feat: Assign candidate functionality added

Backend/models/Quiz.js

@@ -46,10 +46,6 @@ const quizSchema = new mongoose.Schema({
     enum: ['easy', 'medium', 'hard'],
     default: 'medium'
   },
-  topic: {  
-    type: String,
-    trim: true
-  },
   generatedByAI: {
     type: Boolean,
     default: false

Backend/models/User.js

@@ -32,7 +32,16 @@ const userSchema = new mongoose.Schema({
   isLoggedIn: {
     type: Boolean,
     default: false
-  }
+  },
+  level: {
+    type: String,
+    enum: ['beginner', 'intermediate', 'advanced', 'expert'],
+    default: 'beginner'
+  },
+  topicsOfInterest: [{
+    topic: { type: String, required: true },
+    comfortLevel: { type: Number, min: 0, max: 100, required: true }
+  }]
 }, {
   timestamps: true
 });

Backend/routes/admin.js

@@ -98,6 +98,37 @@
     }
   });
 
+  // @route   PUT /api/admin/users/:userId/level
+  // @desc    Update a candidate's level (beginner/intermediate/advanced/expert)
+  // @access  Admin, HR
+  router.put('/users/:userId/level', async (req, res) => {
+    try {
+      const { userId } = req.params;
+      const { level } = req.body;
+
+      const validLevels = ['beginner', 'intermediate', 'advanced', 'expert'];
+      if (!level || !validLevels.includes(level)) {
+        return res.status(400).json({ message: 'Invalid level. Must be one of: beginner, intermediate, advanced, expert' });
+      }
+
+      const user = await User.findById(userId);
+      if (!user) return res.status(404).json({ message: 'User not found' });
+      if (user.role !== 'candidate') return res.status(400).json({ message: 'Level can only be set for candidates' });
+
+      const previousLevel = user.level || 'beginner';
+      user.level = level;
+      await user.save();
+
+      res.json({
+        message: `Level changed from ${previousLevel} to ${level}`,
+        user: { _id: user._id, name: user.name, level: user.level },
+        previousLevel,
+        newLevel: level
+      });
+    } catch (error) {
+      res.status(500).json({ message: 'Server error', error: error.message });
+    }
+  });
   // @route   PUT /api/admin/users/:userId
   // @desc    Edit a user (specifically for HR users to edit email/password)
   // @access  Admin
@@ -477,7 +508,6 @@ IMPORTANT: The "correct" value must be the EXACT TEXT of the option, not the opt
         createdBy: req.user._id,
         category: quizTopic,
         difficulty: diffLevel,
-        topic: quizTopic,
         assignToAll: assignToAll === 'true' || assignToAll === true,
         assignees: assignees || [],
         assignedGroups: assignedGroups || [],
@@ -632,7 +662,7 @@ IMPORTANT: The "correct" value must be the EXACT TEXT of the option, not the opt
         });
       }
 
-      const { title, timer, category, difficulty, topic, assignToAll, assignees, assignedGroups, questions } = req.body;
+      const { title, timer, category, difficulty, assignToAll, assignees, assignedGroups, questions } = req.body;
 
       // Update quiz metadata
       const updateData = {};
@@ -640,7 +670,6 @@ IMPORTANT: The "correct" value must be the EXACT TEXT of the option, not the opt
       if (timer) updateData.timer = parseInt(timer);
       if (category) updateData.category = category;
       if (difficulty) updateData.difficulty = difficulty;
-      if (topic !== undefined) updateData.topic = topic;
       if (assignToAll !== undefined) updateData.assignToAll = assignToAll;
       if (assignees) updateData.assignees = assignees;
       if (assignedGroups) updateData.assignedGroups = assignedGroups;
@@ -893,4 +922,98 @@ IMPORTANT: The "correct" value must be the EXACT TEXT of the option, not the opt
     return a === b;
   }
 
-  module.exports = router;
+// @route   GET /api/admin/quiz/:quizId/assign-candidates
+// @desc    Get candidates filtered by quiz category + difficulty using per-topic comfortLevel
+// @access  Admin
+router.get('/quiz/:quizId/assign-candidates', async (req, res) => {
+  try {
+    const quiz = await Quiz.findById(req.params.quizId);
+    if (!quiz) return res.status(404).json({ message: 'Quiz not found' });
+
+    const allCandidates = await User.find({ role: 'candidate' });
+    
+    // Quiz parameters
+    const quizDifficulty = quiz.difficulty ? quiz.difficulty.toLowerCase() : '';
+    const quizCategory = quiz.category ? quiz.category.toLowerCase() : '';
+    
+    // Comfort level → proficiency mapping:
+    // 0-25   = beginner
+    // 26-50  = intermediate
+    // 51-75  = advanced
+    // 76-100 = expert
+    function comfortToProficiency(comfort) {
+      if (comfort <= 25) return 'beginner';
+      if (comfort <= 50) return 'intermediate';
+      if (comfort <= 75) return 'advanced';
+      return 'expert';
+    }
+    
+    // Quiz difficulty → required proficiency mapping:
+    // Easy   → beginner
+    // Medium → intermediate, advanced
+    // Hard   → expert
+    function getRequiredProficiencies(difficulty) {
+      if (difficulty === 'easy') return ['beginner'];
+      if (difficulty === 'medium') return ['intermediate', 'advanced'];
+      if (difficulty === 'hard') return ['expert'];
+      return ['beginner', 'intermediate', 'advanced', 'expert']; // no difficulty = all
+    }
+    
+    const requiredProficiencies = getRequiredProficiencies(quizDifficulty);
+    const filtered = [];
+    
+    for (const candidate of allCandidates) {
+      // If quiz has no category, show all candidates (no topic filter)
+      if (!quizCategory) {
+        filtered.push({
+          _id: candidate._id,
+          name: candidate.name,
+          email: candidate.email,
+          level: candidate.level,
+          topicsOfInterest: candidate.topicsOfInterest
+        });
+        continue;
+      }
+      
+      // Check if candidate has a matching topic in their interests
+      if (!candidate.topicsOfInterest || candidate.topicsOfInterest.length === 0) continue;
+      
+      const matchingTopic = candidate.topicsOfInterest.find(t => {
+        const ct = t.topic.toLowerCase();
+        return ct.includes(quizCategory) || quizCategory.includes(ct);
+      });
+      
+      if (!matchingTopic) continue; // Candidate has no interest in this category
+      
+      // Map their comfort level for this specific topic to a proficiency
+      const candidateProficiency = comfortToProficiency(matchingTopic.comfortLevel);
+      
+      // Check if their proficiency matches the quiz difficulty requirement
+      if (!requiredProficiencies.includes(candidateProficiency)) continue;
+      
+      filtered.push({
+        _id: candidate._id,
+        name: candidate.name,
+        email: candidate.email,
+        level: candidate.level,
+        topicsOfInterest: candidate.topicsOfInterest,
+        matchedTopic: matchingTopic.topic,
+        matchedComfort: matchingTopic.comfortLevel,
+        matchedProficiency: candidateProficiency
+      });
+    }
+    
+    const assignedIds = quiz.assignees ? quiz.assignees.map(id => id.toString()) : [];
+    
+    res.json({
+      quizTitle: quiz.title,
+      quizDifficulty: quiz.difficulty,
+      quizCategory: quiz.category,
+      assignedIds: assignedIds,
+      filteredCandidates: filtered
+    });
+  } catch (error) {
+    res.status(500).json({ message: 'Server error', error: error.message });
+  }
+});
+module.exports = router;

Backend/routes/candidate.js

@@ -254,4 +254,53 @@ function checkAnswersMatch(arr1, arr2) {
   return a === b;
 }
 
+// @route   GET /api/candidate/profile
+// @desc    Get candidate profile including topics of interest
+// @access  Candidate
+router.get('/profile', async (req, res) => {
+  try {
+    const user = await User.findById(req.user._id).select('-password');
+    if (!user) return res.status(404).json({ message: 'User not found' });
+    
+    res.json(user);
+  } catch (error) {
+    res.status(500).json({ message: 'Server error', error: error.message });
+  }
+});
+
+// @route   PUT /api/candidate/profile
+// @desc    Update candidate profile (topics of interest)
+// @access  Candidate
+router.put('/profile', async (req, res) => {
+  try {
+    const { topicsOfInterest } = req.body;
+    
+    if (topicsOfInterest && !Array.isArray(topicsOfInterest)) {
+      return res.status(400).json({ message: 'Topics of interest must be an array' });
+    }
+
+    const user = await User.findById(req.user._id);
+    if (!user) return res.status(404).json({ message: 'User not found' });
+    
+    if (topicsOfInterest) {
+      user.topicsOfInterest = topicsOfInterest;
+    }
+    
+    await user.save();
+    
+    res.json({
+      message: 'Profile updated successfully',
+      user: {
+        _id: user._id,
+        name: user.name,
+        email: user.email,
+        level: user.level,
+        topicsOfInterest: user.topicsOfInterest
+      }
+    });
+  } catch (error) {
+    res.status(500).json({ message: 'Server error', error: error.message });
+  }
+});
+
 module.exports = router;

