gui: Refactoring Part 1 (#1859)

* gui: Refactoring Part 1

* Fix ProfileDialog.glade path

* Fix Application.Quit assert

* Fix TitleUpdateWindow parent

* Fix TitleUpdate selected item

* Remove extra line in TitleUpdateWindow

* Fix empty assign of Enum.TryParse

* Add Patrons list in the About Window

* update about error messages

Ryujinx/Ui/Widgets/UserErrorDialog.cs

@@ -0,0 +1,122 @@
+using Gtk;
+using Ryujinx.Ui.Helper;
+
+namespace Ryujinx.Ui.Widgets
+{
+    internal class UserErrorDialog : MessageDialog
+    {
+        private const string SetupGuideUrl        = "https://github.com/Ryujinx/Ryujinx/wiki/Ryujinx-Setup-&-Configuration-Guide";
+        private const int    OkResponseId         = 0;
+        private const int    SetupGuideResponseId = 1;
+
+        private readonly UserError _userError;
+
+        private UserErrorDialog(UserError error) : base(null, DialogFlags.Modal, MessageType.Error, ButtonsType.None, null)
+        {
+            _userError = error;
+
+            WindowPosition     = WindowPosition.Center;
+            SecondaryUseMarkup = true;
+
+            Response += UserErrorDialog_Response;
+
+            SetSizeRequest(120, 50);
+
+            AddButton("OK", OkResponseId);
+
+            bool isInSetupGuide = IsCoveredBySetupGuide(error);
+
+            if (isInSetupGuide)
+            {
+                AddButton("Open the Setup Guide", SetupGuideResponseId);
+            }
+
+            string errorCode = GetErrorCode(error);
+
+            SecondaryUseMarkup = true;
+
+            Title         = $"Ryujinx error ({errorCode})";
+            Text          = $"{errorCode}: {GetErrorTitle(error)}";
+            SecondaryText = GetErrorDescription(error);
+
+            if (isInSetupGuide)
+            {
+                SecondaryText += "\n<b>For more information on how to fix this error, follow our Setup Guide.</b>";
+            }
+        }
+
+        private string GetErrorCode(UserError error)
+        {
+            return $"RYU-{(uint)error:X4}";
+        }
+
+        private string GetErrorTitle(UserError error)
+        {
+            return error switch
+            {
+                UserError.NoKeys                => "Keys not found",
+                UserError.NoFirmware            => "Firmware not found",
+                UserError.FirmwareParsingFailed => "Firmware parsing error",
+                UserError.ApplicationNotFound   => "Application not found",
+                UserError.Unknown               => "Unknown error",
+                _                               => "Undefined error",
+            };
+        }
+
+        private string GetErrorDescription(UserError error)
+        {
+            return error switch
+            {
+                UserError.NoKeys                => "Ryujinx was unable to find your 'prod.keys' file",
+                UserError.NoFirmware            => "Ryujinx was unable to find any firmwares installed",
+                UserError.FirmwareParsingFailed => "Ryujinx was unable to parse the provided firmware. This is usually caused by outdated keys.",
+                UserError.ApplicationNotFound   => "Ryujinx couldn't find a valid application at the given path.",
+                UserError.Unknown               => "An unknown error occured!",
+                _                               => "An undefined error occured! This shouldn't happen, please contact a dev!",
+            };
+        }
+
+        private static bool IsCoveredBySetupGuide(UserError error)
+        {
+            return error switch
+            {
+                UserError.NoKeys or
+                UserError.NoFirmware or 
+                UserError.FirmwareParsingFailed => true,
+                _                               => false,
+            };
+        }
+
+        private static string GetSetupGuideUrl(UserError error)
+        {
+            if (!IsCoveredBySetupGuide(error))
+            {
+                return null;
+            }
+
+            return error switch
+            {
+                UserError.NoKeys     => SetupGuideUrl + "#initial-setup---placement-of-prodkeys",
+                UserError.NoFirmware => SetupGuideUrl + "#initial-setup-continued---installation-of-firmware",
+                _                    => SetupGuideUrl,
+            };
+        }
+
+        private void UserErrorDialog_Response(object sender, ResponseArgs args)
+        {
+            int responseId = (int)args.ResponseId;
+
+            if (responseId == SetupGuideResponseId)
+            {
+                OpenHelper.OpenUrl(GetSetupGuideUrl(_userError));
+            }
+
+            Dispose();
+        }
+
+        public static void CreateUserErrorDialog(UserError error)
+        {
+            new UserErrorDialog(error).Run();
+        }
+    }
+}