package service

import (
	"errors"
	"strings"
	"time"
	"unicode/utf8"

	"affiliate_dash/internal/model"

	"gorm.io/gorm"
	"gorm.io/gorm/clause"
)

// ShipNotifyInput 上游发货结果推送。
type ShipNotifyInput struct {
	OrderNo         string
	ShipStatus      string // success / failed
	ProviderOrderNo string
	ShippedAt       *time.Time
	FailReason      string
	RawPayload      string
	GameChannel     *string
	GameUID         *string
	RoleName        *string
	PayScore        *int
}

// ShipNotifyResult 上游推送处理结果。
type ShipNotifyResult struct {
	OrderNo string `json:"order_no"`
	Status  string `json:"status"`
	Message string `json:"message"`
}

// HandleShipNotify 处理上游发货结果推送（幂等），基于 FulfillmentOrder。
func (s *FulfillmentService) HandleShipNotify(in ShipNotifyInput) (*ShipNotifyResult, error) {
	in.ShipStatus = strings.TrimSpace(in.ShipStatus)
	in.FailReason = strings.TrimSpace(in.FailReason)
	if in.OrderNo == "" {
		return nil, errors.New("订单号不能为空")
	}
	if in.ShipStatus != "success" && in.ShipStatus != "failed" {
		return nil, errors.New("无效的 ship_status，仅支持 success/failed")
	}
	if in.ShipStatus == "failed" && in.FailReason == "" {
		return nil, errors.New("发货失败时 fail_reason 必填")
	}
	if utf8.RuneCountInString(in.FailReason) > 512 {
		return nil, errors.New("fail_reason 最长 512 个字符")
	}

	var nextStatus string
	switch in.ShipStatus {
	case "success":
		nextStatus = model.OrderStatusDelivered
	case "failed":
		nextStatus = model.OrderStatusShipFailed
	}

	var result ShipNotifyResult
	var rejectionErr error
	if err := s.db.Transaction(func(tx *gorm.DB) error {
		var order model.FulfillmentOrder
		if err := tx.Clauses(clause.Locking{Strength: "UPDATE"}).
			Preload("MerchantProduct.Product").
			Where("order_no = ?", in.OrderNo).
			First(&order).Error; err != nil {
			if errors.Is(err, gorm.ErrRecordNotFound) {
				return errors.New("订单不存在")
			}
			return err
		}

		// 已交付：success 推送幂等成功。状态读取和后续更新必须在同一把行锁内完成。
		if normalizeOrderStatus(&order) == model.OrderStatusDelivered && in.ShipStatus == "success" {
			result = ShipNotifyResult{
				OrderNo: order.OrderNo,
				Status:  normalizeOrderStatus(&order),
				Message: "订单已交付，幂等成功",
			}
			return writeAudit(tx, &order.MerchantID, nil, nil, "ship.notify", "fulfillment_order", order.OrderNo,
				shipNotifyAuditMetadata(in, normalizeOrderStatus(&order), "订单已交付，幂等忽略"))
		}

		if normalizeOrderStatus(&order) == model.OrderStatusCancelled {
			if err := writeShipNotifyRejectedAudit(tx, &order, in, "订单已取消，拒绝更新"); err != nil {
				return err
			}
			rejectionErr = errors.New("订单已取消，无法更新发货状态")
			return nil
		}

		now := time.Now()
		shippedAt := in.ShippedAt
		if shippedAt == nil && in.ShipStatus == "success" {
			shippedAt = &now
		}

		updates := map[string]interface{}{
			"order_status": nextStatus,
		}
		var message string
		switch in.ShipStatus {
		case "success":
			if err := validateOrderStatusTransition(&order, nextStatus, fulfillmentTransitionShipNotify); err != nil {
				message := "当前状态不允许标记发货成功"
				if err := writeShipNotifyRejectedAudit(tx, &order, in, message); err != nil {
					return err
				}
				rejectionErr = err
				return nil
			}
			updates["delivered_at"] = shippedAt
			updates["failure_reason"] = ""
			if in.ProviderOrderNo != "" {
				updates["provider_order_no"] = in.ProviderOrderNo
			}
			message = "发货成功，订单已交付"
		case "failed":
			if err := validateOrderStatusTransition(&order, nextStatus, fulfillmentTransitionShipNotify); err != nil {
				message := "当前状态不允许标记发货失败"
				if normalizeOrderStatus(&order) == model.OrderStatusDelivered {
					message = "订单已交付，拒绝失败推送"
				}
				if err := writeShipNotifyRejectedAudit(tx, &order, in, message); err != nil {
					return err
				}
				rejectionErr = err
				return nil
			}
			updates["failure_reason"] = in.FailReason
			if in.ProviderOrderNo != "" {
				updates["provider_order_no"] = in.ProviderOrderNo
			}
			message = "已记录发货失败"
		}

		resultData := buildShipNotifyResultData(order.ResultData, in, shippedAt)
		updates["result_data"] = resultData
		if err := tx.Model(&model.FulfillmentOrder{}).Where("id = ?", order.ID).Updates(updates).Error; err != nil {
			return err
		}

		if err := writeAudit(tx, &order.MerchantID, nil, nil, "ship.notify", "fulfillment_order", order.OrderNo,
			shipNotifyAuditMetadata(in, nextStatus, message)); err != nil {
			return err
		}

		var updated model.FulfillmentOrder
		if err := tx.Preload("MerchantProduct.Product").First(&updated, order.ID).Error; err != nil {
			return err
		}
		if s.callbacks != nil {
			if err := s.callbacks.Enqueue(tx, order.MerchantID, "order.shipping.updated", orderCallbackData(&updated)); err != nil {
				return err
			}
		}
		result = ShipNotifyResult{
			OrderNo: order.OrderNo,
			Status:  nextStatus,
			Message: message,
		}
		return nil
	}); err != nil {
		return nil, err
	}
	if rejectionErr != nil {
		return nil, rejectionErr
	}

	return &result, nil
}

func writeShipNotifyRejectedAudit(tx *gorm.DB, order *model.FulfillmentOrder, in ShipNotifyInput, message string) error {
	return writeAudit(tx, &order.MerchantID, nil, nil, "ship.notify", "fulfillment_order", order.OrderNo,
		shipNotifyAuditMetadata(in, normalizeOrderStatus(order), message))
}

func shipNotifyAuditMetadata(in ShipNotifyInput, resultStatus, message string) map[string]interface{} {
	metadata := map[string]interface{}{
		"ship_status":       in.ShipStatus,
		"provider_order_no": in.ProviderOrderNo,
		"fail_reason":       in.FailReason,
		"result_status":     resultStatus,
		"message":           message,
		"payload":           in.RawPayload,
	}
	return metadata
}