SparkleShare/SparkleLib/Git/SparkleRepoGit.cs

//   SparkleShare, a collaboration and sharing tool.
//   Copyright (C) 2010  Hylke Bons <hylkebons@gmail.com>
//
//   This program is free software: you can redistribute it and/or modify
//   it under the terms of the GNU General Public License as published by
//   the Free Software Foundation, either version 3 of the License, or
//   (at your option) any later version.
//
//   This program is distributed in the hope that it will be useful,
//   but WITHOUT ANY WARRANTY; without even the implied warranty of
//   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
//   GNU General Public License for more details.
//
//   You should have received a copy of the GNU General Public License
//   along with this program. If not, see <http://www.gnu.org/licenses/>.


using System;
using System.Collections.Generic;
using System.IO;
using System.Text;
using System.Text.RegularExpressions;
using System.Threading;

using SparkleLib;

namespace SparkleLib.Git {

    public class SparkleRepo : SparkleRepoBase {

		private bool user_is_set;
        private bool use_git_bin;
        private bool is_encrypted;


        public SparkleRepo (string path, SparkleConfig config) : base (path, config)
        {
            // TODO: Set git locale to en-US

            // Check if we should use git-bin
            SparkleGit git = new SparkleGit (LocalPath, "config --get filter.bin.clean");
            git.StartAndWaitForExit ();

            this.use_git_bin = (git.ExitCode == 0);

            git = new SparkleGit (LocalPath, "config remote.origin.url \"" + RemoteUrl + "\"");
            git.StartAndWaitForExit ();

            string rebase_apply_path = new string [] { LocalPath, ".git", "rebase-apply" }.Combine ();

            if (Directory.Exists (rebase_apply_path)) {
                git = new SparkleGit (LocalPath, "rebase --abort");
                git.StartAndWaitForExit ();
            }

            string password_file_path = Path.Combine (LocalPath, ".git", "password");

            if (File.Exists (password_file_path))
                this.is_encrypted = true;
        }


        public override List<string> ExcludePaths {
            get {
                List<string> rules = new List<string> ();
                rules.Add (".git");

                return rules;
            }
        }


        public override double Size {
            get {
                string file_path = new string [] { LocalPath, ".git", "repo_size" }.Combine ();

                try {
                    string size = File.ReadAllText (file_path);
                    return double.Parse (size);

                } catch {
                    return 0;
                }
            }
        }


        public override double HistorySize {
            get {
                string file_path = new string [] { LocalPath, ".git", "repo_history_size" }.Combine ();

                try {
                    string size = File.ReadAllText (file_path);
                    return double.Parse (size);

                } catch {
                    return 0;
                }
            }
        }


        private void UpdateSizes ()
        {
            double size         = CalculateSizes (new DirectoryInfo (LocalPath));
            double history_size = CalculateSizes (new DirectoryInfo (Path.Combine (LocalPath, ".git")));

            string size_file_path = new string [] { LocalPath, ".git", "repo_size" }.Combine ();
            string history_size_file_path = new string [] { LocalPath, ".git", "repo_history_size" }.Combine ();

            File.WriteAllText (size_file_path, size.ToString ());
            File.WriteAllText (history_size_file_path, history_size.ToString ());
        }
        

        public override string [] UnsyncedFilePaths {
            get {
                List<string> file_paths = new List<string> ();
                SparkleGit git          = new SparkleGit (LocalPath, "status --porcelain");
                string output           = git.StartAndReadStandardOutput ();
                string [] lines         = output.Split ("\n".ToCharArray ());

                foreach (string line in lines) {
                    if (line [1].ToString ().Equals ("M") ||
                        line [1].ToString ().Equals ("?") ||
                        line [1].ToString ().Equals ("A")) {

                        string path = line.Substring (3);
                        path        = path.Trim ("\"".ToCharArray ());

