fix: user registration with email support

pages/api/v1/auth/register.ts

@@ -23,12 +23,23 @@ export default async function handler(req: NextApiRequest, res: NextApiResponse)
             return res.status(400).json({ success: false, error: 'Password must be at least 6 characters' });
         }
 
+        if (email && !email.includes('@')) {
+            return res.status(400).json({ success: false, error: 'Invalid email format' });
+        }
+
         // Check if username already exists
         const existingUser = await UserService.getUserByUsername(username);
         if (existingUser) {
             return res.status(409).json({ success: false, error: 'Username already taken' });
         }
 
+        if (email) {
+            const existingEmail = await UserService.getUserByEmail(email);
+            if (existingEmail) {
+                return res.status(409).json({ success: false, error: 'Email already registered' });
+            }
+        }
+
         // Create new user
         const user = await UserService.createUser(username, password, email);
 
@@ -45,6 +56,7 @@ export default async function handler(req: NextApiRequest, res: NextApiResponse)
                 user: {
                     id: user.id,
                     username: user.username,
+                    email: user.email,
                     avatarUrl: user.avatarUrl,
                     role: user.role,
                     status: user.status
@@ -53,7 +65,7 @@ export default async function handler(req: NextApiRequest, res: NextApiResponse)
             }
         });
     } catch (error) {
-        console.error('Registration error:', error);
+        console.error('Registration error details:', error);
         return res.status(500).json({ success: false, error: 'Registration failed' });
     }
 }