refac: several unverified users can exist at once: an empty reset or verification code is stored as no value so it doesn't break the unique constraint, and deleting a user removes the row so the same username and email can register again

internal/infrastructure/persistence/mappers/userMapper.go

@@ -5,15 +5,29 @@ import (
 	"RenewCMS/internal/infrastructure/persistence/models"
 )
 
+func nullableStringToDomain(value *string) string {
+	if value == nil {
+		return ""
+	}
+	return *value
+}
+
+func DomainToNullableString(value string) *string {
+	if value == "" {
+		return nil
+	}
+	return &value
+}
+
 func UserToDomain(m models.User) user.User {
 	return user.User{
 		ID:                     m.ID,
 		Username:               m.Username,
 		Password:               m.Password,
-		PasswordResetCode:      m.PasswordResetCode,
+		PasswordResetCode:      nullableStringToDomain(m.PasswordResetCode),
 		Email:                  m.Email,
 		IsVerified:             m.IsVerified,
-		VerificationCode:       m.VerificationCode,
+		VerificationCode:       nullableStringToDomain(m.VerificationCode),
 		VerificationExpiration: m.VerificationExpiration,
 		CreatedAt:              m.CreatedAt,
 		UpdatedAt:              m.UpdatedAt,
@@ -24,10 +38,10 @@ func UserToModel(a user.User) models.User {
 	return models.User{
 		Username:               a.Username,
 		Password:               a.Password,
-		PasswordResetCode:      a.PasswordResetCode,
+		PasswordResetCode:      DomainToNullableString(a.PasswordResetCode),
 		Email:                  a.Email,
 		IsVerified:             a.IsVerified,
-		VerificationCode:       a.VerificationCode,
+		VerificationCode:       DomainToNullableString(a.VerificationCode),
 		VerificationExpiration: a.VerificationExpiration,
 		CreatedAt:              a.CreatedAt,
 		UpdatedAt:              a.UpdatedAt,

internal/infrastructure/persistence/models/userModel.go

@@ -2,19 +2,16 @@ package models
 
 import (
 	"time"
-
-	"gorm.io/gorm"
 )
 
 type User struct {
-	gorm.Model
-	ID                     uint32 `gorm:"primaryKey;autoIncrement"`
-	Username               string `gorm:"unique;not null"`
-	Password               string `gorm:"not null"`
-	PasswordResetCode      string `gorm:"unique"`
-	Email                  string `gorm:"unique;not null"`
-	IsVerified             bool   `gorm:"default=false;not null"`
-	VerificationCode       string `gorm:"unique"`
+	ID                     uint32  `gorm:"primaryKey;autoIncrement"`
+	Username               string  `gorm:"unique;not null"`
+	Password               string  `gorm:"not null"`
+	PasswordResetCode      *string `gorm:"unique"`
+	Email                  string  `gorm:"unique;not null"`
+	IsVerified             bool    `gorm:"default=false;not null"`
+	VerificationCode       *string `gorm:"unique"`
 	VerificationExpiration time.Time
 	CreatedAt              time.Time `gorm:"autoCreateTime"`
 	UpdatedAt              time.Time `gorm:"autoUpdateTime"`

internal/infrastructure/persistence/repositories/userRepository.go

@@ -30,8 +30,9 @@ func (u *UserRepository) Create(user domainUser.User) (domainUser.User, error) {
 	creationResult := u.db.Create(&entity.User{
 		Username:               user.Username,
 		Password:               user.Password,
+		PasswordResetCode:      mappers.DomainToNullableString(user.PasswordResetCode),
 		Email:                  user.Email,
-		VerificationCode:       user.VerificationCode,
+		VerificationCode:       mappers.DomainToNullableString(user.VerificationCode),
 		VerificationExpiration: user.VerificationExpiration,
 	})
 	if creationResult.Error != nil {
@@ -121,7 +122,7 @@ func (u *UserRepository) UpdatePasswordResetCode(userId uint32, code string) (do
 		return domainUser.User{}, mapNotFoundErr(err, domainUser.ErrUserNotFound)
 	}
 
-	localUser.PasswordResetCode = code
+	localUser.PasswordResetCode = mappers.DomainToNullableString(code)
 	err = u.db.Save(&localUser).Error
 	if err != nil {
 		return domainUser.User{}, err