feat: TelegramLoginButton with OIDC popup + legacy widget fallback

- Add oidc_enabled/oidc_client_id to TelegramWidgetConfig interface and fallback
- Add loginTelegramOIDC API method for id_token auth
- Add loginWithTelegramOIDC to auth store
- Rewrite TelegramLoginButton: OIDC popup when enabled, legacy widget otherwise
- Extend Window.Telegram type with Login SDK in vite-env.d.ts

src/api/auth.ts

@@ -49,6 +49,20 @@ export const authApi = {
     return response.data;
   },
 
+  // Telegram OIDC authentication (popup flow with id_token)
+  loginTelegramOIDC: async (
+    idToken: string,
+    campaignSlug?: string | null,
+    referralCode?: string | null,
+  ): Promise<AuthResponse> => {
+    const response = await apiClient.post<AuthResponse>('/cabinet/auth/telegram/oidc', {
+      id_token: idToken,
+      campaign_slug: campaignSlug || undefined,
+      referral_code: referralCode || undefined,
+    });
+    return response.data;
+  },
+
   // Email login
   loginEmail: async (
     email: string,

src/api/branding.ts

@@ -29,6 +29,8 @@ export interface TelegramWidgetConfig {
   radius: number;
   userpic: boolean;
   request_access: boolean;
+  oidc_enabled: boolean;
+  oidc_client_id: string;
 }
 
 export interface AnalyticsCounters {
@@ -273,6 +275,8 @@ export const brandingApi = {
         radius: 8,
         userpic: true,
         request_access: true,
+        oidc_enabled: false,
+        oidc_client_id: '',
       };
     }
   },

src/components/TelegramLoginButton.tsx

@@ -1,7 +1,9 @@
-import { useEffect, useRef } from 'react';
+import { useEffect, useRef, useCallback, useState } from 'react';
 import { useTranslation } from 'react-i18next';
 import { useQuery } from '@tanstack/react-query';
 import { brandingApi, type TelegramWidgetConfig } from '../api/branding';
+import { useAuthStore } from '../store/auth';
+import { useNavigate } from 'react-router';
 
 interface TelegramLoginButtonProps {
   referralCode?: string;
@@ -9,7 +11,11 @@ interface TelegramLoginButtonProps {
 
 export default function TelegramLoginButton({ referralCode }: TelegramLoginButtonProps) {
   const { t } = useTranslation();
+  const navigate = useNavigate();
   const containerRef = useRef<HTMLDivElement>(null);
+  const [oidcLoading, setOidcLoading] = useState(false);
+  const [oidcError, setOidcError] = useState('');
+  const loginWithTelegramOIDC = useAuthStore((s) => s.loginWithTelegramOIDC);
 
   const { data: widgetConfig } = useQuery<TelegramWidgetConfig>({
     queryKey: ['telegram-widget-config'],
@@ -19,14 +25,68 @@ export default function TelegramLoginButton({ referralCode }: TelegramLoginButto
 
   const botUsername =
     widgetConfig?.bot_username || import.meta.env.VITE_TELEGRAM_BOT_USERNAME || '';
+  const isOIDC = widgetConfig?.oidc_enabled && widgetConfig?.oidc_client_id;
 
-  // Load widget script
+  // OIDC callback handler
+  const handleOIDCCallback = useCallback(
+    async (data: { id_token?: string; error?: string }) => {
+      if (data.error || !data.id_token) {
+        setOidcError(data.error || t('auth.loginFailed'));
+        setOidcLoading(false);
+        return;
+      }
+      try {
+        setOidcLoading(true);
+        await loginWithTelegramOIDC(data.id_token);
+        navigate('/');
+      } catch (err: unknown) {
+        const error = err as { response?: { data?: { detail?: string } } };
+        setOidcError(error.response?.data?.detail || t('common.error'));
+      } finally {
+        setOidcLoading(false);
+      }
+    },
+    [loginWithTelegramOIDC, navigate, t],
+  );
+
+  // Load OIDC script and init
   useEffect(() => {
-    if (!containerRef.current || !botUsername || !widgetConfig) return;
+    if (!isOIDC || !widgetConfig?.oidc_client_id) return;
+
+    const scriptId = 'telegram-login-oidc-script';
+    let script = document.getElementById(scriptId) as HTMLScriptElement | null;
+
+    const initTelegramLogin = () => {
+      if (window.Telegram?.Login) {
+        window.Telegram.Login.init(
+          {
+            client_id: widgetConfig.oidc_client_id,
+            request_access: widgetConfig.request_access ? ['write'] : undefined,
+            lang: document.documentElement.lang || 'en',
+          },
+          handleOIDCCallback,
+        );
+      }
+    };
+
+    if (!script) {
+      script = document.createElement('script');
+      script.id = scriptId;
+      script.src = 'https://oauth.telegram.org/js/telegram-login.js?3';
+      script.async = true;
+      script.onload = initTelegramLogin;
+      document.head.appendChild(script);
+    } else {
+      // Script already loaded, just re-init
+      initTelegramLogin();
+    }
+  }, [isOIDC, widgetConfig?.oidc_client_id, widgetConfig?.request_access, handleOIDCCallback]);
+
+  // Legacy widget effect (only when NOT OIDC)
+  useEffect(() => {
+    if (isOIDC || !containerRef.current || !botUsername || !widgetConfig) return;
 
