api_antrean/internal/database/database.go

package database

import (
	"context"
	"crypto/tls"
	"database/sql"
	"fmt"
	"log"
	"strconv"
	"sync"
	"time"

	"api-service/internal/config"

	_ "github.com/jackc/pgx/v5"
	"github.com/jmoiron/sqlx"
	"github.com/lib/pq"
	_ "gorm.io/driver/mysql"
	_ "gorm.io/driver/postgres"
	_ "gorm.io/driver/sqlserver"

	"go.mongodb.org/mongo-driver/mongo"
	"go.mongodb.org/mongo-driver/mongo/options"
)

// DatabaseType represents supported database types
type DatabaseType string

const (
	Postgres  DatabaseType = "postgres"
	MySQL     DatabaseType = "mysql"
	SQLServer DatabaseType = "sqlserver"
	SQLite    DatabaseType = "sqlite"
	MongoDB   DatabaseType = "mongodb"
)

// Service represents a service that interacts with multiple databases
type Service interface {
	Health() map[string]map[string]string
	GetDB(name string) (*sql.DB, error)
	GetSQLXDB(name string) (*sqlx.DB, error) // Tambahkan metode ini
	GetMongoClient(name string) (*mongo.Client, error)
	GetReadDB(name string) (*sql.DB, error)
	Close() error
	ListDBs() []string
	GetDBType(name string) (DatabaseType, error)
	ListenForChanges(ctx context.Context, dbName string, channels []string, callback func(string, string)) error
	NotifyChange(dbName, channel, payload string) error
	GetPrimaryDB(name string) (*sql.DB, error)
	ExecuteQuery(ctx context.Context, dbName string, query string, args ...interface{}) (*sql.Rows, error)
	ExecuteQueryRow(ctx context.Context, dbName string, query string, args ...interface{}) *sql.Row
	Exec(ctx context.Context, dbName string, query string, args ...interface{}) (sql.Result, error)
}

type service struct {
	sqlDatabases  map[string]*sql.DB
	sqlxDatabases map[string]*sqlx.DB // Tambahkan map untuk sqlx.DB
	mongoClients  map[string]*mongo.Client
	readReplicas  map[string][]*sql.DB
	configs       map[string]config.DatabaseConfig
	readConfigs   map[string][]config.DatabaseConfig
	mu            sync.RWMutex
	readBalancer  map[string]int
	listeners     map[string]*pq.Listener
	listenersMu   sync.RWMutex
}

var (
	dbManager *service
	once      sync.Once
)

// New creates a new database service with multiple connections
func New(cfg *config.Config) Service {
	once.Do(func() {
		dbManager = &service{
			sqlDatabases:  make(map[string]*sql.DB),
			sqlxDatabases: make(map[string]*sqlx.DB), // Inisialisasi map sqlx
			mongoClients:  make(map[string]*mongo.Client),
			readReplicas:  make(map[string][]*sql.DB),
			configs:       make(map[string]config.DatabaseConfig),
			readConfigs:   make(map[string][]config.DatabaseConfig),
			readBalancer:  make(map[string]int),
			listeners:     make(map[string]*pq.Listener),
		}

		log.Println("Initializing database service...")
		dbManager.loadFromConfig(cfg)

		// Initialize all databases
		for name, dbConfig := range dbManager.configs {
			if err := dbManager.addDatabase(name, dbConfig); err != nil {
				log.Printf("Failed to connect to database %s: %v", name, err)
			}
		}

		// Initialize read replicas
		for name, replicaConfigs := range dbManager.readConfigs {
			for i, replicaConfig := range replicaConfigs {
				if err := dbManager.addReadReplica(name, i, replicaConfig); err != nil {
					log.Printf("Failed to connect to read replica %s[%d]: %v", name, i, err)
				}
			}
		}
	})

	return dbManager
}

func (s *service) loadFromConfig(cfg *config.Config) {
	s.mu.Lock()
	defer s.mu.Unlock()

	// Load primary databases
	for name, dbConfig := range cfg.Databases {
		s.configs[name] = dbConfig
	}

	// Load read replicas
	for name, replicaConfigs := range cfg.ReadReplicas {
		s.readConfigs[name] = replicaConfigs
	}
}

func (s *service) addDatabase(name string, config config.DatabaseConfig) error {
	s.mu.Lock()
	defer s.mu.Unlock()

