package service

import (
	"context"
	"errors"
	"fmt"
	"math/rand"
	"time"

	"go.mongodb.org/mongo-driver/v2/bson"
	"order/consts"
	"order/dao"
	"order/model/dto"
	"order/model/entity"
)

type order struct{}

// Order 订单服务
var Order = new(order)

// Init 初始化服务
func Init() error {
	return nil
}

// convertOrderItemsFromDTO 从DTO转换订单商品项
func convertOrderItemsFromDTO(items []dto.OrderItemReq) []entity.OrderItem {
	var result []entity.OrderItem
	for _, item := range items {
		// 转换库存明细，每个库存项只会有一个实例
		var stocks []entity.OrderItemStock
		totalQuantity := len(item.Stocks) // 每个库存项数量为1
		totalAmount := int64(0)

		for _, stock := range item.Stocks {
			stocks = append(stocks, entity.OrderItemStock{
				StockID:    stock.StockID,
				Price:      stock.Price,
				StockAttrs: stock.StockAttrs,
			})
			totalAmount += stock.Price // 每个库存项数量为1
		}

		result = append(result, entity.OrderItem{
			AssetID:    item.AssetID,
			AssetName:  item.AssetName,
			AssetType:  item.AssetType,
			ImageURL:   item.ImageURL,
			Quantity:   totalQuantity,
			TotalPrice: totalAmount,
			Stocks:     stocks,
		})
	}
	return result
}

// convertOrderItems 转换订单商品项
func convertOrderItems(items []entity.OrderItem) []dto.OrderItem {
	var result []dto.OrderItem
	for _, item := range items {
		// 转换库存明细
		var stocks []dto.OrderItemStock
		for _, stock := range item.Stocks {
			stocks = append(stocks, dto.OrderItemStock{
				StockID:    stock.StockID,
				Price:      stock.Price,
				StockAttrs: stock.StockAttrs,
			})
		}

		result = append(result, dto.OrderItem{
			AssetID:    item.AssetID,
			AssetName:  item.AssetName,
			AssetType:  item.AssetType,
			ImageURL:   item.ImageURL,
			Quantity:   item.Quantity,
			TotalPrice: item.TotalPrice,
			Stocks:     stocks,
		})
	}
	return result
}

// convertEntityOrderItemsToDTO 转换entity订单商品项到DTO
func convertEntityOrderItemsToDTO(items []entity.OrderItem) []dto.OrderItem {
	var result []dto.OrderItem
	for _, item := range items {
		// 转换库存明细
		var stocks []dto.OrderItemStock
		for _, stock := range item.Stocks {
			stocks = append(stocks, dto.OrderItemStock{
				StockID:    stock.StockID,
				Price:      stock.Price,
				StockAttrs: stock.StockAttrs,
			})
		}

		result = append(result, dto.OrderItem{
			AssetID:    item.AssetID,
			AssetName:  item.AssetName,
			AssetType:  item.AssetType,
			ImageURL:   item.ImageURL,
			Quantity:   item.Quantity,
			TotalPrice: item.TotalPrice,
			Stocks:     stocks,
		})
	}
	return result
}

// CreateOrder 创建订单
func (s *order) CreateOrder(ctx context.Context, req *dto.CreateOrderReq) (*dto.CreateOrderResp, error) {
	// 1. 参数验证
	if req.TenantID == "" || req.UserID == "" || req.Subject == "" {
		return nil, errors.New("必填参数不能为空")
	}

	if len(req.OrderItems) == 0 {
		return nil, errors.New("订单商品不能为空")
	}

	// 2. 计算订单金额
	totalAmount := int64(0)
	for i := range req.OrderItems {
		item := &req.OrderItems[i]
		itemTotal := int64(0)
		for j := range item.Stocks {
			stock := &item.Stocks[j]
			if stock.Price <= 0 {
				return nil, fmt.Errorf("资产价格无效: %s", item.AssetName)
			}
			itemTotal += stock.Price // 每个库存项数量为1
		}
		totalAmount += itemTotal
	}

	if totalAmount <= 0 {
		return nil, errors.New("订单总金额必须大于0")
	}

	// 3. 生成订单号
	orderNo := s.generateOrderNo(req.TenantID)

	// 4. 设置订单过期时间（30分钟后）
	expiredAt := time.Now().Add(30 * time.Minute)

	// 5. 创建待支付订单
	order := &entity.OrderPending{
		OrderBase: entity.OrderBase{
			TenantID:    req.TenantID,
			OrderNo:     orderNo,
			UserID:      req.UserID,
			TotalAmount: totalAmount,
			PayAmount:   totalAmount, // 暂时没有优惠，实付金额等于总金额
			OrderType:   req.OrderType,
			Subject:     req.Subject,
			Description: req.Description,
			ExpiredAt:   &expiredAt,
		},
		OrderItems:   convertOrderItemsFromDTO(req.OrderItems),
		ShippingInfo: (*entity.ShippingInfo)(&req.ShippingInfo),
		PayInfo:      entity.PayInfo{},
	}

