feat(cli): add output control flags, sort order, and verbose mode

- Add `--verbose`/`-v` flag; gate all diagnostic stderr output behind it
- Add `--no-uuid`, `--no-source`, `--no-location`, `--no-description`,
  `--no-conference-url` flags to suppress individual INFO lines
- Add `--sort` option (`asc`, `desc`, `original`) replacing hardcoded
  descending sort
- Add `--source` option to override calendar name (single-file only)
- Introduce `Config` module with global `ref` flags set at startup from
  CLI args
- Add `Utils.warn` helper that writes to stderr only when
  `Config.verbose` is set
- Normalise all diagnostic messages to a consistent format (`Warning:
  ... (UID: ...)`)
- Remove `debug_print_of_recurrence_and_skip`; inline skip at each call
  site
- Fix `add_common_part` to always emit a trailing `\\\n    `
  continuation line

bin/commandLine.ml

@@ -14,12 +14,69 @@ let timezone =
   let doc = "Target timezone for output (e.g. Europe/Rome). Defaults to local timezone." in
   Arg.(value & opt (some string) None & info [ "timezone"; "z" ] ~docv:"TZ" ~doc)
 
+let verbose =
+  let doc = "Print diagnostic messages (skipped events, unsupported recurrences, etc.) on stderr." in
+  Arg.(value & flag & info [ "verbose"; "v" ] ~doc)
+
+let no_uuid =
+  let doc = "Omit the INFO line with the event UID from output." in
+  Arg.(value & flag & info [ "no-uuid" ] ~doc)
+
+let no_source =
+  let doc = "Omit the INFO line with the calendar source name from output." in
+  Arg.(value & flag & info [ "no-source" ] ~doc)
+
+let no_location =
+  let doc = "Omit the INFO line with the event location from output." in
+  Arg.(value & flag & info [ "no-location" ] ~doc)
+
+let no_description =
+  let doc = "Omit the INFO line with the event description from output." in
+  Arg.(value & flag & info [ "no-description" ] ~doc)
+
+let no_conference_url =
+  let doc = "Omit the INFO line with the conference URL from output." in
+  Arg.(value & flag & info [ "no-conference-url" ] ~doc)
+
+type sort_order = Asc | Desc | Original
+
+let sort_order_enum = [ ("asc", Asc); ("desc", Desc); ("original", Original) ]
+
+let sort =
+  let doc = "Output sort order by date: $(b,desc) (default), $(b,asc), or $(b,none) (file order)." in
+  Arg.(value & opt (enum sort_order_enum) Desc & info [ "sort" ] ~docv:"ORDER" ~doc)
+
+let source =
+  let doc = "Override the calendar source name used in INFO lines. Only valid when processing a single file." in
+  Arg.(value & opt (some string) None & info [ "source" ] ~docv:"NAME" ~doc)
+
+type cli_args = {
+  tz : string option;
+  verbose : bool;
+  no_uuid : bool;
+  no_source : bool;
+  no_location : bool;
+  no_description : bool;
+  no_conference_url : bool;
+  sort : sort_order;
+  source : string option;
+}
+
 let main_command f =
   let doc = "Convert iCalendar files to remind format" in
   let man = [] in
   Cmd.make (Cmd.info "ical2rem" ~version:(version_string ()) ~doc ~man)
   @@
-  let+ files = files and+ tz = timezone in
+  let+ files = files
-  f tz files
+  and+ tz = timezone
+  and+ verbose = verbose
+  and+ no_uuid = no_uuid
+  and+ no_source = no_source
+  and+ no_location = no_location
+  and+ no_description = no_description
+  and+ no_conference_url = no_conference_url
+  and+ sort = sort
+  and+ source = source in
+  f { tz; verbose; no_uuid; no_source; no_location; no_description; no_conference_url; sort; source } files
 
 let main f = Cmd.eval @@ main_command f

bin/config.ml

@@ -0,0 +1,10 @@
+(** Global configuration flags, set once at startup from CLI args. *)
+
+(** Enable diagnostic output on stderr. Off by default; activated by --verbose. *)
+let verbose = ref false
+
+let no_uuid = ref false
+let no_source = ref false
+let no_location = ref false
+let no_description = ref false
+let no_conference_url = ref false

bin/dune

@@ -1,7 +1,7 @@
 (executable
  (public_name ical2rem)
  (name main)
- (modules main commandLine remind eventPredicates utils windows_tz)
+ (modules main commandLine config remind eventPredicates utils windows_tz)
  (preprocess
   (pps ppx_deriving.show))
  (libraries

