import { Test, TestingModule } from '@nestjs/testing';
import { OrdersService } from './orders.service';
import { PrismaService } from '../prisma/prisma.service';
import { SmsService } from '../common/services/sms.service';
import { NotFoundException, BadRequestException } from '@nestjs/common';
import { Prisma } from '@prisma/client';

describe('OrdersService', () => {
  let service: OrdersService;
  let prisma: PrismaService;

  const mockPrisma = {
    product: {
      findUnique: jest.fn(),
      findMany: jest.fn(),
    },
    order: {
      create: jest.fn(),
      findMany: jest.fn(),
      findFirst: jest.fn(),
      count: jest.fn(),
    },
    user: {
      findUnique: jest.fn(),
      update: jest.fn(),
    },
    walletTransaction: {
      create: jest.fn(),
    },
  };

  const mockSmsService = {
    sendOrderConfirmation: jest.fn().mockResolvedValue(true),
  };

  beforeEach(async () => {
    const module: TestingModule = await Test.createTestingModule({
      providers: [
        OrdersService,
        { provide: PrismaService, useValue: mockPrisma },
        { provide: SmsService, useValue: mockSmsService },
      ],
    }).compile();

    service = module.get<OrdersService>(OrdersService);
    prisma = module.get<PrismaService>(PrismaService);
  });

  afterEach(() => {
    jest.clearAllMocks();
  });

  it('should be defined', () => {
    expect(service).toBeDefined();
  });

  describe('create', () => {
    it('should throw BadRequestException if items are empty', async () => {
      const dto = { items: [] };
      await expect(service.create('user-id', dto)).rejects.toThrow(
        BadRequestException,
      );
    });

    it('should throw BadRequestException for duplicate product IDs in order items', async () => {
      const dto = {
        items: [
          { productId: 'prod-1', quantity: 1 },
          { productId: 'prod-1', quantity: 2 },
        ],
      };
      await expect(service.create('user-id', dto)).rejects.toThrow(
        BadRequestException,
      );
    });

    it('should throw BadRequestException for non-positive or non-integer quantities', async () => {
      const dtoZero = { items: [{ productId: 'prod-1', quantity: 0 }] };
      await expect(service.create('user-id', dtoZero)).rejects.toThrow(
        BadRequestException,
      );

      const dtoFloat = { items: [{ productId: 'prod-1', quantity: 1.5 }] };
      await expect(service.create('user-id', dtoFloat)).rejects.toThrow(
        BadRequestException,
      );
    });

    it('should throw NotFoundException if any product is not found in batched query', async () => {
      mockPrisma.product.findMany.mockResolvedValue([
        { id: 'prod-1', priceValue: new Prisma.Decimal('1000') },
      ]);
      const dto = {
        items: [
          { productId: 'prod-1', quantity: 1 },
          { productId: 'prod-missing', quantity: 2 },
        ],
      };
      await expect(service.create('user-id', dto)).rejects.toThrow(
        NotFoundException,
      );
    });

    it('should successfully create order using batched findMany and precise Decimal calculations', async () => {
      const products = [
        { id: 'prod-1', priceValue: new Prisma.Decimal('32.49') },
        { id: 'prod-2', priceValue: new Prisma.Decimal('15.50') },
      ];
      mockPrisma.product.findMany.mockResolvedValue(products);
      mockPrisma.order.create.mockResolvedValue({
        id: 'order-1',
        totalAmount: new Prisma.Decimal('80.48'),
      });

      const dto = {
        items: [
          { productId: 'prod-1', quantity: 2 }, // 32.49 * 2 = 64.98
          { productId: 'prod-2', quantity: 1 }, // 15.50 * 1 = 15.50  Total = 80.48
        ],
      };
      const result = await service.create('user-id', dto);

      expect(prisma.product.findMany).toHaveBeenCalledWith({
        where: { id: { in: ['prod-1', 'prod-2'] } },
      });
      expect(prisma.order.create).toHaveBeenCalled();
      expect(result.id).toBe('order-1');
    });
  });

  describe('findAllByUser', () => {
    it('should find all orders of a user', async () => {
      mockPrisma.order.findMany.mockResolvedValue([{ id: 'order-1' }]);
      mockPrisma.order.count.mockResolvedValue(1);
      const result = await service.findAllByUser('user-id', {});
      expect(prisma.order.findMany).toHaveBeenCalled();
      expect(result.data).toHaveLength(1);
    });
  });

  describe('findOne', () => {
    it('should throw NotFoundException if order does not exist', async () => {
      mockPrisma.order.findFirst.mockResolvedValue(null);
      await expect(service.findOne('order-id', 'user-id')).rejects.toThrow(
        NotFoundException,
      );
    });

    it('should return order if found', async () => {
      const order = { id: 'order-1', userId: 'user-id' };
      mockPrisma.order.findFirst.mockResolvedValue(order);
      const result = await service.findOne('order-1', 'user-id');
      expect(result).toEqual(order);
    });
  });
});