initial: standalone repo from monorepo split

src/billing/billing.service.ts

@@ -0,0 +1,25 @@
+import { Injectable } from '@nestjs/common';
+import { PrismaService } from '../prisma/prisma.service';
+import { UpdateBillingSettingsDto } from './dto/update-billing-settings.dto';
+
+@Injectable()
+export class BillingService {
+  constructor(private readonly prisma: PrismaService) {}
+
+  async getSettings(tenantId: string) {
+    let settings = await this.prisma.billingSetting.findUnique({ where: { tenantId } });
+    if (!settings) {
+      settings = await this.prisma.billingSetting.create({ data: { tenantId } });
+    }
+    return settings;
+  }
+
+  async updateSettings(tenantId: string, dto: UpdateBillingSettingsDto) {
+    await this.prisma.billingSetting.upsert({
+      where: { tenantId },
+      create: { tenantId, ...dto },
+      update: dto,
+    });
+    return this.getSettings(tenantId);
+  }
+}