# Router Enhancement Module

**Enhanced Routing with Guards, Middleware, and Analytics**

The Router Enhancement Module provides advanced routing capabilities with access control, middleware, lazy loading, and analytics.

---

## Features

- **Route Guards** - Access control for routes (auth, permissions, roles)
- **Route Middleware** - Cross-cutting concerns (analytics, loading, etc.)
- **Lazy Route Loading** - Load routes on demand
- **Route Analytics** - Track navigation patterns
- **Integration with LiveComponents** - Seamless integration with LiveComponent system
- **History & Hash Modes** - Support for both history and hash routing

---

## Quick Start

### Basic Usage

```javascript
import { Router, BuiltInGuards, BuiltInMiddleware } from './modules/router/index.js';

// Create router
const router = Router.create({
    mode: 'history',
    base: '/',
    enableAnalytics: true
});

// Register routes
router.routes([
    {
        path: '/',
        component: () => '<div>Home</div>',
        name: 'home',
        title: 'Home'
    },
    {
        path: '/dashboard',
        component: () => '<div>Dashboard</div>',
        name: 'dashboard',
        title: 'Dashboard',
        guards: ['auth'],
        middleware: ['analytics', 'loading']
    },
    {
        path: '/admin',
        component: () => import('./components/Admin.js'),
        name: 'admin',
        title: 'Admin',
        guards: ['auth', 'role:admin'],
        lazy: true
    }
]);

// Register guards
router.guard('auth', async (to, from) => {
    const isAuthenticated = await checkAuth();
    if (!isAuthenticated) {
        return '/login'; // Redirect to login
    }
    return true; // Allow navigation
});

// Add global middleware
router.use(BuiltInMiddleware.analytics);
router.use(BuiltInMiddleware.scrollToTop);

// Navigate
await router.navigate('/dashboard');
```

---

## API Reference

### Router.create(config)

Create a new Router instance.

**Parameters**:
- `config.mode` - Routing mode: 'history' or 'hash'
- `config.base` - Base path
- `config.enableAnalytics` - Enable route analytics

### router.route(path, config)

Register a single route.

**Parameters**:
- `path` - Route path
- `config.component` - Component (string, function, or HTMLElement)
- `config.name` - Route name
- `config.title` - Page title
- `config.guards` - Array of guard names
- `config.middleware` - Array of middleware
- `config.lazy` - Lazy load component

### router.guard(name, guardFn)

Register a route guard.

**Parameters**:
- `name` - Guard name
- `guardFn` - Guard function: `(to, from, context) => boolean | string`

### router.use(middleware)

Add global middleware.

**Parameters**:
- `middleware` - Middleware instance, function, or built-in name

### router.beforeEach(hook)

Add before navigation hook.

**Parameters**:
- `hook` - Hook function: `(to, from) => boolean | string | void`

### router.afterEach(hook)

Add after navigation hook.

**Parameters**:
- `hook` - Hook function: `(to, from) => void`

### router.navigate(path, options)

Navigate to a route.

**Parameters**:
- `path` - Route path
- `options.container` - Container element
- `options.updateHistory` - Update browser history

**Returns**: `Promise<boolean>`

---

## Route Guards

### Authentication Guard

```javascript
router.guard('auth', async (to, from) => {
    if (!isAuthenticated()) {
        return '/login';
    }
    return true;
});

// Use in route
router.route('/dashboard', {
    component: DashboardComponent,
    guards: ['auth']
});
```

### Role Guard

```javascript
router.guard('admin', async (to, from) => {
    if (getUserRole() !== 'admin') {
        return '/unauthorized';
    }
    return true;
});

// Use in route
router.route('/admin', {
    component: AdminComponent,
    guards: ['auth', 'admin']
});
```

### Built-in Guards

```javascript
// Use built-in guards
router.route('/dashboard', {
    component: DashboardComponent,
    guards: ['auth'] // Uses BuiltInGuards.auth
});

router.route('/login', {
    component: LoginComponent,
    guards: ['guest'] // Uses BuiltInGuards.guest
});
```

---

## Route Middleware

### Analytics Middleware

```javascript
// Use built-in analytics middleware
router.use('analytics');

// Or custom middleware
router.use(RouteMiddleware.create('custom', async (to, from, next) => {
    // Track navigation
    analytics.track('page_view', { path: to.path });
    next();
}));
```

### Loading Middleware

```javascript
router.use('loading'); // Shows loading indicator during navigation
```

### Scroll to Top Middleware

```javascript
router.use('scroll-to-top'); // Scrolls to top after navigation
```

---

## Lazy Route Loading

```javascript
router.route('/admin', {
    component: () => import('./components/Admin.js'),
    lazy: true
});

// Or with dynamic import
router.route('/user/:id', {
    component: async (route) => {
        const UserComponent = await import('./components/User.js');
        return UserComponent.default(route.params.id);
    },
    lazy: true
});
```

---

## Integration with LiveComponents

```javascript
import { Router } from './modules/router/index.js';
import { LiveComponent } from './modules/livecomponent/index.js';

const router = Router.create();

router.route('/dashboard', {
    component: async (route) => {
        // Initialize LiveComponents after navigation
        const container = document.querySelector('main');
        container.innerHTML = '<div data-live-component="dashboard"></div>';
        
        // Initialize LiveComponent
        const component = container.querySelector('[data-live-component]');
        LiveComponent.init(component);
        
        return container;
    }
});
```

---

## Route Analytics

```javascript
const router = Router.create({ enableAnalytics: true });

// Get analytics
const analytics = router.getAnalytics();
console.log('Total navigations:', analytics.totalNavigations);
console.log('Navigation history:', analytics.navigations);

// Listen for navigation events
window.addEventListener('router:navigation', (event) => {
    const { to, from, timestamp } = event.detail;
    console.log(`Navigated from ${from} to ${to}`);
});
```

---

## Use Cases

### Protected Routes

```javascript
router.routes([
    {
        path: '/',
        component: HomeComponent,
        name: 'home'
    },
    {
        path: '/dashboard',
        component: DashboardComponent,
        name: 'dashboard',
        guards: ['auth']
    },
    {
        path: '/admin',
        component: AdminComponent,
        name: 'admin',
        guards: ['auth', 'admin']
    }
]);
```

### Route with Middleware

```javascript
router.route('/api-data', {
    component: ApiDataComponent,
    middleware: ['analytics', 'loading']
});
```

### Lazy Loading

```javascript
router.route('/heavy-page', {
    component: () => import('./pages/HeavyPage.js'),
    lazy: true,
    guards: ['auth']
});
```

---

## Best Practices

1. **Use Guards for Access Control** - Protect routes with guards
2. **Use Middleware for Cross-Cutting Concerns** - Analytics, loading, etc.
3. **Lazy Load Heavy Routes** - Improve initial load time
4. **Track Navigation** - Use analytics to understand user behavior
5. **Handle Errors** - Provide fallback routes for errors

---

## Browser Support

- **Chrome/Edge**: 90+
- **Firefox**: 88+
- **Safari**: 14+
- **Mobile**: iOS 14+, Android Chrome 90+

**Required Features**:
- ES2020 JavaScript
- History API (for history mode)
- Promise support

---

**Next**: [Analytics Module](analytics.md) →