add changes

backend/middleware/validation.middleware.js

@@ -0,0 +1,86 @@
+const { body, validationResult } = require('express-validator');
+
+/**
+ * Validation middleware for user registration
+ */
+exports.validateRegistration = [
+  body('username')
+    .trim()
+    .notEmpty()
+    .withMessage('Username is required')
+    .isLength({ min: 3, max: 50 })
+    .withMessage('Username must be between 3 and 50 characters')
+    .matches(/^[a-zA-Z0-9_]+$/)
+    .withMessage('Username can only contain letters, numbers, and underscores'),
+  
+  body('email')
+    .trim()
+    .notEmpty()
+    .withMessage('Email is required')
+    .isEmail()
+    .withMessage('Please provide a valid email address')
+    .normalizeEmail(),
+  
+  body('password')
+    .notEmpty()
+    .withMessage('Password is required')
+    .isLength({ min: 8 })
+    .withMessage('Password must be at least 8 characters long')
+    .matches(/^(?=.*[a-z])(?=.*[A-Z])(?=.*\d)/)
+    .withMessage('Password must contain at least one uppercase letter, one lowercase letter, and one number'),
+  
+  body('guestSessionId')
+    .optional()
+    .trim()
+    .notEmpty()
+    .withMessage('Guest session ID cannot be empty if provided'),
+  
+  // Check for validation errors
+  (req, res, next) => {
+    const errors = validationResult(req);
+    if (!errors.isEmpty()) {
+      return res.status(400).json({
+        success: false,
+        message: 'Validation failed',
+        errors: errors.array().map(err => ({
+          field: err.path,
+          message: err.msg
+        }))
+      });
+    }
+    next();
+  }
+];
+
+/**
+ * Validation middleware for user login
+ */
+exports.validateLogin = [
+  body('email')
+    .trim()
+    .notEmpty()
+    .withMessage('Email is required')
+    .isEmail()
+    .withMessage('Please provide a valid email address')
+    .normalizeEmail(),
+  
+  body('password')
+    .notEmpty()
+    .withMessage('Password is required'),
+  
+  // Check for validation errors
+  (req, res, next) => {
+    const errors = validationResult(req);
+    if (!errors.isEmpty()) {
+      return res.status(400).json({
+        success: false,
+        message: 'Validation failed',
+        errors: errors.array().map(err => ({
+          field: err.path,
+          message: err.msg
+        }))
+      });
+    }
+    next();
+  }
+];