feat: statement api for business module

api_v1/views/business/statements/serializers.py

@@ -13,6 +13,9 @@ class StatementRecordSerializer(serializers.Serializer):
     counterparty_name = serializers.CharField()
     positive_amount = serializers.DecimalField(max_digits=15, decimal_places=2)
     negative_amount = serializers.DecimalField(max_digits=15, decimal_places=2)
+    cumulative_amount = serializers.CharField()
+    current_balance = serializers.CharField()
+    arrears_amount = serializers.CharField()
     extra = serializers.DictField(required=False)
 
 

api_v1/views/business/statements/views.py

@@ -10,6 +10,7 @@ from rest_framework.response import Response
 from basic_info import models as basic_models
 from business import models as business_models
 from api_v1.views.stock_change_views.mixins import StockChangeViewMixin
+from business import services as business_services
 from . import serializers as statement_serializers
 
 TWO_PLACES = Decimal('0.01')
@@ -24,6 +25,11 @@ class StatementViewBase(StockChangeViewMixin, views.APIView):
     permission_classes = [IsAuthenticated]
     serializer_class = statement_serializers.StatementResponseSerializer
 
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        self._current_balance_display: str | None = None
+        self._current_balance_value: Decimal | None = None
+
     def get_serializer_context(self):
         return {
             'request': self.request,
@@ -32,11 +38,12 @@ class StatementViewBase(StockChangeViewMixin, views.APIView):
         }
 
     def _build_response(self, counterparty, records: List[dict]):
+        processed_records = self._attach_running_totals(records)
         serializer = self.serializer_class(
             instance={
                 'counterparty': counterparty.id,
                 'counterparty_name': counterparty.name,
-                'records': records,
+                'records': processed_records,
             },
             context=self.get_serializer_context(),
         )
@@ -102,6 +109,22 @@ class StatementViewBase(StockChangeViewMixin, views.APIView):
             'negative_total': self._decimal_to_string(total_negative),
         }
 
+    def _attach_running_totals(self, records: List[dict]) -> List[dict]:
+        running_total = ZERO
+        current_balance_value = self._current_balance_value or ZERO
+        current_balance_display = self._current_balance_display or self._decimal_to_string(current_balance_value)
+        processed = []
+        for record in records:
+            record_copy = dict(record)
+            record_copy['cumulative_amount'] = self._decimal_to_string(running_total)
+            record_copy['current_balance'] = current_balance_display
+            arrears_amount = current_balance_value - running_total
+            record_copy['arrears_amount'] = self._decimal_to_string(arrears_amount)
+            delta = record_copy['positive_amount'] - record_copy['negative_amount']
+            running_total += delta
+            processed.append(record_copy)
+        return processed
+
 
 class CustomerStatementView(StatementViewBase):
     """
@@ -118,6 +141,7 @@ class CustomerStatementView(StatementViewBase):
         except basic_models.Customer.DoesNotExist:
             return self.not_found_response('客户不存在')
 
+        self._get_customer_balance(merchant, customer)
         records = self._collect_customer_records(merchant, customer)
         return self._build_response(customer, records)
 
@@ -212,6 +236,15 @@ class CustomerStatementView(StatementViewBase):
             )
         return records
 
+    def _get_customer_balance(self, merchant, customer):
+        balance = business_services.BalanceService.get_customer_balance(
+            merchant=merchant,
+            customer=customer,
+        )
+        self._current_balance_value = balance
+        self._current_balance_display = self._decimal_to_string(balance)
+        return self._current_balance_display
+
 
 class SupplierStatementView(StatementViewBase):
     """
@@ -228,6 +261,7 @@ class SupplierStatementView(StatementViewBase):
         except basic_models.Supplier.DoesNotExist:
             return self.not_found_response('供应商不存在')
 
+        self._get_supplier_balance(merchant, supplier)
         records = self._collect_supplier_records(merchant, supplier)
         return self._build_response(supplier, records)
 
@@ -322,4 +356,13 @@ class SupplierStatementView(StatementViewBase):
             )
         return records
 
+    def _get_supplier_balance(self, merchant, supplier):
+        balance = business_services.BalanceService.get_supplier_balance(
+            merchant=merchant,
+            supplier=supplier,
+        )
+        self._current_balance_value = balance
+        self._current_balance_display = self._decimal_to_string(balance)
+        return self._current_balance_display
+