country-api enhancement: api/v1/country

- [x] Contract value USD added
- [x] Contract value local added
- [x] Tender count added

country/serializers.py

@@ -25,10 +25,14 @@ def to_internal_value(self, data):
 class CountrySerializer(serializers.HyperlinkedModelSerializer, SerializerExtensionsMixin):
     id = serializers.IntegerField(read_only=True)
     continent = ChoiceField(choices=Country.CONTINENT_CHOICES)
+    amount_usd = serializers.SerializerMethodField()
+    amount_local = serializers.SerializerMethodField()
+    tender_count = serializers.SerializerMethodField()
 
     class Meta:
         model = Country
         fields = "__all__"
+        extra_fields = ["continent", "id", "amount_usd", "amount_local", "tender_count"]
         lookup_field = "slug"
 
         extra_kwargs = {"url": {"lookup_field": "slug"}}
@@ -42,23 +46,35 @@ class Meta:
 
     def get_amount_usd(self, obj):
         try:
-            total_country_tenders = obj.tenders.filter(country_id=self.id).annotate(
-                amount_usd=Sum("contract_value_usd"),
-                amount_local=Sum("contract_value_local"),
-                tender_count=Count("id"),
-            )
+            if obj.amount_usd:
+                return obj.amount_usd
+            else:
+                None
 
-            tender_data = {
-                "amount_usd": total_country_tenders.amount_usd,
-                "amount_local": total_country_tenders.amount_local,
-                "tender_count": total_country_tenders.tender_count,
-                "latest_contract_Date": "0000-00-00",
-            }
+        except Exception:
+            return obj.tenders.all().aggregate(amount_usd=Sum("goods_services__contract_value_usd"))["amount_usd"]
+
+    def get_amount_local(self, obj):
+        try:
+            if obj.amount_local:
+                return obj.amount_local
+            else:
+                return None
 
         except Exception:
-            tender_data = {"amount_usd": 0, "amount_local": 0, "tender_count": 0, "latest_contract_Date": "0000-00-00"}
+            return obj.tenders.all().aggregate(amount_local=Sum("goods_services__contract_value_local"))[
+                "amount_local"
+            ]
 
-        return tender_data
+    def get_tender_count(self, obj):
+        try:
+            if obj.tender_count:
+                return obj.tender_count
+            else:
+                return None
+
+        except Exception:
+            return obj.tenders.all().aggregate(tender_count=Count("id"))["tender_count"]
 
 
 class LanguageSerializer(serializers.ModelSerializer, SerializerExtensionsMixin):