refactor: replace predicate-based event matching with collector pipeline

- Simplify `.ocamlformat` to use `default` profile with fewer overrides
- Extract shared types and utilities into a `remind_sync` library
  (`icalendar_augmented`, `ptime_augmented`, `timedesc_augmented`,
  `result_augmented`, `utf8`)
- Replace `eventTransformer.ml` and the predicate system in
  `eventPredicates.ml` with a sequential collector pipeline
  (`collect_uuid`, `collect_summary`, `collect_start_end_duration`,
  etc.)
- Simplify `Remind.rem` to a flat record with `Timedesc` date/time
  fields and replace `rem_to_string` with a leaner `string_of_rem`
- Add `separate_master_and_recurrence` and `get_recurrence_id` helpers
  to `utils.ml`
- Wire `main.ml` to call `EventPredicates.remind_of_event` per UID group
  and print results directly
- Remove `eventTransformer` module from `bin/dune` and enable the
  `remind_sync` library dependency

bin/main.ml

@@ -1,6 +1,6 @@
+open Remind_sync
 module Map = MoreLabels.Map.Make (String)
 
-type event = Icalendar.event list
 (*
   We use a list of events here because there can be multiple events with the same UID, and we want to preserve all of
   them. This is important for handling cases where there are multiple events with the same UID but different properties
@@ -15,43 +15,30 @@ let ical2rem ical_file =
   close_in ic;
   let cal_or_error = Icalendar.parse (Bytes.unsafe_to_string s) in
   match cal_or_error with
-  | Error e -> prerr_endline ("Error parsing iCalendar file: " ^ e)
+  | Error e ->
+      if e = ": not enough input" then
+        exit 0 (* This is a common error when the file is empty, so we treat it as a non-error case *)
+      else prerr_endline ("Error parsing iCalendar file: " ^ e)
   | Ok (_, components) -> begin
-    let events_map : event Map.t =
-      ListLabels.fold_left ~init:Map.empty components ~f:(fun acc comp ->
-          match comp with
-          | `Event ev ->
-            let uid = Utils.get_uid ev in
-            let event_list = Map.find_opt uid acc |> Option.value ~default:[] in
-            Map.add ~key:uid ~data:(ev :: event_list) acc
-          | _ -> acc (* Ignore non-event components *))
-    in
+      let events_map : Icalendar.event list Map.t =
+        ListLabels.fold_left ~init:Map.empty components ~f:(fun acc comp ->
+            match comp with
+            | `Event ev ->
+                let uid = Utils.get_uid ev in
+                let event_list = Map.find_opt uid acc |> Option.value ~default:[] in
+                Map.add ~key:uid ~data:(ev :: event_list) acc
+            | _ -> acc (* Ignore non-event components *))
+      in
+      (* Now revert all the lists *)
+      let events_map = Map.map ~f:List.rev events_map in
+      (* Printf.printf "Events: %d\n\n" (Map.cardinal events_map); *)
 
-    (* Now revert all the lists *)
-    let events_map = Map.map ~f:List.rev events_map in
-
-    (* let () = *)
-    (*   Map.iter *)
-    (*     ~f:(fun ~key ~data -> *)
-    (*       let uid = key in *)
-    (*       let evs = data in *)
-    (*       Printf.printf "󰧓 ⇒ UID: %s\n" uid; *)
-    (*       List.iter (fun ev -> Printf.printf "%s\n" (Icalendar.show_component (`Event ev))) evs; *)
-    (*       Printf.printf "\n\n") *)
-    (*     events_map *)
-    (* in *)
-    Printf.printf "Events: %d\n\n" (Map.cardinal events_map);
-    let events =
-      List.filter_map
-        (function
-          | `Event ev -> Some ev
-          | _ -> None)
-        components
-    in
-
-    let _reminders = List.map EventTransformer.remind_of_event events in
-
-    ()
+      Map.iter events_map ~f:(fun ~key:uid ~data:events ->
+          let rem_or_error = EventPredicates.remind_of_event events in
+          match rem_or_error with
+          | Ok rem -> begin Printf.printf "%s\n" (Remind.string_of_rem rem) end
+          | Error (EventPredicates.Invalid_date s) -> Printf.eprintf "UID: %s Invalid date: %s\n" uid s
+          | Error Skip -> Printf.eprintf "UID: %s Skipped\n" uid)
     end
 
 let () = if !Sys.interactive then () else exit (CommandLine.main ical2rem)