	// Check for duplicate database connections
	for existingName, existingConfig := range s.configs {
		if existingName != name &&
			existingConfig.Host == config.Host &&
			existingConfig.Port == config.Port &&
			existingConfig.Database == config.Database &&
			existingConfig.Type == config.Type {
			log.Printf("⚠️  Database %s appears to be a duplicate of %s (same host:port:database), skipping connection", name, existingName)
			return nil
		}
	}

	var db *sql.DB
	var err error

	dbType := DatabaseType(config.Type)

	switch dbType {
	case Postgres:
		db, err = s.openPostgresConnection(config)
	case MySQL:
		db, err = s.openMySQLConnection(config)
	case SQLServer:
		db, err = s.openSQLServerConnection(config)
	case SQLite:
		db, err = s.openSQLiteConnection(config)
	case MongoDB:
		return s.addMongoDB(name, config)
	default:
		return fmt.Errorf("unsupported database type: %s", config.Type)
	}

	if err != nil {
		log.Printf("❌ Error connecting to database %s: %v", name, err)
		return err
	}

	log.Printf("✅ Successfully connected to database: %s", name)
	return s.configureSQLDB(name, db, config)
}

func (s *service) addReadReplica(name string, index int, config config.DatabaseConfig) error {
	s.mu.Lock()
	defer s.mu.Unlock()

	var db *sql.DB
	var err error

	dbType := DatabaseType(config.Type)

	switch dbType {
	case Postgres:
		db, err = s.openPostgresConnection(config)
	case MySQL:
		db, err = s.openMySQLConnection(config)
	case SQLServer:
		db, err = s.openSQLServerConnection(config)
	case SQLite:
		db, err = s.openSQLiteConnection(config)
	default:
		return fmt.Errorf("unsupported database type for read replica: %s", config.Type)
	}

	if err != nil {
		return err
	}

	if s.readReplicas[name] == nil {
		s.readReplicas[name] = make([]*sql.DB, 0)
	}

	// Ensure we have enough slots
	for len(s.readReplicas[name]) <= index {
		s.readReplicas[name] = append(s.readReplicas[name], nil)
	}

	s.readReplicas[name][index] = db
	log.Printf("Successfully connected to read replica %s[%d]", name, index)

	return nil
}

func (s *service) openPostgresConnection(config config.DatabaseConfig) (*sql.DB, error) {
	// Build connection string with security parameters
	// Convert timeout durations to seconds for pgx
	connectTimeoutSec := int(config.ConnectTimeout.Seconds())
	statementTimeoutSec := int(config.StatementTimeout.Seconds())

	connStr := fmt.Sprintf("host=%s port=%d user=%s password=%s dbname=%s sslmode=%s connect_timeout=%d statement_timeout=%d",
		config.Host,
		config.Port,
		config.Username,
		config.Password,
		config.Database,
		config.SSLMode,
		connectTimeoutSec,
		statementTimeoutSec,
	)

	if config.Schema != "" {
		connStr += " search_path=" + config.Schema
	}

	// Add SSL configuration if required
	if config.RequireSSL {
		connStr += " sslcert=" + config.SSLCert + " sslkey=" + config.SSLKey + " sslrootcert=" + config.SSLRootCert
	}

	// Open connection using standard database/sql interface
	db, err := sql.Open("pgx", connStr)
	if err != nil {
		return nil, fmt.Errorf("failed to open PostgreSQL connection: %w", err)
	}

	return db, nil
}

func (s *service) openMySQLConnection(config config.DatabaseConfig) (*sql.DB, error) {
	// Build connection string with security parameters
	connStr := fmt.Sprintf("%s:%s@tcp(%s:%d)/%s?parseTime=true&timeout=%s&readTimeout=%s&writeTimeout=%s",
		config.Username,
		config.Password,
		config.Host,
		config.Port,
		config.Database,
		config.Timeout,
		config.ReadTimeout,
		config.WriteTimeout,
	)

	// Add SSL configuration if required
	if config.RequireSSL {
		connStr += "&tls=true"
		if config.SSLRootCert != "" {
			connStr += "&ssl-ca=" + config.SSLRootCert
		}
		if config.SSLCert != "" {
			connStr += "&ssl-cert=" + config.SSLCert
		}
		if config.SSLKey != "" {
			connStr += "&ssl-key=" + config.SSLKey
		}
	}