                        file_paths.Add (path);
                    }
                }

                return file_paths.ToArray ();
            }
        }


        public override string CurrentRevision {
            get {
                SparkleGit git = new SparkleGit (LocalPath, "rev-parse HEAD");
                string output  = git.StartAndReadStandardOutput ();

                if (git.ExitCode == 0)
                    return output;
                else
                    return null;
            }
        }


        public override bool HasRemoteChanges {
            get {
                SparkleLogger.LogInfo ("Git", Name + " | Checking for remote changes...");
                string current_revision = CurrentRevision;

                SparkleGit git = new SparkleGit (LocalPath, "ls-remote --heads --exit-code \"" + RemoteUrl + "\" master");
                string output  = git.StartAndReadStandardOutput ();

                if (git.ExitCode != 0)
                    return false;

                string remote_revision = output.Substring (0, 40);

                if (!remote_revision.StartsWith (current_revision)) {
                    SparkleLogger.LogInfo ("Git", Name + " | Remote changes found, local: " +
                        current_revision + ", remote: " + remote_revision);

                    Error = ErrorStatus.None;
                    return true;

                } else {
                    SparkleLogger.LogInfo ("Git", Name + " | No remote changes, local+remote: " + current_revision);
                    return false;
                }
            }
        }


        public override bool SyncUp ()
        {
            if (HasLocalChanges) {
                Add ();

                string message = FormatCommitMessage ();
                Commit (message);

                string salt_file_path = new string [] { LocalPath, ".git", "salt" }.Combine ();

                // If the repo is encrypted, create a branch to 
                // store the in and push it to the host
                if (File.Exists (salt_file_path)) {
                    string salt = File.ReadAllText (salt_file_path).Trim ();

                    SparkleGit git_salt = new SparkleGit (LocalPath, "branch salt-" + salt);
                    git_salt.StartAndWaitForExit ();

                    git_salt = new SparkleGit (LocalPath, "push origin salt-" + salt);
                    git_salt.StartAndWaitForExit ();

                    File.Delete (salt_file_path);
                }
            }

            SparkleGit git;

            if (this.use_git_bin) {
                SparkleGitBin git_bin = new SparkleGitBin (LocalPath, "push");
                git_bin.StartAndWaitForExit ();

                // TODO: Progress
            }

            git = new SparkleGit (LocalPath,
                "push --progress " + // Redirects progress stats to standarderror
                "\"" + RemoteUrl + "\" master");

            git.StartInfo.RedirectStandardError = true;
            git.Start ();

            double percentage = 1.0;
            Regex progress_regex = new Regex (@"([0-9]+)%", RegexOptions.Compiled);

            while (!git.StandardError.EndOfStream) {
                string line   = git.StandardError.ReadLine ();
                Match match   = progress_regex.Match (line);
                string speed  = "";
                double number = 0.0;

                if (match.Success) {
                    number = double.Parse (match.Groups [1].Value);

                    // The pushing progress consists of two stages: the "Compressing
                    // objects" stage which we count as 20% of the total progress, and
                    // the "Writing objects" stage which we count as the last 80%
                    if (line.StartsWith ("Compressing")) {
                        // "Compressing objects" stage
                        number = (number / 100 * 20);

                    } else {
                        // "Writing objects" stage
                        number = (number / 100 * 80 + 20);

                        if (line.Contains ("|")) {
                            speed = line.Substring (line.IndexOf ("|") + 1).Trim ();
                            speed = speed.Replace (", done.", "").Trim ();
                            speed = speed.Replace ("i", "");
                            speed = speed.Replace ("KB/s", "ᴋʙ/s");
                            speed = speed.Replace ("MB/s", "ᴍʙ/s");
                        }
                    }

                } else {
                    SparkleLogger.LogInfo ("Git", Name + " | " + line);

                    if (FindError (line))
                        return false;
                }

                if (number >= percentage) {
                    percentage = number;
                    base.OnProgressChanged (percentage, speed);
                }
            }

            git.WaitForExit ();
            UpdateSizes ();

            if (git.ExitCode == 0) {
                ClearCache ();
                return true;

