/*
    * Copyright (C) 2011, Chris Aniszczyk <caniszczyk@gmail.com> 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 org.eclipse.jgit.api.errors.GitAPIException;
  import org.eclipse.jgit.api.errors.JGitInternalException;
  import org.eclipse.jgit.lib.CommitBuilder;
  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.Repository;
  import org.eclipse.jgit.notes.Note;
  import org.eclipse.jgit.notes.NoteMap;
  import org.eclipse.jgit.revwalk.RevCommit;
  import org.eclipse.jgit.revwalk.RevObject;
  import org.eclipse.jgit.revwalk.RevWalk;
  
  /**
   * Add object notes.
   *
   * @see <a href="http://www.kernel.org/pub/software/scm/git/docs/git-notes.html"
   *      >Git documentation about Notes</a>
   */
  public class AddNoteCommand extends GitCommand<Note> {
  
  	private RevObject id;
  
  	private String message;
  
  	private String notesRef = Constants.R_NOTES_COMMITS;
  
  	/**
  	 * Constructor for AddNoteCommand
  	 *
  	 * @param repo
  	 *            the {@link org.eclipse.jgit.lib.Repository}
  	 */
  	protected AddNoteCommand(Repository repo) {
  		super(repo);
  	}
  
  	/** {@inheritDoc} */
  	@Override
  	public Note call() throws GitAPIException {
  		checkCallable();
  		NoteMap map = NoteMap.newEmptyMap();
  		RevCommit notesCommit = null;
  		try (RevWalk walk = new RevWalk(repo);
  				ObjectInserter inserter = repo.newObjectInserter()) {
  			Ref ref = repo.findRef(notesRef);
  			// if we have a notes ref, use it
  			if (ref != null) {
  				notesCommit = walk.parseCommit(ref.getObjectId());
  				map = NoteMap.read(walk.getObjectReader(), notesCommit);
  			}
  			map.set(id, message, inserter);
  			commitNoteMap(repo, notesRef, walk, map, notesCommit, inserter,
  					"Notes added by 'git notes add'"); //$NON-NLS-1$
  			return map.getNote(id);
  		} catch (IOException e) {
  			throw new JGitInternalException(e.getMessage(), e);
  		}
  	}
  
  	/**
  	 * Sets the object id of object you want a note on. If the object already
  	 * has a note, the existing note will be replaced.
  	 *
  	 * @param id
  	 *            a {@link org.eclipse.jgit.revwalk.RevObject}
  	 * @return {@code this}
  	 */
  	public AddNoteCommand setObjectId(RevObject id) {
  		checkCallable();
  		this.id = id;
  		return this;
  	}
  
  	/**
  	 * Set the notes message
  	 *
  	 * @param message
  	 *            the notes message used when adding a note
  	 * @return {@code this}
  	 */
  	public AddNoteCommand setMessage(String message) {
  		checkCallable();
 		this.message = message;
 		return this;
 	}
 
 	static void commitNoteMap(Repository r, String ref, RevWalk walk,
 			NoteMap map,
 			RevCommit notesCommit,
 			ObjectInserter inserter,
 			String msg)
 			throws IOException {
 		// commit the note
 		CommitBuilder builder = new CommitBuilder();
 		builder.setTreeId(map.writeTree(inserter));
 		builder.setAuthor(new PersonIdent(r));
 		builder.setCommitter(builder.getAuthor());
 		builder.setMessage(msg);
 		if (notesCommit != null)
 			builder.setParentIds(notesCommit);
 		ObjectId commit = inserter.insert(builder);
 		inserter.flush();
 		RefUpdate refUpdate = r.updateRef(ref);
 		if (notesCommit != null)
 			refUpdate.setExpectedOldObjectId(notesCommit);
 		else
 			refUpdate.setExpectedOldObjectId(ObjectId.zeroId());
 		refUpdate.setNewObjectId(commit);
 		refUpdate.update(walk);
 	}
 
 	/**
 	 * Set name of a {@code Ref} to read notes from
 	 *
 	 * @param notesRef
 	 *            the ref to read notes from. Note, the default value of
 	 *            {@link org.eclipse.jgit.lib.Constants#R_NOTES_COMMITS} will be
 	 *            used if nothing is set
 	 * @return {@code this}
 	 * @see Constants#R_NOTES_COMMITS
 	 */
 	public AddNoteCommand setNotesRef(String notesRef) {
 		checkCallable();
 		this.notesRef = notesRef;
 		return this;
 	}
 
 }