quiz-frontend/CORE_INFRASTRUCTURE_SUMMARY.md

# Core Infrastructure Setup - Summary

**Date:** November 12, 2025  
**Status:** ✅ Completed (6 of 7 tasks)  
**Angular Version:** v20 with Standalone Components and Signals

---

## Completed Tasks

### ✅ 1. Environment Configuration
**Created:**
- `src/environments/environment.ts` - Production configuration
- `src/environments/environment.development.ts` - Development configuration

**Configuration:**
```typescript
{
  apiUrl: 'http://localhost:3000/api',
  apiTimeout: 30000,
  cacheTimeout: 300000,
  enableLogging: true
}
```

**Updated:**
- `angular.json` - Added fileReplacements for environment switching

---

### ✅ 2. TypeScript Interfaces & Models
**Created 7 comprehensive model files:**

1. **user.model.ts** - User, AuthResponse, AuthState, UserRegistration, UserLogin
2. **category.model.ts** - Category, CategoryDetail, CategoryStats, QuestionPreview
3. **question.model.ts** - Question, QuestionFormData, QuestionSearchFilters
4. **quiz.model.ts** - QuizSession, QuizResults, QuizAnswerSubmission, QuizQuestionResult
5. **guest.model.ts** - GuestSession, GuestSettings, GuestAnalytics, GuestState
6. **dashboard.model.ts** - UserDashboard, CategoryPerformance, AdminStatistics
7. **index.ts** - Barrel export for all models

**Total Interfaces:** 40+ TypeScript interfaces covering all API models

---

### ✅ 3. HTTP Interceptors
**Created 3 functional interceptors:**

1. **auth.interceptor.ts**
   - Adds JWT Bearer token to authenticated requests
   - Skips auth for guest endpoints
   - Uses functional interceptor pattern (Angular v20)

2. **guest.interceptor.ts**
   - Adds `x-guest-token` header for guest user requests
   - Only applies when no auth token exists
   - Handles guest session token management

3. **error.interceptor.ts**
   - Global HTTP error handling
   - Maps HTTP status codes to user-friendly messages
   - Handles 401 with auto-redirect to login
   - Integrates with ToastService for error notifications
   - Rate limiting (429) handling

**Registered in:** `app.config.ts` using `withInterceptors()`

---

### ✅ 4. Core Services
**Created 4 essential services:**

1. **storage.service.ts**
   - Token management (JWT, Guest)
   - User data persistence
   - Theme preference storage
   - Remember me functionality
   - localStorage/sessionStorage abstraction

2. **toast.service.ts**
   - Signal-based notification system
   - 4 notification types: success, error, warning, info
   - Auto-dismiss with configurable duration
   - Action buttons support
   - Queue management

3. **state.service.ts**
   - Signal-based state management utility
   - localStorage/sessionStorage persistence
   - Helper functions for creating persisted signals
   - Loading and error state management

4. **loading.service.ts**
   - Global loading state with signals
   - Loading counter for concurrent requests
   - Customizable loading messages
   - Force stop functionality

---

### ✅ 5. Angular Material Setup
**Installed:** `@angular/material@20.2.12`

**Configuration:**
- Theme: Azure Blue
- Typography: Enabled
- Animations: Enabled

**Updated Files:**
- `package.json` - Material dependencies added
- `src/styles.scss` - Material theme imported
- `src/index.html` - Material fonts and icons

---

### ✅ 6. Shared UI Components
**Created 2 reusable components:**

1. **LoadingSpinnerComponent**
   - Material spinner integration
   - Configurable size and message
   - Overlay mode for full-screen loading
   - Signal-based inputs
   ```html
   <app-loading-spinner 
     message="Loading data..." 
     size="50" 
     overlay="true">
   </app-loading-spinner>
   ```

2. **ToastContainerComponent**
   - Toast notification display
   - 4 notification styles with icons
   - Action button support
   - Auto-dismiss with animations
   - Material icons integration
   - Responsive design (mobile-friendly)

