feat: BalanceChangeRecord

2025-12-01 15:22:59 +08:00
parent 9acc4e14fc
commit a3b4af2602
8 changed files with 359 additions and 14 deletions
--- a/business/ARCHITECTURE.md
+++ b/business/ARCHITECTURE.md
@@ -40,6 +40,7 @@
 - **PaymentOrder**（付款单）：`direction=-1`，`counterparty=supplier`，仅金额字段，不触发库存。
 - **ReceiptOrder**（收款单）：`direction=-1`，`counterparty=customer`，仅金额字段，不触发库存。
 - **SupplierBalance / CustomerBalance**：实时维护供应商应付、客户应收余额，所有审批通过的带金额单据都会写入，供查询接口和报表使用。
+- **BalanceChangeRecord**（余额变动记录）：仿照 `stock.StockSnapshot` 的“流水 + 快照”模式，记录每一次余额写入的来源、方向、前后余额与可能的冲抵关系，为财务审计与未来的红冲能力提供依据。

 通过 mixin，所有单据都具备：
 - 统一的金额聚合与方向计算（资金/库存可共用 `get_signed_total_amount()`）
@@ -57,7 +58,8 @@
 1. **新增单据**：若未来出现调拨单、退货单或更多资金类单据，优先复用 `OrderDirectionMixin + OrderCounterpartyMixin`（如有明细再叠加 `OrderItemsAggregationMixin`），仅通过 `get_direction()` / `get_counterparty_field_name()` 区别方向与主体，减少重复实现。
 2. **审批/状态机**：采购与销售如需共享状态流转，可提炼状态机或 service 层 mixin，而无需在模型层合并。
 3. **统计与报表**：财务/库存统计应依赖 `get_signed_total_amount()` / `get_direction()`，确保采购/销售、退货/正向都能通过统一接口处理。
-4. **文档同步**：新增单据或服务时必须更新本文件，描述新增模型如何复用 mixin、如何影响下游模块，保持设计透明。
+4. **余额审计**：任何会写入 Supplier/CustomerBalance 的流程必须通过 `BalanceService`，以便自动生成 `BalanceChangeRecord`。审批通过后禁止作废，若未来需要冲销，必须新建红冲记录并维护 `offset_to/offset_id` 链路。
+5. **文档同步**：新增单据或服务时必须更新本文件，描述新增模型如何复用 mixin、如何影响下游模块，保持设计透明。

 以上约定的目标是：**保持各类业务单据的独立性，同时通过 mixin/服务层抽象复用绝大多数公共逻辑**。如需变更此架构，请在评估后更新本文件，说明原因与迁移方案。