            } else {
                Error = ErrorStatus.HostUnreachable;
                return false;
            }
        }


        public override bool SyncDown ()
        {
            SparkleGit git = new SparkleGit (LocalPath, "fetch --progress \"" + RemoteUrl + "\" master");

            git.StartInfo.RedirectStandardError = true;
            git.Start ();

            double percentage = 1.0;
            Regex progress_regex = new Regex (@"([0-9]+)%", RegexOptions.Compiled);

            while (!git.StandardError.EndOfStream) {
                string line   = git.StandardError.ReadLine ();
                Match match   = progress_regex.Match (line);
                string speed  = "";
                double number = 0.0;

                if (match.Success) {
                    number = double.Parse (match.Groups [1].Value);

                    // The fetching progress consists of two stages: the "Compressing
                    // objects" stage which we count as 20% of the total progress, and
                    // the "Receiving objects" stage which we count as the last 80%
                    if (line.StartsWith ("Compressing")) {
                        // "Compressing objects" stage
                        number = (number / 100 * 20);

                    } else {
                        // "Writing objects" stage
                        number = (number / 100 * 80 + 20);

                        if (line.Contains ("|")) {
                            speed = line.Substring (line.IndexOf ("|") + 1).Trim ();
                            speed = speed.Replace (", done.", "").Trim ();
                            speed = speed.Replace ("i", "");
                            speed = speed.Replace ("KB/s", "ᴋʙ/s");
                            speed = speed.Replace ("MB/s", "ᴍʙ/s");
                        }
                    }

                } else {
                    SparkleLogger.LogInfo ("Git", Name + " | " + line);

                    if (FindError (line))
                        return false;
                }
                

                if (number >= percentage) {
                    percentage = number;
                    base.OnProgressChanged (percentage, speed);
                }
            }

            git.WaitForExit ();
            UpdateSizes ();

            if (git.ExitCode == 0) {
                Rebase ();

                string identifier_file_path = Path.Combine (LocalPath, ".sparkleshare");
				File.SetAttributes (identifier_file_path, FileAttributes.Hidden);

                ClearCache ();

				return true;

            } else {
                Error = ErrorStatus.HostUnreachable;
                return false;
            }
        }


        public override bool HasLocalChanges {
            get {
                PrepareDirectories (LocalPath);

                SparkleGit git = new SparkleGit (LocalPath, "status --porcelain");
                string output  = git.StartAndReadStandardOutput ();

                return !string.IsNullOrEmpty (output);
            }
        }


        public override bool HasUnsyncedChanges {
            get {
                string unsynced_file_path =  new string [] { LocalPath, ".git", "has_unsynced_changes" }.Combine ();
                return File.Exists (unsynced_file_path);
            }

            set {
                string unsynced_file_path = new string [] { LocalPath, ".git", "has_unsynced_changes" }.Combine ();

                if (value)
                    File.WriteAllText (unsynced_file_path, "");
                else
                    File.Delete (unsynced_file_path);
            }
        }


        // Stages the made changes
        private void Add ()
        {
            SparkleGit git = new SparkleGit (LocalPath, "add --all");
            git.StartAndWaitForExit ();

            SparkleLogger.LogInfo ("Git", Name + " | Changes staged");
        }


        // Commits the made changes
        private void Commit (string message)
		{
			SparkleGit git;

			if (!this.user_is_set) {
	            git = new SparkleGit (LocalPath, "config user.name \"" + base.local_config.User.Name + "\"");
				git.StartAndWaitForExit ();

	            git = new SparkleGit (LocalPath, "config user.email \"" + base.local_config.User.Email + "\"");
				git.StartAndWaitForExit ();

				this.user_is_set = true;
			}

            git = new SparkleGit (LocalPath, "commit --all --message=\"" + message + "\" " +
                "--author=\"" + base.local_config.User.Name + " <" + base.local_config.User.Email + ">\"");

            git.StartAndReadStandardOutput ();
        }


        // Merges the fetched changes
        private void Rebase ()
        {
            if (HasLocalChanges) {
                Add ();

                string commit_message = FormatCommitMessage ();
                Commit (commit_message);
            }

