.errors.JGitInternalException;
import org.eclipse.jgit.api.errors.NoHeadException;
import org.eclipse.jgit.internal.JGitText;
import org.eclipse.jgit.lib.Constants;
import org.eclipse.jgit.lib.ObjectId;
import org.eclipse.jgit.lib.ObjectInserter;
import org.eclipse.jgit.lib.PersonIdent;
import org.eclipse.jgit.lib.Ref;
import org.eclipse.jgit.lib.RefUpdate;
import org.eclipse.jgit.lib.RefUpdate.Result;
import org.eclipse.jgit.lib.Repository;
import org.eclipse.jgit.lib.RepositoryState;
import org.eclipse.jgit.lib.TagBuilder;
import org.eclipse.jgit.revwalk.RevObject;
import org.eclipse.jgit.revwalk.RevWalk;

/**
 * A class used to execute a {@code Tag} command. It has setters for all
 * supported options and arguments of this command and a {@link #call()} method
 * to finally execute the command.
 *
 * @see <a href="http://www.kernel.org/pub/software/scm/git/docs/git-tag.html"
 *      >Git documentation about Tag</a>
 */
public class TagCommand extends GitCommand<Ref> {
	private RevObject id;

	private String name;

	private String message;

	private PersonIdent tagger;

	private boolean signed;

	private boolean forceUpdate;

	/**
	 * @param repo
	 */
	protected TagCommand(Repository repo) {
		super(repo);
	}

	/**
	 * Executes the {@code tag} command with all the options and parameters
	 * collected by the setter methods of this class. Each instance of this
	 * class should only be used for one invocation of the command (means: one
	 * call to {@link #call()})
	 *
	 * @return a {@link Ref} a ref pointing to a tag
	 * @throws NoHeadException
	 *             when called on a git repo without a HEAD reference
	 * @since 2.0
	 */
	public Ref call() throws GitAPIException, ConcurrentRefUpdateException,
			InvalidTagNameException, NoHeadException {
		checkCallable();

		RepositoryState state = repo.getRepositoryState();
		processOptions(state);

		try {
			// create the tag object
			TagBuilder newTag = new TagBuilder();
			newTag.setTag(name);
			newTag.setMessage(message);
			newTag.setTagger(tagger);

			// if no id is set, we should attempt to use HEAD
			if (id == null) {
				ObjectId objectId = repo.resolve(Constants.HEAD + "^{commit}");
				if (objectId == null)
					throw new NoHeadException(
							JGitText.get().tagOnRepoWithoutHEADCurrentlyNotSupported);

				newTag.setObjectId(objectId, Constants.OBJ_COMMIT);
			} else {
				newTag.setObjectId(id);
			}

			// write the tag object
			ObjectInserter inserter = repo.newObjectInserter();
			try {
				ObjectId tagId = inserter.insert(newTag);
				inserter.flush();

				RevWalk revWalk = new RevWalk(repo);
				try {
					String refName = Constants.R_TAGS + newTag.getTag();
					RefUpdate tagRef = repo.updateRef(refName);
					tagRef.setNewObjectId(tagId);
					tagRef.setForceUpdate(forceUpdate);
					tagRef.setRefLogMessage("tagged " + name, false);
					Result updateResult = tagRef.update(revWalk);
					switch (updateResult) {
					case NEW:
					case FORCED:
						return repo.getRef(refName);
					case LOCK_FAILURE:
						throw new ConcurrentRefUpdateException(
								JGitText.get().couldNotLockHEAD,
								tagRef.getRef(), updateResult);
					default:
						throw new JGitInternalException(MessageFormat.format(
								JGitText.get().updatingRefFailed, refName,
								newTag.toString(), updateResult));
					}

				} finally {
					revWalk.release();
				}

			} finally {
				inserter.release();
			}

		} catch (IOException e) {
			throw new JGitInternalException(
					JGitText.get().exceptionCaughtDuringExecutionOfTagCommand,
					e);
		}
	}

	/**
	 * Sets default values for not explicitly specified options. Then validates
	 * that all required data has been provided.
	 *
	 * @param state
	 *            the state of the repository we are working on
	 *
	 * @throws InvalidTagNameException
	 *             if the tag name is null or invalid
	 * @throws UnsupportedOperationException
	 *             if the tag is signed (not supported yet)
	 */
	private void processOptions(RepositoryState state)
			throws InvalidTagNameException {
		if (tagger == null)
			tagger = new PersonIdent(repo);
		if (name == null || !Repository.isValidRefName(Constants.R_TAGS + name))
			throw new InvalidTagNameException(MessageFormat.format(JGitText
					.get().tagNameInvalid, name == null ? "<null>" : name));
		if (signed)
			throw new UnsupportedOperationException(
					JGitText.get().signingNotSupportedOnTag);
	}

	/**
	 * @param name
	 *            the tag name used for the {@code tag}
	 * @return {@code this}
	 */
	public TagCommand setName(String name) {
		checkCallable();
		this.name = name;
		return this;
	}

	/**
	 * @return the tag name used for the <code>tag</code>
	 */
	public String getName() {
		return name;
	}

	/**
	 * @return the tag message used for the <code>tag</code>
	 */
	public String getMessage() {
		return message;
	}

	/**
	 * @param message
	 *            the tag message used for the {@code tag}
	 * @return {@code this}
	 */
	public TagCommand setMessage(String message) {
		checkCallable();
		this.message = message;
		return this;
	}

	/**
	 * @return whether the tag is signed
	 */
	public boolean isSigned() {
		return signed;
	}

	/**
	 * If set to true the Tag command creates a signed tag object. This
	 * corresponds to the parameter -s on the command line.
	 *
	 * @param signed
	 * @return {@code this}
	 */
	public TagCommand setSigned(boolean signed) {
		this.signed = signed;
		return this;
	}

	/**
	 * Sets the tagger of the tag. If the tagger is null, a PersonIdent will be
	 * created from the info in the repository.
	 *
	 * @param tagger
	 * @return {@code this}
	 */
	public TagCommand setTagger(PersonIdent tagger) {
		this.tagger = tagger;
		return this;
	}

	/**
	 * @return the tagger of the tag
	 */
	public PersonIdent getTagger() {
		return tagger;
	}

	/**
	 * @return the object id of the tag
	 */
	public RevObject getObjectId() {
		return id;
	}

	/**
	 * Sets the object id of the tag. If the object id is null, the commit
	 * pointed to from HEAD will be used.
	 *
	 * @param id
	 * @return {@code this}
	 */
	public TagCommand setObjectId(RevObject id) {
		this.id = id;
		return this;
	}

	/**
	 * @return is this a force update
	 */
	public boolean isForceUpdate() {
		return forceUpdate;
	}

	/**
	 * If set to true the Tag command may replace an existing tag object. This
	 * corresponds to the parameter -f on the command line.
	 *
	 * @param forceUpdate
	 * @return {@code this}
	 */
	public TagCommand setForceUpdate(boolean forceUpdate) {
		this.forceUpdate = forceUpdate;
		return this;
	}

}