like this

pttodoest/src/main.rs

@@ -158,12 +158,28 @@ impl File {
 }
 
 #[derive(Debug, Clone, Serialize, Deserialize)]
-struct Delta(json_patch::Patch);
+struct Delta{
+   ts: u64,
+   patch: json_patch::Patch,
+}
 
 #[derive(Debug, Clone, Serialize, Deserialize)]
-struct TaskAt {
+struct TaskTs {
     task: Task,
-    at: usize,
+    ts: u64,
+}
+
+impl Delta {
+   fn new(patch: json_patch::Patch, ts: u64) -> TaskTs {
+      Delta{
+         patch: patch,
+         ts: ts,
+      }
+   }
+
+   fn now(patch: json_patch::Patch) -> Delta {
+      Self::new(patch, std::time::SystemTime::now().duration_since(std::time::UNIX_EPOCH).unwrap().as_secs().try_into().unwrap())
+   }
 }
 
 #[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]