--- a/business/admin.py
+++ b/business/admin.py
@@ -47,3 +47,30 @@ class PurchaseOrderItemAdmin(admin.ModelAdmin):
    @admin.display(description='总金额')
    def _total_amount(self, obj: models.PurchaseOrderItem):
        return obj.total_amount()
+
+
+@admin.register(models.CustomerBalance)
+class CustomerBalancemAdmin(admin.ModelAdmin):
+    list_display = ('id', 'customer', 'balance', 'created_at')
+    search_fields = ('customer_balance__id', 'product__name')
+    ordering = ('-created_at',)
+
+
+@admin.register(models.BalanceChangeRecord)
+class BalanceChangeRecordAdmin(admin.ModelAdmin):
+    list_display = ('id', 'merchant', 'target_type', 'source_type', 'source_id', 'delta', 'balance_before', 'balance_after', 'direction', 'created_at')
+    search_fields = ('merchant__name', 'target_type', 'source_type', 'source_id')
+    list_filter = ('merchant', 'target_type', 'source_type', 'direction', 'created_at')
+    ordering = ('-created_at',)
+
+    @admin.display(description='商户')
+    def merchant(self, obj: models.BalanceChangeRecord):
+        return obj.merchant.name
+
+    @admin.display(description='目标类型')
+    def target_type(self, obj: models.BalanceChangeRecord):
+        return obj.target_type.label
+
+    @admin.display(description='来源类型')
+    def source_type(self, obj: models.BalanceChangeRecord):
+        return obj.source_type.label
--- a/business/migrations/0013_balancechangerecord.py
+++ b/business/migrations/0013_balancechangerecord.py
@@ -0,0 +1,47 @@
+# Generated by Django 5.2.7 on 2025-12-01 06:34
+
+import django.db.models.deletion
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('basic_info', '0016_merchantsetting_type'),
+        ('business', '0012_customerbalance_supplierbalance'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='BalanceChangeRecord',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('created_at', models.DateTimeField(auto_now_add=True, verbose_name='创建时间')),
+                ('updated_at', models.DateTimeField(auto_now=True, verbose_name='更新时间')),
+                ('target_type', models.IntegerField(choices=[(1, '供应商'), (2, '客户')], verbose_name='业务主体类型')),
+                ('source_type', models.IntegerField(choices=[(1, '采购单'), (2, '销售单'), (3, '付款单'), (4, '收款单')], verbose_name='来源业务类型')),
+                ('source_id', models.BigIntegerField(verbose_name='来源业务ID')),
+                ('delta', models.DecimalField(decimal_places=2, max_digits=15, verbose_name='变动金额')),
+                ('direction', models.IntegerField(choices=[(1, '增加'), (2, '减少')], verbose_name='方向')),
+                ('balance_before', models.DecimalField(decimal_places=2, max_digits=15, verbose_name='变动前余额')),
+                ('balance_after', models.DecimalField(decimal_places=2, max_digits=15, verbose_name='变动后余额')),
+                ('request_id', models.CharField(blank=True, max_length=64, null=True, verbose_name='幂等请求ID')),
+                ('remarks', models.TextField(blank=True, null=True, verbose_name='备注')),
+                ('extra_meta', models.JSONField(blank=True, default=dict, verbose_name='扩展信息')),
+                ('offset_to', models.BigIntegerField(blank=True, null=True, verbose_name='冲抵目标ID')),
+                ('offset_at', models.DateTimeField(blank=True, null=True, verbose_name='冲抵时间')),
+                ('offset_id', models.BigIntegerField(blank=True, null=True, verbose_name='冲抵来源ID')),
+                ('cancelled', models.BooleanField(default=False, verbose_name='已被冲抵')),
+                ('cancelled_at', models.DateTimeField(blank=True, null=True, verbose_name='被冲抵时间')),
+                ('customer', models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.PROTECT, related_name='balance_change_records', to='basic_info.customer', verbose_name='客户')),
+                ('merchant', models.ForeignKey(on_delete=django.db.models.deletion.PROTECT, related_name='balance_change_records', to='basic_info.merchant', verbose_name='所属商户')),
+                ('supplier', models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.PROTECT, related_name='balance_change_records', to='basic_info.supplier', verbose_name='供应商')),
+            ],
+            options={
+                'verbose_name': '余额变动记录',
+                'verbose_name_plural': '余额变动记录',
+                'indexes': [models.Index(fields=['merchant', 'source_type', 'source_id'], name='balance_change_source_idx')],
+                'constraints': [models.CheckConstraint(condition=models.Q(models.Q(('customer__isnull', True), ('supplier__isnull', False)), models.Q(('customer__isnull', False), ('supplier__isnull', True)), _connector='OR'), name='balance_change_single_counterparty')],
+            },
+        ),
+    ]
--- a/business/models.py
+++ b/business/models.py
@@ -462,3 +462,89 @@ class CustomerBalance(ModelBase):
        verbose_name = '客户余额'
        verbose_name_plural = '客户余额'
        unique_together = ('merchant', 'customer')
+
+
+class BalanceChangeTargetEnum(models.IntegerChoices):
+    SUPPLIER = 1, '供应商'
+    CUSTOMER = 2, '客户'
+
+
+class BalanceChangeSourceEnum(models.IntegerChoices):
+    PURCHASE_ORDER = 1, '采购单'
+    SALES_ORDER = 2, '销售单'
+    PAYMENT_ORDER = 3, '付款单'
+    RECEIPT_ORDER = 4, '收款单'
+
+
+class BalanceChangeDirectionEnum(models.IntegerChoices):
+    INCREASE = 1, '增加'
+    DECREASE = 2, '减少'
+
+
+class BalanceChangeRecord(ModelBase):
+    merchant = models.ForeignKey(
+        basic_info_models.Merchant,
+        on_delete=models.PROTECT,
+        related_name='balance_change_records',
+        verbose_name='所属商户',
+    )
+    supplier = models.ForeignKey(
+        basic_info_models.Supplier,
+        on_delete=models.PROTECT,
+        related_name='balance_change_records',
+        verbose_name='供应商',
+        null=True,
+        blank=True,
+    )
+    customer = models.ForeignKey(
+        basic_info_models.Customer,
+        on_delete=models.PROTECT,
+        related_name='balance_change_records',
+        verbose_name='客户',
+        null=True,
+        blank=True,
+    )
+    target_type = models.IntegerField(
+        choices=BalanceChangeTargetEnum.choices,
+        verbose_name='业务主体类型',
+    )
+    source_type = models.IntegerField(
+        choices=BalanceChangeSourceEnum.choices,
+        verbose_name='来源业务类型',
+    )
+    source_id = models.BigIntegerField(verbose_name='来源业务ID')
+    delta = models.DecimalField(max_digits=15, decimal_places=2, verbose_name='变动金额')
+    direction = models.IntegerField(
+        choices=BalanceChangeDirectionEnum.choices,
+        verbose_name='方向',
+    )
+    balance_before = models.DecimalField(max_digits=15, decimal_places=2, verbose_name='变动前余额')
+    balance_after = models.DecimalField(max_digits=15, decimal_places=2, verbose_name='变动后余额')
+    request_id = models.CharField(max_length=64, null=True, blank=True, verbose_name='幂等请求ID')
+    remarks = models.TextField(blank=True, null=True, verbose_name='备注')
+    extra_meta = models.JSONField(default=dict, blank=True, verbose_name='扩展信息')
+    offset_to = models.BigIntegerField(null=True, blank=True, verbose_name='冲抵目标ID')
+    offset_at = models.DateTimeField(null=True, blank=True, verbose_name='冲抵时间')
+    offset_id = models.BigIntegerField(null=True, blank=True, verbose_name='冲抵来源ID')
+    cancelled = models.BooleanField(default=False, verbose_name='已被冲抵')
+    cancelled_at = models.DateTimeField(null=True, blank=True, verbose_name='被冲抵时间')
+
+    class Meta:
+        verbose_name = '余额变动记录'
+        verbose_name_plural = '余额变动记录'
+        indexes = [
+            models.Index(fields=['merchant', 'source_type', 'source_id'], name='balance_change_source_idx'),
+        ]
+        constraints = [
+            models.CheckConstraint(
+                check=(
+                    (models.Q(supplier__isnull=False, customer__isnull=True))
+                    | (models.Q(supplier__isnull=True, customer__isnull=False))
+                ),
+                name='balance_change_single_counterparty',
+            ),
+        ]
+
+    def __str__(self):
+        counterparty = self.supplier or self.customer
+        return f'余额变动 {self.id} - {counterparty}'
--- a/business/services.py
+++ b/business/services.py
@@ -25,15 +25,25 @@ class BalanceService:
        merchant: basic_info_models.Merchant,
        supplier: basic_info_models.Supplier,
        delta: Decimal,
+        source_type: models.BalanceChangeSourceEnum,
+        source_id: int,
+        request_id: str | None = None,
+        remarks: str | None = '',
+        extra_meta: Dict[str, Any] | None = None,
    ):
-        with transaction.atomic():
-            balance, _ = models.SupplierBalance.objects.select_for_update().get_or_create(
+        BalanceService._adjust_balance(
            merchant=merchant,
-                supplier=supplier,
-                defaults={'balance': Decimal('0')},
+            counterparty=supplier,
+            balance_model=models.SupplierBalance,
+            balance_field='supplier',
+            delta=delta,
+            target_type=models.BalanceChangeTargetEnum.SUPPLIER,
+            source_type=source_type,
+            source_id=source_id,
+            request_id=request_id,
+            remarks=remarks,
+            extra_meta=extra_meta,
        )
-            balance.balance += delta
-            balance.save(update_fields=['balance', 'updated_at'])

