Add check update

app/App.xaml.cs

@@ -13,6 +13,7 @@ namespace ParsecVDisplay
         const string ID = "QpHOX8IBUHBznGtqk9xm1";
         public const string NAME = "ParsecVDisplay";
         public const string VERSION = "0.45.2";
+        public const string GITHUB_REPO = "nomi-san/parsec-vdd";
 
         public static bool Silent { get; private set; }
 

app/MainWindow.xaml

@@ -99,6 +99,8 @@
             <MenuItem Header="Fallback display" IsCheckable="True" IsChecked="{Binding Path=(local:Config.FallbackDisplay), Mode=TwoWay}" />
             <MenuItem Header="Keep screen on" IsCheckable="True" IsChecked="{Binding Path=(local:Config.KeepScreenOn), Mode=TwoWay}" />
             <Separator />
+            <MenuItem Header="Check for update" x:Name="xMICheckUpdate" Click="CheckUpdate" />
+            <Separator />
             <MenuItem Header="Exit" Click="ExitApp" />
         </ContextMenu>
     </Window.ContextMenu>

app/MainWindow.xaml.cs

@@ -59,6 +59,8 @@ namespace ParsecVDisplay
         {
             Loaded -= Window_Loaded;
 
+            CheckUpdate(null, null);
+
             if (App.Silent)
                 Hide();
 
@@ -167,7 +169,35 @@ namespace ParsecVDisplay
         private void OpenRepoLink(object sender, MouseButtonEventArgs e)
         {
             e.Handled = true;
-            Helper.OpenLink("https://github.com/nomi-san/parsec-vdd");
+            Helper.OpenLink($"https://github.com/{App.GITHUB_REPO}");
+        }
+
+        private async void CheckUpdate(object sender, RoutedEventArgs e)
+        {
+            var oldText = xMICheckUpdate.Header;
+            xMICheckUpdate.Header = "Checking for update...";
+            xMICheckUpdate.IsEnabled = false;
+
+            var newVersion = await Updater.CheckUpdate();
+            if (!string.IsNullOrEmpty(newVersion))
+            {
+                var ret = MessageBox.Show(this,
+                    $"A new version — v{newVersion} is available!\n" +
+                    $"To keep your experience optimal, please update it now.",
+                    App.NAME, MessageBoxButton.YesNo, MessageBoxImage.Question);
+                if (ret == MessageBoxResult.Yes)
+                {
+                    Helper.OpenLink(Updater.DOWNLOAD_URL);
+                }
+            }
+            else if (sender != null)
+            {
+                MessageBox.Show(this, "Your app version is up-to-date.",
+                    App.NAME, MessageBoxButton.OK, MessageBoxImage.Information);
+            }
+
+            xMICheckUpdate.Header = oldText;
+            xMICheckUpdate.IsEnabled = true;
         }
     }
 }

app/ParsecVDisplay.csproj

@@ -86,6 +86,7 @@
     <Compile Include="Shadow.cs" />
     <Compile Include="Tray.cs" />
     <Compile Include="ParsecVDD.cs" />
+    <Compile Include="Updater.cs" />
     <Page Include="Components\Button.xaml">
       <SubType>Designer</SubType>
       <Generator>MSBuild:Compile</Generator>

app/Updater.cs

@@ -0,0 +1,80 @@
+using System;
+using System.Net;
+using System.Net.Http;
+using System.Net.Http.Headers;
+using System.Text.RegularExpressions;
+using System.Threading.Tasks;
+
+namespace ParsecVDisplay
+{
+    internal static class Updater
+    {
+        public static string DOWNLOAD_URL => $"https://github.com/{App.GITHUB_REPO}/releases/latest";
+        static string GH_API_URL => $"https://api.github.com/repos/{App.GITHUB_REPO}/releases/latest";
+
+        static Updater()
+        {
+            ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls11
+                | SecurityProtocolType.Tls12;
+        }
+
+        public static Task<string> CheckUpdate()
+        {
+            return Task.Run(async () =>
+            {
+                var localVersion = new Version(App.VERSION);
+                var remoteVersion = await FetchLatestVersion();
+
+                if (remoteVersion.CompareTo(localVersion) > 0)
+                {
+                    return remoteVersion.ToString();
+                }
+
+                return string.Empty;
+            });
+        }
+
+        static async Task<Version> FetchLatestVersion()
+        {
+            try
+            {
+                var json = await DownloadString(GH_API_URL);
+
+                if (!string.IsNullOrEmpty(json))
+                {
+                    var tagNameRegex = new Regex("\"tag_name\":\\s+\"(.*)\"");
+                    var match = tagNameRegex.Match(json);
+
+                    if (match.Success && match.Groups.Count > 1)
+                    {
+                        var vtag = match.Groups[1].Value.ToLower();
+                        if (vtag.StartsWith("v"))
+                            vtag = vtag.Substring(1);
+
+                        return new Version(vtag);
+                    }
+                }
+            }
+            catch
+            {
+            }
+
+            return new Version(App.VERSION);
+        }
+
+        static async Task<string> DownloadString(string url)
+        {
+            using (var client = new HttpClient())
+            {
+                client.DefaultRequestHeaders.Add("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) " +
+                    "AppleWebKit/537.36 (KHTML, like Gecko) Chrome/126.0.0.0 Safari/537.36");
+                client.DefaultRequestHeaders.CacheControl = new CacheControlHeaderValue
+                {
+                    NoCache = true
+                };
+
+                return await client.GetStringAsync(url);
+            }
+        }
+    }
+}