            SparkleGit git = new SparkleGit (LocalPath, "rebase FETCH_HEAD");
            git.StartInfo.RedirectStandardOutput = false;
            git.StartAndWaitForExit ();

            if (git.ExitCode != 0) {
                SparkleLogger.LogInfo ("Git", Name + " | Conflict detected, trying to get out...");

                while (HasLocalChanges) {
                    try {
                        ResolveConflict ();

                    } catch (IOException e) {
                        SparkleLogger.LogInfo ("Git",
                            Name + " | Failed to resolve conflict, trying again... (" + e.Message + ")");
                    }
                }

                SparkleLogger.LogInfo ("Git", Name + " | Conflict resolved");
                OnConflictResolved ();
            }
        }


        private void ResolveConflict ()
        {
            // This is a list of conflict status codes that Git uses, their
            // meaning, and how SparkleShare should handle them.
            //
            // DD    unmerged, both deleted    -> Do nothing
            // AU    unmerged, added by us     -> Use server's, save ours as a timestamped copy
            // UD    unmerged, deleted by them -> Use ours
            // UA    unmerged, added by them   -> Use server's, save ours as a timestamped copy
            // DU    unmerged, deleted by us   -> Use server's
            // AA    unmerged, both added      -> Use server's, save ours as a timestamped copy
            // UU    unmerged, both modified   -> Use server's, save ours as a timestamped copy
            // ??    unmerged, new files       -> Stage the new files
            //
            // Note that a rebase merge works by replaying each commit from the working branch on
            // top of the upstream branch. Because of this, when a merge conflict happens the
            // side reported as 'ours' is the so-far rebased series, starting with upstream,
            // and 'theirs' is the working branch. In other words, the sides are swapped.
            //
            // So: 'ours' means the 'server's version' and 'theirs' means the 'local version' after this comment

            SparkleGit git_status = new SparkleGit (LocalPath, "status --porcelain");
            string output         = git_status.StartAndReadStandardOutput ();

            string [] lines = output.Split ("\n".ToCharArray ());
            bool changes_added = false;

            foreach (string line in lines) {
                string conflicting_path = line.Substring (3);
                conflicting_path        = EnsureSpecialCharacters (conflicting_path);

                SparkleLogger.LogInfo ("Git", Name + " | Conflict type: " + line);

                // Ignore conflicts in the .sparkleshare file and use the local version
                if (conflicting_path.EndsWith (".sparkleshare") ||
                    conflicting_path.EndsWith (".empty")) {

                    // Recover local version
                    SparkleGit git_theirs = new SparkleGit (LocalPath, "checkout --theirs \"" + conflicting_path + "\"");
                    git_theirs.StartAndWaitForExit ();

                    File.SetAttributes (Path.Combine (LocalPath, conflicting_path), FileAttributes.Hidden);
                    changes_added = true;

                    continue;
                }

                // Both the local and server version have been modified
                if (line.StartsWith ("UU") || line.StartsWith ("AA") ||
                    line.StartsWith ("AU") || line.StartsWith ("UA")) {

                    // Recover local version
                    SparkleGit git_theirs = new SparkleGit (LocalPath, "checkout --theirs \"" + conflicting_path + "\"");
                    git_theirs.StartAndWaitForExit ();

                    // Append a timestamp to local version.
                    // Windows doesn't allow colons in the file name, so
                    // we use "h" between the hours and minutes instead.
                    string timestamp  = DateTime.Now.ToString ("MMM d H\\hmm");
                    string their_path = Path.GetFileNameWithoutExtension (conflicting_path) +
                        " (" + base.local_config.User.Name + ", " + timestamp + ")" + Path.GetExtension (conflicting_path);

                    string abs_conflicting_path = Path.Combine (LocalPath, conflicting_path);
                    string abs_their_path       = Path.Combine (LocalPath, their_path);

                    File.Move (abs_conflicting_path, abs_their_path);

                    // Recover server version
                    SparkleGit git_ours = new SparkleGit (LocalPath, "checkout --ours \"" + conflicting_path + "\"");
                    git_ours.StartAndWaitForExit ();

                    changes_added = true;