    @staticmethod
    def adjust_customer_balance(
@@ -41,16 +51,77 @@ class BalanceService:
        merchant: basic_info_models.Merchant,
        customer: basic_info_models.Customer,
        delta: Decimal,
+        source_type: models.BalanceChangeSourceEnum,
+        source_id: int,
+        request_id: str | None = None,
+        remarks: str | None = '',
+        extra_meta: Dict[str, Any] | None = None,
    ):
-        with transaction.atomic():
-            balance, _ = models.CustomerBalance.objects.select_for_update().get_or_create(
+        BalanceService._adjust_balance(
            merchant=merchant,
-                customer=customer,
-                defaults={'balance': Decimal('0')},
+            counterparty=customer,
+            balance_model=models.CustomerBalance,
+            balance_field='customer',
+            delta=delta,
+            target_type=models.BalanceChangeTargetEnum.CUSTOMER,
+            source_type=source_type,
+            source_id=source_id,
+            request_id=request_id,
+            remarks=remarks,
+            extra_meta=extra_meta,
        )
+
+    @staticmethod
+    def _adjust_balance(
+        *,
+        merchant: basic_info_models.Merchant,
+        counterparty,
+        balance_model,
+        balance_field: str,
+        delta: Decimal,
+        target_type: models.BalanceChangeTargetEnum,
+        source_type: models.BalanceChangeSourceEnum,
+        source_id: int,
+        request_id: str | None,
+        remarks: str | None,
+        extra_meta: Dict[str, Any] | None,
+    ):
+        meta_payload = extra_meta or {}
+        remarks_value = remarks or ''
+        with transaction.atomic():
+            balance, _ = balance_model.objects.select_for_update().get_or_create(
+                merchant=merchant,
+                defaults={'balance': Decimal('0')},
+                **{balance_field: counterparty},
+            )
+            before = balance.balance
            balance.balance += delta
            balance.save(update_fields=['balance', 'updated_at'])

