package service

import (
	"errors"
	"strings"
	"time"

	"affiliate_dash/internal/model"

	"gorm.io/gorm"
)

func (s *FulfillmentService) GetOrder(merchantID uint, orderNo string) (*model.FulfillmentOrder, error) {
	var order model.FulfillmentOrder
	err := s.db.Preload("MerchantProduct.Product").
		Where("merchant_id = ? AND order_no = ?", merchantID, orderNo).
		First(&order).Error
	if errors.Is(err, gorm.ErrRecordNotFound) {
		return nil, errors.New("订单不存在")
	}
	if err != nil {
		return nil, err
	}
	return &order, nil
}

// orderFilters 是商户侧与平台侧共用的订单筛选条件。
// 集中在一处校验，避免以后新增筛选项时只改了一边。
type orderFilters struct {
	// merchantID 为 nil 表示不限商户（仅平台侧使用）；指向 0 时仍会按 merchant_id=0 过滤，
	// 以保持 ListOrders 的原有语义不变。
	merchantID  *uint
	orderStatus string
	orderSource string
	keyword     string
}

func (f orderFilters) apply(tx *gorm.DB) (*gorm.DB, error) {
	if f.merchantID != nil {
		tx = tx.Where("merchant_id = ?", *f.merchantID)
	}
	if f.orderStatus != "" {
		switch f.orderStatus {
		case model.OrderStatusPaid, model.OrderStatusDelivering, model.OrderStatusDelivered, model.OrderStatusShipFailed, model.OrderStatusCancelled:
		default:
			return nil, errors.New("无效的订单状态")
		}
		tx = tx.Where("order_status = ?", f.orderStatus)
	}
	if f.orderSource != "" {
		switch f.orderSource {
		case model.OrderSourceAPI, model.OrderSourceManual, model.OrderSourceTest:
			tx = tx.Where("order_source = ?", f.orderSource)
		default:
			return nil, errors.New("无效的订单来源")
		}
	}
	if keyword := strings.TrimSpace(f.keyword); keyword != "" {
		like := "%" + keyword + "%"
		tx = tx.Where("order_no LIKE ? OR client_order_no LIKE ?", like, like)
	}
	return tx, nil
}

func (s *FulfillmentService) listOrders(f orderFilters, page, size int, withMerchant bool) ([]model.FulfillmentOrder, int64, error) {
	page, size = normalizePage(page, size)
	tx, err := f.apply(s.db.Model(&model.FulfillmentOrder{}))
	if err != nil {
		return nil, 0, err
	}
	var total int64
	if err := tx.Count(&total).Error; err != nil {
		return nil, 0, err
	}
	query := tx.Preload("MerchantProduct.Product")
	if withMerchant {
		// 平台侧跨商户列表需要展示订单属于哪个商户。
		query = query.Preload("Merchant")
	}
	var orders []model.FulfillmentOrder
	err = query.Order("id DESC").Offset((page - 1) * size).Limit(size).Find(&orders).Error
	return orders, total, err
}

// ListOrders 商户后台订单列表，强制按单个商户隔离。
func (s *FulfillmentService) ListOrders(merchantID uint, page, size int, orderStatus, orderSource, keyword string) ([]model.FulfillmentOrder, int64, error) {
	return s.listOrders(orderFilters{
		merchantID:  &merchantID,
		orderStatus: orderStatus,
		orderSource: orderSource,
		keyword:     keyword,
	}, page, size, false)
}

// ListPlatformOrders 平台侧跨商户订单查询，供超管在管理端查看全部下游订单。
// merchantID 为 nil 表示不限商户。这是与 ListOrders 并行的另一条路径，
// 刻意不改动商户侧「必须落到单个商户」的隔离语义。
func (s *FulfillmentService) ListPlatformOrders(merchantID *uint, page, size int, orderStatus, orderSource, keyword string) ([]model.FulfillmentOrder, int64, error) {
	return s.listOrders(orderFilters{
		merchantID:  merchantID,
		orderStatus: orderStatus,
		orderSource: orderSource,
		keyword:     keyword,
	}, page, size, true)
}

type OpenOrderQuery struct {
	OrderNo          string            `json:"order_no"`
	Status           string            `json:"status"`
	CanShip          bool              `json:"can_ship"`
	CannotShipReason string            `json:"cannot_ship_reason,omitempty"`
	Product          *OpenOrderProduct `json:"product,omitempty"`
	BuyerName        string            `json:"buyer_name"`
	Amount           int64             `json:"amount"`
	ProviderOrderNo  string            `json:"provider_order_no,omitempty"`
	CreatedAt        time.Time         `json:"created_at"`
	ShippedAt        *time.Time        `json:"shipped_at"`
	ShipFailReason   string            `json:"ship_fail_reason,omitempty"`
	GameChannel      string            `json:"game_channel,omitempty"`
	GameUID          string            `json:"game_uid,omitempty"`
	RoleName         string            `json:"role_name,omitempty"`
	PayScore         int               `json:"pay_score,omitempty"`
}

// OpenOrderProduct 开放接口返回的商品快照。
type OpenOrderProduct struct {
	Name string `json:"name"`
	SKU  string `json:"sku"`
	Game string `json:"game"`
}

// GetByOrderNo 按订单号查询（不限定商户，供上游 SourceOpen 使用）。
func (s *FulfillmentService) GetByOrderNo(orderNo string) (*model.FulfillmentOrder, error) {
	var order model.FulfillmentOrder
	err := s.db.Preload("MerchantProduct.Product").Where("order_no = ?", orderNo).First(&order).Error
	if errors.Is(err, gorm.ErrRecordNotFound) {
		return nil, errors.New("订单不存在")
	}
	if err != nil {
		return nil, err
	}
	return &order, nil
}

// QueryOpenOrder 供上游查询：商品信息 + 是否可发货。
func (s *FulfillmentService) QueryOpenOrder(orderNo string) (*OpenOrderQuery, error) {
	if orderNo == "" {
		return nil, errors.New("订单号不能为空")
	}
	order, err := s.GetByOrderNo(orderNo)
	if err != nil {
		return nil, err
	}
	canShip, reason := CanFulfill(order)
	out := &OpenOrderQuery{
		OrderNo:          order.OrderNo,
		Status:           normalizeOrderStatus(order),
		CanShip:          canShip,
		CannotShipReason: reason,
		BuyerName:        order.BuyerReference,
		Amount:           order.Amount,
		ProviderOrderNo:  order.ProviderOrderNo,
		CreatedAt:        order.CreatedAt,
		ShippedAt:        order.DeliveredAt,
		ShipFailReason:   order.FailureReason,
	}
	if order.MerchantProduct != nil {
		game := ""
		if order.MerchantProduct.Product != nil {
			game = order.MerchantProduct.Product.Category
		}
		out.Product = &OpenOrderProduct{
			Name: order.ProductName,
			SKU:  order.ProductSKU,
			Game: game,
		}
	}
	// 新模型无独立的游戏字段列，从 RequestData / ResultData JSON 中还原。
	extractGameFields(order.RequestData, out)
	extractGameFields(order.ResultData, out)
	return out, nil
}