Set Child from an argument instead of the timer

core/forms.py

@@ -7,31 +7,51 @@ from django.utils.translation import gettext as _
 from core import models
 
 
-# Sets the default Child instance if only one exists in the database.
 def set_default_child(kwargs):
+    """
+    Sets the default Child for an instance based on the `child` parameter or
+    if only one Child instance exists.
+
+    :param kwargs: Form arguments.
+    :return: Form arguments with updated initial values.
+    """
     instance = kwargs.get('instance', None)
+    child_slug = kwargs.get('child', None)
     if not kwargs.get('initial'):
         kwargs.update(initial={})
-    if instance is None and models.Child.objects.count() == 1:
-        kwargs['initial'].update({'child': models.Child.objects.first()})
+
+    # Do not update initial values for an existing instance (edit operation).
+    if instance is None:
+        if child_slug:
+            kwargs['initial'].update({
+                'child': models.Child.objects.filter(slug=child_slug).first(),
+            })
+        elif models.Child.count() == 1:
+            kwargs['initial'].update({'child': models.Child.objects.first()})
+
+    try:
+        kwargs.pop('child')
+    except KeyError:
+        pass
     return kwargs
 
 
 # Sets default values (start/end date, child) from a timer.
 def set_defaults_from_timer(kwargs):
-    timer = kwargs.get('instance', None)
+    instance = kwargs.get('instance', None)
     timer_id = kwargs.get('timer', None)
     if not kwargs.get('initial'):
         kwargs.update(initial={})
-    if not timer and timer_id:
+
+    # Do not update initial values for an existing instance (edit operation).
+    if not instance and timer_id:
         timer = models.Timer.objects.get(id=timer_id)
         kwargs['initial'].update({
             'timer': timer,
             'start': timer.start,
             'end': timer.end or timezone.now()
         })
-        if timer.child:
-            kwargs['initial'].update({'child': timer.child})
+
     try:
         kwargs.pop('timer')
     except KeyError:

core/templates/core/timer_detail.html

@@ -37,7 +37,7 @@
 
         {% if perms.core.add_feeding %}
             <a class="btn btn-success btn-lg btn-block mb-3"
-               href="{% url 'core:feeding-add' %}?timer={{ timer.id }}"
+               href="{% instance_add_url 'core:feeding-add' %}"
                role="button"><i class="icon icon-feeding" aria-hidden="true"></i>
                 {% trans "Feeding" %}
             </a>
@@ -45,7 +45,7 @@
 
         {% if perms.core.add_sleep %}
             <a class="btn btn-success btn-lg btn-block mb-3"
-               href="{% url 'core:sleep-add' %}?timer={{ timer.id }}"
+               href="{% instance_add_url 'core:sleep-add' %}"
                role="button"><i class="icon icon-sleep" aria-hidden="true"></i>
                 {% trans "Sleep" %}
             </a>
@@ -53,7 +53,7 @@
 
         {% if perms.core.add_tummytime %}
             <a class="btn btn-success btn-lg btn-block mb-3"
-               href="{% url 'core:tummytime-add' %}?timer={{ timer.id }}"
+               href="{% instance_add_url 'core:tummytime-add' %}"
                role="button"><i class="icon icon-tummytime" aria-hidden="true"></i>
                 {% trans "Tummy Time" %}
             </a>

core/templatetags/timers.py

@@ -1,5 +1,6 @@
 # -*- coding: utf-8 -*-
 from django import template
+from django.urls import reverse
 
 from core.models import Timer
 
@@ -20,3 +21,12 @@ def timer_nav(context, active=True):
     perms = context['perms'] or None
     # The 'next' parameter is currently not used.
     return {'timers': timers, 'perms': perms, 'next': request.path}
+
+
+@register.simple_tag(takes_context=True)
+def instance_add_url(context, url_name):
+    timer = context['timer']
+    url = '{}?timer={}'.format(reverse(url_name), timer.id)
+    if timer.child:
+        url += '&child={}'.format(timer.child.slug)
+    return url

core/views.py

@@ -22,6 +22,22 @@ class CoreAddView(PermissionRequired403Mixin, SuccessMessageMixin, CreateView):
             self.success_message = _('%(model)s entry added!')
         return self.success_message % cleaned_data
 
+    def get_form_kwargs(self):
+        """
+        Check for and add "child" and "timer" from request query parameters.
+          - "child" may provide a slug for a Child instance.
+          - "timer" may provided an ID for a Timer instance.
+
+        These arguments are used in some add views to pre-fill initial data in
+        the form fields.
+
+        :return: Updated keyword arguments.
+        """
+        kwargs = super(CoreAddView, self).get_form_kwargs()
+        kwargs.update({'child': self.request.GET.get('child', None)})
+        kwargs.update({'timer': self.request.GET.get('timer', None)})
+        return kwargs
+
 
 class CoreUpdateView(PermissionRequired403Mixin, SuccessMessageMixin,
                      UpdateView):
@@ -137,12 +153,6 @@ class FeedingAdd(CoreAddView):
     form_class = forms.FeedingForm
     success_url = reverse_lazy('core:feeding-list')
 
-    def get_form_kwargs(self):
-        kwargs = super(FeedingAdd, self).get_form_kwargs()
-        # Add timer to be used by FeedingForm.__init__
-        kwargs.update({'timer': self.request.GET.get('timer', None)})
-        return kwargs
-
 
 class FeedingUpdate(CoreUpdateView):
     model = models.Feeding
@@ -199,12 +209,6 @@ class SleepAdd(CoreAddView):
     form_class = forms.SleepForm
     success_url = reverse_lazy('core:sleep-list')
 
-    def get_form_kwargs(self):
-        kwargs = super(SleepAdd, self).get_form_kwargs()
-        # Add timer to be used by SleepForm.__init__
-        kwargs.update({'timer': self.request.GET.get('timer', None)})
-        return kwargs
-
 
 class SleepUpdate(CoreUpdateView):
     model = models.Sleep
@@ -353,12 +357,6 @@ class TummyTimeAdd(CoreAddView):
     form_class = forms.TummyTimeForm
     success_url = reverse_lazy('core:tummytime-list')
 
-    def get_form_kwargs(self):
-        kwargs = super(TummyTimeAdd, self).get_form_kwargs()
-        # Add timer to be used by TummyTimeForm.__init__
-        kwargs.update({'timer': self.request.GET.get('timer', None)})
-        return kwargs
-
 
 class TummyTimeUpdate(CoreUpdateView):
     model = models.TummyTime