+            record_kwargs = {
+                'merchant': merchant,
+                'target_type': target_type,
+                'source_type': source_type,
+                'source_id': source_id,
+                'delta': delta,
+                'direction': (
+                    models.BalanceChangeDirectionEnum.INCREASE
+                    if delta >= 0
+                    else models.BalanceChangeDirectionEnum.DECREASE
+                ),
+                'balance_before': before,
+                'balance_after': balance.balance,
+                'request_id': request_id,
+                'remarks': remarks_value,
+                'extra_meta': meta_payload,
+            }
+            if target_type == models.BalanceChangeTargetEnum.SUPPLIER:
+                record_kwargs['supplier'] = counterparty
+            else:
+                record_kwargs['customer'] = counterparty
+
+            models.BalanceChangeRecord.objects.create(**record_kwargs)
+
    @staticmethod
    def get_customer_balance(
        *,
@@ -373,6 +444,8 @@ def review_payment_order(
                merchant=locked.merchant,
                supplier=locked.supplier,
                delta=-locked.amount,
+                source_type=models.BalanceChangeSourceEnum.PAYMENT_ORDER,
+                source_id=locked.id,
            )
        locked.refresh_from_db(fields=['status', 'updated_at'])
        return locked
@@ -424,6 +497,8 @@ def review_receipt_order(
                merchant=locked.merchant,
                customer=locked.customer,
                delta=-locked.amount,
+                source_type=models.BalanceChangeSourceEnum.RECEIPT_ORDER,
+                source_id=locked.id,
            )
        locked.refresh_from_db(fields=['status', 'updated_at'])
        return locked
@@ -577,6 +652,8 @@ def _approve_purchase_order(
            merchant=locked_order.merchant,
            supplier=locked_order.supplier,
            delta=locked_order.get_total_amount(),
+            source_type=models.BalanceChangeSourceEnum.PURCHASE_ORDER,
+            source_id=locked_order.id,
        )

