changed.对启动器重构的尝试

LanMountainDesktop.Launcher/Update/UpdateSnapshotStore.cs

@@ -0,0 +1,34 @@
+using System.Text.Json;
+using LanMountainDesktop.Launcher.Models;
+
+namespace LanMountainDesktop.Launcher.Update;
+
+internal sealed class UpdateSnapshotStore(UpdateEnginePaths paths)
+{
+    public string CreateSnapshotPath(string snapshotId) => paths.GetSnapshotPath(snapshotId);
+
+    public void Save(string path, SnapshotMetadata snapshot)
+    {
+        File.WriteAllText(path, JsonSerializer.Serialize(snapshot, AppJsonContext.Default.SnapshotMetadata));
+    }
+
+    public (string Path, SnapshotMetadata Snapshot)? LoadLatest()
+    {
+        if (!Directory.Exists(paths.SnapshotsRoot))
+        {
+            return null;
+        }
+
+        var snapshotPath = Directory
+            .EnumerateFiles(paths.SnapshotsRoot, "*.json", SearchOption.TopDirectoryOnly)
+            .OrderByDescending(File.GetCreationTimeUtc)
+            .FirstOrDefault();
+        if (string.IsNullOrWhiteSpace(snapshotPath))
+        {
+            return null;
+        }
+
+        var snapshot = JsonSerializer.Deserialize(File.ReadAllText(snapshotPath), AppJsonContext.Default.SnapshotMetadata);
+        return snapshot is null ? null : (snapshotPath, snapshot);
+    }
+}