- add: DotNet runtime download

Nebula.Shared/Services/DotnetResolverService.cs

@@ -0,0 +1,70 @@
+using System.Diagnostics;
+using System.IO.Compression;
+using System.Runtime.InteropServices;
+using System.Text;
+
+namespace Nebula.Shared.Services;
+
+[ServiceRegister]
+public class DotnetResolverService(DebugService debugService, ConfigurationService configurationService)
+{
+    private HttpClient _httpClient = new HttpClient();
+    
+    private static readonly string FullPath = Path.Join(FileService.RootPath, "dotnet", DotnetUrlHelper.GetRuntimeIdentifier());
+    private static readonly string ExecutePath = Path.Join(FullPath, "dotnet" + DotnetUrlHelper.GetExtension());
+    
+    public async Task<string> EnsureDotnet(){
+        if(!Directory.Exists(FullPath))
+            await Download();
+        
+        return ExecutePath;
+    }
+
+    private async Task Download(){
+        
+        debugService.GetLogger("DotnetResolver").Log($"Downloading dotnet {DotnetUrlHelper.GetRuntimeIdentifier()}...");
+        var ridExt =
+            DotnetUrlHelper.GetCurrentPlatformDotnetUrl(configurationService.GetConfigValue(CurrentConVar.DotnetUrl)!);
+        using var response = await _httpClient.GetAsync(ridExt);
+        using var zipArchive = new ZipArchive(await response.Content.ReadAsStreamAsync());
+        Directory.CreateDirectory(FullPath);
+        zipArchive.ExtractToDirectory(FullPath);
+        debugService.GetLogger("DotnetResolver").Log($"Downloading dotnet complete.");
+    }
+}
+
+public static class DotnetUrlHelper
+{
+    public static string GetExtension()
+    {
+        if (OperatingSystem.IsWindows()) return ".exe";
+        return "";
+    }
+    
+    public static string GetCurrentPlatformDotnetUrl(Dictionary<string, string> dotnetUrl)
+    {
+        string? rid = GetRuntimeIdentifier();
+
+        if (dotnetUrl.TryGetValue(rid, out var url))
+        {
+            return url;
+        }
+
+        throw new PlatformNotSupportedException($"No download URL available for the current platform: {rid}");
+    }
+
+    public static string GetRuntimeIdentifier()
+    {
+        if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+        {
+            return Environment.Is64BitProcess ? "win-x64" : "win-x86";
+        }
+
+        if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux))
+        {
+            return "linux-x64";
+        }
+
+        throw new PlatformNotSupportedException("Unsupported operating system");
+    }
+}