feat: restore credit limits and harden SMS sending

api/src/billing/billing.controller.ts

@@ -1,4 +1,4 @@
-import { Body, Controller, Get, Post } from '@nestjs/common';
+import { Body, Controller, Get, Param, Post } from '@nestjs/common';
 import { ApiTags } from '@nestjs/swagger';
 import { TenantId } from '../common/tenant-id.decorator';
 import { RequireRecentAuthentication } from '../auth/require-recent-authentication.decorator';
@@ -10,6 +10,7 @@ import {
   CreateSmsBillingRecordDto,
   CreateTenantAccountDto,
   EstimateSmsCostDto,
+  UpdateCreditLimitDto,
 } from './billing.service';
 
 @ApiTags('billing')
@@ -27,6 +28,12 @@ export class BillingController {
     return this.billing.createAccount(body);
   }
 
+  @Post('accounts/:tenantId/credit-limit')
+  @RequireRecentAuthentication()
+  updateCreditLimit(@Param('tenantId') tenantId: string, @Body() body: UpdateCreditLimitDto) {
+    return this.billing.updateCreditLimit(tenantId, body);
+  }
+
   @Get('recharges')
   listRechargeOrders(@TenantId() tenantId?: string) {
     return this.billing.listRechargeOrders(tenantId);

api/src/billing/billing.service.spec.ts

@@ -1,7 +1,7 @@
 import { BillingService } from './billing.service';
 
 function createPrismaMock() {
-  const accountState = { tenantId: 'tenant-1', balanceCents: 1000 };
+  const accountState = { id: 'account-1', tenantId: 'tenant-1', balanceCents: 1000, creditCents: 0 };
   return {
     accountState,
     tenantAccount: {
@@ -9,7 +9,8 @@ function createPrismaMock() {
       create: jest.fn(),
       upsert: jest.fn().mockImplementation(() => Promise.resolve({ ...accountState })),
       update: jest.fn().mockImplementation(({ data }) => {
-        accountState.balanceCents = data.balanceCents;
+        if (data.balanceCents !== undefined) accountState.balanceCents = data.balanceCents;
+        if (data.creditCents !== undefined) accountState.creditCents = data.creditCents;
         return Promise.resolve({ ...accountState });
       }),
     },
@@ -62,7 +63,7 @@ describe('BillingService', () => {
     );
   });
 
-  it('checks only the cash balance before sending', async () => {
+  it('allows sending only when cash balance plus credit is greater than zero', async () => {
     const prisma = createPrismaMock();
     const service = new BillingService(prisma as never);
 
@@ -70,8 +71,23 @@ describe('BillingService', () => {
       expect.objectContaining({ availableAmount: 1000, canSend: true }),
     );
     await expect(service.checkAccount({ tenantId: 'tenant-1', amountCents: 1001 })).resolves.toEqual(
-      expect.objectContaining({ canSend: false }),
+      expect.objectContaining({ availableAmount: 1000, canSend: true }),
     );
+    await service.updateCreditLimit('tenant-1', { creditCents: -1000, operatorId: 'admin-1' });
+    await expect(service.checkAccount({ tenantId: 'tenant-1', amountCents: 1 })).resolves.toEqual(
+      expect.objectContaining({ availableAmount: 0, balanceCents: 1000, creditCents: -1000, canSend: false }),
+    );
+    await service.updateCreditLimit('tenant-1', { creditCents: 500, operatorId: 'admin-1' });
+    await expect(service.checkAccount({ tenantId: 'tenant-1', amountCents: 999999 })).resolves.toEqual(
+      expect.objectContaining({ availableAmount: 1500, creditCents: 500, canSend: true }),
+    );
+    await expect(service.updateCreditLimit('tenant-1', { creditCents: 1.5 })).rejects.toThrow('授信额度必须为整数金额');
+    expect(prisma.operationLog.create).toHaveBeenCalledWith({
+      data: expect.objectContaining({
+        action: 'billing.credit_limit_updated',
+        detail: expect.objectContaining({ previousCreditCents: 0, creditCents: -1000 }),
+      }),
+    });
   });
 
   it('creates cash recharge orders and account transactions without plans', async () => {

api/src/billing/billing.service.ts

@@ -1,13 +1,20 @@
-import { Injectable } from '@nestjs/common';
+import { BadRequestException, Injectable } from '@nestjs/common';
 import { Prisma } from '@prisma/client';
 import { PrismaService } from '../prisma/prisma.service';
 
 export interface CreateTenantAccountDto {
   tenantId: string;
   balanceCents?: number;
+  creditCents?: number;
   status?: string;
 }
 
+export interface UpdateCreditLimitDto {
+  creditCents: number;
+  operatorId?: string;
+  remark?: string;
+}
+
 export interface CreateAccountTransactionDto {
   tenantId: string;
   transactionType: string;
@@ -80,14 +87,40 @@ export class BillingService {
   }
 
   createAccount(data: CreateTenantAccountDto) {
+    assertCreditAmount(data.creditCents ?? 0);
     const createData: Prisma.TenantAccountUncheckedCreateInput = {
       tenantId: data.tenantId,
       balanceCents: data.balanceCents ?? 0,
+      creditCents: data.creditCents ?? 0,
       status: data.status ?? 'active',
     };
     return this.prisma.tenantAccount.create({ data: createData });
   }
 
+  async updateCreditLimit(tenantId: string, data: UpdateCreditLimitDto) {
+    assertCreditAmount(data.creditCents);
+    const account = await this.getAccountOrCreate(tenantId);
+    const updated = await this.prisma.tenantAccount.update({
+      where: { tenantId },
+      data: { creditCents: data.creditCents },
+    });
+    await this.prisma.operationLog.create({
+      data: {
+        tenantId,
+        userId: data.operatorId,
+        action: 'billing.credit_limit_updated',
+        resource: 'tenant_account',
+        resourceId: account.id,
+        detail: {
+          previousCreditCents: account.creditCents,
+          creditCents: data.creditCents,
+          remark: data.remark,
+        } as Prisma.InputJsonValue,
+      },
+    });
+    return updated;
+  }
+
   listRechargeOrders(tenantId?: string) {
     return this.prisma.rechargeOrder.findMany({
       where: tenantId ? { tenantId } : undefined,
@@ -195,12 +228,14 @@ export class BillingService {
   async checkAccount(data: BillingActionDto) {
     const account = await this.getAccountOrCreate(data.tenantId);
     const requiredAmount = data.amountCents ?? 0;
-    const availableAmount = account.balanceCents;
+    const availableAmount = account.balanceCents + account.creditCents;
     return {
       tenantId: data.tenantId,
       requiredAmount,
       availableAmount,
-      canSend: availableAmount >= requiredAmount,
+      balanceCents: account.balanceCents,
+      creditCents: account.creditCents,
+      canSend: availableAmount > 0,
     };
   }
 
@@ -296,7 +331,7 @@ export class BillingService {
     return this.prisma.tenantAccount.upsert({
       where: { tenantId },
       update: {},
-      create: { tenantId, balanceCents: 0, status: 'active' },
+      create: { tenantId, balanceCents: 0, creditCents: 0, status: 'active' },
     });
   }
 
@@ -324,6 +359,12 @@ export class BillingService {
   }
 }
 
+function assertCreditAmount(creditCents: number) {
+  if (!Number.isInteger(creditCents)) {
+    throw new BadRequestException('授信额度必须为整数金额（分）');
+  }
+}
+
 function estimateBillingUnits(content: string) {
   const length = [...content].length;
   if (length <= 70) {