	// Open connection
	db, err := sql.Open("mysql", connStr)
	if err != nil {
		return nil, fmt.Errorf("failed to open MySQL connection: %w", err)
	}

	return db, nil
}

func (s *service) openSQLServerConnection(config config.DatabaseConfig) (*sql.DB, error) {
	// Build connection string with security parameters
	// Convert timeout to seconds for SQL Server
	connectTimeoutSec := int(config.ConnectTimeout.Seconds())

	connStr := fmt.Sprintf("sqlserver://%s:%s@%s:%d?database=%s&connection timeout=%d",
		config.Username,
		config.Password,
		config.Host,
		config.Port,
		config.Database,
		connectTimeoutSec,
	)

	// Add SSL configuration if required
	if config.RequireSSL {
		connStr += "&encrypt=true"
		if config.SSLRootCert != "" {
			connStr += "&trustServerCertificate=false"
		} else {
			connStr += "&trustServerCertificate=true"
		}
	}

	// Open connection
	db, err := sql.Open("sqlserver", connStr)
	if err != nil {
		return nil, fmt.Errorf("failed to open SQL Server connection: %w", err)
	}

	return db, nil
}

func (s *service) openSQLiteConnection(config config.DatabaseConfig) (*sql.DB, error) {
	// Open connection
	db, err := sql.Open("sqlite3", config.Path)
	if err != nil {
		return nil, fmt.Errorf("failed to open SQLite connection: %w", err)
	}

	// Enable foreign key constraints and WAL mode for better security and performance
	_, err = db.Exec("PRAGMA foreign_keys = ON; PRAGMA journal_mode = WAL;")
	if err != nil {
		return nil, fmt.Errorf("failed to configure SQLite: %w", err)
	}

	return db, nil
}

func (s *service) addMongoDB(name string, config config.DatabaseConfig) error {
	ctx, cancel := context.WithTimeout(context.Background(), config.Timeout)
	defer cancel()

	// Build MongoDB URI with authentication and TLS options
	uri := fmt.Sprintf("mongodb://%s:%s@%s:%d/%s",
		config.Username,
		config.Password,
		config.Host,
		config.Port,
		config.Database,
	)

	// Configure client options with security settings
	clientOptions := options.Client().ApplyURI(uri)

	// Set TLS configuration if needed
	if config.RequireSSL {
		clientOptions.SetTLSConfig(&tls.Config{
			InsecureSkipVerify: config.SSLMode == "require",
			MinVersion:         tls.VersionTLS12,
		})
	}

	// Set connection timeout
	clientOptions.SetConnectTimeout(config.ConnectTimeout)
	clientOptions.SetServerSelectionTimeout(config.Timeout)

	client, err := mongo.Connect(ctx, clientOptions)
	if err != nil {
		return fmt.Errorf("failed to connect to MongoDB: %w", err)
	}

	// Ping to verify connection
	if err := client.Ping(ctx, nil); err != nil {
		return fmt.Errorf("failed to ping MongoDB: %w", err)
	}

	s.mongoClients[name] = client
	log.Printf("Successfully connected to MongoDB: %s", name)

	return nil
}

func (s *service) configureSQLDB(name string, db *sql.DB, config config.DatabaseConfig) error {
	// Set connection pool limits
	db.SetMaxOpenConns(config.MaxOpenConns)
	db.SetMaxIdleConns(config.MaxIdleConns)
	db.SetConnMaxLifetime(config.ConnMaxLifetime)
	db.SetConnMaxIdleTime(config.MaxIdleTime)

	ctx, cancel := context.WithTimeout(context.Background(), config.Timeout)
	defer cancel()

	if err := db.PingContext(ctx); err != nil {
		db.Close()
		return fmt.Errorf("failed to ping database: %w", err)
	}

	s.sqlDatabases[name] = db

	// PERUBAHAN: Tambahkan pembuatan sqlx.DB dari sql.DB yang sudah ada
	dbType := DatabaseType(config.Type)
	var driverName string

	switch dbType {
	case Postgres:
		driverName = "pgx"
	case MySQL:
		driverName = "mysql"
	case SQLServer:
		driverName = "sqlserver"
	case SQLite:
		driverName = "sqlite3"
	default:
		return fmt.Errorf("unsupported database type for sqlx: %s", config.Type)
	}

	// Buat sqlx.DB dari sql.DB yang sudah ada
	sqlxDB := sqlx.NewDb(db, driverName)
	s.sqlxDatabases[name] = sqlxDB

	log.Printf("Successfully connected to SQL database: %s", name)

	return nil
}

// Health checks the health of all database connections by pinging each database.
func (s *service) Health() map[string]map[string]string {
	s.mu.RLock()
	defer s.mu.RUnlock()

	result := make(map[string]map[string]string)