     const container = containerRef.current;
-
-    // Clear previous widget
     while (container.firstChild) {
       container.removeChild(container.firstChild);
     }
@@ -52,7 +112,7 @@ export default function TelegramLoginButton({ referralCode }: TelegramLoginButto
         container.removeChild(container.firstChild);
       }
     };
-  }, [botUsername, widgetConfig]);
+  }, [isOIDC, botUsername, widgetConfig]);
 
   if (!botUsername || botUsername === 'your_bot') {
     return (
@@ -64,7 +124,33 @@ export default function TelegramLoginButton({ referralCode }: TelegramLoginButto
 
   return (
     <div className="flex flex-col items-center space-y-4">
-      <div ref={containerRef} className="flex justify-center" />
+      {/* OIDC mode: custom button that opens popup */}
+      {isOIDC ? (
+        <div className="flex flex-col items-center space-y-2">
+          <button
+            type="button"
+            onClick={() => {
+              setOidcError('');
+              if (window.Telegram?.Login) {
+                window.Telegram.Login.open();
+              }
+            }}
+            disabled={oidcLoading}
+            className="inline-flex items-center gap-2 rounded-lg bg-[#54a9eb] px-6 py-3 text-sm font-medium text-white shadow-sm transition-colors hover:bg-[#4a96d2] disabled:opacity-50"
+          >
+            <svg className="h-5 w-5" viewBox="0 0 24 24" fill="currentColor">
+              <path d="M11.944 0A12 12 0 0 0 0 12a12 12 0 0 0 12 12 12 12 0 0 0 12-12A12 12 0 0 0 12 0a12 12 0 0 0-.056 0zm4.962 7.224c.1-.002.321.023.465.14a.506.506 0 0 1 .171.325c.016.093.036.306.02.472-.18 1.898-.962 6.502-1.36 8.627-.168.9-.499 1.201-.82 1.23-.696.065-1.225-.46-1.9-.902-1.056-.693-1.653-1.124-2.678-1.8-1.185-.78-.417-1.21.258-1.91.177-.184 3.247-2.977 3.307-3.23.007-.032.014-.15-.056-.212s-.174-.041-.249-.024c-.106.024-1.793 1.14-5.061 3.345-.48.33-.913.49-1.302.48-.428-.008-1.252-.241-1.865-.44-.752-.245-1.349-.374-1.297-.789.027-.216.325-.437.893-.663 3.498-1.524 5.83-2.529 6.998-3.014 3.332-1.386 4.025-1.627 4.476-1.635z" />
+            </svg>
+            {oidcLoading
+              ? t('common.loading')
+              : t('auth.loginWithTelegram', 'Sign in with Telegram')}
+          </button>
+          {oidcError && <p className="text-xs text-red-500">{oidcError}</p>}
+        </div>
+      ) : (
+        /* Legacy widget mode: iframe-based widget */
+        <div ref={containerRef} className="flex justify-center" />
+      )}
 
       <div className="text-center">
         <p className="mb-2 text-xs text-gray-500">{t('auth.orOpenInApp')}</p>

src/store/auth.ts

@@ -37,6 +37,7 @@ interface AuthState {
   checkAdminStatus: () => Promise<void>;
   loginWithTelegram: (initData: string) => Promise<void>;
   loginWithTelegramWidget: (data: TelegramWidgetData) => Promise<void>;
+  loginWithTelegramOIDC: (idToken: string) => Promise<void>;
   loginWithEmail: (email: string, password: string) => Promise<void>;
   loginWithOAuth: (
     provider: string,
@@ -285,6 +286,21 @@ export const useAuthStore = create<AuthState>()(
         await get().checkAdminStatus();
       },
 
+      loginWithTelegramOIDC: async (idToken) => {
+        const campaignSlug = consumeCampaignSlug();
+        const referralCode = consumeReferralCode();
+        const response = await authApi.loginTelegramOIDC(idToken, campaignSlug, referralCode);
+        tokenStorage.setTokens(response.access_token, response.refresh_token);
+        set({
+          accessToken: response.access_token,
+          refreshToken: response.refresh_token,
+          user: response.user,
+          isAuthenticated: true,
+          pendingCampaignBonus: response.campaign_bonus || null,
+        });
+        await get().checkAdminStatus();
+      },
+
       loginWithEmail: async (email, password) => {
         const campaignSlug = consumeCampaignSlug();
         const referralCode = consumeReferralCode();

src/vite-env.d.ts

@@ -19,8 +19,23 @@ interface TelegramWebAppGlobal {
   offEvent?: (event: string, callback: () => void) => void;
 }
 
+/** Telegram Login JS SDK — loaded from https://oauth.telegram.org/js/telegram-login.js */
+interface TelegramLoginGlobal {
+  init: (
+    options: {
+      client_id: string;
+      request_access?: string[];
+      lang?: string;
+    },
+    callback: (data: { id_token?: string; user?: Record<string, unknown>; error?: string }) => void,
+  ) => void;
+  open: () => void;
+  auth: () => void;
+}
+
 interface Window {
   Telegram?: {
     WebApp?: TelegramWebAppGlobal;
+    Login?: TelegramLoginGlobal;
   };
 }