1 files changed, 93 insertions, 0 deletions
diff --git a/module/vcalendar/output.scm b/module/vcalendar/output.scm
new file mode 100644
index 00000000..e4635beb
--- /dev/null
+++ b/module/vcalendar/output.scm
@@ -0,0 +1,93 @@
+(define-module (vcalendar output)
+  #:use-module (vcalendar)
+  #:use-module (vcalendar control)
+  #:use-module (util)
+  #:use-module (srfi srfi-19 util)
+  #:use-module (srfi srfi-26)
+  #:export (print-vcomponent
+            serialize-vcomponent
+            color-if
+            STR-YELLOW STR-RESET))
+
+(define STR-YELLOW "\x1b[0;33m")
+(define STR-RESET "\x1b[m")
+
+(define-syntax-rule (color-if pred color body ...)
+  (let ((pred-value pred))
+    (format #f "~a~a~a"
+            (if pred-value color "")
+            (begin body ...)
+            (if pred-value STR-RESET ""))))
+
+(define* (print-vcomponent comp #:optional (depth 0))
+  (let ((kvs (map (lambda (key) (cons key (attr comp key)))
+                  (attributes comp))))
+    (format #t "~a <~a> :: ~:a~%"
+            (make-string depth #\:)
+            (type comp) comp)
+    (for-each-in kvs
+                 (lambda (kv)
+                   (let ((key (car kv))
+                         (value (cdr kv)))
+                     (format #t "~a ~20@a: ~a~%"
+                             (make-string depth #\:)
+                             key value))))
+    (for-each-in (children comp)
+                 (cut print-vcomponent <> (1+ depth)))))
+
+
+
+;;; TODO
+;; Error in CREATED /home/hugo/.calendars/b85ba2e9-18aa-4451-91bb-b52da930e977/a1a25238-d63d-46a1-87fd-d0c9334a7a30CalSync.ics:
+;; Wrong type argument in position 1 (expecting string): ("20180118T124015Z" "VALARM")
+
+(define (string->ics-safe-string str)
+  "TODO wrap at 75(?) columns."
+  (define (escape char)
+    (string #\\ char))
+
+  (string-concatenate
+   (map (lambda (c)
+          (case c
+            ((#\newline) "\\n")
+            ((#\, #\; #\\) => escape)
+            (else => string)))
+        (string->list str))))
+
+;;; TODO parameters ( ;KEY=val: )
+(define* (serialize-vcomponent comp #:optional (port (current-output-port)))
+  "Recursively write a component back to its ICS form.
+Removes the X-HNH-FILENAME attribute, and sets PRODID to
+\"HugoNikanor-calparse\" in the output."
+  (with-replaced-attrs
+   (comp (prodid "HugoNikanor-calparse"))
+
+   (format port "BEGIN:~a~%" (type comp))
+   (let ((kvs (map (lambda (key) (list key (attr comp key)))
+                   (filter (negate (cut key=? <> 'X-HNH-FILENAME))
+                           (attributes comp)))))
+     (for-each-in
+      kvs (lambda (kv)
+            (let* (((key value) kv))
+              (catch 'wrong-type-arg
+                (lambda ()
+                  (format port "~a:~a~%" key
+                          (string->ics-safe-string
+                           (case key
+                             ((DTSTART DTEND)
+                              (if (string? value)
+                                  value
+                                  (time->string value "~Y~m~dT~H~M~S")))
+
+                             ((RRULE DURATION) "Just forget it")
+
+                             (else value)))))
+
+                ;; Catch
+                (lambda (type proc fmt . args)
+                  (apply format (current-error-port) "[ERR] ~a in ~a (~a) ~a:~%~?~%"
+                         type key proc (attr comp 'X-HNH-FILENAME)
+                         fmt args))))))
+
+     (for-each (cut serialize-vcomponent <> port) (children comp)))
+   (format port "END:~a~%" (type comp))))