backend/src/admin/admin.service.ts

import { Injectable } from '@nestjs/common';
import { InjectRepository } from '@nestjs/typeorm';
import { Repository } from 'typeorm';
import { Course } from '../entities/course.entity';
import { Order, OrderStatus, OrderType } from '../entities/order.entity';
import { CreateCourseDto } from './dto/create-course.dto';

@Injectable()
export class AdminService {
  constructor(
    @InjectRepository(Course)
    private courseRepository: Repository<Course>,
    @InjectRepository(Order)
    private orderRepository: Repository<Order>,
  ) {}

  async createCourse(createCourseDto: CreateCourseDto) {
    const course = this.courseRepository.create(createCourseDto);
    return this.courseRepository.save(course);
  }

  async updateCourse(id: number, updateData: Partial<CreateCourseDto>) {
    await this.courseRepository.update(id, updateData);
    return this.courseRepository.findOne({ where: { id } });
  }

  async deleteCourse(id: number) {
    await this.courseRepository.delete(id);
  }

  async getOrders() {
    return this.orderRepository.find({
      relations: ['user', 'course'],
      order: { createdAt: 'DESC' },
    });
  }

  async getStatistics(startDate?: string, endDate?: string) {
    const query = this.orderRepository.createQueryBuilder('order')
      .select('order.orderType', 'orderType')
      .addSelect('SUM(order.amount)', 'total')
      .where('order.status = :status', { status: OrderStatus.PAID });

    if (startDate) {
      query.andWhere('order.createdAt >= :startDate', { startDate: new Date(startDate) });
    }
    
    if (endDate) {
      const end = new Date(endDate);
      end.setHours(23, 59, 59, 999);
      query.andWhere('order.createdAt <= :endDate', { endDate: end });
    }

    const results = await query.groupBy('order.orderType').getRawMany();

    const stats = {
      vipAmount: 0,
      donationAmount: 0,
      purchaseAmount: 0,
    };

    results.forEach(row => {
      const total = Number(row.total) || 0;
      if (row.orderType === OrderType.VIP) {
        stats.vipAmount += total;
      } else if (row.orderType === OrderType.DONATION) {
        stats.donationAmount += total;
      } else if (row.orderType === OrderType.PURCHASE) {
        stats.purchaseAmount += total;
      }
    });

    return stats;
  }

  async getStatisticsDetails(type: string, startDate?: string, endDate?: string) {
    const query = this.orderRepository.createQueryBuilder('order')
      .leftJoinAndSelect('order.user', 'user')
      .leftJoinAndSelect('order.course', 'course')
      .where('order.status = :status', { status: OrderStatus.PAID });

    if (type && type !== 'all') {
      query.andWhere('order.orderType = :type', { type });
    }

    if (startDate) {
      query.andWhere('order.createdAt >= :startDate', { startDate: new Date(startDate) });
    }
    
    if (endDate) {
      const end = new Date(endDate);
      end.setHours(23, 59, 59, 999);
      query.andWhere('order.createdAt <= :endDate', { endDate: end });
    }

    return query.orderBy('order.createdAt', 'DESC').getMany();
  }
}