/*
    * 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
   * 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 static org.eclipse.jgit.lib.RefDatabase.ALL;
  
  import java.io.IOException;
  import java.text.MessageFormat;
  import java.util.ArrayList;
  import java.util.List;
  import java.util.Map;
  
  import org.eclipse.jgit.api.errors.GitAPIException;
  import org.eclipse.jgit.api.errors.JGitInternalException;
  import org.eclipse.jgit.api.errors.NoHeadException;
  import org.eclipse.jgit.errors.IncorrectObjectTypeException;
  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.ObjectId;
  import org.eclipse.jgit.lib.Ref;
  import org.eclipse.jgit.lib.Repository;
  import org.eclipse.jgit.revwalk.RevCommit;
  import org.eclipse.jgit.revwalk.RevWalk;
  import org.eclipse.jgit.revwalk.filter.AndRevFilter;
  import org.eclipse.jgit.revwalk.filter.MaxCountRevFilter;
  import org.eclipse.jgit.revwalk.filter.SkipRevFilter;
  import org.eclipse.jgit.treewalk.filter.AndTreeFilter;
  import org.eclipse.jgit.treewalk.filter.PathFilter;
  import org.eclipse.jgit.treewalk.filter.PathFilterGroup;
  import org.eclipse.jgit.treewalk.filter.TreeFilter;
  
  /**
   * A class used to execute a {@code Log} 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()})
   * <p>
   * Examples (<code>git</code> is a {@link Git} instance):
   * <p>
   * Get newest 10 commits, starting from the current branch:
   *
   * <pre>
   * ObjectId head = repository.resolve(Constants.HEAD);
   *
   * Iterable&lt;RevCommit&gt; commits = git.log().add(head).setMaxCount(10).call();
   * </pre>
   * <p>
   *
   * <p>
   * Get commits only for a specific file:
   *
   * <pre>
   * git.log().add(head).addPath(&quot;dir/filename.txt&quot;).call();
   * </pre>
   * <p>
   *
   * @see <a href="http://www.kernel.org/pub/software/scm/git/docs/git-log.html"
  *      >Git documentation about Log</a>
  */
 public class LogCommand extends GitCommand<Iterable<RevCommit>> {
 	private RevWalk walk;
 
 	private boolean startSpecified = false;
 
 	private final List<PathFilter> pathFilters = new ArrayList<PathFilter>();
 
 	private int maxCount = -1;
 
 	private int skip = -1;
 
 	/**
 	 * @param repo
 	 */
 	protected LogCommand(Repository repo) {
 		super(repo);
 		walk = new RevWalk(repo);
 	}
 
 	/**
 	 * Executes the {@code Log} command with all the options and parameters
 	 * collected by the setter methods (e.g. {@link #add(AnyObjectId)},
 	 * {@link #not(AnyObjectId)}, ..) 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.
 	 *
 	 * @return an iteration over RevCommits
 	 * @throws NoHeadException
 	 *             of the references ref cannot be resolved
 	 */
 	public Iterable<RevCommit> call() throws GitAPIException, NoHeadException {
 		checkCallable();
 		if (pathFilters.size() > 0)
 			walk.setTreeFilter(AndTreeFilter.create(
 					PathFilterGroup.create(pathFilters), TreeFilter.ANY_DIFF));
 		if (skip > -1 && maxCount > -1)
 			walk.setRevFilter(AndRevFilter.create(SkipRevFilter.create(skip),
 					MaxCountRevFilter.create(maxCount)));
 		else if (skip > -1)
 			walk.setRevFilter(SkipRevFilter.create(skip));
 		else if (maxCount > -1)
 			walk.setRevFilter(MaxCountRevFilter.create(maxCount));
 		if (!startSpecified) {
 			try {
 				ObjectId headId = repo.resolve(Constants.HEAD);
 				if (headId == null)
 					throw new NoHeadException(
 							JGitText.get().noHEADExistsAndNoExplicitStartingRevisionWasSpecified);
 				add(headId);
 			} catch (IOException e) {
 				// all exceptions thrown by add() shouldn't occur and represent
 				// severe low-level exception which are therefore wrapped
 				throw new JGitInternalException(
 						JGitText.get().anExceptionOccurredWhileTryingToAddTheIdOfHEAD,
 						e);
 			}
 		}
 		setCallable(false);
 		return walk;
 	}
 
 	/**
 	 * Mark a commit to start graph traversal from.
 	 *
 	 * @see RevWalk#markStart(RevCommit)
 	 * @param start
 	 * @return {@code this}
 	 * @throws MissingObjectException
 	 *             the commit supplied is not available from the object
 	 *             database. This usually indicates the supplied commit is
 	 *             invalid, but the reference was constructed during an earlier
 	 *             invocation to {@link RevWalk#lookupCommit(AnyObjectId)}.
 	 * @throws IncorrectObjectTypeException
 	 *             the object was not parsed yet and it was discovered during
 	 *             parsing that it is not actually a commit. This usually
 	 *             indicates the caller supplied a non-commit SHA-1 to
 	 *             {@link RevWalk#lookupCommit(AnyObjectId)}.
 	 * @throws JGitInternalException
 	 *             a low-level exception of JGit has occurred. The original
 	 *             exception can be retrieved by calling
 	 *             {@link Exception#getCause()}. Expect only
 	 *             {@code IOException's} to be wrapped. Subclasses of
 	 *             {@link IOException} (e.g. {@link MissingObjectException}) are
 	 *             typically not wrapped here but thrown as original exception
 	 */
 	public LogCommand add(AnyObjectId start) throws MissingObjectException,
 			IncorrectObjectTypeException {
 		return add(true, start);
 	}
 
