db: models: Re-instate avg amount for currency stats on entities

Author: michaelwood

datastore/db/models.py

@@ -279,11 +279,11 @@ def update_aggregate(self, grant):
         #  "maxAwardDate": yyyy-mm-dd,
         #  "currencies": {
         #       "recipient_org": {
-        #         "GBP": { "grants": 0, "total": 0, "min": 0, "max": 0 },
+        #         "GBP": { "grants": 0, "total": 0, "min": 0, "max": 0, "avg":0 },
         #         ...
         #       },
         #       "recipient_ind": {
-        #         "GBP": { "grants": 0, "total": 0, "min": 0, "max": 0 },
+        #         "GBP": { "grants": 0, "total": 0, "min": 0, "max": 0, "avg":0 },
         #         ...
         #       }
         #  },
@@ -335,6 +335,7 @@ def update_aggregate(self, grant):
                 "total": amount,
                 "min": amount,
                 "max": amount,
+                "avg": amount,
                 "grants": 1,
             }
         else:
@@ -343,6 +344,14 @@ def update_aggregate(self, grant):
             self.aggregate[C][currency][recipient_type]["grants"] += 1
             self.aggregate[C][currency][recipient_type]["total"] += amount
 
+            # Important that the avg is calculated _after_ the total number
+            # of grants for the currency has been accumulated.
+            # NOTE: avg currency amount to be deprecated
+            # https://github.com/ThreeSixtyGiving/datastore/issues/292
+            self.aggregate[C][currency][recipient_type]["avg"] = (
+                amount / self.aggregate[C][currency][recipient_type]["grants"]
+            )
+
             if self.aggregate[C][currency][recipient_type]["max"] < amount:
                 self.aggregate[C][currency][recipient_type]["max"] = amount