Implement phone number validation for customer and user registration and updates

Added functionality to check for existing customers and users by phone number during registration and updates. Updated the handler, service, and repository layers to include phone number checks, ensuring unique phone numbers across customers and users.

internal/user/repository.go

@@ -22,6 +22,7 @@ type Repository interface {
 	UpdatePasswordReset(ctx context.Context, id, hashedPassword, updatedBy string) error
 	GetByEmail(ctx context.Context, email string) (*User, error)
 	GetByUsername(ctx context.Context, username string) (*User, error)
+	GetByPhone(ctx context.Context, phone string) (*User, error)
 	GetByIDs(ctx context.Context, userIDs []string) ([]User, error)
 	Search(ctx context.Context, form *SearchUsersForm, pagination *response.Pagination) (*orm.PaginatedResult[User], error)
 }
@@ -38,6 +39,8 @@ func NewRepository(mongoManager *orm.ConnectionManager, logger logger.Logger) Re
 	// Create indexes using the ORM's index management
 	indexes := []orm.Index{
 		*orm.CreateTextIndex("search_idx", "full_name", "email", "username"),
+		*orm.CreateUniqueIndex("phone_idx", bson.D{{Key: "phone", Value: 1}}).
+			WithPartialFilterExpression(bson.M{"phone": bson.M{"$type": "string", "$ne": ""}}),
 	}
 
 	// Create indexes
@@ -250,6 +253,23 @@ func (r *userRepository) GetByEmail(ctx context.Context, email string) (*User, e
 	return user, nil
 }
 
+// GetByPhone retrieves a user by phone number
+func (r *userRepository) GetByPhone(ctx context.Context, phone string) (*User, error) {
+	user, err := r.ormRepo.FindOne(ctx, bson.M{"phone": phone})
+	if err != nil {
+		if errors.Is(err, orm.ErrDocumentNotFound) {
+			return nil, errors.New("user not found")
+		}
+		r.logger.Error("Failed to get user by phone", map[string]interface{}{
+			"error": err.Error(),
+			"phone": phone,
+		})
+		return nil, err
+	}
+
+	return user, nil
+}
+
 // GetByUsername retrieves a user by username
 func (r *userRepository) GetByUsername(ctx context.Context, username string) (*User, error) {
 	user, err := r.ormRepo.FindOne(ctx, bson.M{"username": username})