    created_by_id = getattr(reviewed_by, 'id', None)
@@ -632,6 +709,8 @@ def _approve_sales_order(
            merchant=locked_order.merchant,
            customer=locked_order.customer,
            delta=locked_order.get_total_amount(),
+            source_type=models.BalanceChangeSourceEnum.SALES_ORDER,
+            source_id=locked_order.id,
        )

    created_by_id = getattr(reviewed_by, 'id', None)
--- a/business/tests.py
+++ b/business/tests.py
@@ -179,6 +179,15 @@ class PurchaseOrderServiceTestCase(TestCase):
            supplier=self.supplier,
        )
        self.assertEqual(balance.balance, purchase_order.get_total_amount())
+        record = business_models.BalanceChangeRecord.objects.get(
+            merchant=self.merchant,
+            source_type=business_models.BalanceChangeSourceEnum.PURCHASE_ORDER,
+            source_id=purchase_order.id,
+        )
+        self.assertEqual(record.target_type, business_models.BalanceChangeTargetEnum.SUPPLIER)
+        self.assertEqual(record.delta, purchase_order.get_total_amount())
+        self.assertEqual(record.balance_after, balance.balance)
+        self.assertEqual(record.direction, business_models.BalanceChangeDirectionEnum.INCREASE)

    def test_create_purchase_order_without_items_raises(self):
        with self.assertRaises(ValueError):
@@ -209,6 +218,13 @@ class PurchaseOrderServiceTestCase(TestCase):
            reviewed_by=self.user,
        )
        self.assertEqual(cancelled.status, business_models.PurchaseOrderStatusEnum.CANCELLED)
+        self.assertFalse(
+            business_models.BalanceChangeRecord.objects.filter(
+                merchant=self.merchant,
+                source_type=business_models.BalanceChangeSourceEnum.PURCHASE_ORDER,
+                source_id=purchase_order.id,
+            ).exists()
+        )

    def test_review_purchase_order_cancel_blocked_after_stock_created(self):
        purchase_order = services.create_purchase_order(
@@ -337,6 +353,15 @@ class SalesOrderServiceTestCase(TestCase):
            customer=self.customer,
        )
        self.assertEqual(balance.balance, sales_order.get_total_amount())
+        record = business_models.BalanceChangeRecord.objects.get(
+            merchant=self.merchant,
+            source_type=business_models.BalanceChangeSourceEnum.SALES_ORDER,
+            source_id=sales_order.id,
+        )
+        self.assertEqual(record.target_type, business_models.BalanceChangeTargetEnum.CUSTOMER)
+        self.assertEqual(record.delta, sales_order.get_total_amount())
+        self.assertEqual(record.balance_after, balance.balance)
+        self.assertEqual(record.direction, business_models.BalanceChangeDirectionEnum.INCREASE)

    def test_sales_order_cancel_blocked_after_stock_created(self):
        sales_order = services.create_sales_order(
@@ -361,6 +386,13 @@ class SalesOrderServiceTestCase(TestCase):
                target_status=business_models.SalesOrderStatusEnum.CANCELLED,
                reviewed_by=self.user,
            )
+        self.assertFalse(
+            business_models.BalanceChangeRecord.objects.filter(
+                merchant=self.merchant,
+                source_type=business_models.BalanceChangeSourceEnum.SALES_ORDER,
+                source_id=sales_order.id,
+            ).exists()
+        )

