ics: split long lines according to the iCalendar specification

Signed-off-by: Alban Gruin <alban at pa1ch dot fr>

1 files changed, 23 insertions, 10 deletions

diff --git a/src/ics.ml b/src/ics.ml
index 2ee0269..bf895b0 100644
--- a/src/ics.ml
+++ b/src/ics.ml
@@ -20,6 +20,19 @@ open CalendarLib
 let to_date = Printer.Calendar.sprint "%Y%m%dT%H%M%SZ"
 let current_date () = to_date @@ Calendar.now ()
 
+let ics_split_line =
+  let max_line_length = 73 in
+  let rec aux accu str =
+    String.(
+      let l = length str in
+      if l > max_line_length then
+        let b = sub str 0 max_line_length and
+            e = sub str max_line_length (l - max_line_length) in
+        aux (accu ^ b ^ "\r\n ") e
+      else
+        accu ^ str) in
+  aux ""
+
 module Event = struct
   type t = {
       start: Calendar.t;
@@ -32,16 +45,16 @@ module Event = struct
     {start; stop; summary; location}
 
   let to_string date event id =
-    Printf.sprintf "BEGIN:VEVENT\n\
-                    UID:%s.%d@ucs.pa1ch.fr\n\
-                    DTSTART:%s\n\
-                    DTEND:%s\n\
-                    DTSTAMP:%s\n\
-                    SUMMARY:%s\n\
-                    LOCATION:%s\n\
-                    END:VEVENT\n"
-      date id (to_date event.start) (to_date event.stop)
-      date event.summary event.location
+    ["BEGIN:VEVENT";
+     "UID:" ^ date ^ "." ^ (string_of_int id) ^ "@ucs.pa1ch.fr";
+     "DTSTART:" ^ to_date event.start;
+     "DTEND:" ^ to_date event.stop;
+     "DTSTAMP:" ^ date;
+     "SUMMARY:" ^ event.summary;
+     "LOCATION:" ^ event.location;
+     "END:VEVENT\n"]
+    |> List.map ics_split_line
+    |> String.concat "\n"
 end
 
 type t = Event.t list