                // The local version has been modified, but the server version was removed
                } else if (line.StartsWith ("DU")) {

                    // The modified local version is already in the
                    // checkout, so it just needs to be added.
                    //
                    // We need to specifically mention the file, so
                    // we can't reuse the Add () method
                    SparkleGit git_add = new SparkleGit (LocalPath, "add \"" + conflicting_path + "\"");
                    git_add.StartAndWaitForExit ();

                    changes_added = true;
                }
            }

            Add ();
            SparkleGit git;

            if (changes_added)
                git = new SparkleGit (LocalPath, "rebase --continue");
            else
                git = new SparkleGit (LocalPath, "rebase --skip");

            git.StartInfo.RedirectStandardOutput = false;
            git.StartAndWaitForExit ();
        }


        public override void RestoreFile (string path, string revision, string target_file_path)
        {
            if (path == null)
                throw new ArgumentNullException ("path");

            if (revision == null)
                throw new ArgumentNullException ("revision");

            path = path.Replace ("\\", "/");
            SparkleLogger.LogInfo ("Git", Name + " | Restoring \"" + path + "\" (revision " + revision + ")");

            // FIXME: git-show doesn't decrypt objects, so we can't use it to retrieve
            // files from the index. This is a suboptimal workaround but it does the job
            if (this.is_encrypted) {
                // Restore the older file...
                SparkleGit git = new SparkleGit (LocalPath, "checkout " + revision + " \"" + path + "\"");
                git.StartAndWaitForExit ();

                string local_file_path = Path.Combine (LocalPath, path);

                // ...move it...
                try {
                    File.Move (local_file_path, target_file_path);
                
                } catch {
                    SparkleLogger.LogInfo ("Git",
                        Name + " | Could not move \"" + local_file_path + "\" to \"" + target_file_path + "\"");
                }

                // ...and restore the most recent revision
                git = new SparkleGit (LocalPath, "checkout " + CurrentRevision + " \"" + path + "\"");
                git.StartAndWaitForExit ();
            
            // The correct way
            } else {
                path = path.Replace (" ", "\\ ");

                SparkleGit git = new SparkleGit (LocalPath, "show " + revision + ":" + path + "");
                git.Start ();

                FileStream stream = File.OpenWrite (target_file_path);    
                git.StandardOutput.BaseStream.CopyTo (stream);
                stream.Close ();

                git.WaitForExit ();
            }

            if (target_file_path.StartsWith (LocalPath))
                new Thread (() => OnFileActivity (null)).Start ();
        }


        public override List<SparkleChangeSet> GetChangeSets (string path, int count)
        {
            return GetChangeSetsInternal (path, count);
        }   


        public override List<SparkleChangeSet> GetChangeSets (int count)
        {
            return GetChangeSetsInternal (null, count);
        }


        private bool FindError (string line)
        {
            Error = ErrorStatus.None;
                
            if (line.StartsWith ("WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!") ||
                line.StartsWith ("WARNING: POSSIBLE DNS SPOOFING DETECTED!")) {
                
                Error = ErrorStatus.HostIdentityChanged;
                
            } else if (line.StartsWith ("Permission denied")) {
                Error = ErrorStatus.AuthenticationFailed;
                
            } else if (line.StartsWith ("error: Disk space exceeded")) {
                Error = ErrorStatus.DiskSpaceExcedeed;
            }
            
            if (Error != ErrorStatus.None) {
                SparkleLogger.LogInfo ("Git", Name + " | Error status changed to " + Error);
                return true;
            } else {
                return false;
            }
        }


        private List<SparkleChangeSet> GetChangeSetsInternal (string path, int count)
        {
            if (count < 1)
                throw new ArgumentOutOfRangeException ("count");

            count = 150;
            List <SparkleChangeSet> change_sets = new List <SparkleChangeSet> ();

            SparkleGit git;

            if (path == null) {
                git = new SparkleGit (LocalPath, "log -" + count + " --raw --find-renames --date=iso " +
                    "--format=medium --no-color --no-merges");

