add auto_state_update client & server

src/pellest.ml

@@ -1,3 +1,25 @@
+let regularly_call_fun f v =
+  let () = Sys.set_signal Sys.sigalrm (Sys.Signal_handle (fun _ -> f ())) in
+  let (_ : Unix.interval_timer_status) =
+    Unix.setitimer Unix.ITIMER_REAL { Unix.it_interval = v; Unix.it_value = v }
+  in
+  ()
+
+let update_offline_user_state () =
+  (* TODO *)
+  ()
+
+let update_online_user_state () =
+  Hashtbl.filter_map_inplace
+    (fun _user_id state -> Some (Shared.State.auto_update state))
+    User.state_ht
+
+let () =
+  regularly_call_fun update_online_user_state
+    (float_of_int Shared.State.auto_state_update_rate);
+  regularly_call_fun update_offline_user_state
+    (float_of_int Shared.State.auto_state_update_rate)
+
 let () =
   let logger = if App.log then Dream.logger else Fun.id in
   Dream.run ~port:App.port @@ logger @@ Dream.memory_sessions