feat: change email, export my data, delete account (with data anonymization)

internal/infrastructure/persistence/repositories/userRepository.go

@@ -242,6 +242,80 @@ func (u *UserRepository) UpdateDisplayName(userId uint32, displayName string) (d
 	return mappers.UserToDomain(localUser), nil
 }
 
+func (u *UserRepository) IsEmailInUse(email string, exceptUserId uint32) (bool, error) {
+	return isEmailInUse(u.db, email, exceptUserId)
+}
+
+func isEmailInUse(db *gorm.DB, email string, exceptUserId uint32) (bool, error) {
+	var holders int64
+	err := db.Model(&entity.User{}).Where("LOWER(email) = LOWER(?) AND id <> ?", email, exceptUserId).Count(&holders).Error
+	return holders > 0, err
+}
+
+func (u *UserRepository) SetPendingEmailChange(userId uint32, pendingEmail string, code string, expiration time.Time) (domainUser.User, error) {
+	return u.updatePendingEmailChange(userId, map[string]any{
+		"pending_email":           mappers.DomainToNullableString(pendingEmail),
+		"email_change_code":       mappers.DomainToNullableString(code),
+		"email_change_expiration": expiration,
+	})
+}
+
+func (u *UserRepository) ClearPendingEmailChange(userId uint32) (domainUser.User, error) {
+	return u.updatePendingEmailChange(userId, clearedEmailChange())
+}
+
+func clearedEmailChange() map[string]any {
+	return map[string]any{
+		"pending_email":           nil,
+		"email_change_code":       nil,
+		"email_change_expiration": time.Time{},
+	}
+}
+
+func (u *UserRepository) updatePendingEmailChange(userId uint32, columns map[string]any) (domainUser.User, error) {
+	result := u.db.Model(&entity.User{}).Where("id = ?", userId).Updates(columns)
+	if result.Error != nil {
+		return domainUser.User{}, result.Error
+	}
+	return u.Get(userId)
+}
+
+func (u *UserRepository) ConfirmEmailChange(userId uint32, pendingEmail string, code string, now time.Time) (domainUser.User, error) {
+	taken, err := isEmailInUse(u.db, pendingEmail, userId)
+	if err != nil {
+		return domainUser.User{}, err
+	}
+	columns := clearedEmailChange()
+	if !taken {
+		columns["email"] = pendingEmail
+	}
+	result := pendingChangeOf(u.db, userId, pendingEmail, code).Where("email_change_expiration > ?", now).Updates(columns)
+	if result.Error != nil && isUniqueViolation(result.Error) {
+		return domainUser.User{}, u.refuseTakenAddress(userId, pendingEmail, code)
+	}
+	if result.Error != nil {
+		return domainUser.User{}, result.Error
+	}
+	if result.RowsAffected == 0 {
+		return domainUser.User{}, domainUser.ErrInvalidEmailChangeCode
+	}
+	if taken {
+		return domainUser.User{}, domainUser.ErrEmailUnavailable
+	}
+	return u.Get(userId)
+}
+
+func (u *UserRepository) refuseTakenAddress(userId uint32, pendingEmail string, code string) error {
+	if err := pendingChangeOf(u.db, userId, pendingEmail, code).Updates(clearedEmailChange()).Error; err != nil {
+		return err
+	}
+	return domainUser.ErrEmailUnavailable
+}
+
+func pendingChangeOf(db *gorm.DB, userId uint32, pendingEmail string, code string) *gorm.DB {
+	return db.Model(&entity.User{}).Where("id = ? AND pending_email = ? AND email_change_code = ?", userId, pendingEmail, code)
+}
+
 func (u *UserRepository) UpdateRole(id uint32, from uint32, to uint32, assignedBy uint32) (domainUser.User, error) {
 	err := u.db.Transaction(func(tx *gorm.DB) error {
 		query := tx.Model(&entity.User{}).Where("id = ? AND EXISTS (SELECT 1 FROM roles WHERE id = ?)", id, to)