package refundchannel

import (
	"context"
	"strconv"

	"github.com/bytedance/sonic"
	"gorm.io/gorm"

	"github.com/break/junhong_cmp_fiber/internal/infrastructure/messaging/outbox"
	"github.com/break/junhong_cmp_fiber/pkg/auditcontext"
	"github.com/break/junhong_cmp_fiber/pkg/errors"
	"github.com/break/junhong_cmp_fiber/pkg/outboxid"
)

// EventRefundChannelRefund 是退款进入渠道原路处理中后的执行事件。
const EventRefundChannelRefund = "refund.channel.refund.requested"

// refundChannelPayloadVersion 是渠道原路退款事件的载荷版本。
const refundChannelPayloadVersion = 1

// Payload 是渠道原路退款事件的载荷。
type Payload struct {
	RefundID uint `json:"refund_id"`
	OrderID  uint `json:"order_id"`
}

// AppendRefundChannelRefund 在企微通过事务内幂等写入渠道原路退款执行事件。
// 同一退款申请使用稳定事件 ID，重复投递不会重复创建事实。
func AppendRefundChannelRefund(ctx context.Context, tx *gorm.DB, repository *outbox.Repository, refundID, orderID uint) error {
	if repository == nil {
		return gorm.ErrInvalidDB
	}
	value := strconv.FormatUint(uint64(refundID), 10)
	_, err := repository.AppendIdempotent(ctx, tx, outbox.Envelope{
		EventID:        outboxid.Stable(EventRefundChannelRefund+":", value),
		EventType:      EventRefundChannelRefund,
		PayloadVersion: refundChannelPayloadVersion,
		AggregateType:  "refund", AggregateID: value,
		ResourceType: "refund", ResourceID: value,
		BusinessKey: EventRefundChannelRefund + ":" + value,
		Payload:     Payload{RefundID: refundID, OrderID: orderID},
	})
	return err
}

// Consumer 把渠道原路退款事件转成一次性资金动作。
type Consumer struct {
	service *Service
}

// NewConsumer 创建渠道原路退款事件消费者。
func NewConsumer(service *Service) *Consumer {
	return &Consumer{service: service}
}

// Consume 幂等执行渠道原路退款；重复投递由退款申请状态与渠道请求号共同兜住。
func (c *Consumer) Consume(ctx context.Context, envelope outbox.DeliveryEnvelope) error {
	var payload Payload
	if err := sonic.Unmarshal(envelope.Payload, &payload); err != nil {
		return outbox.Permanent(err)
	}
	if envelope.EventType != EventRefundChannelRefund ||
		envelope.PayloadVersion != refundChannelPayloadVersion || payload.RefundID == 0 {
		return outbox.Permanent(gorm.ErrInvalidData)
	}
	if c == nil || c.service == nil {
		return errors.New(errors.CodeServiceUnavailable, "渠道原路退款执行能力未配置")
	}
	ctx = auditcontext.With(ctx, auditcontext.Context{CorrelationID: envelope.CorrelationID, ParentEventID: envelope.EventID})
	return c.service.Execute(ctx, payload.RefundID)
}

// 编译期断言：渠道原路退款消费者满足公共 Outbox 的消费边界。
var _ outbox.EventConsumer = (*Consumer)(nil)