Backend/routes/hr.js

@@ -164,13 +164,12 @@ router.put('/quiz/:quizId', async (req, res) => {
       return res.status(403).json({ message: 'This quiz cannot be edited because it has already been attempted.', attemptCount });
     }
 
-    const { title, timer, category, difficulty, topic, assignToAll, assignees, assignedGroups, questions } = req.body;
+    const { title, timer, category, difficulty, assignToAll, assignees, assignedGroups, questions } = req.body;
     const updateData = {};
     if (title) updateData.title = title;
     if (timer) updateData.timer = parseInt(timer);
     if (category) updateData.category = category;
     if (difficulty) updateData.difficulty = difficulty;
-    if (topic !== undefined) updateData.topic = topic;
     if (assignToAll !== undefined) updateData.assignToAll = assignToAll;
     if (assignees) updateData.assignees = assignees;
     if (assignedGroups) updateData.assignedGroups = assignedGroups;
@@ -421,4 +420,37 @@ function checkAnswersMatch(arr1, arr2) {
   return a === b;
 }
 
+
+// @route   PUT /api/hr/users/:userId/level
+// @desc    Update a candidate's level
+// @access  HR
+router.put('/users/:userId/level', async (req, res) => {
+  try {
+    const { userId } = req.params;
+    const { level } = req.body;
+
+    const validLevels = ['beginner', 'intermediate', 'advanced', 'expert'];
+    if (!level || !validLevels.includes(level)) {
+      return res.status(400).json({ message: 'Invalid level.' });
+    }
+
+    const user = await User.findById(userId);
+    if (!user) return res.status(404).json({ message: 'User not found' });
+    if (user.role !== 'candidate') return res.status(400).json({ message: 'Level can only be set for candidates' });
+
+    const previousLevel = user.level || 'beginner';
+    user.level = level;
+    await user.save();
+
+    res.json({
+      message: `Level changed from ${previousLevel} to ${level}`,
+      user: { _id: user._id, name: user.name, level: user.level },
+      previousLevel,
+      newLevel: level
+    });
+  } catch (error) {
+    res.status(500).json({ message: 'Server error', error: error.message });
+  }
+});
+
 module.exports = router;

Backend/test-api.js

+const jwt = require('jsonwebtoken');
+const http = require('http');
+
+const JWT_SECRET = 'quiz_app_super_secret_key_2026';
+
+// The admin user id from the previous query was 69d49c922c5d4255f1586365
+const token = jwt.sign({ id: '69d49c922c5d4255f1586365', role: 'admin' }, JWT_SECRET, { expiresIn: '1h' });
+
+const data = JSON.stringify({
+  assigneeIds: ['69dbd7dc839ed359fa93408a', '69e60a415b06f9656a2dc37d']
+});
+
+const options = {
+  hostname: 'localhost',
+  port: 5000,
+  path: '/api/admin/quiz/69e88245efc8e25294852356/assign',
+  method: 'PUT',
+  headers: {
+    'Content-Type': 'application/json',
+    'Content-Length': data.length,
+    'Authorization': `Bearer ${token}`
+  }
+};
+
+const req = http.request(options, (res) => {
+  console.log(`STATUS: ${res.statusCode}`);
+  res.on('data', (chunk) => {
+    console.log(`BODY: ${chunk}`);
+  });
+});
+
+req.on('error', (e) => {
+  console.error(`problem with request: ${e.message}`);
+});
+
+req.write(data);
+req.end();

Backend/test-assign.js

+const mongoose = require('mongoose');
+const Quiz = require('./models/Quiz');
+require('dotenv').config();
+
+const MONGO_URI = process.env.MONGODB_URI || 'mongodb://localhost:27017/quizapp';
+
+async function check() {
+  await mongoose.connect(MONGO_URI);
+  console.log('Connected to DB');
+
+  const quiz = await Quiz.findOne({});
+  if (!quiz) {
+    console.log('No quiz found');
+    process.exit(0);
+  }
+
+  console.log('Quiz found:', quiz.title, 'ID:', quiz._id.toString());
+  console.log('Initial assignees:', quiz.assignees);
+
+  // simulate PUT request assignToAll = false, assignees = [some mock id]
+  const mockId = new mongoose.Types.ObjectId();
+  quiz.assignToAll = false;
+  quiz.assignees = [mockId];
+  await quiz.save();
+  
+  console.log('Saved assignees:', quiz.assignees);
+
+  const reloaded = await Quiz.findById(quiz._id);
+  console.log('Reloaded assignees:', reloaded.assignees);
+
+  await mongoose.disconnect();
+}
+
+check().catch(console.error);

Backend/test-react-quiz-2.js

+const mongoose = require('mongoose');
+const Quiz = require('./models/Quiz');
+require('dotenv').config();
+
+const MONGO_URI = process.env.MONGODB_URI || 'mongodb://localhost:27017/quizapp';
+
+async function check() {
+  await mongoose.connect(MONGO_URI);
+  console.log('Connected to DB');
+
+  const quizzes = await Quiz.find({ title: 'React Basics' });
+  console.log(`Found ${quizzes.length} React Basics quizzes`);
+  quizzes.forEach(q => {
+    console.log(`ID: ${q._id}, assignees: ${q.assignees.length}, createdBy: ${q.createdBy}`);
+  });
+
+  await mongoose.disconnect();
+}
+
+check().catch(console.error);

Backend/test-react-quiz.js

+const mongoose = require('mongoose');
+const Quiz = require('./models/Quiz');
+const User = require('./models/User');
+require('dotenv').config();
+
+const MONGO_URI = process.env.MONGODB_URI || 'mongodb://localhost:27017/quizapp';
+
+async function check() {
+  await mongoose.connect(MONGO_URI);
+  console.log('Connected to DB');
+
+  const quiz = await Quiz.findOne({ title: 'React Basics' });
+  if (!quiz) {
+    console.log('No React Basics quiz found');
+    process.exit(0);
+  }
+
+  console.log('Quiz assignees:', quiz.assignees);
+
+  const users = await User.find({ role: 'candidate' });
+  console.log('Candidates IDs:', users.map(u => ({ name: u.name, id: u._id.toString() })));
+
+  await mongoose.disconnect();
+}
+
+check().catch(console.error);

Frontend/package-lock.json

@@ -8,7 +8,7 @@
       "name": "quiz-app",
       "version": "0.0.0",
       "dependencies": {
-        "@angular/cdk": "^21.2.6",
+        "@angular/cdk": "^21.2.7",
         "@angular/common": "^21.2.0",
         "@angular/compiler": "^21.2.0",
         "@angular/core": "^21.2.0",
@@ -420,9 +420,9 @@
       }
     },
     "node_modules/@angular/cdk": {
-      "version": "21.2.6",
-      "resolved": "https://registry.npmjs.org/@angular/cdk/-/cdk-21.2.6.tgz",
-      "integrity": "sha512-1PBzFf+um/VZ1dFF6cT72Zsq+9C/ZWF9m5dP0uHJgo4psX3yMBoZlZu5YomBiAQ/ePSkqCuryv1vrelK+yd3Mw==",
+      "version": "21.2.7",
+      "resolved": "https://registry.npmjs.org/@angular/cdk/-/cdk-21.2.7.tgz",
+      "integrity": "sha512-GHQZ+d5k3nY9JXPNEJpeuLd8FSy03hxXAYsq6IQI4AcTIQow3QZlHj6g3/sk2QlqnzCaEhfRmwx7AO5iXyzdZQ==",
       "license": "MIT",
       "dependencies": {
         "parse5": "^8.0.0",

Frontend/package.json

@@ -13,7 +13,7 @@
     "node": ">=18.0.0"
   },
   "dependencies": {
-    "@angular/cdk": "^21.2.6",
+    "@angular/cdk": "^21.2.7",
     "@angular/common": "^21.2.0",
     "@angular/compiler": "^21.2.0",
     "@angular/core": "^21.2.0",

Frontend/src/app/app.routes.ts

@@ -57,6 +57,10 @@ export const routes: Routes = [
         path: 'create-quiz',
         loadComponent: () => import('./pages/admin/create-quiz/create-quiz').then(m => m.CreateQuizComponent)
       },
+      {
+        path: 'quiz/:quizId/assign',
+        loadComponent: () => import('./pages/admin/assign-quiz/assign-quiz').then(m => m.AssignQuizComponent)
+      },
       {
         path: 'quiz/:quizId/edit',
         loadComponent: () => import('./pages/admin/edit-quiz/edit-quiz').then(m => m.EditQuizComponent)

