import { Injectable, NotFoundException } from '@nestjs/common';
import type { DeliveryProvider } from '@prisma/client';
import { Prisma } from '@prisma/client';
import { PrismaService } from '../../common/prisma/prisma.module';
import { serializeBigInt } from '../../common/decorators/current-user.decorator';
import type { AdminDeliveriesQueryDto, AdminRedeemRecordsQueryDto } from './dto/admin-query.dto';
import type { UpdateDeliveryDto } from './dto/admin-mutate.dto';

export type CouponRedeemTrace = {
  redeemSummary: {
    couponNo: string;
    totalAmount: number;
    usedAmount: number;
    balance: number;
    status: string;
    redeemCount: number;
    redeemRecordSum: number;
  };
  redeemRecords: Array<{
    id: bigint;
    redeemNo: string;
    amount: number;
    settleAmount: number;
    couponAmount: number;
    role: 'PRIMARY' | 'SECONDARY';
    createdAt: Date;
    store: { id: bigint; name: string; cityName: string | null } | null;
  }>;
};

@Injectable()
export class AdminRedeemService {
  constructor(private readonly prisma: PrismaService) {}

  async listRecords(query: AdminRedeemRecordsQueryDto) {
    const page = query.page ?? 1;
    const pageSize = query.pageSize ?? 20;
    const where: Prisma.RedeemRecordWhereInput = {};
    if (query.redeemNo) where.redeemNo = { contains: query.redeemNo };
    if (query.storeId) where.storeId = BigInt(query.storeId);
    if (query.userId) where.userId = BigInt(query.userId);

    const [items, total] = await Promise.all([
      this.prisma.redeemRecord.findMany({
        where,
        orderBy: { createdAt: 'desc' },
        skip: (page - 1) * pageSize,
        take: pageSize,
        include: {
          user: { select: { id: true, userNo: true, phone: true, nickname: true } },
          store: { select: { id: true, name: true, cityName: true } },
          coupon: { select: { id: true, couponNo: true, balance: true } },
        },
      }),
      this.prisma.redeemRecord.count({ where }),
    ]);
    return serializeBigInt({ items, total, page, pageSize });
  }

  async detailRecord(id: bigint) {
    const record = await this.prisma.redeemRecord.findUnique({
      where: { id },
      include: {
        user: { select: { id: true, userNo: true, phone: true, nickname: true } },
        store: {
          select: {
            id: true,
            name: true,
            cityName: true,
            address: true,
            partnerAccount: { select: { id: true, companyName: true } },
          },
        },
        coupon: {
          select: {
            id: true,
            couponNo: true,
            totalAmount: true,
            usedAmount: true,
            balance: true,
            status: true,
            orderId: true,
            order: { select: { id: true, orderNo: true } },
          },
        },
        allocations: {
          orderBy: { sortOrder: 'asc' },
          include: {
            coupon: {
              select: {
                id: true,
                couponNo: true,
                order: { select: { id: true, orderNo: true } },
              },
            },
          },
        },
        payout: true,
        rating: true,
      },
    });
    if (!record) throw new NotFoundException('核销记录不存在');
    return serializeBigInt({
      ...record,
      allocations: record.allocations.map((a) => ({
        couponId: a.couponId,
        amount: Number(a.amount),
        sortOrder: a.sortOrder,
        couponNo: a.coupon.couponNo,
        orderId: a.coupon.order?.id ?? null,
        orderNo: a.coupon.order?.orderNo ?? null,
      })),
    });
  }

