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*/

using System.IO;
using NGit;
using NGit.Api;
using NGit.Api.Errors;
using NGit.Notes;
using NGit.Revwalk;
using Sharpen;

namespace NGit.Api
{
	/// <summary>Remove object notes.</summary>
	/// <remarks>Remove object notes.</remarks>
	/// <seealso><a href="http://www.kernel.org/pub/software/scm/git/docs/git-notes.html"
	/// *      >Git documentation about Notes</a></seealso>
	public class RemoveNoteCommand : GitCommand<Note>
	{
		private RevObject id;

		private string notesRef = Constants.R_NOTES_COMMITS;

		/// <param name="repo"></param>
		protected internal RemoveNoteCommand(Repository repo) : base(repo)
		{
		}

		/// <exception cref="NGit.Api.Errors.GitAPIException"></exception>
		public override Note Call()
		{
			CheckCallable();
			RevWalk walk = new RevWalk(repo);
			ObjectInserter inserter = repo.NewObjectInserter();
			NoteMap map = NoteMap.NewEmptyMap();
			RevCommit notesCommit = null;
			try
			{
				Ref @ref = repo.GetRef(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, null, inserter);
				CommitNoteMap(walk, map, notesCommit, inserter, "Notes removed by 'git notes remove'"
					);
				return map.GetNote(id);
			}
			catch (IOException e)
			{
				throw new JGitInternalException(e.Message, e);
			}
			finally
			{
				inserter.Release();
				walk.Release();
			}
		}

		/// <summary>Sets the object id of object you want to remove a note</summary>
		/// <param name="id"></param>
		/// <returns>
		/// 
		/// <code>this</code>
		/// </returns>
		public virtual NGit.Api.RemoveNoteCommand SetObjectId(RevObject id)
		{
			CheckCallable();
			this.id = id;
			return this;
		}

		/// <exception cref="System.IO.IOException"></exception>
		private void CommitNoteMap(RevWalk walk, NoteMap map, RevCommit notesCommit, ObjectInserter
			 inserter, string msg)
		{
			// commit the note
			NGit.CommitBuilder builder = new NGit.CommitBuilder();
			builder.TreeId = map.WriteTree(inserter);
			builder.Author = new PersonIdent(repo);
			builder.Committer = builder.Author;
			builder.Message = msg;
			if (notesCommit != null)
			{
				builder.SetParentIds(notesCommit);
			}
			ObjectId commit = inserter.Insert(builder);
			inserter.Flush();
			RefUpdate refUpdate = repo.UpdateRef(notesRef);
			if (notesCommit != null)
			{
				refUpdate.SetExpectedOldObjectId(notesCommit);
			}
			else
			{
				refUpdate.SetExpectedOldObjectId(ObjectId.ZeroId);
			}
			refUpdate.SetNewObjectId(commit);
			refUpdate.Update(walk);
		}

		/// <param name="notesRef">
		/// the ref to read notes from. Note, the default value of
		/// <see cref="NGit.Constants.R_NOTES_COMMITS">NGit.Constants.R_NOTES_COMMITS</see>
		/// will be used if nothing is
		/// set
		/// </param>
		/// <returns>
		/// 
		/// <code>this</code>
		/// </returns>
		/// <seealso cref="NGit.Constants.R_NOTES_COMMITS">NGit.Constants.R_NOTES_COMMITS</seealso>
		public virtual NGit.Api.RemoveNoteCommand SetNotesRef(string notesRef)
		{
			CheckCallable();
			this.notesRef = notesRef;
			return this;
		}
	}
}
