invert minute calculation

Author: joelsa

static/calendar.ics

@@ -26,14 +26,18 @@ END:VTIMEZONE
 {% for termin in site.data.calendar -%}
 {% assign start_uhrzeit = termin.uhrzeit | remove: "h" | remove: "." | append: "00" -%}
 {% assign start = termin.datum | remove: "-" | append: "T" | append: start_uhrzeit -%}
+{% assign start_stunden = start_uhrzeit | divided_by: 100 | floor -%}
+{% assign start_minuten = start_uhrzeit | modulo: 100 | divided_by: 60 -%}
+{% assign start_rational = start_stunden | plus: start_minuten -%}
 {% if termin.dauer -%}
-{%  assign dauer_stunden = termin.dauer | floor -%}
-{%  assign dauer_minuten = termin.dauer | minus: dauer_stunden | times: 60 -%}
-{%  assign dauer = dauer_stunden | times: 100 | plus: dauer_minuten -%}
+{%  assign dauer = termin.dauer -%}
 {% else -%}
-{%  assign dauer = 100 -%}
+{%  assign dauer = 1 -%}
 {% endif -%}
-{% assign end_uhrzeit = termin.uhrzeit | remove: "h" | remove: "." | plus: dauer -%}
+{% assign end_rational = start_rational | plus: termin.dauer -%}
+{% assign end_stunden = end_rational | floor}
+{% assign end_minuten = end_rational | minus: end_stunden | times: 60 -%}
+{% assign end_uhrzeit = end_stunden | times: 100 | plus: end_minuten -%}
 {% assign dauer_tage = end_uhrzeit | divided_by: 2400 | floor -%}
 {% assign end_uhrzeit = end_uhrzeit | modulo: 2400 -%}
 {% assign starttag = termin.datum | date: '%d' -%}