support unlinking external authentication

pkg/core/user_external_auth_type.go

@@ -1,5 +1,7 @@
 package core
 
+const USER_EXTERNAL_AUTH_TYPE_CATEOGRY_OAUTH2 = "oauth2"
+
 // UserExternalAuthType represents the type of user external authentication
 type UserExternalAuthType string
 
@@ -11,14 +13,19 @@ const (
 	USER_EXTERNAL_AUTH_TYPE_OAUTH2_GITHUB    UserExternalAuthType = "github"
 )
 
-// IsValid checks if the UserExternalAuthType is valid
-func (t UserExternalAuthType) IsValid() bool {
+// GetCategory returns the category of the UserExternalAuthType
+func (t UserExternalAuthType) GetCategory() string {
 	switch t {
 	case USER_EXTERNAL_AUTH_TYPE_OAUTH2_OIDC,
 		USER_EXTERNAL_AUTH_TYPE_OAUTH2_NEXTCLOUD,
 		USER_EXTERNAL_AUTH_TYPE_OAUTH2_GITEA,
 		USER_EXTERNAL_AUTH_TYPE_OAUTH2_GITHUB:
-		return true
+		return USER_EXTERNAL_AUTH_TYPE_CATEOGRY_OAUTH2
 	}
-	return false
+	return ""
+}
+
+// IsValid checks if the UserExternalAuthType is valid
+func (t UserExternalAuthType) IsValid() bool {
+	return t.GetCategory() != ""
 }