2 files changed, 81 insertions, 16 deletions

diff --git a/lisp/calendar/icalendar.el b/lisp/calendar/icalendar.el
index e7ad7383456..2f557f547af 100644
--- a/lisp/calendar/icalendar.el
+++ b/lisp/calendar/icalendar.el
@@ -2389,22 +2389,43 @@ END-T is the event's end time in diary format."
           ;; monthly
           ((string-equal frequency "MONTHLY")
            (icalendar--dmsg "monthly")
-           (setq result
-                 (format
-                  "%%%%(and (diary-date %s) (diary-block %s %s)) %s%s%s"
-                  (let ((day (nth 3 dtstart-dec)))
-                    (cond ((eq calendar-date-style 'iso)
-                           (format "t t %d" day))
-                          ((eq calendar-date-style 'european)
-                           (format "%d t t" day))
-                          ((eq calendar-date-style 'american)
-                           (format "t %d t" day))))
-                  dtstart-conv
-                  (if until
-                      until-conv
-                    (if (eq calendar-date-style 'iso) "9999 1 1" "1 1 9999")) ;; FIXME: should be unlimited
-                  (or start-t "")
-                  (if end-t "-" "") (or end-t ""))))
+           (let* ((byday (cadr (assoc 'BYDAY rrule-props)))
+                  (count-weekday
+                   (and byday
+                        (save-match-data
+                          (when (string-match "\\(-?[0-9]+\\)\\([A-Z][A-Z]\\)"
+                                              byday)
+                            (cons (substring byday
+                                             (match-beginning 1)
+                                             (match-end 1))
+                                  (substring byday
+                                             (match-beginning 2)
+                                             (match-end 2)))))))
+                  (rule-part
+                   (if count-weekday
+                       (let ((count (car count-weekday))
+                             (weekdaynum (icalendar--get-weekday-number
+                                          (cdr count-weekday))))
+                         ;; FIXME: this is valid only for interval==1
+                         (format "(diary-float t %s %s)" weekdaynum count))
+                     (format "(diary-date %s)"
+                             (let ((day (nth 3 dtstart-dec)))
+                               (cond ((eq calendar-date-style 'iso)
+                                      (format "t t %d" day))
+                                     ((eq calendar-date-style 'european)
+                                      (format "%d t t" day))
+                                     ((eq calendar-date-style 'american)
+                                      (format "t %d t" day))))))))
+             (setq result
+                   (format
+                    "%%%%(and %s (diary-block %s %s)) %s%s%s"
+                    rule-part
+                    dtstart-conv
+                    (if until
+                        until-conv
+                      (if (eq calendar-date-style 'iso) "9999 1 1" "1 1 9999")) ;; FIXME: should be unlimited
+                    (or start-t "")
+                    (if end-t "-" "") (or end-t "")))))
           ;; daily
           ((and (string-equal frequency "DAILY"))
            (if until
diff --git a/test/lisp/calendar/icalendar-tests.el b/test/lisp/calendar/icalendar-tests.el
index 6db4222697e..307d687f2af 100644
--- a/test/lisp/calendar/icalendar-tests.el
+++ b/test/lisp/calendar/icalendar-tests.el
@@ -1257,6 +1257,50 @@ UID:8814e3f9-7482-408f-996c-3bfe486a1263
  UID: 8814e3f9-7482-408f-996c-3bfe486a1263
 "))
 
+(ert-deftest icalendar-import-bug-24199 ()
+  ;;bug#24199 -- monthly rule with byday-clause
+  (icalendar-tests--test-import
+"
+SUMMARY:Summary
+DESCRIPTION:Desc
+LOCATION:Loc
+DTSTART:20151202T124600
+DTEND:20151202T160000
+RRULE:FREQ=MONTHLY;BYDAY=1WE;INTERVAL=1
+EXDATE:20160106T114600Z
+EXDATE:20160203T114600Z
+EXDATE:20160302T114600Z
+EXDATE:20160504T104600Z
+EXDATE:20160601T104600Z
+CLASS:DEFAULT
+TRANSP:OPAQUE
+BEGIN:VALARM
+ACTION:DISPLAY
+TRIGGER;VALUE=DURATION:-PT3H
+END:VALARM
+LAST-MODIFIED:20160805T191040Z
+UID:9188710a-08a7-4061-bae3-d4cf4972599a
+"
+"&%%(and (not (diary-date 2016 1 6)) (not (diary-date 2016 2 3)) (not (diary-date 2016 3 2)) (not (diary-date 2016 5 4)) (not (diary-date 2016 6 1)) (diary-float t 3 1) (diary-block 2015 12 2 9999 1 1)) 12:46-16:00 Summary
+ Desc: Desc
+ Location: Loc
+ Class: DEFAULT
+ UID: 9188710a-08a7-4061-bae3-d4cf4972599a
+"
+"&%%(and (not (diary-date 6 1 2016)) (not (diary-date 3 2 2016)) (not (diary-date 2 3 2016)) (not (diary-date 4 5 2016)) (not (diary-date 1 6 2016)) (diary-float t 3 1) (diary-block 2 12 2015 1 1 9999)) 12:46-16:00 Summary
+ Desc: Desc
+ Location: Loc
+ Class: DEFAULT
+ UID: 9188710a-08a7-4061-bae3-d4cf4972599a
+"
+"&%%(and (not (diary-date 1 6 2016)) (not (diary-date 2 3 2016)) (not (diary-date 3 2 2016)) (not (diary-date 5 4 2016)) (not (diary-date 6 1 2016)) (diary-float t 3 1) (diary-block 12 2 2015 1 1 9999)) 12:46-16:00 Summary
+ Desc: Desc
+ Location: Loc
+ Class: DEFAULT
+ UID: 9188710a-08a7-4061-bae3-d4cf4972599a
+"
+))
+
 (ert-deftest icalendar-import-multiple-vcalendars ()
   (icalendar-tests--test-import
    "DTSTART;VALUE=DATE:20110723