go mod init fiber-sql-app
go get github.com/gofiber/fiber/v2
go get gorm.io/gorm
go get gorm.io/driver/postgres // or your preferred SQL driver

type Config struct {
    Host     string
    Port     string
    Password string
    User     string
    DBName   string
    SSLMode  string
}

func InitDatabase(config *Config) (*gorm.DB, error) {
    dsn := fmt.Sprintf(
        "host=%s user=%s password=%s dbname=%s port=%s sslmode=%s",
        config.Host, config.User, config.Password, config.DBName, config.Port, config.SSLMode,
    )

    db, err := gorm.Open(postgres.Open(dsn), &gorm.Config{})
    if err != nil {
        return nil, err
    }

    sqlDB, err := db.DB()
    if err != nil {
        return nil, err
    }

    // Configure connection pool
    sqlDB.SetMaxIdleConns(10)
    sqlDB.SetMaxOpenConns(100)
    sqlDB.SetConnMaxLifetime(time.Hour)

    return db, nil
}

func SetupRoutes(app *fiber.App, db *gorm.DB) {
    api := app.Group("/api")

    api.Get("/users", func(c *fiber.Ctx) error {
        var users []User
        result := db.Find(&users)
        if result.Error != nil {
            return c.Status(500).JSON(fiber.Map{
                "error": "Database error",
            })
        }
        return c.JSON(users)
    })

    api.Post("/users", func(c *fiber.Ctx) error {
        user := new(User)
        if err := c.BodyParser(user); err != nil {
            return c.Status(400).JSON(fiber.Map{
                "error": "Invalid request",
            })
        }

        result := db.Create(user)
        if result.Error != nil {
            return c.Status(500).JSON(fiber.Map{
                "error": "Could not create user",
            })
        }

        return c.JSON(user)
    })
}

func DBErrorHandler() fiber.Handler {
    return func(c *fiber.Ctx) error {
        err := c.Next()
        if err != nil {
            if errors.Is(err, gorm.ErrRecordNotFound) {
                return c.Status(404).JSON(fiber.Map{
                    "error": "Resource not found",
                })
            }
            // Handle other database errors
            return c.Status(500).JSON(fiber.Map{
                "error": "Internal server error",
            })
        }
        return nil
    }
}