Frontend/src/app/pages/admin/assign-quiz/assign-quiz.css

+/* ===== Page Container: Match manage-groups exactly ===== */
+.page-container { max-width: 1400px; padding: 32px 40px; margin: 0 auto; height: calc(100vh - 64px); display: flex; box-sizing: border-box; }
+.split-view { gap: 32px; align-items: stretch; }
+
+.main-workspace { flex: 1; min-width: 0; display: flex; flex-direction: column; overflow-y: auto; padding-right: 16px; }
+
+.page-header { margin-bottom: 28px; }
+.page-header h1 { font-size: 26px; font-weight: 700; color: var(--text-primary); margin: 0 0 8px; }
+.page-subtitle { color: var(--text-muted); font-size: 14px; margin: 0; }
+
+/* ===== Quiz Info Bar ===== */
+.quiz-info-bar { margin-bottom: 30px; }
+
+.quiz-info-row {
+  display: flex;
+  gap: 40px;
+  flex-wrap: wrap;
+}
+
+.quiz-info-item {
+  display: flex;
+  align-items: center;
+  gap: 12px;
+}
+
+.quiz-info-item > .material-symbols-rounded {
+  font-size: 20px;
+  color: var(--accent-primary, #667eea);
+  background: rgba(102, 126, 234, 0.1);
+  padding: 10px;
+  border-radius: 10px;
+}
+
+.quiz-info-item div {
+  display: flex;
+  flex-direction: column;
+  gap: 2px;
+}
+
+.quiz-info-item small {
+  font-size: 11px;
+  color: var(--text-muted);
+  text-transform: uppercase;
+  letter-spacing: 0.5px;
+  font-weight: 500;
+}
+
+.quiz-info-item strong {
+  font-size: 14px;
+  color: var(--text-primary);
+  font-weight: 600;
+}
+
+/* ===== Section Title ===== */
+.section-title {
+  display: flex;
+  align-items: center;
+  gap: 8px;
+  font-size: 18px;
+  font-weight: 600;
+  color: var(--text-primary);
+  margin-bottom: 20px;
+  border-bottom: 1px solid var(--border-color);
+  padding-bottom: 8px;
+}
+
+.section-title .material-symbols-rounded {
+  font-size: 22px;
+  color: var(--accent-primary, #667eea);
+}
+
+.count-badge {
+  background: rgba(102, 126, 234, 0.1);
+  color: var(--accent-primary, #667eea);
+  font-size: 12px;
+  font-weight: 600;
+  padding: 2px 8px;
+  border-radius: 20px;
+  margin-left: 4px;
+}
+
+/* ===== Available Candidates Pool ===== */
+.available-pool {
+  display: flex;
+  flex-wrap: wrap;
+  gap: 16px;
+  min-height: 120px;
+  padding: 4px 0;
+}
+
+.empty-pool {
+  display: flex;
+  flex-direction: column;
+  align-items: center;
+  justify-content: center;
+  width: 100%;
+  padding: 48px 20px;
+  color: var(--text-muted);
+  background: var(--bg-hover);
+  border-radius: 12px;
+  border: 2px dashed var(--border-color);
+  text-align: center;
+}
+
+.empty-pool .material-symbols-rounded {
+  font-size: 40px;
+  margin-bottom: 8px;
+  opacity: 0.3;
+}
+
+.empty-pool p { margin: 0; font-size: 14px; }
+
+/* ===== Candidate Cards (Left Pool) ===== */
+.candidate-card {
+  display: flex;
+  align-items: center;
+  gap: 16px;
+  padding: 14px 18px;
+  background: var(--bg-card);
+  border: 1px solid var(--border-color);
+  border-radius: 12px;
+  cursor: grab;
+  transition: all 0.2s ease;
+  min-width: 280px;
+  flex: 0 1 auto;
+  box-shadow: 0 2px 5px rgba(0,0,0,0.02);
+}
+
+.candidate-card:hover {
+  border-color: var(--accent-primary, #667eea);
+  box-shadow: 0 4px 12px rgba(102, 126, 234, 0.08);
+  transform: translateY(-2px);
+}
+
+.candidate-card:active {
+  cursor: grabbing;
+}
+
+.candidate-avatar {
+  width: 44px;
+  height: 44px;
+  border-radius: 50%;
+  background: var(--bg-input);
+  color: var(--text-primary);
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  font-weight: 600;
+  font-size: 18px;
+  flex-shrink: 0;
+}
+
+.candidate-details {
+  flex: 1;
+  min-width: 0;
+}
+
+.candidate-details h4 {
+  margin: 0 0 4px 0;
+  font-size: 15px;
+  font-weight: 600;
+  color: var(--text-primary);
+  white-space: nowrap;
+  overflow: hidden;
+  text-overflow: ellipsis;
+}
+
+.candidate-details p {
+  margin: 0;
+  font-size: 13px;
+  color: var(--text-muted);
+  white-space: nowrap;
+  overflow: hidden;
+  text-overflow: ellipsis;
+}
+
+.candidate-meta {
+  flex-shrink: 0;
+  display: flex;
+  flex-direction: column;
+  align-items: flex-end;
+  gap: 4px;
+}
+
+.comfort-tag {
+  font-size: 11px;
+  font-weight: 600;
+  color: var(--text-muted);
+}
+
+.level-pill {
+  display: inline-block;
+  padding: 3px 12px;
+  border-radius: 12px;
+  font-size: 12px;
+  font-weight: 600;
+}
+
+.level-pill[data-level="beginner"] { background: rgba(16, 185, 129, 0.1); color: #10b981; }
+.level-pill[data-level="intermediate"] { background: rgba(59, 130, 246, 0.1); color: #3b82f6; }
+.level-pill[data-level="advanced"] { background: rgba(245, 158, 11, 0.1); color: #f59e0b; }
+.level-pill[data-level="expert"] { background: rgba(239, 68, 68, 0.1); color: #ef4444; }
+
+.drag-icon {
+  color: var(--text-muted);
+  opacity: 0.5;
+  font-size: 20px;
+  cursor: grab;
+}
+
+/* ===== SIDEBAR: Assigned (matches unassigned-sidebar from manage-groups) ===== */
+.assigned-sidebar {
+  width: 340px;
+  display: flex;
+  flex-direction: column;
+  flex-shrink: 0;
+  height: 100%;
+  overflow: hidden;
+  background: var(--surface, var(--bg-card));
+  border: 1px solid var(--border-color);
+  border-radius: var(--radius-lg, 16px);
+}
+
+.sidebar-header {
+  padding: 20px;
+  border-bottom: 1px solid var(--border-color);
+  display: flex;
+  justify-content: space-between;
+  align-items: center;
+  background: rgba(102,126,234,0.05);
+}
+
+.sidebar-title {
+  display: flex;
+  align-items: center;
+  gap: 10px;
+}
+
+.sidebar-title .material-symbols-rounded {
+  color: #22c55e;
+  font-size: 20px;
+}
+
+.sidebar-title h2 {
+  margin: 0;
+  font-size: 16px;
+  font-weight: 600;
+  color: var(--text-primary);
+}
+
+.sidebar-badge {
+  background: #22c55e;
+  color: white;
+  padding: 2px 8px;
+  border-radius: 20px;
+  font-size: 12px;
+  font-weight: 600;
+}
+
+.assigned-list {
+  flex: 1;
+  overflow-y: auto;
+  padding: 16px;
+  display: flex;
+  flex-direction: column;
+  gap: 12px;
+  min-height: 200px;
+}
+
+.empty-assigned {
+  display: flex;
+  flex-direction: column;
+  align-items: center;
+  justify-content: center;
+  text-align: center;
+  padding: 40px 20px;
+  color: var(--text-muted);
+  opacity: 0.7;
+  min-height: 200px;
+}
+
+.empty-assigned .material-symbols-rounded {
+  font-size: 40px;
+  margin-bottom: 12px;
+  opacity: 0.4;
+}
+
+.empty-assigned p {
+  margin: 0;
+  font-size: 13px;
+}
+
+/* Highlight when dragging over the assigned zone */
+.assigned-list.cdk-drop-list-receiving {
+  background: rgba(102,126,234,0.04);
+}
+
+/* ===== Assigned Cards (Sidebar Items — match unassigned-card from manage-groups) ===== */
+.assigned-card {
+  display: flex;
+  align-items: center;
+  gap: 16px;
+  padding: 14px;
+  background: var(--bg-card);
+  border: 1px solid var(--border-color);
+  border-radius: 12px;
+  cursor: grab;
+  transition: border-color 0.2s, box-shadow 0.2s;
+  position: relative;
+}
+
+.assigned-card:hover {
+  border-color: var(--accent-primary, #667eea);
+  box-shadow: 0 4px 12px rgba(102,126,234,0.08);
+  transform: translateY(-2px);
+}
+
+.assigned-card:active {
+  cursor: grabbing;
+}
+
+.assigned-avatar {
+  width: 44px;
+  height: 44px;
+  border-radius: 50%;
+  background: var(--bg-input);
+  color: var(--text-primary);
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  font-weight: 600;
+  font-size: 18px;
+  flex-shrink: 0;
+}
+
+.assigned-details {
+  flex: 1;
+  min-width: 0;
+}
+
+.assigned-details h4 {
+  margin: 0 0 4px 0;
+  font-size: 15px;
+  font-weight: 600;
+  color: var(--text-primary);
+  white-space: nowrap;
+  overflow: hidden;
+  text-overflow: ellipsis;
+}
+
+.assigned-details p {
+  margin: 0;
+  font-size: 13px;
+  color: var(--text-muted);
+  white-space: nowrap;
+  overflow: hidden;
+  text-overflow: ellipsis;
+}
+
+/* ===== Sidebar Footer ===== */
+.sidebar-footer {
+  padding: 16px 20px;
+  border-top: 1px solid var(--border-color);
+  display: flex;
+  flex-direction: column;
+  gap: 10px;
+}
+
+.save-btn {
+  width: 100%;
+  display: inline-flex;
+  align-items: center;
+  justify-content: center;
+  gap: 8px;
+  padding: 14px 24px;
+  border: none;
+  border-radius: 12px;
+  font-weight: 600;
+  cursor: pointer;
+  transition: all 0.3s;
+  font-size: 15px;
+  font-family: inherit;
+  background: var(--accent-gradient, linear-gradient(135deg, #667eea, #764ba2));
+  color: #fff;
+  box-shadow: 0 4px 15px rgba(102,126,234,0.3);
+}
+
+.save-btn:hover:not(:disabled) {
+  transform: translateY(-2px);
+  box-shadow: 0 6px 20px rgba(102,126,234,0.4);
+}
+
+.save-btn:disabled {
+  opacity: 0.6;
+  cursor: not-allowed;
+  transform: none;
+  box-shadow: none;
+}
+
+.save-toast {
+  display: flex;
+  align-items: center;
+  gap: 6px;
+  font-size: 13px;
+  font-weight: 500;
+  color: #22c55e;
+  justify-content: center;
+}
+
+/* ===== CDK Drag & Drop (matches manage-groups exactly) ===== */
+.custom-drag-placeholder {
+  opacity: 0.3;
+  background: rgba(102,126,234,0.1);
+  border: 2px dashed var(--accent-primary, #667eea);
+  border-radius: 12px;
+  min-height: 60px;
+  transition: transform 250ms cubic-bezier(0, 0, 0.2, 1);
+}
+
+.cdk-drag-preview {
+  box-shadow: 0 10px 30px rgba(0,0,0,0.15);
+  border-radius: 12px;
+  opacity: 0.95;
+  z-index: 1000 !important;
+  cursor: grabbing !important;
+}
+
+.cdk-drag-animating {
+  transition: transform 250ms cubic-bezier(0, 0, 0.2, 1);
+}
+
+.available-pool.cdk-drop-list-dragging .candidate-card:not(.cdk-drag-placeholder) {
+  transition: transform 250ms cubic-bezier(0, 0, 0.2, 1);
+}
+
+.assigned-list.cdk-drop-list-dragging .assigned-card:not(.cdk-drag-placeholder) {
+  transition: transform 250ms cubic-bezier(0, 0, 0.2, 1);
+}
+
+/* ===== Loading State ===== */
+.loading-center { display: flex; flex-direction: column; align-items: center; justify-content: center; padding: 80px 20px; color: var(--text-muted); gap: 16px; }
+
+/* ===== Responsive ===== */
+@media (max-width: 900px) {
+  .split-view { flex-direction: column; }
+  .assigned-sidebar { width: 100%; height: 400px; }
+  .page-container { height: auto; padding: 20px 16px; }
+  .quiz-info-row { flex-direction: column; gap: 16px; }
+}

