feat: user creation

internal/domain/user.go

@@ -0,0 +1,49 @@
+package domain
+
+import (
+	"context"
+	"errors"
+	"time"
+
+	"golang.org/x/crypto/bcrypt"
+)
+
+type User struct {
+	ID        string    `json:"id"`
+	Email     string    `json:"email"`
+	Name      string    `json:"name"`
+	CreatedAt time.Time `json:"created_at"`
+}
+
+type UserRepository interface {
+	CreateUser(ctx context.Context, email string, name string, passwordHash string) (*User, error)
+}
+
+type UserService struct {
+	repo UserRepository
+}
+
+func NewUserService(r UserRepository) *UserService {
+	return &UserService{repo: r}
+}
+
+func (s *UserService) CreateUser(ctx context.Context, email string, name string, password string) (*User, error) {
+	if len(email) == 0 {
+		return nil, errors.New("email is required")
+	}
+
+	if len(name) == 0 {
+		return nil, errors.New("name is required")
+	}
+
+	if len(password) == 0 {
+		return nil, errors.New("password is required")
+	}
+
+	hash, err := bcrypt.GenerateFromPassword([]byte(password), bcrypt.DefaultCost)
+	if err != nil {
+		return nil, err
+	}
+
+	return s.repo.CreateUser(ctx, email, name, string(hash))
+}