services.py 文件源码

def calculate_min_max_consumption_watt():
    """ Returns the lowest and highest Wattage consumed for each phase. """
    FIELDS = {
        'total_min': ('currently_delivered', ''),
        'total_max': ('currently_delivered', '-'),
        'l1_max': ('phase_currently_delivered_l1', '-'),
        'l2_max': ('phase_currently_delivered_l2', '-'),
        'l3_max': ('phase_currently_delivered_l3', '-'),
    }
    data = {}

    for name, args in FIELDS.items():
        field, sorting = args

        try:
            read_at, value = ElectricityConsumption.objects.filter(**{
                '{}__gt'.format(field): 0,  # Skip (obvious) zero values.
                '{}__isnull'.format(field): False,  # And skip empty data.
            }).order_by(
                '{}{}'.format(sorting, field)
            ).values_list('read_at', field)[0]
        except IndexError:
            continue

        data.update({
            name: (
                formats.date_format(timezone.localtime(read_at), 'DSMR_GRAPH_LONG_DATE_FORMAT'),
                int(value * 1000)
            )
        })

    return data