    def test_sales_order_requires_consume_ids_for_strict_out(self):
        with self.assertRaises(ValueError):
@@ -443,6 +475,14 @@ class PaymentReceiptServiceTestCase(TestCase):
            supplier=self.supplier,
        )
        self.assertEqual(balance.balance, Decimal('-120.50'))
+        record = business_models.BalanceChangeRecord.objects.get(
+            merchant=self.merchant,
+            source_type=business_models.BalanceChangeSourceEnum.PAYMENT_ORDER,
+            source_id=order.id,
+        )
+        self.assertEqual(record.direction, business_models.BalanceChangeDirectionEnum.DECREASE)
+        self.assertEqual(record.delta, Decimal('-120.50'))
+        self.assertEqual(record.balance_after, balance.balance)
        with self.assertRaises(ValueError):
            services.review_payment_order(
                payment_order=order,
@@ -465,6 +505,13 @@ class PaymentReceiptServiceTestCase(TestCase):
            reviewed_by=self.operator,
        )
        self.assertEqual(cancelled.status, business_models.ReceiptOrderStatusEnum.CANCELLED)
+        self.assertFalse(
+            business_models.BalanceChangeRecord.objects.filter(
+                merchant=self.merchant,
+                source_type=business_models.BalanceChangeSourceEnum.RECEIPT_ORDER,
+                source_id=order.id,
+            ).exists()
+        )

    def test_payment_amount_must_be_positive(self):
        with self.assertRaises(ValueError):
@@ -500,6 +547,44 @@ class PaymentReceiptServiceTestCase(TestCase):
            customer=self.customer,
        )
        self.assertEqual(balance.balance, Decimal('-10'))
+        records = business_models.BalanceChangeRecord.objects.filter(
+            merchant=self.merchant,
+            source_type=business_models.BalanceChangeSourceEnum.RECEIPT_ORDER,
+            source_id=order.id,
+        )
+        self.assertEqual(records.count(), 1)
+        self.assertEqual(records.first().balance_after, balance.balance)
+
+    def test_payment_approval_is_idempotent(self):
+        order = services.create_payment_order(
+            merchant=self.merchant,
+            supplier=self.supplier,
+            payment_date=timezone.now().date(),
+            amount='75.00',
+            operator=self.operator,
+        )
+        services.review_payment_order(
+            payment_order=order,
+            target_status=business_models.PaymentOrderStatusEnum.APPROVED,
+            reviewed_by=self.operator,
+        )
+        services.review_payment_order(
+            payment_order=order,
+            target_status=business_models.PaymentOrderStatusEnum.APPROVED,
+            reviewed_by=self.operator,
+        )
+        balance = business_models.SupplierBalance.objects.get(
+            merchant=self.merchant,
+            supplier=self.supplier,
+        )
+        self.assertEqual(balance.balance, Decimal('-75.00'))
+        records = business_models.BalanceChangeRecord.objects.filter(
+            merchant=self.merchant,
+            source_type=business_models.BalanceChangeSourceEnum.PAYMENT_ORDER,
+            source_id=order.id,
+        )
+        self.assertEqual(records.count(), 1)
+        self.assertEqual(records.first().balance_after, balance.balance)


 class PurchaseOrderStockServiceTestCase(TestCase):
@@ -668,6 +753,13 @@ class SalesOrderConcurrencyTestCase(TransactionTestCase):
            customer=self.customer,
        )
        self.assertEqual(balance.balance, self.sales_order.get_total_amount())
+        records = business_models.BalanceChangeRecord.objects.filter(
+            merchant=self.merchant,
+            source_type=business_models.BalanceChangeSourceEnum.SALES_ORDER,
+            source_id=self.sales_order.id,
+        )
+        self.assertEqual(records.count(), 1)
+        self.assertEqual(records.first().balance_after, balance.balance)