	// Check SQL databases
	for name, db := range s.sqlDatabases {
		ctx, cancel := context.WithTimeout(context.Background(), 1*time.Second)
		defer cancel()

		stats := make(map[string]string)

		err := db.PingContext(ctx)
		if err != nil {
			stats["status"] = "down"
			stats["error"] = fmt.Sprintf("db down: %v", err)
			stats["type"] = "sql"
			stats["role"] = "primary"
			result[name] = stats
			continue
		}

		stats["status"] = "up"
		stats["message"] = "It's healthy"
		stats["type"] = "sql"
		stats["role"] = "primary"

		dbStats := db.Stats()
		stats["open_connections"] = strconv.Itoa(dbStats.OpenConnections)
		stats["in_use"] = strconv.Itoa(dbStats.InUse)
		stats["idle"] = strconv.Itoa(dbStats.Idle)
		stats["wait_count"] = strconv.FormatInt(dbStats.WaitCount, 10)
		stats["wait_duration"] = dbStats.WaitDuration.String()
		stats["max_idle_closed"] = strconv.FormatInt(dbStats.MaxIdleClosed, 10)
		stats["max_lifetime_closed"] = strconv.FormatInt(dbStats.MaxLifetimeClosed, 10)

		if dbStats.OpenConnections > 40 {
			stats["message"] = "The database is experiencing heavy load."
		}

		if dbStats.WaitCount > 1000 {
			stats["message"] = "The database has a high number of wait events, indicating potential bottlenecks."
		}

		if dbStats.MaxIdleClosed > int64(dbStats.OpenConnections)/2 {
			stats["message"] = "Many idle connections are being closed, consider revising the connection pool settings."
		}

		if dbStats.MaxLifetimeClosed > int64(dbStats.OpenConnections)/2 {
			stats["message"] = "Many connections are being closed due to max lifetime, consider increasing max lifetime or revising the connection usage pattern."
		}

		result[name] = stats
	}

	// Check read replicas
	for name, replicas := range s.readReplicas {
		for i, db := range replicas {
			if db == nil {
				continue
			}

			ctx, cancel := context.WithTimeout(context.Background(), 1*time.Second)
			defer cancel()

			replicaName := fmt.Sprintf("%s_replica_%d", name, i)
			stats := make(map[string]string)

			err := db.PingContext(ctx)
			if err != nil {
				stats["status"] = "down"
				stats["error"] = fmt.Sprintf("read replica down: %v", err)
				stats["type"] = "sql"
				stats["role"] = "replica"
				result[replicaName] = stats
				continue
			}

			stats["status"] = "up"
			stats["message"] = "Read replica healthy"
			stats["type"] = "sql"
			stats["role"] = "replica"

			dbStats := db.Stats()
			stats["open_connections"] = strconv.Itoa(dbStats.OpenConnections)
			stats["in_use"] = strconv.Itoa(dbStats.InUse)
			stats["idle"] = strconv.Itoa(dbStats.Idle)

			result[replicaName] = stats
		}
	}

	// Check MongoDB connections
	for name, client := range s.mongoClients {
		ctx, cancel := context.WithTimeout(context.Background(), 1*time.Second)
		defer cancel()

		stats := make(map[string]string)

		err := client.Ping(ctx, nil)
		if err != nil {
			stats["status"] = "down"
			stats["error"] = fmt.Sprintf("mongodb down: %v", err)
			stats["type"] = "mongodb"
			result[name] = stats
			continue
		}

		stats["status"] = "up"
		stats["message"] = "It's healthy"
		stats["type"] = "mongodb"

		result[name] = stats
	}

	return result
}

// GetDB returns a specific SQL database connection by name
func (s *service) GetDB(name string) (*sql.DB, error) {
	s.mu.RLock()
	defer s.mu.RUnlock()

	db, exists := s.sqlDatabases[name]
	if !exists {
		return nil, fmt.Errorf("database %s not found", name)
	}

	return db, nil
}

// PERUBAHAN: Tambahkan metode GetSQLXDB
// GetSQLXDB returns a specific SQLX database connection by name
func (s *service) GetSQLXDB(name string) (*sqlx.DB, error) {
	s.mu.RLock()
	defer s.mu.RUnlock()

	db, exists := s.sqlxDatabases[name]
	if !exists {
		return nil, fmt.Errorf("database %s not found", name)
	}

	return db, nil
}

// GetReadDB returns a read replica connection using round-robin load balancing
func (s *service) GetReadDB(name string) (*sql.DB, error) {
	s.mu.RLock()
	defer s.mu.RUnlock()

	replicas, exists := s.readReplicas[name]
	if !exists || len(replicas) == 0 {
		// Fallback to primary if no replicas available
		return s.GetDB(name)
	}

