feat: Implement Two-Factor Authentication (2FA) functionality

- Added support for Two-Factor Authentication, including setup, verification, and disabling features.
- Introduced new components for 2FA setup and verification, enhancing user security.
- Updated user model to include fields for 2FA secret, status, and backup codes.
- Created migration to add necessary database fields for 2FA.
- Enhanced authentication handlers to manage 2FA processes during login and profile updates.
- Updated routes to include 2FA-related endpoints for setup and verification.

internal/db/db.go

@@ -25,6 +25,9 @@ type User struct {
 	AccountLocked       *bool `gorm:"default:false"`
 	LockoutUntil        *time.Time
 	Theme               string `gorm:"default:'light'"`
+	TwoFactorSecret     string `gorm:"type:varchar(32)"`
+	TwoFactorEnabled    bool   `gorm:"default:false"`
+	BackupCodes         string `gorm:"type:text"` // Comma-separated backup codes
 	CreatedAt           time.Time
 	UpdatedAt           time.Time
 }

internal/db/migrations/003_add_2fa.go

@@ -0,0 +1,80 @@
+package migrations
+
+import (
+	"fmt"
+	"os"
+	"time"
+
+	"github.com/go-gormigrate/gormigrate/v2"
+	"gorm.io/gorm"
+)
+
+// Add2FA creates a migration for adding Two-Factor Authentication fields
+func Add2FA() *gormigrate.Migration {
+	return &gormigrate.Migration{
+		ID: "003_add_2fa",
+		Migrate: func(tx *gorm.DB) error {
+			// Check if any tables exist (indicating an existing database)
+			var count int64
+			if err := tx.Raw("SELECT count(*) FROM sqlite_master WHERE type='table' AND name NOT LIKE 'sqlite_%'").Scan(&count).Error; err != nil {
+				return fmt.Errorf("failed to check for existing tables: %v", err)
+			}
+
+			// If tables exist, create a backup
+			if count > 0 {
+				// Get the database path
+				sqlDB, err := tx.DB()
+				if err != nil {
+					return fmt.Errorf("failed to get underlying database: %v", err)
+				}
+
+				var seq int
+				var name, dbPath string
+				if err := sqlDB.QueryRow("PRAGMA database_list").Scan(&seq, &name, &dbPath); err != nil {
+					return fmt.Errorf("failed to get database path: %v", err)
+				}
+
+				// Create backup file with timestamp
+				backupFile := fmt.Sprintf("%s.backup.%s", dbPath, time.Now().Format("20060102_150405"))
+
+				// Read original database
+				data, err := os.ReadFile(dbPath)
+				if err != nil {
+					return fmt.Errorf("failed to read database for backup: %v", err)
+				}
+
+				// Write backup
+				if err := os.WriteFile(backupFile, data, 0600); err != nil {
+					return fmt.Errorf("failed to create database backup: %v", err)
+				}
+
+				fmt.Printf("Created database backup at: %s\n", backupFile)
+			}
+
+			// Add new columns for 2FA - one at a time for SQLite compatibility
+			if err := tx.Exec(`ALTER TABLE users ADD COLUMN two_factor_secret VARCHAR(32)`).Error; err != nil {
+				return err
+			}
+			if err := tx.Exec(`ALTER TABLE users ADD COLUMN two_factor_enabled BOOLEAN DEFAULT FALSE`).Error; err != nil {
+				return err
+			}
+			if err := tx.Exec(`ALTER TABLE users ADD COLUMN backup_codes TEXT`).Error; err != nil {
+				return err
+			}
+			return nil
+		},
+		Rollback: func(tx *gorm.DB) error {
+			// Remove 2FA columns - one at a time for SQLite compatibility
+			if err := tx.Exec(`ALTER TABLE users DROP COLUMN two_factor_secret`).Error; err != nil {
+				return err
+			}
+			if err := tx.Exec(`ALTER TABLE users DROP COLUMN two_factor_enabled`).Error; err != nil {
+				return err
+			}
+			if err := tx.Exec(`ALTER TABLE users DROP COLUMN backup_codes`).Error; err != nil {
+				return err
+			}
+			return nil
+		},
+	}
+}

internal/db/migrations/migrations.go

@@ -10,6 +10,7 @@ func InitMigrations(db *gorm.DB) *gormigrate.Gormigrate {
 	migrations := []*gormigrate.Migration{
 		InitialSchema(),
 		UpdateGDriveType(),
+		Add2FA(),
 	}
 
 	return gormigrate.New(db, gormigrate.DefaultOptions, migrations)