    def tearDown(self):
        connections.close_all()
--- a/docs/business_api_reference.md
+++ b/docs/business_api_reference.md
@@ -15,6 +15,7 @@
 | 金额字段 | 字符串形式的十进制数（例如 `"123.45"`），与后端 `Decimal` 精度一致。 |
 | items 结构 | 受仓库模式影响：<br>• 严进/严进严出：`numbers: [int,…]` 表示条数明细<br>• 宽进宽出：`quantity` + `num_of_rolls`<br>• 严出：`consume_detail_ids: [detail_id,…]` |
 | 审批副作用 | 采购/销售审批通过后根据商户设置触发 Celery 入/出库任务；付款/收款审批通过将同步写入余额表。 |
+| 余额审计 | 审批成功后会同步写入 `BalanceChangeRecord`，记录来源单据、方向、前后余额与冲抵占位字段，供审计/红冲使用。 |

 错误响应统一为 `{"error": "代码", "message": "描述"}`，字段可能因场景扩展（如 `record_id`、`fields` 等）。

@@ -189,6 +190,17 @@

 目前仅内部使用（审批写入），如需对外查询可在此基础上新增 `/suppliers/<id>/balance/`，逻辑与客户一致：采购单审批增加余额、付款单审批减少余额。

+### 6.3 余额变动记录（BalanceChangeRecord）
+
+- **写入时机**：仅在审批通过瞬间写入；审批成功后禁止作废，若需冲销必须通过红冲/对冲流程生成反向记录。
+- **字段概要**：
+  - `target_type`：供应商 / 客户
+  - `source_type` + `source_id`：关联具体业务对象（采购/销售/付款/收款）
+  - `delta / balance_before / balance_after / direction`：记录本次增减与余额快照
+  - `offset_to / offset_id`：预留冲抵链路，与库存 `StockSnapshot` 设计一致
+  - `request_id / extra_meta`：用于幂等和记录审批上下文（操作者、触发渠道等）
+- **用途**：对账、审计、未来的余额红冲。目前未开放对外查询 API，可在内部管理端或报表服务中直接访问；若后续开放，请提供分页、时间范围与 `source_type` 过滤能力。
+
 ---

 ## 7. 错误码与常见响应
--- a/docs/payment_receipt_workflow.md
+++ b/docs/payment_receipt_workflow.md
@@ -5,7 +5,7 @@
 - `ReceiptOrder`：针对客户的资金收入单据，审批通过后代表“确认收款”。
 - 两者均位于 `business` 模块，API 路径分别为 `/api/v1/payment-orders/`、`/api/v1/receipt-orders/`。
 - 与采购/销售相比，不涉及产品与库存，仅维护资金方向、对方主体、金额与状态。
- 审批通过会同步更新供应商/客户余额表（`SupplierBalance` / `CustomerBalance`），提供 O(1) 的欠款查询。
+- 审批通过会同步更新供应商/客户余额表（`SupplierBalance` / `CustomerBalance`），并写入 `BalanceChangeRecord`，提供 O(1) 的欠款查询与可追溯的余额流水。

 ## 2. 创建流程
 | 字段 | 付款单 | 收款单 |
@@ -20,8 +20,8 @@
 ## 3. 审批 / 作废
 - 接口：`POST /api/v1/<payment|receipt>-orders/<id>/review/`
 - 请求体：`{"action": "approve"}` 或 `{"action": "cancel"}`
- 审批通过：状态变为 `APPROVED`，后续可用于应付/应收对账。
- 作废：状态变为 `CANCELLED`；若已是目标状态则返回原状态（幂等）。
+- 审批通过：状态变为 `APPROVED`，同步写入余额表与 `BalanceChangeRecord`（记录来源单据、方向、前后余额）；审批成功后禁止再作废。
+- 作废：仅允许 `PENDING` 状态作废，状态变为 `CANCELLED`。若已审批或已作废会抛出业务错误（幂等）。

 ## 4. 常见异常
 | 场景 | 响应 |