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(define-module (output ical)
:use-module (ice-9 format)
:use-module (ice-9 match)
:use-module (util)
:use-module (vcomponent)
:use-module (srfi srfi-1)
:use-module (datetime)
:use-module (datetime util)
:use-module (srfi srfi-41)
:use-module (srfi srfi-41 util)
)
;; Format value depending on key type.
;; Should NOT emit the key.
(define (value-format key vline)
(with-throw-handler 'wrong-type-arg
(lambda ()
(case key
((DTSTART DTEND RECURRENCE-ID)
(with-output-to-string
(lambda ()
(case (and=> (prop vline 'VALUE) car)
[(DATE) (display (date->string (as-date (value vline))
"~Y~m~d"))]
[(DATE-TIME)
(display (datetime->string (value vline) "~Y~m~dT~H~M~S"))
(let ((tz (and=> (prop vline 'TZID) car)))
(when (and tz (string= tz "UTC"))
(display #\Z)))]
[else
(error "Unknown VALUE type")]))))
((DURATION X-HNH-DURATION)
#; (time->string value "~H~M~S")
(let ((s (second (value vline))))
(format #f "~a~a~a"
(floor/ s 3600)
(floor/ (modulo s 3600) 60)
(modulo s 60))
))
((RRULE) (value vline))
(else (escape-chars (value vline)))))
(lambda (err caller fmt args call-args)
(format (current-error-port)
"WARNING: key = ~a, caller = ~s, call-args = ~s~%~k~%" key caller call-args fmt args)
(with-output-to-string (lambda () (display (value vline))))
)))
(define (escape-chars str)
(with-output-to-string
(lambda ()
(string-for-each
(lambda (ch)
(case ch
((#\, #\; #\\) => (lambda (c) (display "\\") (display c)))
((#\newline) (display "\\n"))
(else (display ch))))
str))))
;; Fold long lines to limit width.
;; Since this works in characters, but ics works in bytes
;; this will overshoot when faced with multi-byte characters.
;; But since the line wrapping is mearly a recomendation it's
;; not a problem.
;; Setting the wrap-len to slightly lower than allowed also help
;; us not overshoot.
(define* (ical-line-fold string #:key (wrap-len 70))
(cond [(< wrap-len (string-length string))
(format #f "~a\r\n ~a"
(string-take string wrap-len)
(ical-line-fold (string-drop string wrap-len)))]
[else string]))
(define (component->ical-string component)
(format #t "BEGIN:~a\r\n" (type component))
(hash-for-each
;; Special cases depending on key.
;; Value formatting is handled in @code{value-format}.
(match-lambda*
;; Handled below
[('X-HNH-ALTERNATIVES _) 'noop]
[(key vline)
(display
(ical-line-fold
;; Expected output: key;p1=v;p3=10:value
(format #f "~a~:{;~a=~@{~a~^,~}~}:~a"
key (properties vline)
(value-format key vline))))
(display "\r\n")])
(attributes component))
(for-each component->ical-string (children component))
(format #t "END:~a\r\n" (type component))
;; If we have alternatives, splice them in here.
(cond [(attr component 'X-HNH-ALTERNATIVES)
=> (lambda (alts) (map component->ical-string alts))]))
(define (print-header)
(format #t
"BEGIN:VCALENDAR\r
PRODID:-//hugo//Calparse 0.5//EN\r
VERSION:2.0\r
CALSCALE:GREGORIAN\r
"
))
(define (print-footer)
(format #t "END:VCALENDAR\r\n"))
;; list x list x list x time x time →
(define-public (ical-main calendars regular-events repeating-events start end)
(print-header)
(let ((tzs (make-hash-table)))
(for cal in calendars
(for tz in (filter (lambda (e) (eq? 'VTIMEZONE (type e))) (children cal))
(hash-set! tzs (attr tz 'TZID) tz)))
(hash-for-each (lambda (key component) (component->ical-string component))
tzs))
;; TODO add support for running without a range limiter, emiting all objects.
(for-each
component->ical-string
(filter-sorted (lambda (ev) ((in-date-range? start end)
(as-date (attr ev 'DTSTART))))
regular-events))
;; TODO RECCURENCE-ID exceptions
;; We just dump all repeating objects, since it's much cheaper to do it this way than
;; to actually figure out which are applicable for the given date range.
(for-each component->ical-string repeating-events)
(print-footer))
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