refactor<*>: rewrite all with AvaloniaUI

src/ViewModels/AddSubmodule.cs

@@ -0,0 +1,61 @@
+using System.ComponentModel.DataAnnotations;
+using System.IO;
+using System.Threading.Tasks;
+
+namespace SourceGit.ViewModels {
+    public class AddSubmodule : Popup {
+        [Required(ErrorMessage = "Url is required!!!")]
+        [CustomValidation(typeof(AddSubmodule), nameof(ValidateURL))]
+        public string Url {
+            get => _url;
+            set => SetProperty(ref _url, value, true);
+        }
+
+        [Required(ErrorMessage = "Reletive path is required!!!")]
+        [CustomValidation(typeof(AddSubmodule), nameof(ValidateRelativePath))]
+        public string RelativePath {
+            get => _relativePath;
+            set => SetProperty(ref _relativePath, value, true);
+        }
+
+        public bool Recursive {
+            get;
+            set;
+        }
+
+        public AddSubmodule(Repository repo) {
+            _repo = repo;
+            View = new Views.AddSubmodule() { DataContext = this };
+        }
+
+        public static ValidationResult ValidateURL(string url, ValidationContext ctx) {
+            if (!Models.Remote.IsValidURL(url)) return new ValidationResult("Invalid repository URL format");
+            return ValidationResult.Success;
+        }
+
+        public static ValidationResult ValidateRelativePath(string path, ValidationContext ctx) {
+            if (Path.Exists(path)) {
+                return new ValidationResult("Give path is exists already!");
+            }
+
+            if (Path.IsPathRooted(path)) {
+                return new ValidationResult("Path must be relative to this repository!");
+            }
+
+            return ValidationResult.Success;
+        }
+
+        public override Task<bool> Sure() {
+            _repo.SetWatcherEnabled(false);
+            return Task.Run(() => {
+                var succ = new Commands.Submodule(_repo.FullPath).Add(_url, _relativePath, Recursive, SetProgressDescription);
+                CallUIThread(() => _repo.SetWatcherEnabled(true));
+                return succ;
+            });
+        }
+
+        private Repository _repo = null;
+        private string _url = string.Empty;
+        private string _relativePath = string.Empty;
+    }
+}