bin/eventPredicates.ml

@@ -52,7 +52,8 @@ let collect_start_end_duration rem ev : (Remind.rem, error) result =
           begin match ev.dtend_or_duration with
           | None -> { rem with Remind.date = day_start } |> Result.ok
           | Some (`Dtend (_, `Datetime _)) ->
-              skip (* Start is a date, end is a datetime: invalid case for all-day event *)
+              Utils.warn "Warning: DTSTART is DATE but DTEND is DATETIME, skipping (UID: %s)\n" rem.Remind.original_uuid;
+              skip
           | Some (`Dtend (_, `Date (year, month, day))) ->
               begin match Timedesc.Date.Ymd.make ~year ~month ~day with
               | Error e -> invalid_date "DTEND" e
@@ -96,7 +97,7 @@ let collect_start_end_duration rem ev : (Remind.rem, error) result =
               Ok rem
             end
           | `Date (_year, _month, _day) ->
-              (* Start is a datetime, end is a date: invalid case for timed event *)
+              Utils.warn "Warning: DTSTART is DATETIME but DTEND is DATE, skipping (UID: %s)\n" rem.Remind.original_uuid;
               skip
           end
       | Some (`Duration (_, duration)) ->
@@ -121,20 +122,15 @@ let yearly_simple_date rem ev : (Remind.rem, error) result =
   | Some _ -> Ok rem
   | None -> Ok rem
 
-let debug_print_of_recurrence_and_skip ev recurs =
-  let uid = Utils.get_uid ev in
-  Printf.eprintf "RRULE: %s\t\t\tUID: %s\n" (Icalendar.show_recurrence recurs) uid;
-  skip
-
 let simple_recurrence rem ev : (Remind.rem, error) result =
   match ev.rrule with
   | Some (_, (`Yearly, None, None, [])) -> Ok rem (* handled in yearly_simple_date *)
   | Some (_, ((`Weekly as freq), count_or_until, interval, recurs))
   | Some (_, ((`Daily as freq), count_or_until, interval, recurs)) ->
       begin if List.length rem.recurring > 0 then (
-        Printf.eprintf "Warning: skipping complex recurrence with EXDATE/RDATE/overrides, not supported\t\t\tUID: %s\n"
+        Utils.warn "Warning: complex recurrence with EXDATE/RDATE/overrides not supported, skipping (UID: %s)\n"
           (Utils.get_uid ev);
-        debug_print_of_recurrence_and_skip ev (freq, count_or_until, interval, recurs))
+        skip)
       else
         let days =
           ListLabels.filter_map recurs ~f:(function
@@ -162,8 +158,8 @@ let simple_recurrence rem ev : (Remind.rem, error) result =
   | Some (_, (`Monthly, count_or_until, interval, recurs)) ->
       begin match interval with
       | Some n when n > 1 ->
-          Printf.eprintf "Warning: MONTHLY INTERVAL=%d not supported\t\t\tUID: %s\n" n (Utils.get_uid ev);
+          Utils.warn "Warning: MONTHLY INTERVAL=%d not supported, skipping (UID: %s)\n" n (Utils.get_uid ev);
-          debug_print_of_recurrence_and_skip ev (`Monthly, count_or_until, interval, recurs)
+          skip
       | _ -> (
           let bymonthday =
             List.find_map
@@ -187,11 +183,13 @@ let simple_recurrence rem ev : (Remind.rem, error) result =
           in
           match pattern with
           | None ->
-              Printf.eprintf "Warning: MONTHLY with unsupported BYDAY\t\t\tUID: %s\n" (Utils.get_uid ev);
+              Utils.warn "Warning: MONTHLY with unsupported BYDAY, skipping (UID: %s)\n" (Utils.get_uid ev);
-              debug_print_of_recurrence_and_skip ev (`Monthly, count_or_until, interval, recurs)
+              skip
           | Some p -> Ok { rem with Remind.monthly = Some { count_or_until; interval; pattern = p } })
       end
-  | Some (_, recurs) -> debug_print_of_recurrence_and_skip ev recurs
+  | Some (_, recurs) ->
+      Utils.warn "Warning: unsupported recurrence rule, skipping (UID: %s)\n" (Utils.get_uid ev);
+      skip
   | None -> Ok rem
 
 let is_cancelled (ev : Icalendar.event) : bool =
@@ -219,7 +217,8 @@ let collect_overrides rem _ev : (Remind.rem, error) result =
         let exdates =
           match recur_id_opt with
           | None ->
-              Printf.eprintf "Warning: override event has no RECURRENCE-ID\t\t\tUID: %s\n" (Utils.get_uid override_ev);
+              Utils.warn "Warning: override event has no RECURRENCE-ID, skipping (UID: %s)\n"
+                (Utils.get_uid override_ev);
               exdates
           | Some date_or_dt -> date_or_dt :: exdates
         in
@@ -228,7 +227,7 @@ let collect_overrides rem _ev : (Remind.rem, error) result =
           else
             match build_override_rem rem.Remind.source override_ev with
             | Error _ ->
-                Printf.eprintf "Warning: could not build override REM\t\t\tUID: %s\n" (Utils.get_uid override_ev);
+                Utils.warn "Warning: could not build override REM, skipping (UID: %s)\n" (Utils.get_uid override_ev);
                 overrides
             | Ok override_rem -> override_rem :: overrides
         in

bin/main.ml

@@ -14,16 +14,32 @@ let read_file filename =
   close_in ic;
   Bytes.unsafe_to_string s
 