Frontend/src/app/pages/admin/assign-quiz/assign-quiz.html

+<div class="page-container animate-fade-in split-view" cdkDropListGroup>
+
+  <div class="main-workspace">
+    <div class="page-header">
+      <a routerLink="/admin/quizzes" class="back-link">
+        <span class="material-symbols-rounded">arrow_back</span> Back to Quizzes
+      </a>
+      <h1>Assign Quiz</h1>
+      <p class="page-subtitle">Drag candidates to assign them to <strong>{{ quizTitle() }}</strong></p>
+    </div>
+
+    <!-- Quiz Info Badge -->
+    <div class="quiz-info-bar card card-padding" style="margin-bottom: 30px;">
+      <div class="quiz-info-row">
+        <div class="quiz-info-item">
+          <span class="material-symbols-rounded">quiz</span>
+          <div>
+            <small>Quiz</small>
+            <strong>{{ quizTitle() }}</strong>
+          </div>
+        </div>
+        <div class="quiz-info-item">
+          <span class="material-symbols-rounded">speed</span>
+          <div>
+            <small>Difficulty</small>
+            <strong>{{ quizDifficulty() | titlecase }}</strong>
+          </div>
+        </div>
+        <div class="quiz-info-item">
+          <span class="material-symbols-rounded">category</span>
+          <div>
+            <small>Category</small>
+            <strong>{{ quizCategory() || 'General' }}</strong>
+          </div>
+        </div>
+        <div class="quiz-info-item">
+          <span class="material-symbols-rounded">filter_list</span>
+          <div>
+            <small>Filter Criteria</small>
+            <strong>{{ getFilterDescription() }}</strong>
+          </div>
+        </div>
+      </div>
+    </div>
+
+    @if (loading()) {
+      <div class="loading-center">
+        <div class="spinner spinner-lg"></div>
+        <p>Loading candidates...</p>
+      </div>
+    } @else {
+      <!-- Available Candidates Pool -->
+      <h2 class="section-title">
+        <span class="material-symbols-rounded">person_search</span>
+        Eligible Candidates
+        <span class="count-badge">{{ availableCandidates.length }}</span>
+      </h2>
+
+      <div class="available-pool" cdkDropList [cdkDropListData]="availableCandidates" (cdkDropListDropped)="drop($event)">
+        @if (availableCandidates.length === 0) {
+          <div class="empty-pool">
+            <span class="material-symbols-rounded">done_all</span>
+            <p>All matching candidates have been assigned!</p>
+          </div>
+        }
+        @for (candidate of availableCandidates; track candidate._id) {
+          <div class="candidate-card" cdkDrag [cdkDragData]="candidate">
+            <div class="candidate-avatar">{{ candidate.name.charAt(0).toUpperCase() }}</div>
+            <div class="candidate-details">
+              <h4>{{ candidate.name }}</h4>
+              <p>{{ candidate.email }}</p>
+            </div>
+            <div class="candidate-meta">
+              @if (candidate.matchedProficiency) {
+                <span class="level-pill" [attr.data-level]="candidate.matchedProficiency">{{ candidate.matchedProficiency | titlecase }}</span>
+                <span class="comfort-tag">{{ candidate.matchedComfort }}%</span>
+              } @else {
+                <span class="level-pill" [attr.data-level]="candidate.level">{{ candidate.level | titlecase }}</span>
+              }
+            </div>
+            <span class="material-symbols-rounded drag-icon">drag_indicator</span>
+            <div class="custom-drag-placeholder" *cdkDragPlaceholder></div>
+          </div>
+        }
+      </div>
+    }
+  </div>
+
+  <!-- Sidebar: Assigned Candidates -->
+  <aside class="assigned-sidebar card">
+    <div class="sidebar-header">
+      <div class="sidebar-title">
+        <span class="material-symbols-rounded">how_to_reg</span>
+        <h2>Assigned</h2>
+      </div>
+      <div class="sidebar-badge">{{ assignedCandidates.length }}</div>
+    </div>
+
+    <div class="assigned-list" cdkDropList [cdkDropListData]="assignedCandidates" (cdkDropListDropped)="drop($event)">
+      @if (assignedCandidates.length === 0) {
+        <div class="empty-assigned">
+          <span class="material-symbols-rounded">move_down</span>
+          <p>Drag candidates here to assign</p>
+        </div>
+      }
+      @for (candidate of assignedCandidates; track candidate._id) {
+        <div class="assigned-card" cdkDrag [cdkDragData]="candidate">
+          <div class="assigned-avatar">{{ candidate.name.charAt(0).toUpperCase() }}</div>
+          <div class="assigned-details">
+            <h4>{{ candidate.name }}</h4>
+            <p>{{ candidate.email }}</p>
+          </div>
+          <span class="material-symbols-rounded drag-icon">drag_indicator</span>
+          <div class="custom-drag-placeholder" *cdkDragPlaceholder></div>
+        </div>
+      }
+    </div>
+
+    <!-- Save Button -->
+    <div class="sidebar-footer">
+      @if (successMessage()) {
+        <span class="save-toast">
+          <span class="material-symbols-rounded">check_circle</span>
+          {{ successMessage() }}
+        </span>
+      }
+      <button class="btn btn-primary save-btn" (click)="saveAssignments()" [disabled]="isSaving()">
+        @if (isSaving()) {
+          <span class="spinner"></span> Saving...
+        } @else {
+          <span class="material-symbols-rounded">save</span> Save Assignments
+        }
+      </button>
+    </div>
+  </aside>
+
+</div>

