feat: require invitation code for registration

internal/accounts/service.go

@@ -155,7 +155,7 @@ func (s *Service) Register(ctx context.Context, input RegisterInput) (*Result, e
 	if len([]rune(input.Password)) < 6 || len([]byte(input.Password)) > 72 {
 		return nil, ErrPasswordInvalid
 	}
-	if input.ReferralCode != "" && !referralPattern.MatchString(input.ReferralCode) {
+	if !referralPattern.MatchString(input.ReferralCode) {
 		return nil, ErrReferralInvalid
 	}
 	if !input.PrivacyAccepted {

internal/accounts/service_test.go

@@ -46,8 +46,9 @@ func TestRegisterValidation(t *testing.T) {
 		{name: "username", input: RegisterInput{Username: "张 三", Phone: "13800138000", Password: "secret1", PrivacyAccepted: true}, want: ErrUsernameInvalid},
 		{name: "phone", input: RegisterInput{Username: "alice", Phone: "12800138000", Password: "secret1", PrivacyAccepted: true}, want: ErrPhoneInvalid},
 		{name: "password", input: RegisterInput{Username: "alice", Phone: "13800138000", Password: "123", PrivacyAccepted: true}, want: ErrPasswordInvalid},
+		{name: "referral required", input: RegisterInput{Username: "alice", Phone: "13800138000", Password: "secret1", PrivacyAccepted: true}, want: ErrReferralInvalid},
 		{name: "referral", input: RegisterInput{Username: "alice", Phone: "13800138000", Password: "secret1", ReferralCode: "bad!", PrivacyAccepted: true}, want: ErrReferralInvalid},
-		{name: "privacy", input: RegisterInput{Username: "alice", Phone: "13800138000", Password: "secret1"}, want: ErrPrivacyNotAccepted},
+		{name: "privacy", input: RegisterInput{Username: "alice", Phone: "13800138000", Password: "secret1", ReferralCode: "ABC123"}, want: ErrPrivacyNotAccepted},
 	}
 	for _, test := range tests {
 		t.Run(test.name, func(t *testing.T) {

internal/store/accounts.go

@@ -129,7 +129,7 @@ func accountByMobile(ctx context.Context, db queryer, tenantID int64, mobile str
 func referralParent(ctx context.Context, tx *sqlx.Tx, tenantID int64, code string) (int64, int, string, error) {
 	code = strings.TrimSpace(code)
 	if code == "" {
-		return 0, 1, "", nil
+		return 0, 0, "", ErrReferralInvalid
 	}
 	var parent struct {
 		ID    int64  `db:"id"`