**Integrated:**
- Toast container added to main `app.html`
- Ready for app-wide notifications

---

## Project Structure

```
frontend/
├── src/
│   ├── app/
│   │   ├── core/
│   │   │   ├── models/
│   │   │   │   ├── user.model.ts
│   │   │   │   ├── category.model.ts
│   │   │   │   ├── question.model.ts
│   │   │   │   ├── quiz.model.ts
│   │   │   │   ├── guest.model.ts
│   │   │   │   ├── dashboard.model.ts
│   │   │   │   └── index.ts
│   │   │   ├── interceptors/
│   │   │   │   ├── auth.interceptor.ts
│   │   │   │   ├── guest.interceptor.ts
│   │   │   │   ├── error.interceptor.ts
│   │   │   │   └── index.ts
│   │   │   └── services/
│   │   │       ├── storage.service.ts
│   │   │       ├── toast.service.ts
│   │   │       ├── state.service.ts
│   │   │       ├── loading.service.ts
│   │   │       └── index.ts
│   │   ├── shared/
│   │   │   └── components/
│   │   │       ├── loading-spinner/
│   │   │       │   ├── loading-spinner.ts
│   │   │       │   ├── loading-spinner.html
│   │   │       │   └── loading-spinner.scss
│   │   │       └── toast-container/
│   │   │           ├── toast-container.ts
│   │   │           ├── toast-container.html
│   │   │           └── toast-container.scss
│   │   ├── app.config.ts (interceptors configured)
│   │   ├── app.ts (toast container imported)
│   │   └── app.html (toast container added)
│   └── environments/
│       ├── environment.ts
│       └── environment.development.ts
├── angular.json (updated)
└── package.json (Material added)
```

---

## Technologies & Patterns

**Angular v20 Features:**
- ✅ Standalone components
- ✅ Signals for state management
- ✅ Functional interceptors
- ✅ Signal-based inputs
- ✅ Control flow syntax (@for, @if)
- ✅ Zoneless change detection

**Material Design:**
- ✅ Azure Blue theme
- ✅ Progress spinner
- ✅ Icons
- ✅ Buttons

**State Management:**
- ✅ Signal-based reactive state
- ✅ Persistent storage (localStorage/sessionStorage)
- ✅ Loading and error states
- ✅ Toast notifications

---

## Next Steps (Remaining Task)

### 🔲 7. Configure Routing Structure
- [ ] Create route guards (auth, admin, guest)
- [ ] Set up lazy loading for feature modules
- [ ] Configure route paths
- [ ] Implement 404 handling
- [ ] Add route preloading strategy

---

## Usage Examples

### Using Storage Service
```typescript
import { StorageService } from './core/services';

constructor(private storage: StorageService) {}

// Save token
this.storage.setToken('jwt-token', true);

// Get token
const token = this.storage.getToken();

// Check authentication
if (this.storage.isAuthenticated()) {
  // User is logged in
}
```

### Using Toast Service
```typescript
import { ToastService } from './core/services';

constructor(private toast: ToastService) {}

// Show notifications
this.toast.success('Login successful!');
this.toast.error('Something went wrong');
this.toast.warning('Session expiring soon');
this.toast.info('New feature available');

// With action button
this.toast.showWithAction(
  'Item deleted',
  'Undo',
  () => this.undoDelete(),
  'warning'
);
```

### Using Loading Service
```typescript
import { LoadingService } from './core/services';

constructor(private loading: LoadingService) {}

// Start loading
this.loading.start('Fetching data...');

// Stop loading
this.loading.stop();

// Check loading state
if (this.loading.getLoadingState()) {
  // Currently loading
}
```

---

## File Statistics

**Files Created:** 21  
**Lines of Code:** ~2,000+  
**Interfaces Defined:** 40+  
**Services Created:** 4  
**Interceptors Created:** 3  
**Components Created:** 2

---

## Quality Checklist

- ✅ TypeScript strict mode enabled
- ✅ All interfaces properly typed
- ✅ Error handling implemented
- ✅ Loading states managed
- ✅ Responsive design ready
- ✅ Material Design integrated
- ✅ Signal-based reactivity
- ✅ Service injection patterns
- ✅ Separation of concerns
- ✅ Reusable components

---

**Status:** Ready for feature module development!  
**Next:** Authentication Module, Guest Module, Category Module