            } else {
                path = path.Replace ("\\", "/");

                git = new SparkleGit (LocalPath, "log -" + count + " --raw --find-renames --date=iso " +
                    "--format=medium --no-color --no-merges -- \"" + path + "\"");
            }

            string output = git.StartAndReadStandardOutput ();

            string [] lines      = output.Split ("\n".ToCharArray ());
            List<string> entries = new List <string> ();

            int line_number = 0;
            bool first_pass = true;
            string entry = "", last_entry = "";
            foreach (string line in lines) {
                if (line.StartsWith ("commit") && !first_pass) {
                    entries.Add (entry);
                    entry = "";
                    line_number = 0;

                } else {
                    first_pass = false;
                }

                // Only parse 250 files to prevent memory issues
                if (line_number < 254) {
                    entry += line + "\n";
                    line_number++;
                }

                last_entry = entry;
            }

            entries.Add (last_entry);

            Regex regex = new Regex (@"commit ([a-z0-9]{40})\n" +
                "Author: (.+) <(.+)>\n" +
                "*" +
                "Date:   ([0-9]{4})-([0-9]{2})-([0-9]{2}) " +
                "([0-9]{2}):([0-9]{2}):([0-9]{2}) (.[0-9]{4})\n" +
                "*", RegexOptions.Compiled);

            foreach (string log_entry in entries) {
                Match match = regex.Match (log_entry);

                if (match.Success) {
                    SparkleChangeSet change_set = new SparkleChangeSet ();

                    change_set.Folder    = new SparkleFolder (Name);
                    change_set.Revision  = match.Groups [1].Value;
                    change_set.User      = new SparkleUser (match.Groups [2].Value, match.Groups [3].Value);
                    change_set.RemoteUrl = RemoteUrl;

                    change_set.Timestamp = new DateTime (int.Parse (match.Groups [4].Value),
                        int.Parse (match.Groups [5].Value), int.Parse (match.Groups [6].Value),
                        int.Parse (match.Groups [7].Value), int.Parse (match.Groups [8].Value),
                        int.Parse (match.Groups [9].Value));

                    string time_zone     = match.Groups [10].Value;
                    int our_offset       = TimeZone.CurrentTimeZone.GetUtcOffset(DateTime.Now).Hours;
                    int their_offset     = int.Parse (time_zone.Substring (0, 3));
                    change_set.Timestamp = change_set.Timestamp.AddHours (their_offset * -1);
                    change_set.Timestamp = change_set.Timestamp.AddHours (our_offset);

                    string [] entry_lines = log_entry.Split ("\n".ToCharArray ());

                    foreach (string entry_line in entry_lines) {
                        if (entry_line.StartsWith (":")) {
                            string type_letter = entry_line [37].ToString ();
                            string file_path   = entry_line.Substring (39);
                            bool change_is_folder = false;

                            if (file_path.Equals (".sparkleshare"))
                                continue;

                            if (file_path.EndsWith (".empty")) { 
                                file_path        = file_path.Substring (0, file_path.Length - ".empty".Length);
                                change_is_folder = true;
                            }

                            file_path = EnsureSpecialCharacters (file_path);
                            file_path = file_path.Replace ("\\\"", "\"");

                            if (type_letter.Equals ("R")) {
                                int tab_pos         = entry_line.LastIndexOf ("\t");
                                file_path           = entry_line.Substring (42, tab_pos - 42);
                                string to_file_path = entry_line.Substring (tab_pos + 1);

                                file_path    = EnsureSpecialCharacters (file_path);
                                to_file_path = EnsureSpecialCharacters (to_file_path);

                                file_path = file_path.Replace ("\\\"", "\"");
                                to_file_path = to_file_path.Replace ("\\\"", "\"");

                                if (file_path.EndsWith (".empty")) {
                                    file_path = file_path.Substring (0, file_path.Length - 6);
                                    change_is_folder = true;
                                }

                                if (to_file_path.EndsWith (".empty")) {
                                    to_file_path = to_file_path.Substring (0, to_file_path.Length - 6);
                                    change_is_folder = true;
                                }

