/*
    * Copyright (C) 2011, GitHub Inc.
    * 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.File;
  import java.io.FileInputStream;
  import java.io.FileNotFoundException;
  import java.io.IOException;
  import java.io.InputStream;
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.Collections;
  
  import org.eclipse.jgit.api.errors.GitAPIException;
  import org.eclipse.jgit.api.errors.JGitInternalException;
  import org.eclipse.jgit.blame.BlameGenerator;
  import org.eclipse.jgit.blame.BlameResult;
  import org.eclipse.jgit.diff.DiffAlgorithm;
  import org.eclipse.jgit.diff.RawText;
  import org.eclipse.jgit.diff.RawTextComparator;
  import org.eclipse.jgit.dircache.DirCache;
  import org.eclipse.jgit.lib.AnyObjectId;
  import org.eclipse.jgit.lib.Constants;
  import org.eclipse.jgit.lib.CoreConfig.AutoCRLF;
  import org.eclipse.jgit.lib.ObjectId;
  import org.eclipse.jgit.lib.Repository;
  import org.eclipse.jgit.treewalk.WorkingTreeOptions;
  import org.eclipse.jgit.util.IO;
  import org.eclipse.jgit.util.io.AutoLFInputStream;
  
  /**
   * Blame command for building a {@link BlameResult} for a file path.
   */
  public class BlameCommand extends GitCommand<BlameResult> {
  
  	private String path;
  
  	private DiffAlgorithm diffAlgorithm;
  
  	private RawTextComparator textComparator;
  
  	private ObjectId startCommit;
  
  	private Collection<ObjectId> reverseEndCommits;
  
  	private Boolean followFileRenames;
  
  	/**
  	 * @param repo
  	 */
  	public BlameCommand(Repository repo) {
  		super(repo);
  	}
  
  	/**
  	 * Set file path.
  	 *
  	 * @param filePath
  	 *            file path (with <code>/</code> as separator)
 	 * @return this command
 	 */
 	public BlameCommand setFilePath(String filePath) {
 		this.path = filePath;
 		return this;
 	}
 
 	/**
 	 * Set diff algorithm
 	 *
 	 * @param diffAlgorithm
 	 * @return this command
 	 */
 	public BlameCommand setDiffAlgorithm(DiffAlgorithm diffAlgorithm) {
 		this.diffAlgorithm = diffAlgorithm;
 		return this;
 	}
 
 	/**
 	 * Set raw text comparator
 	 *
 	 * @param textComparator
 	 * @return this command
 	 */
 	public BlameCommand setTextComparator(RawTextComparator textComparator) {
 		this.textComparator = textComparator;
 		return this;
 	}
 
 	/**
 	 * Set start commit id
 	 *
 	 * @param commit
 	 * @return this command
 	 */
 	public BlameCommand setStartCommit(AnyObjectId commit) {
 		this.startCommit = commit.toObjectId();
 		return this;
 	}
 
 	/**
 	 * Enable (or disable) following file renames.
 	 * <p>
 	 * If true renames are followed using the standard FollowFilter behavior
 	 * used by RevWalk (which matches {@code git log --follow} in the C
 	 * implementation). This is not the same as copy/move detection as
 	 * implemented by the C implementation's of {@code git blame -M -C}.
 	 *
 	 * @param follow
 	 *            enable following.
 	 * @return {@code this}
 	 */
 	public BlameCommand setFollowFileRenames(boolean follow) {
 		followFileRenames = Boolean.valueOf(follow);
 		return this;
 	}
 
 	/**
 	 * Configure the command to compute reverse blame (history of deletes).
 	 *
 	 * @param start
 	 *            oldest commit to traverse from. The result file will be loaded
 	 *            from this commit's tree.
 	 * @param end
 	 *            most recent commit to stop traversal at. Usually an active
 	 *            branch tip, tag, or HEAD.
 	 * @return {@code this}
 	 * @throws IOException
 	 *             the repository cannot be read.
 	 */
 	public BlameCommand reverse(AnyObjectId start, AnyObjectId end)
 			throws IOException {
 		return reverse(start, Collections.singleton(end.toObjectId()));
 	}
 
