feat: add support for more username formats

backend/internal/dto/user_dto.go

@@ -23,8 +23,3 @@ type OneTimeAccessTokenCreateDto struct {
 	UserID    string    `json:"userId" binding:"required"`
 	ExpiresAt time.Time `json:"expiresAt" binding:"required"`
 }
-
-type LoginUserDto struct {
-	Username string `json:"username" binding:"required"`
-	Password string `json:"password" binding:"required"`
-}

backend/internal/dto/validations.go

@@ -20,7 +20,10 @@ var validateUrlList validator.Func = func(fl validator.FieldLevel) bool {
 }
 
 var validateUsername validator.Func = func(fl validator.FieldLevel) bool {
-	regex := "^[a-z0-9_]*$"
+	// [a-zA-Z0-9]      : The username must start with an alphanumeric character
+	// [a-zA-Z0-9_.@-]* : The rest of the username can contain alphanumeric characters, dots, underscores, hyphens, and "@" symbols
+	// [a-zA-Z0-9]$     : The username must end with an alphanumeric character
+	regex := "^[a-zA-Z0-9][a-zA-Z0-9_.@-]*[a-zA-Z0-9]$"
 	matched, _ := regexp.MatchString(regex, fl.Field().String())
 	return matched
 }

backend/internal/utils/controller_error_util.go

@@ -46,7 +46,7 @@ func handleValidationError(validationErrors validator.ValidationErrors) string {
 		case "email":
 			errorMessage = fmt.Sprintf("%s must be a valid email address", fieldName)
 		case "username":
-			errorMessage = fmt.Sprintf("%s must contain only lowercase letters, numbers, and underscores", fieldName)
+			errorMessage = fmt.Sprintf("%s must only contain lowercase letters, numbers, underscores, dots, hyphens, and '@' symbols and not start or end with a special character", fieldName)
 		case "url":
 			errorMessage = fmt.Sprintf("%s must be a valid URL", fieldName)
 		case "min":

frontend/src/routes/settings/admin/users/user-form.svelte

@@ -32,7 +32,10 @@
 			.string()
 			.min(2)
 			.max(30)
-			.regex(/^[a-z0-9_]+$/, 'Only lowercase letters, numbers, and underscores are allowed'),
+			.regex(
+				/^[a-z0-9_@.-]+$/,
+				"Username can only contain lowercase letters, numbers, underscores, dots, hyphens, and '@' symbols"
+			),
 		email: z.string().email(),
 		isAdmin: z.boolean()
 	});