                                change_set.Changes.Add (
                                    new SparkleChange () {
                                        Path        = file_path,
                                        IsFolder    = change_is_folder,
                                        MovedToPath = to_file_path,
                                        Timestamp   = change_set.Timestamp,
                                        Type        = SparkleChangeType.Moved
                                    }
                                );

                            } else {
                                SparkleChangeType change_type = SparkleChangeType.Added;

                                if (type_letter.Equals ("M")) {
                                    change_type = SparkleChangeType.Edited;

                                } else if (type_letter.Equals ("D")) {
                                   change_type = SparkleChangeType.Deleted;
                                }

                                change_set.Changes.Add (
                                    new SparkleChange () {
                                        Path      = file_path,
                                        IsFolder  = change_is_folder,
                                        Timestamp = change_set.Timestamp,
                                        Type      = change_type
                                    }
                                );
                            }
                        }
                    }

                    if (change_sets.Count > 0 && path == null) {
                        SparkleChangeSet last_change_set = change_sets [change_sets.Count - 1];

                        if (change_set.Timestamp.Year  == last_change_set.Timestamp.Year &&
                            change_set.Timestamp.Month == last_change_set.Timestamp.Month &&
                            change_set.Timestamp.Day   == last_change_set.Timestamp.Day &&
                            change_set.User.Name.Equals (last_change_set.User.Name)) {

                            last_change_set.Changes.AddRange (change_set.Changes);

                            if (DateTime.Compare (last_change_set.Timestamp, change_set.Timestamp) < 1) {
                                last_change_set.FirstTimestamp = last_change_set.Timestamp;
                                last_change_set.Timestamp      = change_set.Timestamp;
                                last_change_set.Revision       = change_set.Revision;

                            } else {
                                last_change_set.FirstTimestamp = change_set.Timestamp;
                            }

                        } else {
                            change_sets.Add (change_set);
                        }

                    } else {
                        if (path != null) {
                            bool skip_change_set = false;;

                            foreach (SparkleChange change in change_set.Changes) {
                                if ((change.Type == SparkleChangeType.Deleted ||
                                     change.Type == SparkleChangeType.Moved) && change.Path.Equals (path)) {

                                     skip_change_set = true;
                                }
                            }

                            if (skip_change_set)
                                continue;
                        }
                                        
                        change_sets.Add (change_set);
                    }
                }
            }

            return change_sets;
        }


        private string EnsureSpecialCharacters (string path)
        {
            // The path is quoted if it contains special characters
            if (path.StartsWith ("\""))
                path = ResolveSpecialChars (path.Substring (1, path.Length - 2));

            return path;
        }


        private string ResolveSpecialChars (string s)
        {
            StringBuilder builder = new StringBuilder (s.Length);
            List<byte> codes      = new List<byte> ();

            for (int i = 0; i < s.Length; i++) {
                while (s [i] == '\\' &&
                    s.Length - i > 3 &&
                    char.IsNumber (s [i + 1]) &&
                    char.IsNumber (s [i + 2]) &&
                    char.IsNumber (s [i + 3])) {

                    codes.Add (Convert.ToByte (s.Substring (i + 1, 3), 8));
                    i += 4;
                }

                if (codes.Count > 0) {
                    builder.Append (Encoding.UTF8.GetString (codes.ToArray ()));
                    codes.Clear ();
                }

                builder.Append (s [i]);
            }

            return builder.ToString ();
        }


        private void ClearCache ()
        {
            if (!this.use_git_bin)
                return;

            SparkleGitBin git_bin = new SparkleGitBin (LocalPath, "clear -f");
            git_bin.StartAndWaitForExit ();
        }


        // Git doesn't track empty directories, so this method
        // fills them all with a hidden empty file.
        //
        // It also prevents git repositories from becoming
        // git submodules by renaming the .git/HEAD file
        private void PrepareDirectories (string path)
        {
            try {
                foreach (string child_path in Directory.GetDirectories (path)) {
                    if (IsSymlink (child_path))
                        continue;

                    if (child_path.EndsWith (".git")) {
                        if (child_path.Equals (Path.Combine (LocalPath, ".git")))
                            continue;
    
