api: org: Add method to provide backward compatibility with API v1

This provides API v1 compatibility with the new aggregate data format
for currencies on entities.

Author: michaelwood

datastore/api/org/serializers.py

@@ -27,7 +27,9 @@ def get_self(self, org):
 
 
 class OrganisationAggregateCurrencySerializer(serializers.Serializer):
-    avg = serializers.FloatField()
+    # NOTE: avg to be deprecated in version 2
+    # https://github.com/ThreeSixtyGiving/datastore/issues/292
+    avg = serializers.floatfield()
     max = serializers.FloatField()
     min = serializers.FloatField()
     total = serializers.FloatField()
@@ -36,8 +38,66 @@ class OrganisationAggregateCurrencySerializer(serializers.Serializer):
 
 class OrganisationAggregateSerializer(serializers.Serializer):
     grants = serializers.IntegerField()
-    currencies = serializers.DictField(child=OrganisationAggregateCurrencySerializer())
 
+    currencies = serializers.SerializerMethodField(serializer_class=OrganisationAggregateCurrencySerializer)
+
+    # NOTE: This field will be deprecated in future version in favour of
+    # the direct representation from the model. This method is to provide API v1
+    # compatibility.
+    def get_currencies(self, org):
+        def combine_currencies_org_ind(currency):
+            """ recombine currency stats from both recipient_org and recipient_ind"""
+            combined_grants = recipient_org[currency]["grants"] + recipient_ind[currency]["grants"]
+            combined_total = recipient_org[currency]["total"] + recipient_ind[currency]["total"]
+
+            # Calculate the new average
+            if combined_grants > 0:
+                combined_avg = combined_total / combined_grants
+            else:
+                combined_avg = 0.0
+
+            # Determine the new min and max using direct key access
+            combined_min = min(recipient_org[currency]["min"], recipient_ind[currency]["min"])
+            combined_max = max(recipient_org[currency]["max"], recipient_ind[currency]["max"])
+
+            return {
+                "min": combined_min,
+                "max": combined_max,
+                "avg": combined_avg,
+                "grants": combined_grants,
+                "total": combined_total,
+            }
+
+
+        recipient_org = org["currencies"].get("recipient_org")
+        recipient_ind = org["currencies"].get("recipient_ind")
+
+        if recipient_org and not recipient_ind:
+            return recipient_org
+
+        if recipient_ind and not recipient_org:
+            return recipient_ind
+
+        if recipient_org and recipient_ind:
+            ret = {}
+
+            set_recipient_org_currencies = set(recipient_org.keys())
+            set_recipient_ind_currencies = set(recipient_ind.keys())
+
+            common_currencies = list(set_recipient_org_currencies.intersection(set_recipient_ind_currencies))
+            currencies_only_in_recipient_org_currencies = list(set_recipient_org_currencies.difference(set_recipient_ind_currencies))
+            currencies_only_in_recipient_ind_currencies = list(set_recipient_ind_currencies.difference(set_recipient_org_currencies))
+
+            for currency in common_currencies:
+                ret[currency] =combine_currencies_org_ind(currency)
+
+            for currency in currencies_only_in_recipient_org_currencies:
+                ret[currency] = recipient_org[currency]
+
+            for currency in currencies_only_in_recipient_ind_currencies:
+                ret[currency] = recipient_org[currency]
+
+            return ret
 
 class OrganisationFunderSerializer(serializers.ModelSerializer):
     class Meta: