feat: add ability to create an account via the webui (#223)

* feat: add ability to create an account via the webui without the need for autobrrctl

* refactor redundant code block.

* fix: early return and 0 value

internal/auth/service.go

@@ -10,7 +10,9 @@ import (
 )
 
 type Service interface {
+	GetUserCount(ctx context.Context) (int, error)
 	Login(ctx context.Context, username, password string) (*domain.User, error)
+	CreateUser(ctx context.Context, username, password string) error
 }
 
 type service struct {
@@ -23,9 +25,13 @@ func NewService(userSvc user.Service) Service {
 	}
 }
 
+func (s *service) GetUserCount(ctx context.Context) (int, error) {
+	return s.userSvc.GetUserCount(ctx)
+}
+
 func (s *service) Login(ctx context.Context, username, password string) (*domain.User, error) {
 	if username == "" || password == "" {
-		return nil, errors.New("bad credentials")
+		return nil, errors.New("empty credentials supplied")
 	}
 
 	// find user
@@ -50,3 +56,33 @@ func (s *service) Login(ctx context.Context, username, password string) (*domain
 
 	return u, nil
 }
+
+func (s *service) CreateUser(ctx context.Context, username, password string) error {
+	if username == "" || password == "" {
+		return errors.New("empty credentials supplied")
+	}
+
+	userCount, err := s.userSvc.GetUserCount(ctx)
+	if err != nil {
+		return err
+	}
+
+	if userCount > 0 {
+		return errors.New("only 1 user account is supported at the moment")
+	}
+
+	hashed, err := argon2id.CreateHash(password, argon2id.DefaultParams)
+	if err != nil {
+		return errors.New("failed to hash password")
+	}
+
+	newUser := domain.User{
+		Username: username,
+		Password: hashed,
+	}
+	if err := s.userSvc.CreateUser(context.Background(), newUser); err != nil {
+		return errors.New("failed to create new user")
+	}
+
+	return nil
+}