files tree made better.

src/Yavsc.Abstract/FileSystem/UserDirectoryInfo.cs

@@ -0,0 +1,57 @@
+using System;
+using System.IO;
+using System.Linq;
+using Yavsc.Abstract.FileSystem;
+
+namespace Yavsc.ViewModels.UserFiles
+{
+    public class UserDirectoryInfo
+    {
+        public string UserName { get; set; }
+        public string SubPath { get; set; }
+        public RemoteFileInfo [] Files {
+            get; set;
+        }
+        public DirectoryShortInfo [] SubDirectories { 
+            get; set;
+        }
+        private DirectoryInfo dInfo;
+
+        // for deserialization
+        public UserDirectoryInfo()
+        {
+
+        }
+        public UserDirectoryInfo(string userReposPath, string username, string path)
+        {
+            if (string.IsNullOrWhiteSpace(username))
+                throw new NotSupportedException("No user name, no user dir.");
+            UserName = username;
+            var finalPath =  username;
+            if (!finalPath.IsValidYavscPath())
+                throw new InvalidOperationException(
+                    $"File name contains invalid chars ({finalPath})");
+
+            dInfo = new DirectoryInfo(
+                userReposPath+Path.DirectorySeparatorChar+finalPath);
+            if (dInfo.Exists) {
+
+                Files = dInfo.GetFiles().Select
+                    ( entry => new RemoteFileInfo { Name = entry.Name, Size = entry.Length,
+                    CreationTime = entry.CreationTime, LastModified = entry.LastWriteTime  }).ToArray();
+                SubDirectories = dInfo.GetDirectories().Select
+                    ( d=> new DirectoryShortInfo { Name= d.Name, IsEmpty=false } ).ToArray();
+            }
+            else {
+                // don't return null, but empty arrays
+                Files = new RemoteFileInfo[0];
+                SubDirectories = new DirectoryShortInfo[0];
+            }
+        }
+    }
+
+    public class DirectoryShortInfo: IDirectoryShortInfo {
+        public string Name { get; set; }
+        public bool IsEmpty { get; set; }
+    }
+}