package service

import (
	"errors"
	"time"

	"affiliate_dash/internal/model"
	"gorm.io/gorm"
	"gorm.io/gorm/clause"
)

type FulfillmentUpdateInput struct {
	MerchantID      uint
	APIClientID     uint
	OrderNo         string
	Status          string
	ProviderOrderNo string
	FailureReason   string
	ResultData      interface{}
}

func (s *FulfillmentService) UpdateFulfillment(in FulfillmentUpdateInput) (*model.FulfillmentOrder, error) {
	switch in.Status {
	case model.OrderStatusDelivering, model.OrderStatusDelivered, model.OrderStatusShipFailed:
	default:
		return nil, errors.New("无效的订单状态")
	}
	nextOrderStatus := in.Status
	var resultData string
	hasResultData := in.ResultData != nil
	if in.ResultData != nil {
		encoded, err := encodeFulfillmentResultData(in.ResultData)
		if err != nil {
			return nil, errors.New("发货结果无法序列化")
		}
		resultData = encoded
	}
	var out model.FulfillmentOrder
	err := s.db.Transaction(func(tx *gorm.DB) error {
		var order model.FulfillmentOrder
		if err := tx.Clauses(clause.Locking{Strength: "UPDATE"}).
			Where("merchant_id = ? AND order_no = ?", in.MerchantID, in.OrderNo).
			First(&order).Error; err != nil {
			if errors.Is(err, gorm.ErrRecordNotFound) {
				return errors.New("订单不存在")
			}
			return err
		}
		if normalizeOrderStatus(&order) == model.OrderStatusDelivered && nextOrderStatus == model.OrderStatusDelivered {
			out = order
			return nil
		}
		if err := validateOrderStatusTransition(&order, nextOrderStatus, fulfillmentTransitionUpdate); err != nil {
			return err
		}
		now := time.Now()
		updates := map[string]interface{}{"order_status": nextOrderStatus}
		if hasResultData {
			updates["result_data"] = resultData
		}
		if in.ProviderOrderNo != "" {
			updates["provider_order_no"] = in.ProviderOrderNo
		}
		switch nextOrderStatus {
		case model.OrderStatusDelivered:
			updates["delivered_at"] = now
			updates["failure_reason"] = ""
		case model.OrderStatusShipFailed:
			updates["failure_reason"] = in.FailureReason
		}
		if err := tx.Model(&order).Updates(updates).Error; err != nil {
			return err
		}
		if err := tx.First(&out, order.ID).Error; err != nil {
			return err
		}
		if err := writeAudit(tx, &in.MerchantID, nil, &in.APIClientID, "fulfillment.update", "fulfillment_order", order.OrderNo, map[string]string{"status": nextOrderStatus}); err != nil {
			return err
		}
		if s.callbacks != nil {
			if err := s.callbacks.Enqueue(tx, in.MerchantID, "order.shipping.updated", orderCallbackData(&out)); err != nil {
				return err
			}
		}
		return nil
	})
	if err != nil {
		return nil, err
	}
	return &out, nil
}