1 files changed, 34 insertions, 0 deletions
diff --git a/module/vcalendar/datetime.scm b/module/vcalendar/datetime.scm
new file mode 100644
index 00000000..360b8348
--- /dev/null
+++ b/module/vcalendar/datetime.scm
@@ -0,0 +1,34 @@
+(define-module (vcalendar datetime)
+  #:use-module (vcalendar)
+  #:use-module (srfi srfi-19)
+  #:use-module (srfi srfi-19 util)
+
+  #:export (parse-datetime
+            event-overlaps?
+            event-in?)
+  )
+
+(define (parse-datetime dtime)
+  "Parse the given date[time] string into a date object."
+  ;; localize-date
+  (date->time-utc
+   (string->date
+    dtime
+    (case (string-length dtime)
+      ((8) "~Y~m~d")
+      ((15) "~Y~m~dT~H~M~S")
+      ((16) "~Y~m~dT~H~M~S~z")))))
+
+(define (event-overlaps? event begin end)
+  "Returns if the event overlaps the timespan.
+Event must have the DTSTART and DTEND attribute set."
+  (timespan-overlaps? (attr event 'DTSTART)
+                      (attr event 'DTEND)
+                      begin end))
+
+(define (event-in? ev time)
+  "Does event overlap the date that contains time."
+  (let* ((date (time-utc->date time))
+         (start (date->time-utc (drop-time date)))
+         (end (add-duration start (make-duration (* 60 60 24)))))
+    (event-overlaps? ev start end)))