###### MODELS.PY ########################
# Create your models here.
class Store(models.Model):
    """ unique store ids """
    store = models.IntegerField(primary_key=True)
    system_name = models.CharField(max_length=10)
    city_signifier = models.CharField(max_length=60, blank=True, null=True)
    three_letter_code = models.CharField(max_length=3, blank=True, null=True)
    """ district / division / region"""
    district = models.ForeignKey('District', related_name='district')
    dma = models.PositiveIntegerField(blank=True, null=True)
    """ supplying dcs """
    primary_supplier = models.ForeignKey('Supplier', related_name='supplier')
    bulk_supplier = models.PositiveIntegerField()
    """ geolocation """
    latitude = models.DecimalField(max_digits=13, decimal_places=9)
    longitude = models.DecimalField(max_digits=13, decimal_places=9)
    """ address """
    address = models.CharField(max_length=200)
    city = models.CharField(max_length=200)
    state = USStateField()
    zip_code = models.PositiveIntegerField()
    """ sla """
    is_hub = models.BooleanField(default=False)
    previous_sales = models.PositiveIntegerField(default=0)
    open_date = models.DateField(blank=True, null=True)
    closed_date = models.DateField(null=True, blank=True)
    """ store hours """
    timezone = models.CharField(max_length=5, choices=get_timezones())
    weekdays_open = models.TimeField(default='7:00')
    weekdays_close = models.TimeField(default='21:00')
    saturday_open = models.TimeField(default='7:00')
    saturday_close = models.TimeField(default='21:00')
    sunday_open = models.TimeField(default='7:00', blank=True, null=True)
    sunday_close = models.TimeField(default='21:00', blank=True, null=True)

    def is_closed(self):
        if self.closed_date is None or self.closed_date == '0001-01-01':
            return False
        else:
            return True

    def is_open(self):
        from datetime import datetime
        if self.opened_date < datetime.now().date:
            return True
        else:
            return False

    def is_dc(self):
        if self.store < 100:
            return True
        else:
            return False

    def get_absolute_url(self):
        return reverse("store-detail", kwargs={'store': self.store})

    def get_district_url(self):
        return reverse("district-detail", kwargs={'pk': self.district})

    def get_supplier_url(self):
        return reverse("supplier-detail", kwargs={'pk': self.primary_supplier})

    def __str__(self):
        return '{0}'.format(self.store)


class District(models.Model):
    district_number = models.PositiveIntegerField(primary_key=True)
    region = models.ForeignKey('Region')
    manager = models.CharField(max_length=50, blank=True, null=True)
    manager_cell = PhoneNumberField(blank=True, null=True)
    manager_office_phone = PhoneNumberField(blank=True, null=True)
    office_at_store = models.ForeignKey(Store, blank=True, null=True, related_name="district_manager_office")

    def __str__(self):
        return '{0}'.format(self.district_number)

    def get_absolute_url(self):
        return reverse('district-detail', kwargs={'pk': self.district_number})

    def locations(self):
        return Store.objects.filter(district=self.district_number)

    def district_installers(self):
        return DistrictInstaller.objects.filter(from_district=self.district_number)


##### serializer.py #################

from rest_framework.serializers import ModelSerializer, CharField, SerializerMethodField, HyperlinkedIdentityField
from locations.models import Store, District, DistrictInstaller, Region, Division, Supplier


class StoreListSerializer(ModelSerializer):
    url = HyperlinkedIdentityField(view_name='store-detail', lookup_field='store')

    class Meta:
        model = Store
        fields = ['store', 'url']


class StoreDetailSerializer(ModelSerializer):
    district_url = HyperlinkedIdentityField(view_name='district-detail', lookup_field='pk')
    supplier_url = HyperlinkedIdentityField(view_name='supplier-detail', lookup_field='pk')

    class Meta:
        model = Store
        fields = '__all__'


class DistrictListSerializer(ModelSerializer):
    url = HyperlinkedIdentityField(view_name='district-detail', lookup_field='pk')

    class Meta:
        model = District
        fields = ['district_number', 'url']


class DistrictDetailSerializer(ModelSerializer):
    #office_at_store = StoreDetailSerializer(read_only=True, many=True)
    stores = SerializerMethodField()
    #district_installers = SerializerMethodField()

    class Meta:
        model = District
        fields = '__all__'

    def get_stores(self, obj):
        return StoreListSerializer(obj.locations, many=True, read_only=True)


####### views.py #####################
from rest_framework.generics import ListAPIView, UpdateAPIView, RetrieveAPIView

from locations.models import Store, District, DistrictInstaller, Region, Division, Supplier

from .serializers import (
        StoreListSerializer,
        StoreDetailSerializer,
        DistrictListSerializer,
        DistrictDetailSerializer,
        DistrictInstallerListSerializer,
        DistrictInstallerDetailSerializer,
        RegionListSerializer,
        RegionDetailSerializer,
        DivisionListSerializer,
        DivisionDetailSerializer,
        SupplierListSerializer,

)


class StoreDetailAPIView(RetrieveAPIView):
    queryset = Store.objects.all()
    serializer_class = StoreDetailSerializer
    lookup_field = 'store'


class StoreListAPIView(ListAPIView):
    queryset = Store.objects.all()
    serializer_class = StoreListSerializer


class DistrictListAPIView(ListAPIView):
    queryset = District.objects.all()
    serializer_class = DistrictListSerializer
    lookup_field = 'pk'


class DistrictDetailsAPIView(RetrieveAPIView):
    queryset = District.objects.all()
    serializer_class = DistrictDetailSerializer
    lookup_field = 'pk'


class DistrictInstallerListAPIView(ListAPIView):
    queryset = DistrictInstaller.objects.all()
    serializer_class = DistrictInstallerListSerializer


class DistrictInstallerDetailAPIView(RetrieveAPIView):
    queryset = DistrictInstaller.objects.all()
    serializer_class = DistrictInstallerDetailSerializer
    lookup_field = 'pk'



##### Expected output #########################

{
  'district_number': 218,
  'url': 'localhost/api/locations/district/218',
  'stores': [
        'store':2942, 'url': 'localhost/api/locations/stores/2942',
        'store':2922, 'url': 'localhost/api/locations/stores/2922',
    ]
}



###### Error message ######
StoreListSerializer(<bound method District.locations of <District: 218>>, many=True, read_only=True):
    store = IntegerField(validators=[<UniqueValidator(queryset=Store.objects.all())>])
    url = HyperlinkedIdentityField(lookup_field='store', view_name='store-detail') is not JSON serializable