  /** 按权益券聚合核销追溯（含跨券 FIFO 次券） */
  async buildCouponRedeemTrace(coupon: {
    id: bigint;
    couponNo: string;
    totalAmount: Prisma.Decimal | number;
    usedAmount: Prisma.Decimal | number;
    balance: Prisma.Decimal | number;
    status: string;
  }): Promise<CouponRedeemTrace> {
    await this.ensureRedeemAllocationsForCoupon(coupon.id);

    const redeemRows = await this.prisma.redeemRecord.findMany({
      where: {
        OR: [
          { couponId: coupon.id },
          { allocations: { some: { couponId: coupon.id } } },
        ],
      },
      orderBy: { createdAt: 'desc' },
      include: {
        store: { select: { id: true, name: true, cityName: true } },
        allocations: {
          where: { couponId: coupon.id },
          select: { amount: true, sortOrder: true },
        },
      },
    });

    const redeemRecords = redeemRows.map((r) => {
      const couponAmount =
        r.allocations[0] != null
          ? Number(r.allocations[0].amount)
          : r.couponId === coupon.id
            ? Number(r.amount)
            : 0;
      return {
        id: r.id,
        redeemNo: r.redeemNo,
        amount: Number(r.amount),
        settleAmount: Number(r.settleAmount),
        couponAmount,
        role: (r.couponId === coupon.id ? 'PRIMARY' : 'SECONDARY') as 'PRIMARY' | 'SECONDARY',
        createdAt: r.createdAt,
        store: r.store,
      };
    });
    const redeemRecordSum = redeemRecords.reduce((sum, r) => sum + r.couponAmount, 0);

    return {
      redeemSummary: {
        couponNo: coupon.couponNo,
        totalAmount: Number(coupon.totalAmount),
        usedAmount: Number(coupon.usedAmount),
        balance: Number(coupon.balance),
        status: coupon.status,
        redeemCount: redeemRecords.length,
        redeemRecordSum,
      },
      redeemRecords,
    };
  }

  private async ensureRedeemAllocationsForCoupon(couponId: bigint) {
    const coupon = await this.prisma.benefitCoupon.findUnique({
      where: { id: couponId },
      select: { id: true, userId: true },
    });
    if (!coupon) return;

    const pendings = await this.prisma.redeemPendingRecord.findMany({
      where: { userId: coupon.userId, redeemRecordId: { not: null } },
      select: { redeemRecordId: true, allocationsJson: true },
    });

    for (const pending of pendings) {
      if (!pending.redeemRecordId) continue;
      const allocs = this.parseAllocationsJson(pending.allocationsJson);
      if (!allocs.some((a) => a.couponId === couponId.toString())) continue;

      const existing = await this.prisma.redeemRecordAllocation.count({
        where: { redeemRecordId: pending.redeemRecordId },
      });
      if (existing > 0) continue;

      await this.prisma.redeemRecordAllocation.createMany({
        data: allocs.map((a, index) => ({
          redeemRecordId: pending.redeemRecordId!,
          couponId: BigInt(a.couponId),
          amount: a.amount,
          sortOrder: index,
        })),
        skipDuplicates: true,
      });
    }

    const ledgers = await this.prisma.commonEvent.findMany({
      where: {
        eventType: 'BENEFIT_LEDGER',
        param1: 'REDEEM',
        param2: couponId.toString(),
        actorType: 'USER',
        actorId: coupon.userId,
        refType: 'STORE',
      },
      select: { id: true, refId: true, amount1: true, createdAt: true },
      orderBy: { createdAt: 'asc' },
    });

    for (const ledger of ledgers) {
      if (ledger.refId == null || ledger.amount1 == null) continue;
      const allocAmount = Math.abs(Number(ledger.amount1));
      if (!(allocAmount > 0)) continue;

      const already = await this.prisma.redeemRecordAllocation.findFirst({
        where: {
          couponId,
          amount: allocAmount,
          redeemRecord: {
            userId: coupon.userId,
            storeId: ledger.refId,
            createdAt: {
              gte: new Date(ledger.createdAt.getTime() - 8000),
              lte: new Date(ledger.createdAt.getTime() + 8000),
            },
          },
        },
        select: { id: true },
      });
      if (already) continue;

      const candidates = await this.prisma.redeemRecord.findMany({
        where: {
          userId: coupon.userId,
          storeId: ledger.refId,
          createdAt: {
            gte: new Date(ledger.createdAt.getTime() - 8000),
            lte: new Date(ledger.createdAt.getTime() + 8000),
          },
          amount: { gte: allocAmount },
          allocations: { none: { couponId } },
        },
        orderBy: { createdAt: 'asc' },
        take: 5,
      });
      if (!candidates.length) continue;