 	/**
 	 * Same as {@code --not start}, or {@code ^start}
 	 *
 	 * @param start
 	 * @return {@code this}
 	 * @throws MissingObjectException
 	 *             the commit supplied is not available from the object
 	 *             database. This usually indicates the supplied commit is
 	 *             invalid, but the reference was constructed during an earlier
 	 *             invocation to {@link RevWalk#lookupCommit(AnyObjectId)}.
 	 * @throws IncorrectObjectTypeException
 	 *             the object was not parsed yet and it was discovered during
 	 *             parsing that it is not actually a commit. This usually
 	 *             indicates the caller supplied a non-commit SHA-1 to
 	 *             {@link RevWalk#lookupCommit(AnyObjectId)}.
 	 * @throws JGitInternalException
 	 *             a low-level exception of JGit has occurred. The original
 	 *             exception can be retrieved by calling
 	 *             {@link Exception#getCause()}. Expect only
 	 *             {@code IOException's} to be wrapped. Subclasses of
 	 *             {@link IOException} (e.g. {@link MissingObjectException}) are
 	 *             typically not wrapped here but thrown as original exception
 	 */
 	public LogCommand not(AnyObjectId start) throws MissingObjectException,
 			IncorrectObjectTypeException {
 		return add(false, start);
 	}
 
 	/**
 	 * Adds the range {@code since..until}
 	 *
 	 * @param since
 	 * @param until
 	 * @return {@code this}
 	 * @throws MissingObjectException
 	 *             the commit supplied is not available from the object
 	 *             database. This usually indicates the supplied commit is
 	 *             invalid, but the reference was constructed during an earlier
 	 *             invocation to {@link RevWalk#lookupCommit(AnyObjectId)}.
 	 * @throws IncorrectObjectTypeException
 	 *             the object was not parsed yet and it was discovered during
 	 *             parsing that it is not actually a commit. This usually
 	 *             indicates the caller supplied a non-commit SHA-1 to
 	 *             {@link RevWalk#lookupCommit(AnyObjectId)}.
 	 * @throws JGitInternalException
 	 *             a low-level exception of JGit has occurred. The original
 	 *             exception can be retrieved by calling
 	 *             {@link Exception#getCause()}. Expect only
 	 *             {@code IOException's} to be wrapped. Subclasses of
 	 *             {@link IOException} (e.g. {@link MissingObjectException}) are
 	 *             typically not wrapped here but thrown as original exception
 	 */
 	public LogCommand addRange(AnyObjectId since, AnyObjectId until)
 			throws MissingObjectException, IncorrectObjectTypeException {
 		return not(since).add(until);
 	}
 
 	/**
 	 * Add all refs as commits to start the graph traversal from.
 	 *
 	 * @see #add(AnyObjectId)
 	 * @return {@code this}
 	 * @throws IOException
 	 *             the references could not be accessed
 	 */
 	public LogCommand all() throws IOException {
 		Map<String, Ref> refs = getRepository().getRefDatabase().getRefs(ALL);
 		for (Ref ref : refs.values()) {
 			if(!ref.isPeeled())
 				ref = getRepository().peel(ref);
 
 			ObjectId objectId = ref.getPeeledObjectId();
 			if (objectId == null)
 				objectId = ref.getObjectId();
 			RevCommit commit = null;
 			try {
 				commit = walk.parseCommit(objectId);
 			} catch (MissingObjectException e) {
 				// ignore: the ref points to an object that does not exist;
 				// it should be ignored as traversal starting point.
 			} catch (IncorrectObjectTypeException e) {
 				// ignore: the ref points to an object that is not a commit
 				// (e.g. a tree or a blob);
 				// it should be ignored as traversal starting point.
 			}
 			if (commit != null)
 				add(commit);
 		}
 		return this;
 	}
 
 	/**
 	 * Show only commits that affect any of the specified paths. The path must
 	 * either name a file or a directory exactly and use <code>/</code> (slash)
 	 * as separator. Note that regex expressions or wildcards are not supported.
 	 *
 	 * @param path
 	 *            a repository-relative path (with <code>/</code> as separator)
 	 * @return {@code this}
 	 */
 	public LogCommand addPath(String path) {
 		checkCallable();
 		pathFilters.add(PathFilter.create(path));
 		return this;
 	}
 
 	/**
 	 * Skip the number of commits before starting to show the commit output.
 	 *
 	 * @param skip
 	 *            the number of commits to skip
 	 * @return {@code this}
 	 */
 	public LogCommand setSkip(int skip) {
 		checkCallable();
 		this.skip = skip;
 		return this;
 	}
 
 	/**
 	 * Limit the number of commits to output.
 	 *
 	 * @param maxCount
 	 *            the limit
 	 * @return {@code this}
 	 */
 	public LogCommand setMaxCount(int maxCount) {
 		checkCallable();
 		this.maxCount = maxCount;
 		return this;
 	}
 
 	private LogCommand add(boolean include, AnyObjectId start)
 			throws MissingObjectException, IncorrectObjectTypeException,
 			JGitInternalException {
 		checkCallable();
 		try {
 			if (include) {
 				walk.markStart(walk.lookupCommit(start));
 				startSpecified = true;
 			} else
 				walk.markUninteresting(walk.lookupCommit(start));
 			return this;
 		} catch (MissingObjectException e) {
 			throw e;
 		} catch (IncorrectObjectTypeException e) {
 			throw e;
 		} catch (IOException e) {
 			throw new JGitInternalException(MessageFormat.format(
 					JGitText.get().exceptionOccurredDuringAddingOfOptionToALogCommand
 					, start), e);
 		}
 	}
 }