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(define-module (vcomponent recurrence internal)
#:export (repeating? format-recur-rule make-recur-rule)
#:use-module (srfi srfi-88) ; better keywords
#:use-module ((vcomponent base) :select (prop))
#:use-module (srfi srfi-9)
#:use-module (srfi srfi-9 gnu)
#:use-module (ice-9 format)
#:use-module (hnh util)
)
;; EXDATE is also a property linked to recurense rules
;; but that property alone don't create a recuring event.
(define (repeating? ev)
"Does this event repeat?"
(or (prop ev 'RRULE)
(prop ev 'RDATE)
(prop ev '-X-HNH-ALTERNATIVES)))
;; weekday := [0, 7)
;; Immutable, since I easily want to be able to generate the recurence set for
;; the same event multiple times.
(define-immutable-record-type <recur-rule>
(make-recur-rule% freq until count interval bysecond byminute byhour
byday bymonthday byyearday byweekno bymonth bysetpos
wkst)
recur-rule?
(freq freq) ; 'SECONDLY | 'MINUTELY | 'HOURLY | 'DAILY | 'WEEKLY | 'MONTHLY | 'YEARLY
(until until) ; <date> | <datetime>
(count count) ; 𝐙₊
(interval interval) ; 𝐙₊
(bysecond bysecond) ; (list [0, 60])
(byminute byminute) ; (list [0, 59])
(byhour byhour) ; (list [0, 23])
(byday byday) ; (list (cons [#f | 𝐙] weekday)
(bymonthday bymonthday) ; (list [-31, 31] \ { 0 })
(byyearday byyearday) ; (list [-366, 366] \ { 0 })
(byweekno byweekno) ; (list [-53, 53] \ { 0 })
(bymonth bymonth) ; (list [-12, 12] \ { 0 })
(bysetpos bysetpos) ; (list [-366, 366] \ { 0 })
(wkst wkst) ; weekday
)
(export freq until interval bysecond byminute byhour
byday bymonthday byyearday byweekno bymonth bysetpos
wkst)
(export! count)
;; Interval and wkst have default values, since those are assumed
;; anyways, and having them set frees us from having to check them at
;; the use site.
(define*-public (make-recur-rule
key:
freq until count (interval 1) bysecond byminute byhour
byday bymonthday byyearday byweekno bymonth bysetpos
(wkst monday))
;; TODO possibly validate fields here
;; to prevent creation of invalid rules.
;; This was made apparent when wkst was (incorrectly) set to MO,
;; which later crashed generate-recurrence-set.
(make-recur-rule% freq until count interval bysecond byminute byhour
byday bymonthday byyearday byweekno bymonth bysetpos
wkst))
;; only print fields with actual values.
(set-record-type-printer!
<recur-rule>
(lambda (r port)
(define (get f)
((record-accessor <recur-rule> f) r))
(with-output-to-string
(lambda ()
(display "#<<recur-rule>" port)
(for field in (record-type-fields <recur-rule>)
(awhen (get field)
(format port " ~a=~a" field it)))
(display ">" port)))))
(define (byday->string pair)
(let* (((off . day) pair))
(string-append
(or (and=> off number->string) "")
(string-upcase
(week-day-name day 2
locale: (make-locale (list LC_TIME) "C"))))))
(use-modules (ice-9 i18n)
(datetime)
(srfi srfi-1))
(define (field->string field value)
(case field
[(wkst)
(string-upcase
(week-day-name value 2
locale: (make-locale (list LC_TIME) "C")))]
[(byday)
(string-join (map byday->string value) ",")]
[(freq count interval)
(format #f "~a" value)]
[(until)
(if (date? value)
(date->string value "~Y~m~d")
(datetime->string value "~Y~m~dT~H~M~S~Z"))]
[else (format #f "~{~a~^,~}" value)]))
(define (map-fields proc rrule)
(define (get f)
((record-accessor <recur-rule> f) rrule))
(filter-map
(lambda (field)
(if (not (get field))
#f (proc field (get field))))
(record-type-fields <recur-rule>)))
(define-public (recur-rule->rrule-string rrule)
(string-join
(map-fields
(lambda (field value)
(string-append
(string-upcase (symbol->string field))
"=" (field->string field value)))
rrule)
";"))
(define-public (recur-rule->rrule-sxml rrule)
(map-fields
(lambda (field value)
(cond [(string-ci=? "UNTIL" (symbol->string field))
`(until
,(if (date? value)
(date->string value "~Y-~m-~d")
(datetime->string
value "~Y-~m-~dT~H:~M:~S~Z")))]
[(string-ci=? "BYDAY" (symbol->string field))
(map (lambda (v)
`(,(downcase-symbol field)
,(byday->string v)))
value)
]
[(string-ci=? "BY" (substring (symbol->string field)
0 2))
(map (lambda (v)
`(,(downcase-symbol field)
,v))
value)]
[else
`(,(downcase-symbol field)
,(field->string field value))]))
rrule))
(define-public weekdays
(weekday-list sun))
(define-public intervals
'(SECONDLY MINUTELY HOURLY DAILY WEEKLY MONTHLY YEARLY))
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