	// Round-robin load balancing
	s.readBalancer[name] = (s.readBalancer[name] + 1) % len(replicas)
	selected := replicas[s.readBalancer[name]]

	if selected == nil {
		// Fallback to primary if replica is nil
		return s.GetDB(name)
	}

	return selected, nil
}

// GetMongoClient returns a specific MongoDB client by name
func (s *service) GetMongoClient(name string) (*mongo.Client, error) {
	s.mu.RLock()
	defer s.mu.RUnlock()

	client, exists := s.mongoClients[name]
	if !exists {
		return nil, fmt.Errorf("MongoDB client %s not found", name)
	}

	return client, nil
}

// ListDBs returns list of available database names
func (s *service) ListDBs() []string {
	s.mu.RLock()
	defer s.mu.RUnlock()

	names := make([]string, 0, len(s.sqlDatabases)+len(s.mongoClients))

	for name := range s.sqlDatabases {
		names = append(names, name)
	}

	for name := range s.mongoClients {
		names = append(names, name)
	}

	return names
}

// GetDBType returns the type of a specific database
func (s *service) GetDBType(name string) (DatabaseType, error) {
	s.mu.RLock()
	defer s.mu.RUnlock()

	config, exists := s.configs[name]
	if !exists {
		return "", fmt.Errorf("database %s not found", name)
	}

	return DatabaseType(config.Type), nil
}

// Close closes all database connections
func (s *service) Close() error {
	s.mu.Lock()
	defer s.mu.Unlock()

	var errs []error

	// Close listeners first
	for name, listener := range s.listeners {
		if err := listener.Close(); err != nil {
			errs = append(errs, fmt.Errorf("failed to close listener for %s: %w", name, err))
		}
	}

	for name, db := range s.sqlDatabases {
		if err := db.Close(); err != nil {
			errs = append(errs, fmt.Errorf("failed to close database %s: %w", name, err))
		} else {
			log.Printf("Disconnected from SQL database: %s", name)
		}
	}

	for name, replicas := range s.readReplicas {
		for i, db := range replicas {
			if db != nil {
				if err := db.Close(); err != nil {
					errs = append(errs, fmt.Errorf("failed to close read replica %s[%d]: %w", name, i, err))
				} else {
					log.Printf("Disconnected from read replica: %s[%d]", name, i)
				}
			}
		}
	}

	for name, client := range s.mongoClients {
		if err := client.Disconnect(context.Background()); err != nil {
			errs = append(errs, fmt.Errorf("failed to disconnect MongoDB client %s: %w", name, err))
		} else {
			log.Printf("Disconnected from MongoDB: %s", name)
		}
	}

	s.sqlDatabases = make(map[string]*sql.DB)
	s.sqlxDatabases = make(map[string]*sqlx.DB) // Reset map sqlx
	s.mongoClients = make(map[string]*mongo.Client)
	s.readReplicas = make(map[string][]*sql.DB)
	s.configs = make(map[string]config.DatabaseConfig)
	s.readConfigs = make(map[string][]config.DatabaseConfig)
	s.listeners = make(map[string]*pq.Listener)

	if len(errs) > 0 {
		return fmt.Errorf("errors closing databases: %v", errs)
	}

	return nil
}

// GetPrimaryDB returns primary database connection
func (s *service) GetPrimaryDB(name string) (*sql.DB, error) {
	return s.GetDB(name)
}

// ExecuteQuery executes a query with parameters and returns rows
func (s *service) ExecuteQuery(ctx context.Context, dbName string, query string, args ...interface{}) (*sql.Rows, error) {
	db, err := s.GetDB(dbName)
	if err != nil {
		return nil, fmt.Errorf("failed to get database %s: %w", dbName, err)
	}

