package packagetrafficalert

import (
	"context"
	"strconv"

	"gorm.io/gorm"

	notificationapp "github.com/break/junhong_cmp_fiber/internal/application/notification"
	app "github.com/break/junhong_cmp_fiber/internal/application/packagetrafficalert"
	"github.com/break/junhong_cmp_fiber/internal/infrastructure/audit"
	"github.com/break/junhong_cmp_fiber/internal/infrastructure/messaging/outbox"
	"github.com/break/junhong_cmp_fiber/internal/model"
	"github.com/break/junhong_cmp_fiber/internal/store/postgres"
	"github.com/break/junhong_cmp_fiber/pkg/constants"
	"github.com/break/junhong_cmp_fiber/pkg/errors"
)

// AlertWriter 在同一 GORM 事务内写入预警事实、可靠通知事件与成功审计。
//
// 依据 ENG-OUTBOX-001，业务事实与可靠异步副作用必须同事务写 Outbox；
// 依据 ENG-TX-001，成功必达的审计与关键状态事实同事务，且事务内不持有不可回滚的外部 I/O。
// 事务粒度为一个命中资产：单资产失败不阻塞其余资产，锁持有时间可控。
type AlertWriter struct {
	db          *gorm.DB
	store       *postgres.PackageTrafficAlertStore
	outbox      *outbox.Repository
	auditWriter *audit.Writer
}

// NewAlertWriter 创建套餐真流量预警写入 Adapter。
func NewAlertWriter(db *gorm.DB, store *postgres.PackageTrafficAlertStore, repository *outbox.Repository, auditWriter *audit.Writer) *AlertWriter {
	return &AlertWriter{db: db, store: store, outbox: repository, auditWriter: auditWriter}
}

// SaveAlert 幂等创建预警，并在同一事务内写入通知事件与审计。
// 唯一键冲突（同一使用记录 + 同一阈值快照）视为已处理：不写事件、不写审计，直接提交。
func (w *AlertWriter) SaveAlert(ctx context.Context, candidate app.AlertCandidate) (bool, error) {
	if w == nil || w.db == nil || w.store == nil {
		return false, errors.New(errors.CodeInternalError, "套餐真流量达量预警写入 Adapter 未配置")
	}
	if w.auditWriter == nil {
		return false, errors.New(errors.CodeInvalidStatus, "套餐真流量达量预警统一审计接缝未配置")
	}
	alert := candidate.Alert
	created := false
	err := w.db.WithContext(ctx).Transaction(func(tx *gorm.DB) error {
		store := w.store.WithTx(tx)
		inserted, insertErr := store.CreateAlertIdempotent(ctx, &alert)
		if insertErr != nil {
			return errors.Wrap(errors.CodeDatabaseError, insertErr, "创建套餐真流量达量预警失败")
		}
		if !inserted {
			return nil
		}
		created = true
		if candidate.Notification != nil {
			eventID, appendErr := w.appendNotificationEvent(ctx, tx, alert, *candidate.Notification)
			if appendErr != nil {
				return appendErr
			}
			if updateErr := tx.WithContext(ctx).Model(&model.PackageTrafficAlert{}).
				Where("id = ?", alert.ID).Update("notification_event_id", eventID).Error; updateErr != nil {
				return errors.Wrap(errors.CodeDatabaseError, updateErr, "回填预警通知事件ID失败")
			}
			alert.NotificationEventID = eventID
		}
		return w.appendTriggerAudit(ctx, tx, alert)
	})
	if err != nil {
		return false, err
	}
	return created, nil
}

// appendNotificationEvent 幂等追加动态通知事件。
// 接收人是触发时冻结的业务员账号（TargetKind=account），投递期不再重新解析店铺业务员，
// 因此业务员变更不会把通知送给不属于它的新账号，也不会在触发时无业务员的情况下补发。
func (w *AlertWriter) appendNotificationEvent(ctx context.Context, tx *gorm.DB, alert model.PackageTrafficAlert, request app.NotificationRequest) (string, error) {
	if w.outbox == nil {
		return "", errors.New(errors.CodeInternalError, "套餐真流量达量预警 Outbox 仓储未配置")
	}
	eventID := app.EventIDFor(alert.PackageUsageID, alert.ThresholdPercentSnapshot)
	alertID := strconv.FormatUint(uint64(alert.ID), 10)
	expiresAt := request.ExpiresAt
	_, err := w.outbox.AppendIdempotent(ctx, tx, outbox.Envelope{
		EventID:        eventID,
		EventType:      constants.OutboxEventTypeAdminDynamicNotification,
		PayloadVersion: constants.NotificationPayloadVersionV1,
		AggregateType:  constants.PackageTrafficAlertScanAggregateType,
		AggregateID:    alertID,
		ResourceType:   constants.NotificationRefTypePackageTrafficAlert,
		ResourceID:     alertID,
		BusinessKey:    eventID,
		Payload: notificationapp.AdminDynamicPayload{
			TargetKind:       constants.NotificationTargetKindAccount,
			TargetID:         request.RecipientAccountID,
			NotificationType: constants.NotificationTypePackageTrafficAlert,
			TemplateData:     request.TemplateData,
			RefType:          constants.NotificationRefTypePackageTrafficAlert,
			RefID:            alertID,
			RefKey:           alert.AssetIdentifierSnapshot,
			ExpiresAt:        &expiresAt,
		},
	})
	if err != nil {
		return "", errors.Wrap(errors.CodeDatabaseError, err, "写入套餐真流量达量预警通知事件失败")
	}
	return eventID, nil
}