Frontend/src/app/pages/admin/assign-quiz/assign-quiz.ts

+import { Component, OnInit, signal } from '@angular/core';
+import { CommonModule } from '@angular/common';
+import { RouterLink, ActivatedRoute } from '@angular/router';
+import { FormsModule } from '@angular/forms';
+import { CdkDragDrop, moveItemInArray, transferArrayItem, DragDropModule } from '@angular/cdk/drag-drop';
+import { QuizService } from '../../../services/quiz.service';
+
+@Component({
+  selector: 'app-assign-quiz',
+  standalone: true,
+  imports: [CommonModule, RouterLink, FormsModule, DragDropModule],
+  templateUrl: './assign-quiz.html',
+  styleUrl: './assign-quiz.css'
+})
+export class AssignQuizComponent implements OnInit {
+  quizId = '';
+  quizTitle = signal('');
+  quizDifficulty = signal('');
+  quizCategory = signal('');
+
+  // Use plain arrays for CDK drag-drop (signals break mutation)
+  availableCandidates: any[] = [];
+  assignedCandidates: any[] = [];
+
+  loading = signal(true);
+  isSaving = signal(false);
+  successMessage = signal('');
+
+  constructor(private route: ActivatedRoute, private quizService: QuizService) {}
+
+  ngOnInit() {
+    this.quizId = this.route.snapshot.paramMap.get('quizId') || '';
+    if (this.quizId) {
+      this.loadCandidates();
+    }
+  }
+
+  loadCandidates() {
+    this.loading.set(true);
+    this.quizService.getAssignCandidates(this.quizId).subscribe({
+      next: (res) => {
+        this.quizTitle.set(res.quizTitle);
+        this.quizDifficulty.set(res.quizDifficulty || 'General');
+        this.quizCategory.set(res.quizCategory || '');
+
+        // Only show filtered (recommended) candidates
+        const filtered = res.filteredCandidates || [];
+
+        const assigned: any[] = [];
+        const available: any[] = [];
+
+        filtered.forEach((c: any) => {
+          if (res.assignedIds.includes(c._id)) {
+            assigned.push(c);
+          } else {
+            available.push(c);
+          }
+        });
+
+        this.assignedCandidates = assigned;
+        this.availableCandidates = available;
+        this.loading.set(false);
+      },
+      error: (err) => {
+        console.error(err);
+        this.loading.set(false);
+      }
+    });
+  }
+
+  drop(event: CdkDragDrop<any[]>) {
+    if (event.previousContainer === event.container) {
+      moveItemInArray(event.container.data, event.previousIndex, event.currentIndex);
+    } else {
+      transferArrayItem(
+        event.previousContainer.data,
+        event.container.data,
+        event.previousIndex,
+        event.currentIndex,
+      );
+    }
+  }
+
+  saveAssignments() {
+    this.isSaving.set(true);
+    const assignedIds = this.assignedCandidates.map(c => c._id);
+    console.log('assignedCandidates:', this.assignedCandidates);
+    console.log('assignedIds:', assignedIds);
+    this.quizService.assignQuiz(this.quizId, { assignees: assignedIds }).subscribe({
+      next: () => {
+        this.isSaving.set(false);
+        this.successMessage.set('Assignments saved successfully!');
+        setTimeout(() => this.successMessage.set(''), 3000);
+      },
+      error: () => {
+        this.isSaving.set(false);
+        alert('Failed to update assignments');
+      }
+    });
+  }
+
+  getFilterDescription(): string {
+    const d = this.quizDifficulty().toLowerCase();
+    const cat = this.quizCategory() || 'Any';
+    let levelDesc = 'All levels';
+    if (d === 'easy') levelDesc = 'Beginner (0-25% comfort)';
+    if (d === 'medium') levelDesc = 'Intermediate & Advanced (26-75%)';
+    if (d === 'hard') levelDesc = 'Expert (76-100% comfort)';
+    return `${levelDesc} in "${cat}"`;
+  }
+}

Frontend/src/app/pages/admin/create-quiz/create-quiz.html

@@ -54,8 +54,8 @@
         </div>
 
         <div class="form-group">
-          <label class="form-label">Topic</label>
-          <input class="form-input" [(ngModel)]="topic" name="topicExcel" placeholder="e.g. Arrays & Loops">
+          <label class="form-label">Category</label>
+          <input class="form-input" [(ngModel)]="category" name="categoryExcel" placeholder="e.g. Java, Angular, Data Structures">
         </div>
 
         <div class="form-group">
@@ -86,7 +86,7 @@
 
           <div class="form-group">
             <label class="form-label">Describe Your Quiz *</label>
-            <textarea class="form-input form-textarea" [(ngModel)]="topic" name="topic" rows="4"
+            <textarea class="form-input form-textarea" [(ngModel)]="category" name="category" rows="4"
                       placeholder="e.g. Generate a quiz on Operating Systems covering process scheduling, memory management, and file systems. Include 10 questions that a student can answer in 15 minutes."></textarea>
             <p class="format-hint">
               <span class="material-symbols-rounded" style="font-size:14px">lightbulb</span>
@@ -109,6 +109,7 @@
       <div class="form-group">
         <label class="form-label">Assign To</label>
         <select class="form-select" [(ngModel)]="assignmentType" name="assignmentType">
+          <option value="none">None (Assign Later)</option>
           <option value="all">All Candidates</option>
           <option value="users">Individual People</option>
           <option value="groups">Specific Groups</option>

Frontend/src/app/pages/admin/create-quiz/create-quiz.ts

@@ -19,7 +19,7 @@ export class CreateQuizComponent implements OnInit {
   title = '';
   timer = 30;
   difficulty = 'medium';
-  topic = '';
+  category = '';
   selectedFile: File | null = null;
   fileName = signal('');
 
@@ -125,7 +125,7 @@ export class CreateQuizComponent implements OnInit {
     formData.append('timer', this.timer.toString());
     formData.append('questionsFile', this.selectedFile);
     if (this.difficulty) formData.append('difficulty', this.difficulty);
-    if (this.topic) formData.append('topic', this.topic);
+    if (this.category) formData.append('category', this.category);
 
     this.appendAssignment(formData);
 
@@ -143,14 +143,14 @@ export class CreateQuizComponent implements OnInit {
   }
 
   private submitAI(): void {
-    if (!this.topic.trim()) { this.error.set('Please describe your quiz topic'); return; }
+    if (!this.category.trim()) { this.error.set('Please describe your quiz topic/category'); return; }
 
     this.loading.set(true);
     this.error.set('');
     this.success.set('');
 
     const data: any = {
-      prompt: this.topic,
+      prompt: this.category,
       difficulty: this.difficulty
     };
 
@@ -162,6 +162,10 @@ export class CreateQuizComponent implements OnInit {
     } else if (this.assignmentType === 'groups') {
       data.assignToAll = false;
       data.assignedGroups = this.selectedGroups;
+    } else if (this.assignmentType === 'none') {
+      data.assignToAll = false;
+      data.assignees = [];
+      data.assignedGroups = [];
     }
 
     this.quizService.generateAIQuiz(data).subscribe({
@@ -186,6 +190,10 @@ export class CreateQuizComponent implements OnInit {
     } else if (this.assignmentType === 'groups') {
       formData.append('assignToAll', 'false');
       formData.append('assignedGroups', JSON.stringify(this.selectedGroups));
+    } else if (this.assignmentType === 'none') {
+      formData.append('assignToAll', 'false');
+      formData.append('assignees', JSON.stringify([]));
+      formData.append('assignedGroups', JSON.stringify([]));
     }
   }
 }

Frontend/src/app/pages/admin/edit-quiz/edit-quiz.html

@@ -39,15 +39,9 @@
             </select>
           </div>
         </div>
-        <div class="form-row">
         <div class="form-group">
           <label class="form-label">Category</label>
-            <input class="form-input" [(ngModel)]="category" placeholder="Category">
-          </div>
-          <div class="form-group">
-            <label class="form-label">Topic</label>
-            <input class="form-input" [(ngModel)]="topic" placeholder="Topic">
-          </div>
+          <input class="form-input" [(ngModel)]="category" placeholder="e.g. Java, Angular, Data Structures">
         </div>
       </div>
     </div>

Frontend/src/app/pages/admin/edit-quiz/edit-quiz.ts

@@ -17,7 +17,6 @@ export class EditQuizComponent implements OnInit {
   timer = 30;
   category = '';
   difficulty = 'medium';
-  topic = '';
   questions = signal<any[]>([]);
 
   loading = signal(true);
@@ -45,7 +44,6 @@ export class EditQuizComponent implements OnInit {
         this.timer = q.timer;
         this.category = q.category || '';
         this.difficulty = q.difficulty || 'medium';
-        this.topic = q.topic || '';
         this.questions.set(q.questions || []);
         this.locked.set(res.hasAttempts || false);
         this.loading.set(false);
@@ -87,7 +85,6 @@ onSave(): void {
     timer: this.timer,
     category: this.category,
     difficulty: this.difficulty,
-    topic: this.topic,
     questions: formattedQuestions
   }; // ✅ closes data object
 

Frontend/src/app/pages/admin/quizzes/quizzes.html

@@ -51,10 +51,10 @@
               {{ quiz.category || 'Uncategorized' }}
             </div>
           </div>
-          @if (quiz.topic) {
-            <div class="quiz-topic">{{ quiz.topic }}</div>
-          }
           <div class="quiz-card-actions">
+            <a [routerLink]="['/admin/quiz', quiz._id, 'assign']" class="btn btn-primary btn-sm">
+              <span class="material-symbols-rounded">person_add</span> Assign
+            </a>
             @if (quiz.attemptCount > 0) {
               <span class="attempted-badge">
                 <span class="material-symbols-rounded">lock</span>

