From 22552ce1a9f87043048e252ceb5e2175db41fb2a Mon Sep 17 00:00:00 2001
From: Tim Young <tim.young@lightsys.org>
Date: Sat, 5 Aug 2017 12:41:42 -0500
Subject: [PATCH] Create basic backup file rotation functions and direcories.

---
 EduNetworkBuilder/NB.cs | 62 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 62 insertions(+)

diff --git a/EduNetworkBuilder/NB.cs b/EduNetworkBuilder/NB.cs
index 20d4893..1398eb4 100644
--- a/EduNetworkBuilder/NB.cs
+++ b/EduNetworkBuilder/NB.cs
@@ -1010,6 +1010,68 @@ namespace EduNetworkBuilder
             return OFD;
         }
 
+
+        /// <summary>
+        /// Move a file out of the way, making a rotating backup at the same time.
+        /// </summary>
+        /// <param name="SourceFileWithDir">A source filename with a directory</param>
+        /// <param name="DestDir">The directory where to put the file</param>
+        /// <param name="rotation">The number of rotation backups to make</param>
+        public static void MoveFileWithRotation(string SourceFileWithDir, string DestDir, int rotation)
+        {
+            if (!File.Exists(SourceFileWithDir)) return; //we do not rotate if the source does not exist
+            if (!Directory.Exists(DestDir))
+                Directory.CreateDirectory(DestDir);
+            //Rotate the old file first, then move the new one over.
+            string dest_file = Path.Combine(DestDir, Path.GetFileName(SourceFileWithDir));
+            RotateFile(dest_file, rotation);
+            File.Move(SourceFileWithDir, dest_file);
+        }
+
+        /// <summary>
+        /// Move a file out of the way, making a rotating backup at the same time.  backup to appdata
+        /// </summary>
+        /// <param name="SourceFileWithDir">A source filename with a directory</param>
+        /// <param name="rotation">The number of rotation backups to make</param>
+        public static void MoveFileWithRotation(string SourceFileWithDir, int rotation)
+        {
+            string StandardDest = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData), "EduNetworkBuilder");
+            MoveFileWithRotation(SourceFileWithDir, StandardDest, rotation);
+        }
+
+        /// <summary>
+        /// Given a file, rotate it with the specified number of versions.
+        /// </summary>
+        /// <param name="filename"></param>
+        /// <param name="count"></param>
+        public static void RotateFile(string filename, int count)
+        {
+            if (count < 1) return;
+            string currentfile = GenFilenameWithInt(filename, count);
+            string rotatefile;
+            if (File.Exists(currentfile)) File.Delete(currentfile); //The last rotation gets deleted
+            for(int i=count -1; i >= 1; i--)
+            {
+                currentfile = GenFilenameWithInt(filename, i);
+                rotatefile = GenFilenameWithInt(filename, i + 1);
+                if (File.Exists(currentfile))
+                    File.Move(currentfile, rotatefile);
+            }
+            //The final case is when there is no version number on the file.
+            currentfile = filename;
+            rotatefile = GenFilenameWithInt(filename, 1);
+            if (File.Exists(currentfile))
+                File.Move(currentfile, rotatefile);
+        }
+
+        private static string GenFilenameWithInt(string filename, int version)
+        {
+            string FileOnly = Path.GetFileNameWithoutExtension(filename);
+            string FileWithInt = FileOnly + "-" + version.ToString("00") + Path.GetExtension(filename);
+            string Combined = Path.Combine(Path.GetDirectoryName(filename), FileWithInt);
+            return Combined;
+        }
+
         public static void NotImplimentedMessage()
         {
             MessageBox.Show(Translate("NB_NotImplimented"));