Notify users when there is a new version of the CLI (#242)

Do this only when not running unattended.

src/Cli/Cli.csproj

@@ -16,6 +16,7 @@
   </PropertyGroup>
 
   <ItemGroup>
+    <PackageReference Include="NuGet.Protocol" Version="6.10.0" />
     <PackageReference Include="NuGetizer" Version="1.2.2" PrivateAssets="all" />
     <PackageReference Include="Spectre.Console.Cli" Version="0.49.1" />
     <PackageReference Include="Devlooped.JQ" Version="1.7.1.1" />
@@ -32,6 +33,8 @@
     <ProjectProperty Include="ToolCommandName" />
     <ProjectProperty Include="BuildDate" />
     <ProjectProperty Include="BuildRef" />
+    <ProjectProperty Include="PackageId" />
+    <ProjectProperty Include="PackageVersion" />
   </ItemGroup>
 
 </Project>

src/Cli/Program.cs

@@ -3,6 +3,9 @@
 using Devlooped.Sponsors;
 using DotNetConfig;
 using Microsoft.Extensions.DependencyInjection;
+using NuGet.Configuration;
+using NuGet.Protocol.Core.Types;
+using NuGet.Versioning;
 using Spectre.Console;
 using Spectre.Console.Cli;
 
@@ -40,7 +43,7 @@
     // Force run welcome if --welcome is passed or no tos was accepted yet
     // preserve all other args just in case the welcome command adds more in the future.
     var result = await app.RunAsync(args.TakeWhile(x => x == ToSSettings.ToSOption).Prepend("welcome").ToArray());
-    
+
     if (result != 0)
         return result;
 
@@ -67,4 +70,48 @@
 }
 #endif
 
-return app.Run(args);
+var updates = Task.Run(() => CheckUpdates(args));
+var exit = app.Run(args);
+
+if (await updates is { Length: > 0 } messages)
+{
+    foreach (var message in messages)
+        AnsiConsole.MarkupLine(message);
+}
+
+return exit;
+
+static async Task<string[]> CheckUpdates(string[] args)
+{
+    if (args.Contains("-u") && !args.Contains("--unattended"))
+        return [];
+
+    var providers = Repository.Provider.GetCoreV3();
+    var repository = new SourceRepository(new PackageSource("https://api.nuget.org/v3/index.json"), providers);
+    var resource = await repository.GetResourceAsync<PackageMetadataResource>();
+    var localVersion = new NuGetVersion(ThisAssembly.Project.Version);
+    var metadata = await resource.GetMetadataAsync(ThisAssembly.Project.PackageId, true, false,
+        new SourceCacheContext
+        {
+            NoCache = true,
+            RefreshMemoryCache = true,
+        },
+        NuGet.Common.NullLogger.Instance, CancellationToken.None);
+
+    var update = metadata
+        .Select(x => x.Identity)
+        .Where(x => x.Version > localVersion)
+        .OrderByDescending(x => x.Version)
+        .Select(x => x.Version)
+        .FirstOrDefault();
+
+    if (update != null)
+    {
+        return [
+            $"There is a new version of [yellow]{ThisAssembly.Project.PackageId}[/]: [dim]v{localVersion.ToNormalizedString()}[/] -> [lime]v{update.ToNormalizedString()}[/]",
+            $"Update with: [yellow]dotnet[/] tool update -g {ThisAssembly.Project.PackageId}"
+        ];
+    }
+
+    return [];
+}