 	/**
 	 * Configure the generator to compute reverse blame (history of deletes).
 	 *
 	 * @param start
 	 *            oldest commit to traverse from. The result file will be loaded
 	 *            from this commit's tree.
 	 * @param end
 	 *            most recent commits to stop traversal at. Usually an active
 	 *            branch tip, tag, or HEAD.
 	 * @return {@code this}
 	 * @throws IOException
 	 *             the repository cannot be read.
 	 */
 	public BlameCommand reverse(AnyObjectId start, Collection<ObjectId> end)
 			throws IOException {
 		startCommit = start.toObjectId();
 		reverseEndCommits = new ArrayList<>(end);
 		return this;
 	}
 
 	/**
 	 * Generate a list of lines with information about when the lines were
 	 * introduced into the file path.
 	 *
 	 * @return list of lines
 	 */
 	@Override
 	public BlameResult call() throws GitAPIException {
 		checkCallable();
 		try (BlameGenerator gen = new BlameGenerator(repo, path)) {
 			if (diffAlgorithm != null)
 				gen.setDiffAlgorithm(diffAlgorithm);
 			if (textComparator != null)
 				gen.setTextComparator(textComparator);
 			if (followFileRenames != null)
 				gen.setFollowFileRenames(followFileRenames.booleanValue());
 
 			if (reverseEndCommits != null)
 				gen.reverse(startCommit, reverseEndCommits);
 			else if (startCommit != null)
 				gen.push(null, startCommit);
 			else {
 				gen.push(null, repo.resolve(Constants.HEAD));
 				if (!repo.isBare()) {
 					DirCache dc = repo.readDirCache();
 					int entry = dc.findEntry(path);
 					if (0 <= entry)
 						gen.push(null, dc.getEntry(entry).getObjectId());
 
 					File inTree = new File(repo.getWorkTree(), path);
 					if (repo.getFS().isFile(inTree)) {
 						RawText rawText = getRawText(inTree);
 						gen.push(null, rawText);
 					}
 				}
 			}
 			return gen.computeBlameResult();
 		} catch (IOException e) {
 			throw new JGitInternalException(e.getMessage(), e);
 		}
 	}
 
 	private RawText getRawText(File inTree) throws IOException,
 			FileNotFoundException {
 		RawText rawText;
 
 		WorkingTreeOptions workingTreeOptions = getRepository().getConfig()
 				.get(WorkingTreeOptions.KEY);
 		AutoCRLF autoCRLF = workingTreeOptions.getAutoCRLF();
 		switch (autoCRLF) {
 		case FALSE:
 		case INPUT:
 			// Git used the repo format on checkout, but other tools
 			// may change the format to CRLF. We ignore that here.
 			rawText = new RawText(inTree);
 			break;
 		case TRUE:
 			try (AutoLFInputStream in = new AutoLFInputStream(
 					new FileInputStream(inTree), true)) {
 				// Canonicalization should lead to same or shorter length
 				// (CRLF to LF), so the file size on disk is an upper size bound
 				rawText = new RawText(toByteArray(in, (int) inTree.length()));
 			}
 			break;
 		default:
 			throw new IllegalArgumentException(
 					"Unknown autocrlf option " + autoCRLF); //$NON-NLS-1$
 		}
 		return rawText;
 	}
 
 	private static byte[] toByteArray(InputStream source, int upperSizeLimit)
 			throws IOException {
 		byte[] buffer = new byte[upperSizeLimit];
 		try {
 			int read = IO.readFully(source, buffer, 0);
 			if (read == upperSizeLimit)
 				return buffer;
 			else {
 				byte[] copy = new byte[read];
 				System.arraycopy(buffer, 0, copy, 0, read);
 				return copy;
 			}
 		} finally {
 			source.close();
 		}
 	}
 }