重构 API 为 8 领域 + 应用层架构

将后端模块拆分为 domains、applications、shared 三层，结算计算器移入 domain 纯函数目录，API 路径与测试保持不变。

Co-authored-by: Cursor <cursoragent@cursor.com>

apps/api/src/domains/operations/cashback/cashback.service.ts

@@ -0,0 +1,108 @@
+import { Injectable, BadRequestException } from '@nestjs/common';
+import { PrismaService } from '../../../shared/prisma/prisma.service';
+import { WalletService } from '../../ledger/wallet.service';
+import { Decimal } from '@prisma/client/runtime/library';
+import { generateBatchNo } from '../../../shared/common/decorators';
+
+@Injectable()
+export class CashbackService {
+  constructor(
+    private prisma: PrismaService,
+    private wallet: WalletService,
+  ) {}
+
+  async previewBatch(periodStart: Date, periodEnd: Date) {
+    const settledBets = await this.prisma.bet.findMany({
+      where: {
+        status: { in: ['WON', 'LOST', 'SETTLED'] },
+        settledAt: { gte: periodStart, lte: periodEnd },
+      },
+      include: { user: { include: { agentProfile: true } } },
+    });
+
+    const playerStakes = new Map<string, { userId: bigint; stake: Decimal; rate: Decimal }>();
+
+    for (const bet of settledBets) {
+      if (bet.status === 'PUSH' || bet.status === 'VOID') continue;
+
+      const key = bet.userId.toString();
+      const existing = playerStakes.get(key) ?? {
+        userId: bet.userId,
+        stake: new Decimal(0),
+        rate: new Decimal(0.01),
+      };
+      existing.stake = existing.stake.add(bet.stake);
+      playerStakes.set(key, existing);
+    }
+
+    const items = Array.from(playerStakes.values()).map((p) => ({
+      userId: p.userId,
+      effectiveStake: p.stake,
+      rate: p.rate,
+      amount: p.stake.mul(p.rate),
+    }));
+
+    const totalAmount = items.reduce((s, i) => s.add(i.amount), new Decimal(0));
+
+    const batch = await this.prisma.cashbackBatch.create({
+      data: {
+        batchNo: generateBatchNo('CB'),
+        periodStart,
+        periodEnd,
+        status: 'PREVIEW',
+        totalAmount,
+        playerCount: items.length,
+      },
+    });
+
+    for (const item of items) {
+      await this.prisma.cashbackItem.create({
+        data: {
+          batchId: batch.id,
+          userId: item.userId,
+          effectiveStake: item.effectiveStake,
+          rate: item.rate,
+          amount: item.amount,
+        },
+      });
+    }
+
+    return { batch, items, totalAmount };
+  }
+
+  async confirmBatch(batchId: bigint, operatorId: bigint) {
+    const batch = await this.prisma.cashbackBatch.findUnique({
+      where: { id: batchId },
+      include: { items: true },
+    });
+    if (!batch) throw new BadRequestException('Batch not found');
+    if (batch.status !== 'PREVIEW') throw new BadRequestException('Already confirmed');
+
+    for (const item of batch.items) {
+      if (item.amount.gt(0)) {
+        await this.wallet.deposit(
+          item.userId,
+          item.amount,
+          operatorId,
+          `Cashback batch ${batch.batchNo}`,
+          batch.batchNo,
+        );
+      }
+    }
+
+    await this.prisma.cashbackBatch.update({
+      where: { id: batchId },
+      data: { status: 'CONFIRMED', confirmedAt: new Date(), operatorId },
+    });
+
+    return { success: true };
+  }
+
+  async getUserCashbacks(userId: bigint) {
+    return this.prisma.cashbackItem.findMany({
+      where: { userId },
+      include: { batch: true },
+      orderBy: { createdAt: 'desc' },
+    });
+  }
+}