Frontend/src/app/pages/admin/user-history/user-history.css

@@ -22,8 +22,19 @@
 .student-header {
   display: flex;
   align-items: center;
-  gap: 20px;
+  justify-content: space-between;
   margin-bottom: 32px;
+  padding: 24px;
+  background: var(--bg-card);
+  border: 1px solid var(--border-color);
+  border-radius: 16px;
+  box-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
+}
+
+.student-profile {
+  display: flex;
+  align-items: center;
+  gap: 20px;
 }
 
 .student-avatar {
@@ -34,19 +45,19 @@
   display: flex;
   align-items: center;
   justify-content: center;
-  color: var(--text-primary);
+  color: #ffffff;
   font-weight: 700;
   font-size: 28px;
 }
 
-.student-header h1 {
+.student-info h1 {
   font-size: 24px;
   font-weight: 700;
   color: var(--text-primary);
   margin: 0 0 4px;
 }
 
-.student-header p {
+.student-info p {
   color: var(--text-secondary);
   font-size: 14px;
   margin: 0;
@@ -219,3 +230,99 @@
   max-width: 1100px;
   margin: 0; /* force left alignment */
 }
+
+.student-level-control {
+  display: flex;
+  flex-direction: column;
+  align-items: flex-end;
+  gap: 8px;
+}
+
+.level-label {
+  font-size: 11px;
+  font-weight: 600;
+  color: var(--text-muted);
+  text-transform: uppercase;
+  letter-spacing: 1px;
+}
+
+.level-pills {
+  display: flex;
+  background: rgba(0, 0, 0, 0.04);
+  padding: 4px;
+  border-radius: 12px;
+  gap: 4px;
+}
+
+.level-pill {
+  border: none;
+  background: transparent;
+  padding: 8px 16px;
+  font-size: 13px;
+  font-weight: 600;
+  color: var(--text-secondary);
+  border-radius: 8px;
+  cursor: pointer;
+  transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
+}
+
+.level-pill:hover {
+  color: var(--text-primary);
+  background: rgba(0, 0, 0, 0.02);
+}
+
+.level-pill.active {
+  background: var(--bg-card);
+  color: var(--text-primary);
+  box-shadow: 0 2px 8px rgba(0,0,0,0.08);
+}
+
+.level-pill.active[data-level="beginner"] { color: #64748b; }
+.level-pill.active[data-level="intermediate"] { color: #3b82f6; }
+.level-pill.active[data-level="advanced"] { color: #a855f7; }
+.level-pill.active[data-level="expert"] { color: #f59e0b; }
+
+@media (max-width: 640px) {
+  .student-header {
+    flex-direction: column;
+    align-items: flex-start;
+    gap: 24px;
+  }
+  .student-level-control {
+    align-items: flex-start;
+    width: 100%;
+  }
+  .level-pills {
+    width: 100%;
+    overflow-x: auto;
+  }
+}
+
+/* Toast Notification */
+.toast {
+  position: fixed;
+  top: 24px;
+  right: 24px;
+  display: flex;
+  align-items: center;
+  gap: 12px;
+  padding: 16px 24px;
+  border-radius: 12px;
+  font-size: 15px;
+  font-weight: 500;
+  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.2);
+  z-index: 1000;
+  color: #fff;
+}
+
+.toast-success {
+  background: linear-gradient(135deg, #10b981, #059669);
+}
+
+.toast-error {
+  background: linear-gradient(135deg, #ef4444, #dc2626);
+}
+
+.toast .material-symbols-rounded {
+  font-size: 20px;
+}
\ No newline at end of file

Frontend/src/app/pages/admin/user-history/user-history.html

@@ -12,12 +12,28 @@
     } @else {
       @if (user()) {
         <div class="student-header">
+          <div class="student-profile">
             <div class="student-avatar">{{ user().name?.charAt(0) }}</div>
-          <div>
+            <div class="student-info">
               <h1>{{ user().name }}</h1>
               <p>{{ user().email }}</p>
             </div>
           </div>
+
+          <div class="student-level-control">
+            <span class="level-label">Candidate Level</span>
+            <div class="level-pills">
+              @for (lvl of levels; track lvl.value) {
+                <button class="level-pill"
+                        [class.active]="currentLevel() === lvl.value"
+                        [attr.data-level]="lvl.value"
+                        (click)="changeLevel(lvl.value)">
+                  {{ lvl.label }}
+                </button>
+              }
+            </div>
+          </div>
+        </div>
       }
 
       <h2 class="section-title">Test History</h2>
@@ -69,3 +85,11 @@
     }
   </div>
 </div>
+
+<!-- Toast Notification -->
+@if (toast()) {
+  <div class="toast animate-fade-in" [class.toast-success]="toast()?.type === 'success'" [class.toast-error]="toast()?.type === 'error'">
+    <span class="material-symbols-rounded">{{ toast()?.type === 'success' ? 'check_circle' : 'error' }}</span>
+    {{ toast()?.message }}
+  </div>
+}
\ No newline at end of file

Frontend/src/app/pages/admin/user-history/user-history.ts

@@ -16,6 +16,15 @@ export class UserHistoryComponent implements OnInit {
   user = signal<any>(null);
   submissions = signal<any[]>([]);
   loading = signal<boolean>(true);
+  currentLevel = signal<string>('beginner');
+  toast = signal<{ message: string; type: 'success' | 'error' } | null>(null);
+
+  levels = [
+    { value: 'beginner', label: 'Beginner' },
+    { value: 'intermediate', label: 'Intermediate' },
+    { value: 'advanced', label: 'Advanced' },
+    { value: 'expert', label: 'Expert' }
+  ];
 
   constructor(
     private route: ActivatedRoute,
@@ -32,6 +41,7 @@ export class UserHistoryComponent implements OnInit {
     this.quizService.getUserHistory(this.userId).subscribe({
       next: (res) => {
         this.user.set(res.user);
+        this.currentLevel.set(res.user.level || 'beginner');
         this.submissions.set(res.submissions);
         this.loading.set(false);
       },
@@ -39,6 +49,35 @@ export class UserHistoryComponent implements OnInit {
     });
   }
 
+  changeLevel(newLevel: string): void {
+    if (newLevel === this.currentLevel()) return;
+
+    const previousLevel = this.currentLevel();
+    const userRole = this.authService.currentUser()?.role || 'admin';
+
+    this.quizService.updateUserLevel(this.userId, newLevel, userRole).subscribe({
+      next: (res) => {
+        this.currentLevel.set(newLevel);
+        this.showToast(
+          `Level changed from ${this.capitalize(res.previousLevel)} to ${this.capitalize(res.newLevel)}`,
+          'success'
+        );
+      },
+      error: (err) => {
+        this.showToast(err.error?.message || 'Failed to update level', 'error');
+      }
+    });
+  }
+
+  private showToast(message: string, type: 'success' | 'error'): void {
+    this.toast.set({ message, type });
+    setTimeout(() => this.toast.set(null), 3500);
+  }
+
+  private capitalize(str: string): string {
+    return str.charAt(0).toUpperCase() + str.slice(1);
+  }
+
   formatTime(seconds: number): string {
     const m = Math.floor(seconds / 60);
     const s = seconds % 60;

Frontend/src/app/pages/admin/users/users.css

@@ -146,11 +146,18 @@ color: var(--text-primary);
   flex: 1;
 }
 
+.name-row {
+  display: flex;
+  align-items: center;
+  gap: 8px;
+  margin-bottom: 4px;
+}
+
 .user-card-info h4 {
-color: var(--text-primary);
+  color: var(--text-primary);
   font-size: 15px;
   font-weight: 600;
-  margin: 0 0 4px;
+  margin: 0;
 }
 
 .user-card-info p {
@@ -212,6 +219,36 @@ color: var(--text-secondary);
   color: #ef4444;
 }
 
+.level-badge {
+  padding: 4px 12px;
+  border-radius: 20px;
+  font-size: 11px;
+  font-weight: 700;
+  text-transform: uppercase;
+  letter-spacing: 0.5px;
+  flex-shrink: 0;
+}
+
+.level-badge[data-level="beginner"] {
+  background: rgba(148, 163, 184, 0.15);
+  color: #94a3b8;
+}
+
+.level-badge[data-level="intermediate"] {
+  background: rgba(59, 130, 246, 0.15);
+  color: #3b82f6;
+}
+
+.level-badge[data-level="advanced"] {
+  background: rgba(168, 85, 247, 0.15);
+  color: #a855f7;
+}
+
+.level-badge[data-level="expert"] {
+  background: rgba(245, 158, 11, 0.15);
+  color: #f59e0b;
+}
+
 @media (max-width: 768px) {
   .page-container {
     padding: 24px 16px;

