package wallet

import (
	"context"
	"strconv"

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

	notificationapp "github.com/break/junhong_cmp_fiber/internal/application/notification"
	walletapp "github.com/break/junhong_cmp_fiber/internal/application/wallet"
	"github.com/break/junhong_cmp_fiber/internal/infrastructure/messaging/outbox"
	"github.com/break/junhong_cmp_fiber/internal/model"
	"github.com/break/junhong_cmp_fiber/pkg/constants"
	"github.com/break/junhong_cmp_fiber/pkg/errors"
)

// DebitEventConsumer 校验已投递的代理主钱包扣款事件具有对应权威资金流水。
// 后续余额预警等消费者在此稳定接缝上扩展，不需要回读或改写订单扣款事务。
type DebitEventConsumer struct {
	db     *gorm.DB
	outbox *outbox.Repository
}

// NewDebitEventConsumer 创建代理主钱包扣款事件消费者。
func NewDebitEventConsumer(db *gorm.DB) *DebitEventConsumer {
	return &DebitEventConsumer{db: db, outbox: outbox.NewRepository()}
}

// Consume 校验事件载荷及不可变流水，保证未知或损坏事件不会被静默确认。
func (c *DebitEventConsumer) Consume(ctx context.Context, envelope outbox.DeliveryEnvelope) error {
	if c == nil || c.db == nil || c.outbox == nil {
		return errors.New(errors.CodeInternalError, "代理主钱包扣款事件消费者未配置")
	}
	if envelope.EventType != constants.OutboxEventTypeAgentMainWalletDebited ||
		envelope.PayloadVersion != constants.AgentMainWalletDebitedPayloadVersionV1 {
		return errors.New(errors.CodeInvalidParam, "代理主钱包扣款事件类型或版本不受支持")
	}
	var event walletapp.DebitedEvent
	if err := sonic.Unmarshal(envelope.Payload, &event); err != nil {
		return errors.Wrap(errors.CodeInvalidParam, err, "代理主钱包扣款事件载荷无法解析")
	}
	if event.EventID != envelope.EventID || event.WalletID == 0 || event.ShopID == 0 || event.ReferenceID == 0 ||
		event.ReferenceType != constants.ReferenceTypeOrder || event.TransactionType != constants.AgentTransactionTypeDeduct ||
		event.Amount <= 0 {
		return errors.New(errors.CodeInvalidParam, "代理主钱包扣款事件载荷不完整")
	}

	return c.db.WithContext(ctx).Transaction(func(tx *gorm.DB) error {
		return c.consumeInTx(ctx, tx, event)
	})
}

// consumeInTx 复核权威扣款流水，并在余额首次跨过固定阈值时追加业务员通知事件。
func (c *DebitEventConsumer) consumeInTx(ctx context.Context, tx *gorm.DB, event walletapp.DebitedEvent) error {
	var transaction model.AgentWalletTransaction
	err := tx.WithContext(ctx).Unscoped().
		Where("agent_wallet_id = ? AND reference_type = ? AND reference_id = ? AND transaction_type = ? AND status = ?",
			event.WalletID, event.ReferenceType, event.ReferenceID, constants.AgentTransactionTypeDeduct, constants.TransactionStatusSuccess).
		First(&transaction).Error
	if err != nil {
		if err == gorm.ErrRecordNotFound {
			return errors.New(errors.CodeInternalError, "代理主钱包扣款事件缺少权威资金流水")
		}
		return errors.Wrap(errors.CodeDatabaseError, err, "查询代理主钱包扣款流水失败")
	}
	if transaction.Amount != -event.Amount || transaction.BalanceBefore != event.BalanceBefore ||
		transaction.BalanceAfter != event.BalanceAfter {
		return errors.New(errors.CodeInternalError, "代理主钱包扣款事件与权威资金流水不一致")
	}
	if event.BalanceBefore < constants.AgentMainWalletLowBalanceThreshold ||
		event.BalanceAfter >= constants.AgentMainWalletLowBalanceThreshold {
		return nil
	}

	recipientID, err := resolveBusinessOwnerAccountID(ctx, tx, event.ShopID)
	if err != nil {
		return err
	}
	if recipientID == 0 {
		return nil
	}
	shopID := strconv.FormatUint(uint64(event.ShopID), 10)
	notificationEventID := "wallet-low:order:" + strconv.FormatUint(uint64(event.ReferenceID), 10)
	_, err = c.outbox.AppendIdempotent(ctx, tx, outbox.Envelope{
		EventID: notificationEventID, EventType: constants.OutboxEventTypeAdminDirectNotification,
		PayloadVersion: constants.NotificationPayloadVersionV1,
		AggregateType:  "agent_wallet", AggregateID: strconv.FormatUint(uint64(event.WalletID), 10),
		ResourceType: constants.NotificationRefTypeShopFund, ResourceID: shopID,
		BusinessKey: notificationEventID, RequestID: event.RequestID, CorrelationID: event.CorrelationID,
		Payload: notificationapp.AdminDirectPayload{
			RecipientID: recipientID, NotificationType: constants.NotificationTypeAgentMainWalletLowBalance,
			RefType: constants.NotificationRefTypeShopFund, RefID: shopID,
		},
	})
	if err != nil {
		return errors.Wrap(errors.CodeDatabaseError, err, "写入主钱包低余额通知事件失败")
	}
	return nil
}

// resolveBusinessOwnerAccountID 返回店铺当前启用的平台业务员账号；无有效归属时返回零值。
func resolveBusinessOwnerAccountID(ctx context.Context, tx *gorm.DB, shopID uint) (uint, error) {
	var shop model.Shop
	err := tx.WithContext(ctx).Select("business_owner_account_id").Where("id = ?", shopID).Take(&shop).Error
	if err == gorm.ErrRecordNotFound || shop.BusinessOwnerAccountID == nil {
		return 0, nil
	}
	if err != nil {
		return 0, errors.Wrap(errors.CodeDatabaseError, err, "查询店铺业务员归属失败")
	}

	var account model.Account
	err = tx.WithContext(ctx).Select("id").
		Where("id = ? AND status = ? AND user_type = ?", *shop.BusinessOwnerAccountID, constants.StatusEnabled, constants.UserTypePlatform).
		Take(&account).Error
	if err == gorm.ErrRecordNotFound {
		return 0, nil
	}
	if err != nil {
		return 0, errors.Wrap(errors.CodeDatabaseError, err, "校验店铺业务员账号失败")
	}
	return account.ID, nil
}