backend-service/internal/repositories/user_repository.go

package repositories

import (
	"errors"
	"fmt"

	"attune-heart-therapy/internal/models"

	"gorm.io/gorm"
)

// userRepository implements the UserRepository interface
type userRepository struct {
	db *gorm.DB
}

// NewUserRepository creates a new instance of UserRepository
func NewUserRepository(db *gorm.DB) UserRepository {
	return &userRepository{
		db: db,
	}
}

// Create creates a new user in the database
func (r *userRepository) Create(user *models.User) error {
	if user == nil {
		return errors.New("user cannot be nil")
	}

	if err := r.db.Create(user).Error; err != nil {
		if errors.Is(err, gorm.ErrDuplicatedKey) {
			return fmt.Errorf("user with email %s already exists", user.Email)
		}
		return fmt.Errorf("failed to create user: %w", err)
	}

	return nil
}

// GetByID retrieves a user by their ID
func (r *userRepository) GetByID(id uint) (*models.User, error) {
	if id == 0 {
		return nil, errors.New("invalid user ID")
	}

	var user models.User
	if err := r.db.First(&user, id).Error; err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return nil, fmt.Errorf("user with ID %d not found", id)
		}
		return nil, fmt.Errorf("failed to get user by ID: %w", err)
	}

	return &user, nil
}

// GetByEmail retrieves a user by their email address
func (r *userRepository) GetByEmail(email string) (*models.User, error) {
	if email == "" {
		return nil, errors.New("email cannot be empty")
	}

	var user models.User
	if err := r.db.Where("email = ?", email).First(&user).Error; err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return nil, fmt.Errorf("user with email %s not found", email)
		}
		return nil, fmt.Errorf("failed to get user by email: %w", err)
	}

	return &user, nil
}

// Update updates an existing user in the database
func (r *userRepository) Update(user *models.User) error {
	if user == nil {
		return errors.New("user cannot be nil")
	}

	if user.ID == 0 {
		return errors.New("user ID is required for update")
	}

	// Check if user exists
	var existingUser models.User
	if err := r.db.First(&existingUser, user.ID).Error; err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return fmt.Errorf("user with ID %d not found", user.ID)
		}
		return fmt.Errorf("failed to check user existence: %w", err)
	}

	// Update the user
	if err := r.db.Save(user).Error; err != nil {
		if errors.Is(err, gorm.ErrDuplicatedKey) {
			return fmt.Errorf("user with email %s already exists", user.Email)
		}
		return fmt.Errorf("failed to update user: %w", err)
	}

	return nil
}

// GetActiveUsersCount returns the count of active (non-deleted) users
func (r *userRepository) GetActiveUsersCount() (int64, error) {
	var count int64
	if err := r.db.Model(&models.User{}).Count(&count).Error; err != nil {
		return 0, fmt.Errorf("failed to get active users count: %w", err)
	}

	return count, nil
}

// GetAllUsers retrieves all users with pagination
func (r *userRepository) GetAllUsers(limit, offset int) ([]models.User, int64, error) {
	var users []models.User
	var total int64

	// Get total count
	if err := r.db.Model(&models.User{}).Count(&total).Error; err != nil {
		return nil, 0, fmt.Errorf("failed to get users count: %w", err)
	}

	// Get users with pagination
	if err := r.db.Limit(limit).Offset(offset).Order("created_at DESC").Find(&users).Error; err != nil {
		return nil, 0, fmt.Errorf("failed to get users: %w", err)
	}

	// Clear password hashes for security
	for i := range users {
		users[i].PasswordHash = ""
	}

	return users, total, nil
}