fix: Improve login error handling and database resilience

 Better Error Differentiation:
- 401 INVALID_CREDENTIALS: Wrong email/password (user error)
- 503 SERVICE_UNAVAILABLE: Database/server issues (system error)
- Clear error messages for different failure types

 Database Wake-up for Login:
- Retry login with database wake-up on 503/network errors
- 2-second wait for database to wake up before retry
- Graceful fallback to original error if retry fails

 Frontend Error Handling:
- Specific error messages for different failure types
- Network error detection and user-friendly messages
- Better UX with actionable error descriptions

Now users will know if it's their credentials or if the server is sleeping!
401 = Wrong password, 503 = Database sleeping, Network Error = Connection issue

Author: GigaElk

backend/src/controllers/authController.ts

@@ -113,14 +113,30 @@ export class AuthController {
         data: result,
       });
     } catch (error: any) {
-      res.status(401).json({
-        error: {
-          code: 'LOGIN_FAILED',
-          message: error.message,
-        },
-        timestamp: new Date().toISOString(),
-        path: req.path,
-      });
+      // Check if it's a database/server error vs authentication error
+      if (error.message === 'Invalid email or password') {
+        // Legitimate authentication failure
+        res.status(401).json({
+          error: {
+            code: 'INVALID_CREDENTIALS',
+            message: error.message,
+          },
+          timestamp: new Date().toISOString(),
+          path: req.path,
+        });
+      } else {
+        // Likely a server/database error
+        console.error('Login server error:', error);
+        res.status(503).json({
+          error: {
+            code: 'SERVICE_UNAVAILABLE',
+            message: 'Login service temporarily unavailable. Please try again in a moment.',
+            details: process.env.NODE_ENV === 'development' ? error.message : undefined,
+          },
+          timestamp: new Date().toISOString(),
+          path: req.path,
+        });
+      }
     }
   }
 

frontend/src/contexts/AuthContext.tsx

@@ -57,7 +57,22 @@ export const AuthProvider: React.FC<{ children: React.ReactNode }> = ({ children
       // Set user
       setUser(response.user)
     } catch (error: any) {
-      const message = error.response?.data?.error?.message || 'Login failed'
+      let message = 'Login failed'
+      
+      if (error.response?.data?.error) {
+        const errorData = error.response.data.error
+        
+        if (errorData.code === 'INVALID_CREDENTIALS') {
+          message = 'Invalid email or password. Please check your credentials and try again.'
+        } else if (errorData.code === 'SERVICE_UNAVAILABLE') {
+          message = 'Login service is temporarily unavailable. Please try again in a moment.'
+        } else {
+          message = errorData.message || 'Login failed'
+        }
+      } else if (error.code === 'ERR_NETWORK') {
+        message = 'Unable to connect to the server. Please check your internet connection and try again.'
+      }
+      
       throw new Error(message)
     }
   }

frontend/src/services/authService.ts

@@ -46,8 +46,33 @@ export interface UsernameAvailabilityResponse {
 export const authService = {
   // Authentication
   async login(data: LoginRequest): Promise<AuthResponse> {
-    const response = await api.post('/auth/login', data)
-    return response.data.data
+    try {
+      const response = await api.post('/auth/login', data)
+      return response.data.data
+    } catch (error: any) {
+      // If we get a 503 (service unavailable), try to wake up the database and retry once
+      if (error.response?.status === 503 || error.code === 'ERR_NETWORK') {
+        console.log('Login failed, attempting to wake up database and retry...')
+        
+        try {
+          // Try to wake up the database
+          await api.get('/wake')
+          
+          // Wait a moment for the database to wake up
+          await new Promise(resolve => setTimeout(resolve, 2000))
+          
+          // Retry the login
+          const response = await api.post('/auth/login', data)
+          return response.data.data
+        } catch (retryError) {
+          // If retry fails, throw the original error
+          throw error
+        }
+      }
+      
+      // For other errors (like 401), throw immediately
+      throw error
+    }
   },
 
   async register(data: RegisterRequest): Promise<AuthResponse> {