      const target =
        candidates.find((r) => r.couponId !== couponId) ??
        (candidates.length === 1 ? candidates[0] : null);
      if (!target) continue;

      await this.prisma.redeemRecordAllocation
        .create({
          data: {
            redeemRecordId: target.id,
            couponId,
            amount: allocAmount,
            sortOrder: target.couponId === couponId ? 0 : 1,
          },
        })
        .catch(() => {
          /* unique 冲突忽略 */
        });
    }

    const primaryWithoutAlloc = await this.prisma.redeemRecord.findMany({
      where: {
        couponId,
        allocations: { none: {} },
      },
      select: { id: true, amount: true },
    });
    if (primaryWithoutAlloc.length) {
      await this.prisma.redeemRecordAllocation.createMany({
        data: primaryWithoutAlloc.map((r) => ({
          redeemRecordId: r.id,
          couponId,
          amount: r.amount,
          sortOrder: 0,
        })),
        skipDuplicates: true,
      });
    }
  }

  private parseAllocationsJson(
    value: Prisma.JsonValue,
  ): Array<{ couponId: string; amount: number }> {
    if (!Array.isArray(value)) return [];
    return value
      .map((item) => {
        if (!item || typeof item !== 'object') return null;
        const row = item as { couponId?: unknown; amount?: unknown };
        const id = row.couponId != null ? String(row.couponId) : '';
        const amount = Number(row.amount);
        if (!id || !Number.isFinite(amount) || amount <= 0) return null;
        return { couponId: id, amount };
      })
      .filter((item): item is { couponId: string; amount: number } => !!item);
  }
}

@Injectable()
export class AdminDeliveriesService {
  constructor(private readonly prisma: PrismaService) {}

  async list(query: AdminDeliveriesQueryDto) {
    const page = query.page ?? 1;
    const pageSize = query.pageSize ?? 20;
    const where: Prisma.OrderDeliveryWhereInput = {};
    if (query.provider) where.provider = query.provider as DeliveryProvider;
    if (query.trackingNo) where.trackingNo = { contains: query.trackingNo };
    if (query.orderNo) {
      where.order = { orderNo: { contains: query.orderNo } };
    }

    const [items, total] = await Promise.all([
      this.prisma.orderDelivery.findMany({
        where,
        orderBy: { updatedAt: 'desc' },
        skip: (page - 1) * pageSize,
        take: pageSize,
        include: {
          order: {
            select: {
              id: true,
              orderNo: true,
              status: true,
              receiverName: true,
              receiverPhone: true,
              deliveryType: true,
              productName: true,
              quantity: true,
            },
          },
        },
      }),
      this.prisma.orderDelivery.count({ where }),
    ]);
    return serializeBigInt({ items, total, page, pageSize });
  }

  async detail(id: bigint) {
    const delivery = await this.prisma.orderDelivery.findUnique({
      where: { id },
      include: {
        order: {
          include: {
            user: { select: { id: true, userNo: true, phone: true } },
            imageResource: { select: { url: true } },
          },
        },
      },
    });
    if (!delivery) throw new NotFoundException('配送单不存在');
    return serializeBigInt(delivery);
  }

  async update(id: bigint, dto: UpdateDeliveryDto) {
    const delivery = await this.prisma.orderDelivery.update({
      where: { id },
      data: {
        ...(dto.provider !== undefined ? { provider: dto.provider as DeliveryProvider } : {}),
        ...(dto.providerOrderNo !== undefined ? { providerOrderNo: dto.providerOrderNo } : {}),
        ...(dto.trackingNo !== undefined ? { trackingNo: dto.trackingNo } : {}),
      },
      include: { order: { select: { orderNo: true, status: true } } },
    });
    return serializeBigInt(delivery);
  }
}