Frontend/src/app/pages/admin/users/users.html

@@ -26,11 +26,17 @@
           <a [routerLink]="['/admin/users', user._id, 'history']" class="user-card">
             <div class="user-card-avatar">{{ user.name?.charAt(0) || '?' }}</div>
             <div class="user-card-info">
+              <div class="name-row">
                 <h4>{{ user.name }}</h4>
+                <span class="level-badge" [attr.data-level]="user.level || 'beginner'">
+                  {{ (user.level || 'beginner') | titlecase }}
+                </span>
+              </div>
               <p>{{ user.email }}</p>
               <span class="user-joined">Joined {{ user.createdAt | date:'mediumDate' }}</span>
             </div>
-            <div class="status-dot" [class.online]="user.isLoggedIn"></div>
+            
+            <div class="status-dot" [class.online]="user.isLoggedIn" title="Online Status"></div>
             
             <button class="action-btn text-danger ml-auto" (click)="$event.preventDefault(); $event.stopPropagation(); deleteUser(user._id)" title="Delete Student">
               <span class="material-symbols-rounded">delete</span>

Frontend/src/app/pages/candidate/dashboard/dashboard.css

@@ -9,23 +9,35 @@
 
 .quiz-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(320px, 1fr)); gap: 20px; }
 
-.quiz-card { padding: 24px; display: flex; flex-direction: column; gap: 12px; }
+.quiz-card { padding: 24px; display: flex; flex-direction: column; gap: 12px; height: 100%; box-sizing: border-box; }
 .quiz-card.taken { opacity: 0.85; }
-.quiz-card-header { display: flex; align-items: center; justify-content: space-between; }
+.quiz-card-header { display: flex; align-items: flex-start; justify-content: flex-start; gap: 12px; }
 
 .quiz-icon-wrap {
-  width: 40px; height: 40px; border-radius: var(--radius-md);
+  width: 40px; height: 40px; border-radius: var(--radius-md); flex-shrink: 0;
   background: var(--accent-primary-light); display: flex; align-items: center; justify-content: center;
 }
 .quiz-icon-wrap .material-symbols-rounded { font-size: 22px; color: var(--accent-primary); }
 .quiz-icon-wrap.completed { background: var(--success-light); }
 .quiz-icon-wrap.completed .material-symbols-rounded { color: var(--success); }
 
-.quiz-meta { display: flex; gap: 6px; }
+.quiz-meta { display: flex; gap: 8px; flex: 1; flex-wrap: wrap; justify-content: flex-start; align-items: center; min-width: 0; margin-left: 4px; width: 100%; }
+
+.difficulty-badge { margin-left: auto; }
+
+.quiz-meta .badge {
+  white-space: nowrap;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  max-width: 15vw; /* Keeps it contained so it truncation kicks in */
+}
+@media (max-width: 768px) {
+  .quiz-meta .badge { max-width: 40vw; }
+}
 
 .quiz-title { font-size: 16px; font-weight: 600; color: var(--text-primary); margin: 0; }
 
-.quiz-details { display: flex; gap: 16px; }
+.quiz-details { display: flex; gap: 16px; margin-bottom: 8px; }
 .quiz-detail { display: flex; align-items: center; gap: 4px; font-size: 13px; color: var(--text-muted); }
 .quiz-detail .material-symbols-rounded { font-size: 16px; }
 
@@ -37,7 +49,7 @@
 .fill-poor { background: var(--danger); }
 .result-score { font-size: 13px; color: var(--text-secondary); font-weight: 500; }
 
-.quiz-card-footer { display: flex; align-items: center; justify-content: space-between; margin-top: 4px; }
+.quiz-card-footer { display: flex; align-items: center; justify-content: space-between; margin-top: auto; }
 
 @media (max-width: 768px) {
   .page { padding: 20px; }

Frontend/src/app/pages/candidate/dashboard/dashboard.html

@@ -24,18 +24,18 @@
         <div class="quiz-card card" [class.taken]="quiz.taken">
           <div class="quiz-card-header">
             <div class="quiz-icon-wrap" [class.completed]="quiz.taken">
-              <span class="material-symbols-rounded">{{ quiz.taken ? 'check_circle' : 'quiz' }}</span>
+              <span class="material-symbols-rounded">{{ quiz.taken ? 'task_alt' : 'description' }}</span>
             </div>
             <div class="quiz-meta">
               @if (quiz.category) {
-                <span class="badge badge-primary">{{ quiz.category }}</span>
+                <span class="badge badge-primary" title="{{ quiz.category }}">{{ quiz.category | uppercase }}</span>
               }
               @if (quiz.difficulty) {
-                <span class="badge" [ngClass]="{
-                  'badge-success': quiz.difficulty === 'Beginner',
-                  'badge-warning': quiz.difficulty === 'Intermediate',
-                  'badge-danger': quiz.difficulty === 'Advanced'
-                }">{{ quiz.difficulty }}</span>
+                <span class="badge difficulty-badge" [ngClass]="{
+                  'badge-success': quiz.difficulty.toLowerCase() === 'easy',
+                  'badge-warning': quiz.difficulty.toLowerCase() === 'medium',
+                  'badge-danger': quiz.difficulty.toLowerCase() === 'hard'
+                }">{{ quiz.difficulty | uppercase }}</span>
               }
             </div>
           </div>

Frontend/src/app/pages/candidate/profile/profile.css

@@ -52,3 +52,202 @@
   .stats-row { grid-template-columns: 1fr; }
   .result-item { flex-wrap: wrap; }
 }
+
+/* Topics of Interest Section */
+.topics-section {
+  margin-bottom: 32px;
+}
+
+.section-header {
+  display: flex;
+  justify-content: space-between;
+  align-items: center;
+  margin-bottom: 8px;
+}
+
+.section-title {
+  margin-bottom: 0px !important;
+}
+
+.saving-indicator {
+  font-size: 13px;
+  color: #667eea;
+  font-weight: 500;
+  animation: pulse 1.5s infinite;
+}
+
+@keyframes pulse {
+  0% { opacity: 0.6; }
+  50% { opacity: 1; }
+  100% { opacity: 0.6; }
+}
+
+.section-desc {
+  color: var(--text-secondary);
+  font-size: 14px;
+  margin-bottom: 24px;
+}
+
+/* Existing Topics Tags */
+.existing-topics {
+  display: flex;
+  flex-wrap: wrap;
+  gap: 12px;
+  margin-bottom: 32px;
+}
+
+.no-topics-msg {
+  color: var(--text-muted);
+  font-size: 14px;
+  font-style: italic;
+  width: 100%;
+}
+
+.topic-tag {
+  display: flex;
+  align-items: center;
+  background: var(--bg-hover);
+  border: 1px solid var(--border-color);
+  border-radius: 20px;
+  padding: 4px 6px 4px 16px;
+  gap: 12px;
+  transition: all 0.2s ease;
+}
+
+.topic-tag:hover {
+  background: var(--bg-card);
+  box-shadow: 0 2px 8px rgba(0,0,0,0.05);
+}
+
+.topic-tag-info {
+  display: flex;
+  align-items: center;
+  gap: 8px;
+}
+
+.topic-tag-name {
+  font-size: 14px;
+  font-weight: 600;
+  color: var(--text-primary);
+}
+
+.topic-tag-level {
+  font-size: 12px;
+  font-weight: 700;
+  padding: 2px 8px;
+  border-radius: 12px;
+  background: var(--bg-card);
+}
+.topic-tag-level.high { color: #22c55e; background: rgba(34, 197, 94, 0.1); }
+.topic-tag-level.medium { color: #f59e0b; background: rgba(245, 158, 11, 0.1); }
+.topic-tag-level.low { color: #ef4444; background: rgba(239, 68, 68, 0.1); }
+
+.topic-tag-remove {
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  width: 28px;
+  height: 28px;
+  border-radius: 50%;
+  border: none;
+  background: rgba(239, 68, 68, 0.1);
+  color: #ef4444;
+  cursor: pointer;
+  transition: all 0.2s;
+}
+
+.topic-tag-remove:hover {
+  background: #ef4444;
+  color: #fff;
+}
+
+.topic-tag-remove .material-symbols-rounded {
+  font-size: 16px;
+}
+
+/* Add New Topic Form */
+.add-topic-form {
+  display: flex;
+  align-items: flex-end;
+  gap: 24px;
+  padding: 20px;
+  background: rgba(102, 126, 234, 0.03);
+  border-radius: 12px;
+  border: 1px dashed rgba(102, 126, 234, 0.3);
+}
+
+.topic-input-group,
+.topic-slider-group {
+  display: flex;
+  flex-direction: column;
+  gap: 8px;
+}
+
+.topic-input-group {
+  flex: 1.5;
+}
+
+.topic-slider-group {
+  flex: 2;
+}
+
+.add-topic-form label {
+  font-size: 12px;
+  font-weight: 600;
+  color: var(--text-primary);
+  text-transform: uppercase;
+  letter-spacing: 0.5px;
+}
+
+.slider-header {
+  display: flex;
+  justify-content: space-between;
+  align-items: center;
+}
+
+.comfort-value {
+  font-size: 13px;
+  font-weight: 700;
+  padding: 2px 8px;
+  border-radius: 12px;
+  background: var(--bg-card);
+}
+.comfort-value.high { color: #22c55e; }
+.comfort-value.medium { color: #f59e0b; }
+.comfort-value.low { color: #ef4444; }
+
+.input-field {
+  padding: 10px 16px;
+  border: 1px solid var(--border-color);
+  background: var(--bg-input);
+  color: var(--text-primary);
+  border-radius: 8px;
+  font-size: 14px;
+  transition: all 0.2s;
+}
+
+.input-field:focus {
+  outline: none;
+  border-color: #667eea;
+  box-shadow: 0 0 0 2px rgba(102, 126, 234, 0.2);
+}
+
+.slider-field {
+  width: 100%;
+  accent-color: #667eea;
+}
+
+.btn-add {
+  display: flex;
+  align-items: center;
+  gap: 6px;
+  padding: 10px 20px;
+  height: 42px; /* Match input heights roughly */
+}
+
+@media (max-width: 640px) {
+  .add-topic-form {
+    flex-direction: column;
+    align-items: stretch;
+  }
+}