	// 6. 保存订单
	if err := dao.Order.CreatePendingOrder(ctx, order); err != nil {
		return nil, fmt.Errorf("创建订单失败: %w", err)
	}

	// 7. 返回结果
	resp := &dto.CreateOrderResp{
		OrderNo:     orderNo,
		TotalAmount: totalAmount,
		PayAmount:   totalAmount,
		ExpiredAt:   expiredAt.Format(time.RFC3339),
	}

	return resp, nil
}

// generateOrderNo 生成订单号
func (s *order) generateOrderNo(tenantID string) string {
	timestamp := time.Now().Format("20060102150405")
	random := rand.Intn(10000)
	return fmt.Sprintf("%s%s%04d", tenantID, timestamp, random)
}

// QueryOrder 查询订单详情
func (s *order) QueryOrder(ctx context.Context, req *dto.QueryOrderReq) (*dto.QueryOrderResp, error) {
	// 1. 参数验证
	if req.TenantID == "" || req.OrderNo == "" {
		return nil, errors.New("必填参数不能为空")
	}

	// 2. 查询订单
	order, status, err := dao.Order.GetOrderByNo(ctx, req.TenantID, req.OrderNo)
	if err != nil {
		return nil, fmt.Errorf("获取订单失败: %w", err)
	}

	if order == nil {
		return nil, errors.New("订单不存在")
	}

	// 3. 构建响应
	var resp dto.QueryOrderResp

	switch status {
	case consts.OrderStatusPending:
		if pendingOrder, ok := order.(*entity.OrderPending); ok {
			resp.Order = s.convertPendingOrderToDetail(pendingOrder)
		}
	case consts.OrderStatusPaid:
		if paidOrder, ok := order.(*entity.OrderPaid); ok {
			resp.Order = s.convertPaidOrderToDetail(paidOrder)
		}
	case consts.OrderStatusShipped:
		if shippedOrder, ok := order.(*entity.OrderShipped); ok {
			resp.Order = s.convertShippedOrderToDetail(shippedOrder)
		}
	case consts.OrderStatusCompleted:
		if completedOrder, ok := order.(*entity.OrderCompleted); ok {
			resp.Order = s.convertCompletedOrderToDetail(completedOrder)
		}
	default:
		return nil, fmt.Errorf("不支持的订单状态: %s", status)
	}

	return &resp, nil
}

// convertPendingOrderToDetail 转换待支付订单为详情
func (s *order) convertPendingOrderToDetail(order *entity.OrderPending) dto.OrderDetail {
	return dto.OrderDetail{
		ID:          order.ID.Hex(),
		TenantID:    order.TenantID,
		OrderNo:     order.OrderNo,
		UserID:      order.UserID,
		TotalAmount: order.TotalAmount,
		PayAmount:   order.PayAmount,
		Status:      string(consts.OrderStatusPending),
		PayMethod:   order.PayMethod,
		PayStatus:   "unpaid",
		OrderType:   order.OrderType,
		Subject:     order.Subject,
		Description: order.Description,
		OrderItems:  convertOrderItems(order.OrderItems),
		ShippingInfo: dto.ShippingInfo{
			Consignee:  order.ShippingInfo.Consignee,
			Phone:      order.ShippingInfo.Phone,
			Province:   order.ShippingInfo.Province,
			City:       order.ShippingInfo.City,
			District:   order.ShippingInfo.District,
			Address:    order.ShippingInfo.Address,
			PostalCode: order.ShippingInfo.PostalCode,
		},
		PayInfo: dto.PayInfo{
			OutTradeNo: order.PayInfo.OutTradeNo,
			PrepayID:   order.PayInfo.PrepayID,
			QRCode:     order.PayInfo.QRCode,
			PayURL:     order.PayInfo.PayURL,
		},
		CreatedAt: order.CreatedAt,
		UpdatedAt: order.UpdatedAt,
		ExpiredAt: order.ExpiredAt,
	}
}

