feat: implement account email mismatch error handling and improve user feedback in authentication flows

src/langbot/pkg/api/http/controller/groups/user.py

@@ -4,6 +4,7 @@ import asyncio
 import traceback
 
 from .. import group
+from .....entity.errors import account as account_errors
 
 
 @group.group_class('user', '/api/v1/user')
@@ -141,6 +142,8 @@ class UserRouterGroup(group.RouterGroup):
                         'user': user_obj.user,
                     }
                 )
+            except account_errors.AccountEmailMismatchError as e:
+                return self.fail(3, str(e))
             except ValueError as e:
                 traceback.print_exc()
                 return self.fail(1, str(e))

src/langbot/pkg/api/http/service/user.py

@@ -10,6 +10,7 @@ import asyncio
 from ....core import app
 from ....entity.persistence import user
 from ....utils import constants
+from ....entity.errors import account as account_errors
 
 
 class UserService:
@@ -174,9 +175,7 @@ class UserService:
             # Check if system is already initialized
             is_initialized = await self.is_initialized()
             if is_initialized:
-                raise ValueError(
-                    'This LangBot instance already has an account. Please use the existing account to login.'
-                )
+                raise account_errors.AccountEmailMismatchError()
 
             # Create new Space user (first time initialization)
             await self.ap.persistence_mgr.execute_async(

src/langbot/pkg/entity/errors/account.py

@@ -0,0 +1,6 @@
+from __future__ import annotations
+
+
+class AccountEmailMismatchError(Exception):
+    def __str__(self):
+        return 'Account email mismatch'

web/src/app/auth/space/callback/page.tsx

@@ -48,9 +48,15 @@ function SpaceOAuthCallbackContent() {
         setTimeout(() => {
           router.push('/home');
         }, 1000);
-      } catch {
+      } catch (err) {
         setStatus('error');
-        setErrorMessage(t('common.spaceLoginFailed'));
+        const errorObj = err as { msg?: string };
+        const errMsg = (errorObj?.msg || '').toLowerCase();
+        if (errMsg.includes('account email mismatch')) {
+          setErrorMessage(t('account.spaceEmailMismatch'));
+        } else {
+          setErrorMessage(t('common.spaceLoginFailed'));
+        }
       }
     },
     [router, t],
@@ -74,9 +80,13 @@ function SpaceOAuthCallbackContent() {
         }, 1000);
       } catch (err) {
         setStatus('error');
-        setErrorMessage(
-          err instanceof Error ? err.message : t('account.bindSpaceFailed'),
-        );
+        const errorObj = err as { msg?: string };
+        const errMsg = (errorObj?.msg || '').toLowerCase();
+        if (errMsg.includes('account email mismatch')) {
+          setErrorMessage(t('account.spaceEmailMismatch'));
+        } else {
+          setErrorMessage(t('account.bindSpaceFailed'));
+        }
       } finally {
         setIsProcessing(false);
       }

web/src/app/infra/http/BackendClient.ts

@@ -753,7 +753,7 @@ export class BackendClient extends BaseHttpClient {
     });
   }
 
-  public bindSpaceAccount(
+  public async bindSpaceAccount(
     code: string,
     state: string,
   ): Promise<{
@@ -761,7 +761,17 @@ export class BackendClient extends BaseHttpClient {
     user: string;
     account_type: 'local' | 'space';
   }> {
-    return this.post('/api/v1/user/bind-space', { code, state });
+    const response = await this.instance.post('/api/v1/user/bind-space', {
+      code,
+      state,
+    });
+    if (response.data.code !== 0) {
+      throw {
+        code: response.data.code,
+        msg: response.data.msg || 'Unknown error',
+      };
+    }
+    return response.data.data;
   }
 
   // ============ Space OAuth API (Redirect Flow) ============
@@ -778,10 +788,19 @@ export class BackendClient extends BaseHttpClient {
     return this.get('/api/v1/user/space/authorize-url', params);
   }
 
-  public exchangeSpaceOAuthCode(code: string): Promise<{
+  public async exchangeSpaceOAuthCode(code: string): Promise<{
     token: string;
     user: string;
   }> {
-    return this.post('/api/v1/user/space/callback', { code });
+    const response = await this.instance.post('/api/v1/user/space/callback', {
+      code,
+    });
+    if (response.data.code !== 0) {
+      throw {
+        code: response.data.code,
+        msg: response.data.msg || 'Unknown error',
+      };
+    }
+    return response.data.data;
   }
 }

web/src/app/infra/http/BaseHttpClient.ts

@@ -93,9 +93,7 @@ export abstract class BaseHttpClient {
         // 统一错误处理
         if (error.response) {
           const { status, data } = error.response;
-          // Backend uses 'msg' field, also check 'message' for compatibility
-          const errMessage =
-            (data as { msg?: string })?.msg || data?.message || error.message;
+          const errMsg = (data as { msg?: string })?.msg || error.message;
 
           switch (status) {
             case 401:
@@ -107,23 +105,23 @@ export abstract class BaseHttpClient {
               }
               break;
             case 403:
-              console.error('Permission denied:', errMessage);
+              console.error('Permission denied:', errMsg);
               break;
             case 500:
-              console.error('Server error:', errMessage);
+              console.error('Server error:', errMsg);
               break;
           }
 
           return Promise.reject({
             code: data?.code || status,
-            message: errMessage,
+            msg: errMsg,
             data: data?.data || null,
           });
         }
 
         return Promise.reject({
           code: -1,
-          message: error.message || 'Network Error',
+          msg: error.message || 'Network Error',
           data: null,
         });
       },

web/src/i18n/locales/en-US.ts

@@ -789,6 +789,8 @@ const enUS = {
     bindSpaceInvalidState:
       'Invalid bind request. Please try again from account settings.',
     setPasswordHint: 'Set a password to login with email and password',
+    spaceEmailMismatch:
+      'Space login email does not match the local account email',
   },
 };
 

web/src/i18n/locales/ja-JP.ts

@@ -798,6 +798,8 @@ const jaJP = {
       '無効な連携リクエストです。アカウント設定から再度お試しください。',
     setPasswordHint:
       'パスワードを設定するとメールとパスワードでログインできます',
+    spaceEmailMismatch:
+      'Spaceログインのメールアドレスがローカルアカウントのメールアドレスと一致しません',
   },
 };
 

web/src/i18n/locales/zh-Hans.ts

@@ -753,6 +753,7 @@ const zhHans = {
     bindSpaceFailed: '绑定 Space 账户失败',
     bindSpaceInvalidState: '无效的绑定请求，请从账户设置重新发起',
     setPasswordHint: '设置密码后可使用邮箱密码登录',
+    spaceEmailMismatch: 'Space登录账号邮箱与本实例账号邮箱不匹配',
   },
 };
 

web/src/i18n/locales/zh-Hant.ts

@@ -750,6 +750,7 @@ const zhHant = {
     bindSpaceFailed: '綁定 Space 帳戶失敗',
     bindSpaceInvalidState: '無效的綁定請求，請從帳戶設定重新發起',
     setPasswordHint: '設定密碼後可使用電子郵件密碼登入',
+    spaceEmailMismatch: 'Space登入帳號電子郵件與本實例帳號電子郵件不匹配',
   },
 };