-let ical2rem tz_opt ical_files =
+let ical2rem (args : CommandLine.cli_args) ical_files =
-  Utils.init_target_tz tz_opt;
+  (* Validate --source with multiple files *)
+  (match args.source with
+  | Some _ when List.length ical_files > 1 ->
+      Printf.eprintf "Error: --source can only be used with a single input file.\n";
+      exit 1
+  | _ -> ());
+  Config.verbose := args.verbose;
+  Config.no_uuid := args.no_uuid;
+  Config.no_source := args.no_source;
+  Config.no_location := args.no_location;
+  Config.no_description := args.no_description;
+  Config.no_conference_url := args.no_conference_url;
+  Utils.init_target_tz args.tz;
   let good_rems =
     ListLabels.fold_left ~init:[] ical_files ~f:(fun good_rems_acc filename ->
         try
           let file_content = read_file filename in
-          let basename = Filename.remove_extension (Filename.basename filename) in
+          let basename =
+            match args.source with
+            | Some name -> name
+            | None -> Filename.remove_extension (Filename.basename filename)
+          in
           match Icalendar.parse file_content with
           | Error e ->
-              if e <> ": not enough input" then prerr_endline ("Error parsing iCalendar file: " ^ e);
+              if e <> ": not enough input" then Utils.warn "Error: could not parse %s: %s\n" filename e;
               good_rems_acc
           | Ok (_, components) -> begin
               let events_map : Icalendar.event list Map.t =
@@ -44,21 +60,26 @@ let ical2rem tz_opt ical_files =
                     match rem_or_error with
                     | Ok rem -> rem :: good_rems
                     | Error (EventPredicates.Invalid_date s) ->
-                        Printf.eprintf "UID: %s Invalid date: %s\n" uid s;
+                        Utils.warn "Warning: invalid date: %s (UID: %s)\n" s uid;
                         good_rems
                     | Error Skip ->
-                        Printf.eprintf "UID: %s Skipped\n" uid;
+                        Utils.warn "Warning: event skipped (UID: %s)\n" uid;
                         good_rems)
               in
               let good_rems = List.rev good_rems in
               good_rems @ good_rems_acc
             end
         with e ->
-          prerr_endline ("Error reading file " ^ filename ^ ": " ^ Printexc.to_string e);
+          Utils.warn "Error: could not read file %s: %s\n" filename (Printexc.to_string e);
           good_rems_acc)
   in
 
-  let good_rems = List.sort (fun a b -> Timedesc.Date.compare b.Remind.date a.Remind.date) good_rems in
+  let good_rems =
+    match args.sort with
+    | CommandLine.Desc -> List.sort (fun a b -> Timedesc.Date.compare b.Remind.date a.Remind.date) good_rems
+    | CommandLine.Asc -> List.sort (fun a b -> Timedesc.Date.compare a.Remind.date b.Remind.date) good_rems
+    | CommandLine.Original -> good_rems
+  in
   try ListLabels.iter good_rems ~f:(fun rem -> Printf.printf "%s" (Remind.string_of_rem rem))
   with e ->
     Printf.eprintf "Error processing reminders: %s\n" (Printexc.to_string e);

bin/remind.ml

@@ -164,10 +164,13 @@ let render_alarm (rem : rem) : alarm_rendering =
         end
 
 (* ── buffer primitives ────────────────────────────────────────── *)
-
 let add_rem b = Buffer.add_string b "REM "
-let add_uid b uuid = Buffer.add_string b (spf "\\\n    INFO \"UID: %s\" " uuid)
+let add_uid b uuid = if not !Config.no_uuid then Buffer.add_string b (spf "\\\n    INFO \"UID: %s\" " uuid)
-let add_source b source = Buffer.add_string b (spf "\\\n    INFO \"Calendar: %s\" " (String.uppercase_ascii source))
+
+let add_source b source =
+  if not !Config.no_source then
+    Buffer.add_string b (spf "\\\n    INFO \"Calendar: %s\" " (String.uppercase_ascii source))
+
 let add_date b date = Buffer.add_string b (Timedesc.Date.to_rfc3339 date)
 let add_weekday b wd = Buffer.add_string b (spf "%s " (string_of_weekday wd))
 