// convertPaidOrderToDetail 转换已支付订单为详情
func (s *order) convertPaidOrderToDetail(order *entity.OrderPaid) dto.OrderDetail {
	return dto.OrderDetail{
		ID:          order.ID.Hex(),
		TenantID:    order.TenantID,
		OrderNo:     order.OrderNo,
		UserID:      order.UserID,
		TotalAmount: order.TotalAmount,
		PayAmount:   order.PayAmount,
		Status:      string(consts.OrderStatusPaid),
		PayMethod:   order.PayMethod,
		PayStatus:   "paid",
		OrderType:   order.OrderType,
		Subject:     order.Subject,
		Description: order.Description,
		OrderItems:  convertOrderItems(order.OrderItems),
		ShippingInfo: dto.ShippingInfo{
			Consignee:  order.ShippingInfo.Consignee,
			Phone:      order.ShippingInfo.Phone,
			Province:   order.ShippingInfo.Province,
			City:       order.ShippingInfo.City,
			District:   order.ShippingInfo.District,
			Address:    order.ShippingInfo.Address,
			PostalCode: order.ShippingInfo.PostalCode,
		},
		PayInfo: dto.PayInfo{
			TransactionID: order.TransactionID,
			OutTradeNo:    order.OrderNo,
		},
		CreatedAt: order.CreatedAt,
		UpdatedAt: order.UpdatedAt,
		PaidAt:    &order.PaidAt,
	}
}

// convertShippedOrderToDetail 转换已发货订单为详情
func (s *order) convertShippedOrderToDetail(order *entity.OrderShipped) dto.OrderDetail {
	return dto.OrderDetail{
		ID:          order.ID.Hex(),
		TenantID:    order.TenantID,
		OrderNo:     order.OrderNo,
		UserID:      order.UserID,
		TotalAmount: order.TotalAmount,
		PayAmount:   order.PayAmount,
		Status:      string(consts.OrderStatusShipped),
		PayMethod:   order.PayMethod,
		PayStatus:   "paid",
		OrderType:   order.OrderType,
		Subject:     order.Subject,
		Description: order.Description,
		OrderItems:  convertOrderItems(order.OrderItems),
		ShippingInfo: dto.ShippingInfo{
			Consignee:  order.ShippingInfo.Consignee,
			Phone:      order.ShippingInfo.Phone,
			Province:   order.ShippingInfo.Province,
			City:       order.ShippingInfo.City,
			District:   order.ShippingInfo.District,
			Address:    order.ShippingInfo.Address,
			PostalCode: order.ShippingInfo.PostalCode,
		},
		CreatedAt: order.CreatedAt,
		UpdatedAt: order.UpdatedAt,
		PaidAt:    &order.PaidAt,
	}
}

// convertCompletedOrderToDetail 转换已完成订单为详情
func (s *order) convertCompletedOrderToDetail(order *entity.OrderCompleted) dto.OrderDetail {
	return dto.OrderDetail{
		ID:          order.ID.Hex(),
		TenantID:    order.TenantID,
		OrderNo:     order.OrderNo,
		UserID:      order.UserID,
		TotalAmount: order.TotalAmount,
		PayAmount:   order.PayAmount,
		Status:      string(consts.OrderStatusCompleted),
		PayMethod:   order.PayMethod,
		PayStatus:   "paid",
		OrderType:   order.OrderType,
		Subject:     order.Subject,
		Description: order.Description,
		OrderItems:  convertOrderItems(order.OrderItems),
		ShippingInfo: dto.ShippingInfo{
			Consignee:  order.ShippingInfo.Consignee,
			Phone:      order.ShippingInfo.Phone,
			Province:   order.ShippingInfo.Province,
			City:       order.ShippingInfo.City,
			District:   order.ShippingInfo.District,
			Address:    order.ShippingInfo.Address,
			PostalCode: order.ShippingInfo.PostalCode,
		},
		CreatedAt: order.CreatedAt,
		UpdatedAt: order.UpdatedAt,
		PaidAt:    &order.PaidAt,
	}
}

// convertOrderItems 转换订单商品项
func (s *order) convertOrderItems(items []*entity.OrderItem) []dto.OrderItem {
	var result []dto.OrderItem
	for _, item := range items {
		// 转换库存明细
		var stocks []dto.OrderItemStock
		for _, stock := range item.Stocks {
			stocks = append(stocks, dto.OrderItemStock{
				StockID:    stock.StockID,
				Price:      stock.Price,
				StockAttrs: stock.StockAttrs,
			})
		}

		result = append(result, dto.OrderItem{
			AssetID:    item.AssetID,
			AssetName:  item.AssetName,
			AssetType:  item.AssetType,
			ImageURL:   item.ImageURL,
			Quantity:   item.Quantity,
			TotalPrice: item.TotalPrice,
			Stocks:     stocks,
		})
	}
	return result
}

// CancelOrder 取消订单
func (s *order) CancelOrder(ctx context.Context, req *dto.CancelOrderReq) (*dto.CancelOrderResp, error) {
	// 1. 参数验证
	if req.TenantID == "" || req.OrderNo == "" {
		return nil, errors.New("必填参数不能为空")
	}

