Add a diaper lifetimes box plot graph.

dashboard/templates/dashboard/child.html

@@ -17,6 +17,7 @@
                     aria-expanded="false"><i class="icon icon-graph" aria-hidden="true"></i> Reports</button>
             <div class="dropdown-menu" aria-labelledby="reports-dropdown">
                 <a class="dropdown-item" href="{% url 'reports:report-diaperchange-types-child' object.slug %}">Diaper Change Types</a>
+                <a class="dropdown-item" href="{% url 'reports:report-diaperchange-lifetimes-child' object.slug %}">Diaper Lifetimes</a>
                 <a class="dropdown-item" href="{% url 'reports:report-sleep-pattern-child' object.slug %}">Sleep Pattern</a>
                 <a class="dropdown-item" href="{% url 'reports:report-sleep-totals-child' object.slug %}">Sleep Totals</a>
                 <a class="dropdown-item" href="{% url 'reports:report-timeline-child' object.slug %}">Timeline</a>

reports/graphs.py

@@ -17,6 +17,40 @@ from core.utils import duration_string, duration_parts
 from .utils import default_graph_layout_options, split_graph_output
 
 
+def diaperchange_lifetimes(child):
+    """Create a graph showing how long diapers last (time between changes)."""
+    changes = DiaperChange.objects.filter(child=child).order_by('time')
+
+    durations = []
+    last_change = changes.first()
+    for change in changes[1:]:
+        duration = change.time - last_change.time
+        if duration.seconds > 0:
+            durations.append(duration)
+        last_change = change
+
+    trace = go.Box(
+        y=[round(d.seconds/3600, 2) for d in durations],
+        name='Changes',
+        jitter=0.3,
+        pointpos=-1.8,
+        boxpoints='all'
+    )
+
+    layout_args = default_graph_layout_options()
+    layout_args['title'] = '<b>Diaper Lifetimes</b><br>{}'.format(child)
+    layout_args['yaxis']['title'] = 'Time between changes (hours)'
+    layout_args['yaxis']['zeroline'] = False
+    layout_args['yaxis']['dtick'] = 1
+
+    fig = go.Figure({
+        'data': [trace],
+        'layout': go.Layout(**layout_args)
+    })
+    output = plotly.plot(fig, output_type='div', include_plotlyjs=False)
+    return split_graph_output(output)
+
+
 def diaperchange_types(child):
     """Create a graph showing types of totals for diaper changes."""
     changes = DiaperChange.objects.filter(child=child) \

reports/templates/reports/diaperchange_lifetimes.html

@@ -0,0 +1,8 @@
+{% extends 'reports/report_base.html' %}
+
+{% block title %}Diaper Lifetimes - {{ object }}{% endblock %}
+
+{% block javascript %}
+    {{ block.super }}
+    {{ javascript|safe }}
+{% endblock %}

reports/urls.py

@@ -6,6 +6,9 @@ from django.conf.urls import url
 from . import views
 
 urlpatterns = [
+    url(r'^reports/changes/lifetimes/(?P<slug>[^/.]+)/$',
+        views.DiaperChangeLifetimesChildReport.as_view(),
+        name='report-diaperchange-lifetimes-child'),
     url(r'^reports/changes/types/(?P<slug>[^/.]+)/$',
         views.DiaperChangeTypesChildReport.as_view(),
         name='report-diaperchange-types-child'),

reports/views.py

@@ -5,9 +5,24 @@ from django.contrib.auth.mixins import PermissionRequiredMixin
 from django.views.generic.detail import DetailView
 from django.utils import timezone
 
-from core.models import Child, DiaperChange
+from core.models import Child
 
-from .graphs import diaperchange_types, sleep_pattern, sleep_totals, timeline
+from .graphs import (diaperchange_types, diaperchange_lifetimes, sleep_pattern,
+                     sleep_totals, timeline)
+
+
+class DiaperChangeLifetimesChildReport(PermissionRequiredMixin, DetailView):
+    """Graph of diaper changes by day and type."""
+    model = Child
+    permission_required = ('core.view_child',)
+    template_name = 'reports/diaperchange_lifetimes.html'
+
+    def get_context_data(self, **kwargs):
+        context = super(DiaperChangeLifetimesChildReport, self).get_context_data(
+            **kwargs)
+        child = context['object']
+        context['html'], context['javascript'] = diaperchange_lifetimes(child)
+        return context
 
 
 class DiaperChangeTypesChildReport(PermissionRequiredMixin, DetailView):