class Member(models.Model):
  name = models.CharField(max_length=100, verbose_name='姓名')
  province = models.CharField(max_length=100, null=True, blank=True, verbose_name='省份')
  city = models.CharField(max_length=100, null=True, blank=True, verbose_name='城市')
  district = models.CharField(max_length=100, null=True, blank=True, verbose_name='區(qū)/縣')

  class Meta:
    verbose_name_plural = verbose_name = '人員'

  def __str__(self):
    return self.name

# views
LOCATION = {'吉林省': {'長春市': ['南關(guān)區(qū)', '朝陽區(qū)', '二道區(qū)', '綠園區(qū)']}}


def choose_province(request):
  province = list(LOCATION.keys())
  return JsonResponse(province, safe=False)


def choose_city(request):
  province = request.GET.get('p')
  cities = list(LOCATION[province].keys())
  return JsonResponse(cities, safe=False)


def choose_district(request):
  province = request.GET.get('p')
  city = request.GET.get('c')
  districts = LOCATION[province][city]
  return JsonResponse(districts, safe=False)
  
# urls
from person.views import choose_province, choose_city, choose_district

urlpatterns = [
  path('province/', choose_province),
  path('city/', choose_city),
  path('district/', choose_district),
  path('admin/', admin.site.urls),
]

class MemberForm(forms.ModelForm):
  class Meta:
    widgets = {
      'province': forms.Select(),
      'city': forms.Select(),
      'district': forms.Select()
    }

@admin.register(Member)
class MemberAdmin(admin.ModelAdmin):
  form = MemberForm
  fields = ('name', ('province', 'city', 'district'))
  list_display = ('name', 'province', 'city', 'district')
  change_form_template = 'area.html'

{% block admin_change_form_document_ready %}
  <script type="text/javascript"
      id="django-admin-form-add-constants"
      src="{% static 'admin/js/change_form.js' %}"
      {% if adminform and add %}
        data-model-name="{{ opts.model_name }}"
      {% endif %}>
  </script>

  <script type="text/javascript">
    (function($) {
      $('#id_city').change(function() {
        let p_id = $('#id_province').val();
        let c_id = $('#id_city').val();
        $.get('/district/', {"p": p_id, "c": c_id }, function(a_info) {
          var area_info = $('#id_district').empty().append('<option value>' + '---------' + '</option>');
          $.each(a_info, function(i, area) {
            area_info.append('<option value="' + area + '">' + area + '</option>')
          });
          {% if change %}
            $("#id_district").find("option:contains({{ original.district }})").attr('selected', true);
          {% endif %}
        });
      });

      $('#id_province').change(function() {
        let p_id = $('#id_province').val();
        $.get('/city/', { 'p': p_id }, function(c_info) {
          var city_info = $('#id_city').empty().append('<option value>' + '---------' + '</option>');
          $.each(c_info, function(i, city) {
            city_info.append('<option value="' + city + '">' + city + '</option>')
          });
          {% if change %}
            $("#id_city").find("option:contains({{ original.city }})").attr('selected', true);
            $("#id_city").trigger("change");
          {% endif %}
        });
      });

      $.get('/province/', function(p_info) {
        var province_info = $('#id_province').empty().append('<option value>' + '---------' + '</option>');
        $.each(p_info, function(i, province) {
          province_info.append('<option value="' + province + '">' + province + '</option>')
        });
        {% if change %}
          $("#id_province").find("option:contains({{ original.province }})").attr('selected', true);
          $("#id_province").trigger("change");
        {% endif %}
      });
    })(django.jQuery);
  </script>