package alert

import (

"context"

"fmt"

"time"

"github.com/redis/go-redis/v9"

)

const (

keyPrefixAlert = "alert" // Base prefix for all alert keys

keyFailures = "cf" // Set for consecutive failure attempt IDs

)

// AlertStore manages alert-related data persistence

type AlertStore interface {

IncrementConsecutiveFailureCount(ctx context.Context, tenantID, destinationID, attemptID string) (int, error)

ResetConsecutiveFailureCount(ctx context.Context, tenantID, destinationID string) error

}

type redisAlertStore struct {

client redis.Cmdable

deploymentID string

}

// NewRedisAlertStore creates a new Redis-backed alert store

func NewRedisAlertStore(client redis.Cmdable, deploymentID string) AlertStore {

return &redisAlertStore{

client: client,

deploymentID: deploymentID,

}

}

func (s *redisAlertStore) IncrementConsecutiveFailureCount(ctx context.Context, tenantID, destinationID, attemptID string) (int, error) {

key := s.getFailuresKey(destinationID)

// Use a transaction to ensure atomicity between SADD, SCARD, and EXPIRE operations.

// SADD is idempotent — adding the same attemptID on replay is a no-op,

// preventing double-counting when messages are redelivered.

pipe := s.client.TxPipeline()

pipe.SAdd(ctx, key, attemptID)

scardCmd := pipe.SCard(ctx, key)

pipe.Expire(ctx, key, 24*time.Hour)

_, err := pipe.Exec(ctx)

if err != nil {

return 0, fmt.Errorf("failed to execute consecutive failure count transaction: %w", err)

}

count, err := scardCmd.Result()

if err != nil {

return 0, fmt.Errorf("failed to get consecutive failure count: %w", err)

}

return int(count), nil

}

func (s *redisAlertStore) ResetConsecutiveFailureCount(ctx context.Context, tenantID, destinationID string) error {

return s.client.Del(ctx, s.getFailuresKey(destinationID)).Err()

}

func (s *redisAlertStore) deploymentPrefix() string {

if s.deploymentID == "" {

return ""

}

return fmt.Sprintf("%s:", s.deploymentID)

}

func (s *redisAlertStore) getFailuresKey(destinationID string) string {

return fmt.Sprintf("%s%s:%s:%s", s.deploymentPrefix(), keyPrefixAlert, destinationID, keyFailures)

}