Frontend/src/app/pages/candidate/profile/profile.html

@@ -29,6 +29,63 @@
       </div>
     </div>
 
+    <!-- Topics of Interest Section -->
+    <div class="section topics-section card card-padding">
+      <div class="section-header">
+        <h2 class="section-title">Topics of Interest</h2>
+        @if (isSavingTopics()) {
+          <span class="saving-indicator">Saving...</span>
+        }
+      </div>
+      <p class="section-desc">Define your preferred topics to help admins assign relevant quizzes based on your comfort level.</p>
+      
+      <!-- Existing Topics Display -->
+      <div class="existing-topics">
+        @for (topic of topics(); track $index) {
+          <div class="topic-tag">
+            <div class="topic-tag-info">
+              <span class="topic-tag-name">{{ topic.topic }}</span>
+              <span class="topic-tag-level" 
+                [class.high]="topic.comfortLevel >= 75" 
+                [class.medium]="topic.comfortLevel >= 40 && topic.comfortLevel < 75" 
+                [class.low]="topic.comfortLevel < 40">
+                {{ topic.comfortLevel }}%
+              </span>
+            </div>
+            <button class="topic-tag-remove" (click)="removeTopic($index)" title="Remove topic">
+              <span class="material-symbols-rounded">close</span>
+            </button>
+          </div>
+        }
+        @if (topics().length === 0) {
+          <p class="no-topics-msg">You haven't added any topics yet.</p>
+        }
+      </div>
+
+      <!-- Add New Topic Form -->
+      <div class="add-topic-form">
+        <div class="topic-input-group">
+          <label>Topic Name</label>
+          <input type="text" [(ngModel)]="newTopicName" placeholder="e.g., Python, React..." class="input-field" (keyup.enter)="addTopic()" />
+        </div>
+        <div class="topic-slider-group">
+          <div class="slider-header">
+            <label>Comfort Level</label>
+            <span class="comfort-value" 
+              [class.high]="newTopicComfort() >= 75" 
+              [class.medium]="newTopicComfort() >= 40 && newTopicComfort() < 75" 
+              [class.low]="newTopicComfort() < 40">
+              {{ newTopicComfort() }}%
+            </span>
+          </div>
+          <input type="range" [(ngModel)]="newTopicComfort" min="0" max="100" class="slider-field" />
+        </div>
+        <button class="btn btn-primary btn-add" (click)="addTopic()" [disabled]="!newTopicName().trim() || isSavingTopics()">
+          <span class="material-symbols-rounded">add</span> Add
+        </button>
+      </div>
+    </div>
+
     <div class="section">
       <h2 class="section-title">Test Results</h2>
       @if (submissions().length === 0) {

Frontend/src/app/pages/candidate/profile/profile.ts

 import { Component, OnInit, signal } from '@angular/core';
 import { CommonModule } from '@angular/common';
 import { RouterLink } from '@angular/router';
+import { FormsModule } from '@angular/forms';
 import { AuthService } from '../../../services/auth.service';
 import { QuizService } from '../../../services/quiz.service';
 
+interface TopicOfInterest {
+  topic: string;
+  comfortLevel: number;
+}
+
 @Component({
   selector: 'app-candidate-profile',
   standalone: true,
-  imports: [CommonModule, RouterLink],
+  imports: [CommonModule, RouterLink, FormsModule],
   templateUrl: './profile.html',
   styleUrl: './profile.css'
 })
@@ -16,12 +22,21 @@ export class CandidateProfileComponent implements OnInit {
   submissions = signal<any[]>([]);
   loading = signal(true);
   
+  topics = signal<TopicOfInterest[]>([]);
+  
+  // State for new topic form
+  newTopicName = signal('');
+  newTopicComfort = signal(50);
+  
+  isSavingTopics = signal(false);
+
   constructor(public authService: AuthService, private quizService: QuizService) {}
 
   ngOnInit(): void {
     this.quizService.getCandidateProfile().subscribe({
       next: (res) => {
         this.user.set(res.user);
+        this.topics.set(res.user.topicsOfInterest || []);
         this.submissions.set(res.submissions || []);
         this.loading.set(false);
       },
@@ -40,4 +55,38 @@ export class CandidateProfileComponent implements OnInit {
     if (subs.length === 0) return 0;
     return Math.max(...subs.map(s => s.percentage));
   }
+
+  addTopic() {
+    const topic = this.newTopicName().trim();
+    if (!topic) return;
+
+    const newTopicList = [...this.topics(), { topic, comfortLevel: this.newTopicComfort() }];
+    this.topics.set(newTopicList);
+    
+    // Clear form
+    this.newTopicName.set('');
+    this.newTopicComfort.set(50);
+    
+    this.saveTopics(newTopicList);
+  }
+
+  removeTopic(index: number) {
+    const newTopicList = this.topics().filter((_, i) => i !== index);
+    this.topics.set(newTopicList);
+    this.saveTopics(newTopicList);
+  }
+
+  private saveTopics(updatedTopics: TopicOfInterest[]) {
+    this.isSavingTopics.set(true);
+    this.quizService.updateCandidateProfile({ topicsOfInterest: updatedTopics }).subscribe({
+      next: () => {
+        this.isSavingTopics.set(false);
+      },
+      error: () => {
+        this.isSavingTopics.set(false);
+        alert('Failed to update topics.');
+      }
+    });
+  }
 }
+

Frontend/src/app/pages/hr/create-quiz/create-quiz.html

@@ -37,11 +37,7 @@
       <div class="form-row">
         <div class="form-group">
           <label class="form-label">Category</label>
-          <input class="form-input" [(ngModel)]="category" name="category" placeholder="e.g. Programming">
-        </div>
-        <div class="form-group">
-          <label class="form-label">Topic</label>
-          <input class="form-input" [(ngModel)]="topic" name="topic" placeholder="e.g. Arrays & Loops">
+          <input class="form-input" [(ngModel)]="category" name="category" placeholder="e.g. Java, Angular, Data Structures">
         </div>
       </div>
       <div class="form-group">

Frontend/src/app/pages/hr/create-quiz/create-quiz.ts

@@ -16,7 +16,6 @@ export class HRCreateQuizComponent {
   timer = 30;
   category = '';
   difficulty = 'medium';
-  topic = '';
   selectedFile: File | null = null;
   fileName = signal('');
 
@@ -49,7 +48,6 @@ export class HRCreateQuizComponent {
     formData.append('questionsFile', this.selectedFile);
     if (this.category) formData.append('category', this.category);
     if (this.difficulty) formData.append('difficulty', this.difficulty);
-    if (this.topic) formData.append('topic', this.topic);
 
     this.quizService.createHRQuiz(formData).subscribe({
       next: (res) => {

Frontend/src/app/services/quiz.service.ts

@@ -43,6 +43,11 @@
       return this.http.get(`${this.adminUrl}/users/${userId}/history`);
     }
 
+    updateUserLevel(userId: string, level: string, role: string = 'admin'): Observable<any> {
+      const baseUrl = role === 'hr' ? this.hrUrl : this.adminUrl;
+      return this.http.put(`${baseUrl}/users/${userId}/level`, { level });
+    }
+
     getSubmissionDetails(submissionId: string): Observable<any> {
       return this.http.get(`${this.adminUrl}/submissions/${submissionId}`);
     }
@@ -75,6 +80,10 @@
       return this.http.put(`${this.adminUrl}/quiz/${quizId}/assign`, data);
     }
 
+    getAssignCandidates(quizId: string): Observable<any> {
+      return this.http.get(`${this.adminUrl}/quiz/${quizId}/assign-candidates`);
+    }
+
     deleteQuiz(quizId: string): Observable<any> {
       return this.http.delete(`${this.adminUrl}/quiz/${quizId}`);
     }
@@ -155,6 +164,10 @@
       return this.http.get(`${this.candidateUrl}/profile`);
     }
 
+    updateCandidateProfile(data: any): Observable<any> {
+      return this.http.put(`${this.candidateUrl}/profile`, data);
+    }
+
     getResultDetails(submissionId: string): Observable<any> {
       return this.http.get(`${this.candidateUrl}/results/${submissionId}`);
     }