	// 2. 查询订单
	order, status, err := dao.Order.GetOrderByNo(ctx, req.TenantID, req.OrderNo)
	if err != nil {
		return nil, fmt.Errorf("获取订单失败: %w", err)
	}

	if order == nil {
		return nil, errors.New("订单不存在")
	}

	// 3. 检查订单状态（只有待支付订单可以取消）
	if status != consts.OrderStatusPending {
		return nil, fmt.Errorf("订单状态不正确，当前状态: %s", status)
	}

	// 4. 将订单移动到已取消状态
	updateData := bson.M{
		"cancel_reason": req.Reason,
	}

	if err := dao.Order.MoveOrderToStatus(ctx, consts.OrderStatusPending, consts.OrderStatusCancelled, req.TenantID, req.OrderNo, updateData); err != nil {
		return nil, fmt.Errorf("取消订单失败: %w", err)
	}

	// 5. 返回结果
	resp := &dto.CancelOrderResp{
		OrderNo: req.OrderNo,
		Status:  string(consts.OrderStatusCancelled),
	}

	return resp, nil
}

// ListOrders 查询订单列表
func (s *order) ListOrders(ctx context.Context, req *dto.ListOrdersReq) (*dto.ListOrdersResp, error) {
	// 1. 参数验证
	if req.TenantID == "" {
		return nil, errors.New("租户ID不能为空")
	}

	if req.Page <= 0 {
		req.Page = 1
	}
	if req.PageSize <= 0 || req.PageSize > 100 {
		req.PageSize = 20
	}

	// 2. 根据状态查询订单列表
	var status consts.OrderStatus
	if req.Status != "" {
		status = consts.OrderStatus(req.Status)
	} else {
		// 默认查询所有状态
		status = consts.OrderStatusPending
	}

	orders, total, err := dao.Order.ListOrdersByStatus(ctx, status, req.TenantID, req.UserID, req.Page, req.PageSize)
	if err != nil {
		return nil, fmt.Errorf("查询订单列表失败: %w", err)
	}

	// 3. 转换订单列表
	var orderSummaries []dto.OrderSummary

	switch status {
	case consts.OrderStatusPending:
		if pendingOrders, ok := orders.([]entity.OrderPending); ok {
			for _, order := range pendingOrders {
				orderSummaries = append(orderSummaries, dto.OrderSummary{
					ID:          order.ID.Hex(),
					OrderNo:     order.OrderNo,
					TotalAmount: order.TotalAmount,
					PayAmount:   order.PayAmount,
					Status:      string(consts.OrderStatusPending),
					Subject:     order.Subject,
					CreatedAt:   order.CreatedAt,
				})
			}
		}
	case consts.OrderStatusPaid:
		if paidOrders, ok := orders.([]entity.OrderPaid); ok {
			for _, order := range paidOrders {
				orderSummaries = append(orderSummaries, dto.OrderSummary{
					ID:          order.ID.Hex(),
					OrderNo:     order.OrderNo,
					TotalAmount: order.TotalAmount,
					PayAmount:   order.PayAmount,
					Status:      string(consts.OrderStatusPaid),
					Subject:     order.Subject,
					CreatedAt:   order.CreatedAt,
					PaidAt:      &order.PaidAt,
				})
			}
		}
		// 其他状态类似处理...
	}

	// 4. 返回结果
	resp := &dto.ListOrdersResp{
		Orders:   orderSummaries,
		Total:    total,
		Page:     req.Page,
		PageSize: req.PageSize,
	}

	return resp, nil
}

// ProcessExpiredOrders 处理过期订单
func (s *order) ProcessExpiredOrders(ctx context.Context, tenantID string) error {
	// 获取过期的待支付订单
	expiredOrders, err := dao.Order.GetExpiredPendingOrders(ctx, tenantID)
	if err != nil {
		return fmt.Errorf("获取过期订单失败: %w", err)
	}

	// 批量取消过期订单
	for _, order := range expiredOrders {
		updateData := bson.M{
			"cancel_reason": "订单超时自动取消",
		}

		if err := dao.Order.MoveOrderToStatus(ctx, consts.OrderStatusPending, consts.OrderStatusCancelled, tenantID, order.OrderNo, updateData); err != nil {
			// 记录错误但继续处理其他订单
			fmt.Printf("取消过期订单失败: %s, 错误: %v\n", order.OrderNo, err)
		}
	}

	return nil
}

// UpdatePayInfo 更新支付信息
func (s *order) UpdatePayInfo(ctx context.Context, tenantID, orderNo string, payInfo entity.PayInfo) error {
	return dao.Order.UpdatePayInfo(ctx, tenantID, orderNo, payInfo)
}