def get_queryset(self):
    entries = Entry.objects.filter(user=self.request.user).values(
        'project__name'
    ).annotate(
        total_duration=Sum('duration'),
        billable_duration=Sum(
            Case(
                When(billable=True, then='duration'),
                output_field=DurationField(),
            )
        ),
        unbillable_duration=Sum(
            Case(
                When(billable=False, then='duration'),
                output_field=DurationField(),
            )
        )
    )

def get_context_data(self, **kwargs):
        context_data = super().get_context_data(**kwargs)
        qs = self.get_dated_queryset()
        context_data['total_duration'] = qs.aggregate(Sum('total_duration'))['total_duration__sum']
        context_data['billable_duration'] = qs.aggregate(Sum('billable_duration'))['billable_duration__sum']
        context_data['unbillable_duration'] = qs.aggregate(Sum('unbillable_duration'))['unbillable_duration__sum']
        return context_data