feat: use six-digit numeric member invite codes

internal/accounts/service.go

@@ -8,6 +8,8 @@ import (
 	"encoding/hex"
 	"encoding/json"
 	"errors"
+	"fmt"
+	"math/big"
 	"regexp"
 	"strconv"
 	"strings"
@@ -39,7 +41,7 @@ var (
 
 var (
 	phonePattern         = regexp.MustCompile(`^1[3-9][0-9]{9}$`)
-	referralPattern      = regexp.MustCompile(`^[A-Za-z0-9]{1,32}$`)
+	referralPattern      = regexp.MustCompile(`^[0-9]{6}$`)
 	tradePasswordPattern = regexp.MustCompile(`^[0-9]{6}$`)
 )
 
@@ -170,26 +172,40 @@ func (s *Service) Register(ctx context.Context, input RegisterInput) (*Result, e
 	if err != nil {
 		return nil, err
 	}
-	inviteCode, err := newPublicID("", 8)
-	if err != nil {
-		return nil, err
-	}
-	account, err := s.repository.RegisterAccount(ctx, store.AccountRegistration{
-		TenantID:     s.cfg.DefaultTenantID,
-		MemberNo:     memberNo,
-		Username:     input.Username,
-		Mobile:       input.Phone,
-		PasswordHash: string(passwordHash),
-		ReferralCode: input.ReferralCode,
-		InviteCode:   inviteCode,
-	})
-	if err != nil {
+	for attempt := 0; attempt < 10; attempt++ {
+		inviteCode, err := newInviteCode()
+		if err != nil {
+			return nil, err
+		}
+		account, err := s.repository.RegisterAccount(ctx, store.AccountRegistration{
+			TenantID:     s.cfg.DefaultTenantID,
+			MemberNo:     memberNo,
+			Username:     input.Username,
+			Mobile:       input.Phone,
+			PasswordHash: string(passwordHash),
+			ReferralCode: input.ReferralCode,
+			InviteCode:   inviteCode,
+		})
+		if errors.Is(err, store.ErrInviteCodeExists) {
+			continue
+		}
 		if errors.Is(err, store.ErrReferralInvalid) {
 			return nil, ErrReferralInvalid
 		}
-		return nil, err
+		if err != nil {
+			return nil, err
+		}
+		return s.issueSession(ctx, account, input.DeviceID)
 	}
-	return s.issueSession(ctx, account, input.DeviceID)
+	return nil, ErrUnavailable
+}
+
+func newInviteCode() (string, error) {
+	number, err := rand.Int(rand.Reader, big.NewInt(1000000))
+	if err != nil {
+		return "", err
+	}
+	return fmt.Sprintf("%06d", number.Int64()), nil
 }
 
 func validMemberName(value string) bool {