/*
    * Copyright (C) 2011, 2019 GitHub Inc. and others
    *
    * This program and the accompanying materials are made available under the
    * terms of the Eclipse Distribution License v. 1.0 which is available at
    * https://www.eclipse.org/org/documents/edl-v10.php.
    *
    * SPDX-License-Identifier: BSD-3-Clause
    */
  package org.eclipse.jgit.api;
  
  import java.io.IOException;
  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.RawTextComparator;
  import org.eclipse.jgit.lib.AnyObjectId;
  import org.eclipse.jgit.lib.ObjectId;
  import org.eclipse.jgit.lib.Repository;
  
  /**
   * Blame command for building a {@link org.eclipse.jgit.blame.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;
  
  	/**
  	 * Constructor for BlameCommand
  	 *
  	 * @param repo
  	 *            the {@link org.eclipse.jgit.lib.Repository}
  	 */
  	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
  	 *            a {@link org.eclipse.jgit.diff.DiffAlgorithm} object.
  	 * @return this command
  	 */
  	public BlameCommand setDiffAlgorithm(DiffAlgorithm diffAlgorithm) {
  		this.diffAlgorithm = diffAlgorithm;
  		return this;
  	}
  
  	/**
  	 * Set raw text comparator
  	 *
  	 * @param textComparator
  	 *            a {@link org.eclipse.jgit.diff.RawTextComparator}
  	 * @return this command
  	 */
  	public BlameCommand setTextComparator(RawTextComparator textComparator) {
  		this.textComparator = textComparator;
  		return this;
  	}
  
  	/**
  	 * Set start commit id
  	 *
  	 * @param commit
  	 *            id of a 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 java.io.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 java.io.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;
 	}
 
 	/**
 	 * {@inheritDoc}
 	 * <p>
 	 * Generate a list of lines with information about when the lines were
 	 * introduced into the file path.
 	 */
 	@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.prepareHead();
 			}
 			return gen.computeBlameResult();
 		} catch (IOException e) {
 			throw new JGitInternalException(e.getMessage(), e);
 		}
 	}
 }