	// Use parameterized queries to prevent SQL injection
	rows, err := db.QueryContext(ctx, query, args...)
	if err != nil {
		return nil, fmt.Errorf("failed to execute query: %w", err)
	}

	return rows, nil
}

// ExecuteQueryRow executes a query with parameters and returns a single row
func (s *service) ExecuteQueryRow(ctx context.Context, dbName string, query string, args ...interface{}) *sql.Row {
	db, err := s.GetDB(dbName)
	if err != nil {
		// Return an empty row with error
		row := &sql.Row{}
		return row
	}

	// Use parameterized queries to prevent SQL injection
	return db.QueryRowContext(ctx, query, args...)
}

// Exec executes a query with parameters and returns the result
func (s *service) Exec(ctx context.Context, dbName string, query string, args ...interface{}) (sql.Result, error) {
	db, err := s.GetDB(dbName)
	if err != nil {
		return nil, fmt.Errorf("failed to get database %s: %w", dbName, err)
	}

	// Use parameterized queries to prevent SQL injection
	result, err := db.ExecContext(ctx, query, args...)
	if err != nil {
		return nil, fmt.Errorf("failed to execute query: %w", err)
	}

	return result, nil
}

// ListenForChanges implements PostgreSQL LISTEN/NOTIFY for real-time updates
func (s *service) ListenForChanges(ctx context.Context, dbName string, channels []string, callback func(string, string)) error {
	s.mu.RLock()
	config, exists := s.configs[dbName]
	s.mu.RUnlock()

	if !exists {
		return fmt.Errorf("database %s not found", dbName)
	}

	// Only support PostgreSQL for LISTEN/NOTIFY
	if DatabaseType(config.Type) != Postgres {
		return fmt.Errorf("LISTEN/NOTIFY only supported for PostgreSQL databases")
	}

	// Create connection string for listener
	// Convert timeout to seconds for pq
	connectTimeoutSec := int(config.ConnectTimeout.Seconds())

	connStr := fmt.Sprintf("postgres://%s:%s@%s:%d/%s?sslmode=%s&connect_timeout=%d",
		config.Username,
		config.Password,
		config.Host,
		config.Port,
		config.Database,
		config.SSLMode,
		connectTimeoutSec,
	)

	// Create listener
	listener := pq.NewListener(
		connStr,
		10*time.Second,
		time.Minute,
		func(ev pq.ListenerEventType, err error) {
			if err != nil {
				log.Printf("Database listener (%s) error: %v", dbName, err)
			}
		},
	)

	// Store listener for cleanup
	s.listenersMu.Lock()
	s.listeners[dbName] = listener
	s.listenersMu.Unlock()

	// Listen to specified channels
	for _, channel := range channels {
		err := listener.Listen(channel)
		if err != nil {
			listener.Close()
			return fmt.Errorf("failed to listen to channel %s: %w", channel, err)
		}
		log.Printf("Listening to database channel: %s on %s", channel, dbName)
	}

	// Start listening loop
	go func() {
		defer func() {
			listener.Close()
			s.listenersMu.Lock()
			delete(s.listeners, dbName)
			s.listenersMu.Unlock()
			log.Printf("Database listener for %s stopped", dbName)
		}()

		for {
			select {
			case n := <-listener.Notify:
				if n != nil {
					callback(n.Channel, n.Extra)
				}
			case <-ctx.Done():
				return
			case <-time.After(90 * time.Second):
				// Send ping to keep connection alive
				go func() {
					if err := listener.Ping(); err != nil {
						log.Printf("Listener ping failed for %s: %v", dbName, err)
					}
				}()
			}
		}
	}()

	return nil
}

// NotifyChange sends a notification to a PostgreSQL channel
func (s *service) NotifyChange(dbName, channel, payload string) error {
	db, err := s.GetDB(dbName)
	if err != nil {
		return fmt.Errorf("failed to get database %s: %w", dbName, err)
	}

	// Check if it's PostgreSQL
	s.mu.RLock()
	config, exists := s.configs[dbName]
	s.mu.RUnlock()

	if !exists {
		return fmt.Errorf("database %s configuration not found", dbName)
	}

	if DatabaseType(config.Type) != Postgres {
		return fmt.Errorf("NOTIFY only supported for PostgreSQL databases")
	}

	// Execute NOTIFY with parameterized query to prevent SQL injection
	query := "SELECT pg_notify($1, $2)"
	_, err = db.Exec(query, channel, payload)
	if err != nil {
		return fmt.Errorf("failed to send notification: %w", err)
	}

	log.Printf("Sent notification to channel %s on %s: %s", channel, dbName, payload)
	return nil
}