Rename module vcalendar => vcomponent.

1 files changed, 58 insertions, 0 deletions

diff --git a/module/vcomponent/datetime.scm b/module/vcomponent/datetime.scm
new file mode 100644
index 00000000..2270d10e
--- /dev/null
+++ b/module/vcomponent/datetime.scm
@@ -0,0 +1,58 @@
+(define-module (vcomponent datetime)
+  #:use-module (vcomponent)
+  #:use-module (srfi srfi-19)
+  #:use-module (srfi srfi-19 util)
+  #:use-module (util)
+
+  #:export (parse-datetime
+            event-overlaps?
+            overlapping?
+            event-in?
+            ev-time<?)
+  )
+
+;;; date time pointer
+(define (parse-datetime dtime)
+  "Parse the given date[time] string into a date object."
+  (string->date
+   dtime (case (string-length dtime)
+           ((8)  "~Y~m~d")              ; All day
+           ((15) "~Y~m~dT~H~M~S")       ; "local" or TZID-param
+           ((16) "~Y~m~dT~H~M~S~z"))))  ; UTC-time
+
+(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 (overlapping? event-a event-b)
+  (timespan-overlaps? (attr event-a 'DTSTART)
+                      (attr event-a 'DTEND)
+                      (attr event-b 'DTSTART)
+                      (attr event-b 'DTEND)))
+
+(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-day start)))
+    (event-overlaps? ev start end)))
+
+(define (ev-time<? a b)
+  (time<? (attr a 'DTSTART)
+          (attr b 'DTSTART)))
+
+;; Returns length of the event @var{e}, as a time-duration object.
+(define-public (event-length e)
+  (time-difference
+   (attr e 'DTEND)
+   (attr e 'DTSTART)))
+
+;; Returns the length of the part of @var{e} which is within the day
+;; starting at the time @var{start-of-day}.
+(define-public (event-length/day e start-of-day)
+  (time-difference
+   (time-min (add-day start-of-day) (attr e 'DTEND))
+   (time-max start-of-day (attr e 'DTSTART))))