add custom filter to format shift durations

shiftregister/app/templates/partials/shift_listitem.html

@@ -1,3 +1,4 @@
+{% load shift_extras %}
 <div class="column is-one-quarter">
     <div class="box">
         <div class="content">
@@ -6,7 +7,7 @@
 {% endif %}
             <strong>Ort:</strong> {{ shift.room.name }}<br>
             <strong>Beginn:</strong> {{ shift.start_at }}<br>
-            <strong>Dauer:</strong> {{ shift.duration }}
+            <strong>Dauer:</strong> {{ shift.duration|duration }}
         </div>
         <div class="buttons is-right">
             <a class="button is-info is-small mr-0" href="{% url 'shift' shift.id %}">Details</a>

shiftregister/app/templates/shift.html

@@ -1,4 +1,5 @@
 {% extends "helper_base.html" %}
+{% load shift_extras %}
 
 {% block title %}Schichtansicht{% endblock %}
 
@@ -17,7 +18,7 @@
         <p>
             <strong>Ort:</strong> <a href="{% url 'pages:view' 'map' %}#{{ shift.room.name|slugify }}">{{ shift.room.name }} 📍</a><br>
             <strong>Beginn:</strong> {{ shift.start_at }}<br>
-            <strong>Dauer:</strong> {{ shift.duration }}<br>
+            <strong>Dauer:</strong> {{ shift.duration|duration }}<br>
             <strong>Treffpunkt:</strong> {{ shift.room.meeting_location|linebreaksbr }}
         </p>
         {% if shift.room.description %}

shiftregister/app/templatetags/shift_extras.py

@@ -0,0 +1,12 @@
+from django import template
+
+register = template.Library()
+
+
+@register.filter(name="duration")
+def duration(value):
+    secs = value.total_seconds()
+    hours = int(secs // (60 * 60))
+    secs = secs % (hours * 60 * 60)
+    minutes = int(secs // 60)
+    return f"{hours}:{minutes:02d}"