gistfile1.ml

let expand_event range exceptions timezones ((props: Icalendar.eventprop list), alarms) =
  let f acc dtstart =
    let recur_id : Icalendar.eventprop = match List.find_opt (function `Dtstart (prop, v) -> true | _ -> false) props with
    | None -> assert false
    | Some (`Dtstart (props', v)) ->
      let props'', v' = normalize_date_or_datetime props' timezones (`Datetime (dtstart, false)) in
      let id = function
         | `Iana_param (a, b) -> `Iana_param (a, b)
         | `Tzid (a, b) -> `Tzid (a, b)
         | `Valuetype v -> `Valuetype v
         | `Xparam ((a, b), c) -> `Xparam ((a, b), c)
      in
      `Recur_id (List.map id props'', v') in
    let props' = List.map (function
      | `Dtstart (props', `Datetime (_, utc)) ->
          let props'', dtstart' = normalize_tz dtstart props' timezones in
          `Dtstart (props'', `Datetime (dtstart', utc))
      | `Dtstart (props', `Date _) ->
          let props'', dtstart' = normalize_tz dtstart props' timezones in
          `Dtstart (props'', `Date (ptime_to_date dtstart))
      | `Rrule _ -> recur_id
      | `Recur_id (props', `Datetime (dtstart, utc)) ->
          let is_tzid = function `Tzid _ -> true | _ -> false in
          let tzid = List.find_opt is_tzid props' in
          begin
            match tzid with
            | None -> `Recur_id (props', `Datetime (dtstart, utc))
            | Some (`Tzid tzid) ->
                let props'' = List.filter (fun p -> not (is_tzid p)) props' in
                let dtstart' = Icalendar.normalize_timezone dtstart (`Tzid tzid) timezones in
                `Recur_id (props'', `Datetime (dtstart', utc))
            | _ -> assert false (* without this line, the type of props' is too small - why does this solution also solve the following match case though? *)
          end
      | `Recur_id (props', `Date date) ->
          begin
            let is_tzid = function `Tzid _ -> true | _ -> false in
            match List.find_opt is_tzid props' with
            | None -> `Recur_id (props', `Date date)
            | Some (`Tzid tzid) ->
                let dtstart = date_to_ptime date in
                let props'' = List.filter (fun p -> not (is_tzid p)) props' in
                let dtstart' = Icalendar.normalize_timezone dtstart (`Tzid tzid) timezones in
                `Recur_id (props'', `Date (ptime_to_date dtstart'))
          end
      | x -> x) props in
    `Event (props', alarms) :: acc
  in
  fold_event f [] range exceptions (`Event (props, alarms))