{% with start=event.time end=event.until_time all_day=event.all_day %}
{% if not end %}
{% if all_day %}
Am {{ start|date:'d. F Y' }}, ganztägig
{% else %}
Am {{ start|date:'d. F Y' }} um {{ start|date:'H:i' }} Uhr
{% endif %}
{% else %}
{% if start.date == end.date %}
{% if all_day %}
Am {{ start|date:'d. F Y' }}, ganztägig
{% else %}
Am {{ start|date:'d. F Y' }} von {{ start|date:'H:i' }} Uhr bis {{ end|date:'H:i' }} Uhr
{% endif %}
{% else %}
{% if all_day %}
Vom {{ start|date:'d. F Y' }} bis {{ start|date:'d. F Y' }}
{% else %}
Vom {{ start|date:'d. F Y' }} um {{ start|date:'H:i' }} Uhr bis {{ end|date:'d. F Y' }} um {{ end|date:'H:i' }} Uhr
{% endif %}
{% endif %}
{% endif %}
{% endwith %}