fix: clarify OpenAI OAuth proxy errors

frontend/src/composables/__tests__/useOpenAIOAuth.spec.ts

@@ -6,6 +6,19 @@ vi.mock('@/stores/app', () => ({
   })
 }))
 
+vi.mock('vue-i18n', () => ({
+  useI18n: () => ({
+    t: (key: string) => {
+      const messages: Record<string, string> = {
+        'admin.accounts.oauth.openai.failedToExchangeCode': 'OpenAI 授权码兑换失败',
+        'admin.accounts.oauth.openai.errors.OPENAI_OAUTH_PROXY_REQUIRED':
+          '未设置代理，当前服务器无法直连 OpenAI，导致 OpenAI OAuth 请求失败。请先选择可访问 OpenAI 的代理后重试；如果授权码已失效，请重新生成授权链接。'
+      }
+      return messages[key] ?? key
+    }
+  })
+}))
+
 vi.mock('@/api/admin', () => ({
   adminAPI: {
     accounts: {
@@ -17,6 +30,7 @@ vi.mock('@/api/admin', () => ({
 }))
 
 import { useOpenAIOAuth } from '@/composables/useOpenAIOAuth'
+import { adminAPI } from '@/api/admin'
 
 describe('useOpenAIOAuth.buildCredentials', () => {
   it('should keep client_id when token response contains it', () => {
@@ -46,3 +60,21 @@ describe('useOpenAIOAuth.buildCredentials', () => {
     expect(creds.refresh_token).toBe('rt')
   })
 })
+
+describe('useOpenAIOAuth.exchangeAuthCode', () => {
+  it('shows a clear proxy hint when code exchange fails without a proxy', async () => {
+    vi.mocked(adminAPI.accounts.exchangeCode).mockRejectedValueOnce({
+      status: 502,
+      reason: 'OPENAI_OAUTH_PROXY_REQUIRED',
+      message: 'OpenAI OAuth token exchange failed: no proxy is configured.'
+    })
+    const oauth = useOpenAIOAuth()
+
+    const tokenInfo = await oauth.exchangeAuthCode('code', 'session-id', 'state')
+
+    expect(tokenInfo).toBeNull()
+    expect(oauth.error.value).toBe(
+      '未设置代理，当前服务器无法直连 OpenAI，导致 OpenAI OAuth 请求失败。请先选择可访问 OpenAI 的代理后重试；如果授权码已失效，请重新生成授权链接。'
+    )
+  })
+})

frontend/src/composables/useOpenAIOAuth.ts

@@ -1,6 +1,8 @@
 import { ref } from 'vue'
+import { useI18n } from 'vue-i18n'
 import { useAppStore } from '@/stores/app'
 import { adminAPI } from '@/api/admin'
+import { extractApiErrorMessage, extractI18nErrorMessage } from '@/utils/apiError'
 
 export interface OpenAITokenInfo {
   access_token?: string
@@ -26,6 +28,7 @@ export type OpenAIOAuthPlatform = 'openai'
 
 export function useOpenAIOAuth() {
   const appStore = useAppStore()
+  const { t } = useI18n()
   const endpointPrefix = '/admin/openai'
 
   // State
@@ -78,7 +81,7 @@ export function useOpenAIOAuth() {
       }
       return true
     } catch (err: any) {
-      error.value = err.response?.data?.detail || 'Failed to generate OpenAI auth URL'
+      error.value = extractApiErrorMessage(err, t('admin.accounts.oauth.openai.failedToGenerateUrl'))
       appStore.showError(error.value)
       return false
     } finally {
@@ -114,7 +117,12 @@ export function useOpenAIOAuth() {
       const tokenInfo = await adminAPI.accounts.exchangeCode(`${endpointPrefix}/exchange-code`, payload)
       return tokenInfo as OpenAITokenInfo
     } catch (err: any) {
-      error.value = err.response?.data?.detail || 'Failed to exchange OpenAI auth code'
+      error.value = extractI18nErrorMessage(
+        err,
+        t,
+        'admin.accounts.oauth.openai.errors',
+        t('admin.accounts.oauth.openai.failedToExchangeCode')
+      )
       appStore.showError(error.value)
       return null
     } finally {
@@ -147,7 +155,12 @@ export function useOpenAIOAuth() {
       )
       return tokenInfo as OpenAITokenInfo
     } catch (err: any) {
-      error.value = err.response?.data?.detail || err.message || 'Failed to validate refresh token'
+      error.value = extractI18nErrorMessage(
+        err,
+        t,
+        'admin.accounts.oauth.openai.errors',
+        t('admin.accounts.oauth.openai.failedToValidateRT')
+      )
       appStore.showError(error.value)
       return null
     } finally {