// appendTriggerAudit 在业务事务内追加达量预警审计事实。
// 审计动作的 actor/source 固定为系统任务与 Worker，与注册表声明一致。
func (w *AlertWriter) appendTriggerAudit(ctx context.Context, tx *gorm.DB, alert model.PackageTrafficAlert) error {
	alertID := strconv.FormatUint(uint64(alert.ID), 10)
	usageID := strconv.FormatUint(uint64(alert.PackageUsageID), 10)
	summary := "创建套餐真流量达量预警"
	if alert.NotificationEventID == "" {
		summary = "创建套餐真流量达量预警（触发时无有效业务员，未生成通知）"
	}
	// 使用 AppendAndGet：达量预警审计属于「要求成功必达」的事实，失败必须回滚整个事务（ENG-TX-001）。
	if _, err := w.auditWriter.AppendAndGet(ctx, tx, audit.AppendInput{
		EventID:    audit.TaskEventID(constants.AuditResourcePackageTrafficAlert, alert.ID, "trigger"),
		ActionCode: constants.AuditActionPackageTrafficAlertTriggered, Summary: summary,
		// Actor.ID 必须非空且稳定：审计写入要求操作者标识，缺省会静默失败。
		Actor: audit.ActorInput{
			Kind: constants.AuditActorSystemTask,
			ID:   constants.TaskTypePackageTrafficAlertScan,
			Name: "套餐真流量达量扫描",
		},
		Source: constants.AuditSourceWorker, ScopeType: constants.AuditScopePlatform,
		Result: constants.AuditResultSuccess,
		Resources: []audit.ResourceInput{{
			Type: constants.AuditResourcePackageTrafficAlert, ID: &alertID, Key: usageID,
			DisplayName: alert.PackageNameSnapshot,
			Relation:    constants.AuditResourceRelationPrimary, Role: constants.AuditResourceRolePackageTrafficAlertTarget,
			IdentitySnapshot: alertAuditIdentity(alert), AfterData: alertAuditSnapshot(alert),
		}},
	}); err != nil {
		return err
	}
	return nil
}

// alertAuditIdentity 返回预警审计身份快照，字段落在注册表白名单内。
func alertAuditIdentity(alert model.PackageTrafficAlert) map[string]any {
	identity := map[string]any{
		"id": alert.ID, "package_usage_id": alert.PackageUsageID, "package_id": alert.PackageID,
		"asset_type": alert.AssetType, "asset_id": alert.AssetID,
		"threshold_percent_snapshot": alert.ThresholdPercentSnapshot,
		"used_mb_snapshot":           alert.UsedMBSnapshot, "limit_mb_snapshot": alert.LimitMBSnapshot,
		"usage_percent_snapshot": alert.UsagePercentSnapshot,
		"shop_id":                alert.ShopIDSnapshot,
	}
	if alert.BusinessOwnerAccountIDSnapshot != nil {
		identity["business_owner_account_id"] = *alert.BusinessOwnerAccountIDSnapshot
	} else {
		identity["business_owner_account_id"] = nil
	}
	return identity
}

// alertAuditSnapshot 返回预警审计的 after 快照，用于忠实还原触发时的冻结事实。
func alertAuditSnapshot(alert model.PackageTrafficAlert) map[string]any {
	snapshot := alertAuditIdentity(alert)
	snapshot["rule_id"] = alert.RuleID
	snapshot["asset_identifier"] = alert.AssetIdentifierSnapshot
	snapshot["card_identifier"] = alert.CardIdentifierSnapshot
	snapshot["counterpart_identifier"] = alert.CounterpartIdentifierSnapshot
	snapshot["package_name"] = alert.PackageNameSnapshot
	snapshot["shop_name"] = alert.ShopNameSnapshot
	snapshot["notification_event_id"] = alert.NotificationEventID
	if alert.BusinessOwnerAccountIDSnapshot != nil {
		snapshot["business_owner_account_id"] = *alert.BusinessOwnerAccountIDSnapshot
	} else {
		snapshot["business_owner_account_id"] = nil
	}
	if alert.ExpiresAtSnapshot != nil {
		snapshot["expires_at"] = alert.ExpiresAtSnapshot.UTC()
	} else {
		snapshot["expires_at"] = nil
	}
	snapshot["triggered_at"] = alert.TriggeredAt.UTC()
	return snapshot
}