@@ -275,14 +278,15 @@ let add_msg b ?(alarm = empty_alarm) ?(timed = false) summary =
   Buffer.add_string b (spf " MSG %s\n" body)
 
 let add_location b loc =
+  if not !Config.no_location then
     match loc with
-  | Some loc -> begin
+    | Some loc ->
         let loc = String.trim loc in
         Buffer.add_string b (spf "\\\n    INFO \"Location: %s\" " (escape_msg loc))
-    end
     | None -> ()
 
 let add_description b desc =
+  if not !Config.no_description then
     match desc with
     | Some desc ->
         let desc = String.trim desc in
@@ -290,6 +294,7 @@ let add_description b desc =
     | None -> ()
 
 let add_url b url =
+  if not !Config.no_conference_url then
     match url with
     | Some url ->
         let url = String.trim url in
@@ -302,7 +307,8 @@ let add_common_part b rem =
   add_source b rem.source;
   add_location b rem.location;
   add_description b rem.description;
-  add_url b rem.conference_url
+  add_url b rem.conference_url;
+  Buffer.add_string b "\\\n    "
 
 let date_of_date_or_datetime (d : Icalendar.date_or_datetime) : Timedesc.Date.t =
   match d with

bin/utils.ml

@@ -68,6 +68,9 @@ let string_of_month = function
 
 let spf = Printf.sprintf
 
+(** Print a diagnostic message on stderr, but only when --verbose is active. *)
+let warn fmt = if !Config.verbose then Printf.eprintf fmt else Printf.ifprintf stderr fmt
+
 let get_uid ev =
   let _, uid = ev.uid in
   uid
@@ -114,7 +117,7 @@ let timedesc_of_timestamp (ts : timestamp) : Timedesc.t =
         match Timedesc.Time_zone.make candidate with
         | Some tz -> tz
         | None ->
-            Printf.eprintf "Warning: unresolvable timezone %S, falling back to local timezone\n" tz_name;
+            warn "Warning: unresolvable timezone %S, falling back to local timezone\n" tz_name;
             !target_tz
       in
       let wrong_ts = Timedesc.Utils.timestamp_of_ptime ts in
@@ -193,7 +196,6 @@ let get_rdates ev =
         | _ -> None)
       event_props
   in
-
   let datetimes, dates, periods =
     ListLabels.fold_left ~init:([], [], []) dates_or_datetimes_or_periods
       ~f:(fun (acc_datetimes, acc_dates, acc_periods) dates ->
@@ -203,11 +205,12 @@ let get_rdates ev =
         | `Periods period_list -> (acc_datetimes, acc_dates, acc_periods @ period_list))
   in
 
-  if List.length dates > 0 then Printf.eprintf "Found RDATE with dates: %d entries; UID: %s\n" (List.length dates) uid;
+  if List.length dates > 0 then
+    warn "Warning: RDATE with dates (%d entries) not supported, skipping (UID: %s)\n" (List.length dates) uid;
   if List.length datetimes > 0 then
-    Printf.eprintf "Found RDATE with datetimes: %d entries; UID: %s\n" (List.length datetimes) uid;
+    warn "Warning: RDATE with datetimes (%d entries) not supported, skipping (UID: %s)\n" (List.length datetimes) uid;
   if List.length periods > 0 then
-    Printf.eprintf "Found RDATE with periods: %d entries; UID: %s\n" (List.length periods) uid;
+    warn "Warning: RDATE with periods (%d entries) not supported, skipping (UID: %s)\n" (List.length periods) uid;
   []
 
 let add_months (date : Timedesc.Date.t) (n : int) : Timedesc.Date.t =
@@ -259,7 +262,6 @@ let get_conference_url ev =
 
 let separate_master_and_recurrence (events : Icalendar.event list) : Icalendar.event * Icalendar.event list =
   let recur_ids = List.map (fun ev -> (ev, get_recurrence_id ev)) events in
-
   let master_and_recurrences =
     List.partition_map
       (fun (ev, recur_id_opt) ->
@@ -272,6 +274,6 @@ let separate_master_and_recurrence (events : Icalendar.event list) : Icalendar.e
   | [], _ -> failwith "No master event found"
   | [ master ], recurrences -> (master, recurrences)
   | master :: rest, recurrences ->
-      Printf.eprintf "Warning: %d extra master events (no RECURRENCE-ID) for UID: %s — only first used\n"
+      warn "Warning: %d extra master events (no RECURRENCE-ID), only first used (UID: %s)\n" (List.length rest)
-        (List.length rest) (get_uid master);
+        (get_uid master);
       (master, recurrences)