                        string HEAD_file_path = Path.Combine (child_path, "HEAD");
    
                        if (File.Exists (HEAD_file_path)) {
                            File.Move (HEAD_file_path, HEAD_file_path + ".backup");
                            SparkleLogger.LogInfo ("Git", Name + " | Renamed " + HEAD_file_path);
                        }
    
                        continue;
                    }
    
                    PrepareDirectories (child_path);
                }
    
                if (Directory.GetFiles (path).Length == 0 &&
                    Directory.GetDirectories (path).Length == 0 &&
                    !path.Equals (LocalPath)) {

                    if (!File.Exists (Path.Combine (path, ".empty"))) {
                        try {
                            File.WriteAllText (Path.Combine (path, ".empty"), "I'm a folder!");
                            File.SetAttributes (Path.Combine (path, ".empty"), FileAttributes.Hidden);

                        } catch {
                            SparkleLogger.LogInfo ("Git", Name + " | Failed adding empty folder " + path);
                        }
                    }
                }

            } catch (IOException e) {
                SparkleLogger.LogInfo ("Git", "Failed preparing directory: " + e.Message);
            }
        }


        // Creates a pretty commit message based on what has changed
        private string FormatCommitMessage ()
        {
            int count      = 0;
            string message = "";

            SparkleGit git_status = new SparkleGit (LocalPath, "status --porcelain");
            git_status.Start ();

            while (!git_status.StandardOutput.EndOfStream) {
                string line = git_status.StandardOutput.ReadLine ();

                if (line.EndsWith (".empty") || line.EndsWith (".empty\""))
                    line = line.Replace (".empty", "");

                if (line.StartsWith ("R")) {
                    string path = line.Substring (3, line.IndexOf (" -> ") - 3).Trim ("\"".ToCharArray ());
                    string moved_to_path = line.Substring (line.IndexOf (" -> ") + 4).Trim ("\"".ToCharArray ());

                    message +=  "< ‘" + EnsureSpecialCharacters (path) + "’\n";
                    message +=  "> ‘" + EnsureSpecialCharacters (moved_to_path) + "’\n";

                } else {
                    if (line.StartsWith ("M")) {
                        message += "/";

                    } else if (line.StartsWith ("D")) {
                        message += "-";

                    } else {
                        message += "+";
                    }

                    string path = line.Substring (3).Trim ("\"".ToCharArray ());
                    message += " ‘" + EnsureSpecialCharacters (path) + "’\n";
                }

                count++;
                if (count == 10) {
                    message += "...\n";
                    break;
                }
            }

            git_status.StandardOutput.ReadToEnd ();
            git_status.WaitForExit ();

            return message;
        }


        // Recursively gets a folder's size in bytes
        private double CalculateSizes (DirectoryInfo parent)
        {
            if (!Directory.Exists (parent.FullName) || parent.Name.Equals ("rebase-apply"))
                return 0;

            double size = 0;

            try {
                foreach (FileInfo file in parent.GetFiles ()) {
                    if (!file.Exists)
                        return 0;

                    if (file.Name.Equals (".empty"))
                        File.SetAttributes (file.FullName, FileAttributes.Hidden);

                    size += file.Length;
                }

            } catch (Exception e) {
                SparkleLogger.LogInfo ("Local", "Error calculating size: " + e.Message);
                return 0;
            }


            try {
                foreach (DirectoryInfo directory in parent.GetDirectories ())
                    size += CalculateSizes (directory);

            } catch (Exception e) {
                SparkleLogger.LogInfo ("Local", "Error calculating size: " + e.Message);
                return 0;
            }

            return size;
        }

        
        private bool IsSymlink (string file)
        {
            FileAttributes attributes = File.GetAttributes (file);
            return ((attributes & FileAttributes.ReparsePoint) == FileAttributes.ReparsePoint);
        }
    }
}