package com.org.flashsalesystem.service;

import com.org.flashsalesystem.dto.ProductDTO;
import com.org.flashsalesystem.entity.Order;
import com.org.flashsalesystem.entity.OrderItem;
import com.org.flashsalesystem.repository.OrderItemRepository;
import com.org.flashsalesystem.repository.OrderRepository;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import java.util.HashMap;
import java.util.List;
import java.util.Map;

@Service
@Slf4j
public class OrderMigrationService {

    @Autowired
    private OrderRepository orderRepository;

    @Autowired
    private OrderItemRepository orderItemRepository;

    @Autowired
    private ProductService productService;

    @Transactional
    public Map<String, Object> migrateLegacyOrderItems() {
        List<Order> orders = orderRepository.findAll();
        int migrated = 0;
        int skipped = 0;

        for (Order order : orders) {
            if (orderItemRepository.existsByOrderId(order.getId())) {
                skipped++;
                continue;
            }

            ProductDTO product = productService.getProductById(order.getProductId());
            OrderItem orderItem = new OrderItem();
            orderItem.setOrderId(order.getId());
            orderItem.setProductId(order.getProductId());
            orderItem.setProductName(product != null ? product.getName() : "未知商品");
            orderItem.setProductImageUrl(product != null ? product.getImageUrl() : null);
            orderItem.setPrice(order.getQuantity() != null && order.getQuantity() > 0
                    ? order.getTotalPrice().divide(java.math.BigDecimal.valueOf(order.getQuantity()), 2, java.math.RoundingMode.HALF_UP)
                    : order.getTotalPrice());
            orderItem.setQuantity(order.getQuantity());
            orderItem.setSubtotal(order.getTotalPrice());
            orderItemRepository.save(orderItem);
            migrated++;
        }

        Map<String, Object> result = new HashMap<>();
        result.put("totalOrders", orders.size());
        result.put("migrated", migrated);
        result.put("skipped", skipped);
        return result;
    }
}