# 🤠 Authentik + Heady Architecture Design

## 🎯 Design Philosophy

**"Security Through Simplicity"** - Build Authentik integration that's both powerful and maintainable, leveraging Astro + Alpine.js strengths.

## 🏗️ Architecture Overview

### **Authentication Flow**
```
User → Heady Login → Authentik → Auth Callback → Session Created → Dashboard
```

### **Technology Stack**
- **Frontend**: Alpine.js reactive components
- **Backend**: Astro API routes 
- **Sessions**: HTTP-only cookies + server-side storage
- **Identity**: Authentik OIDC provider
- **Security**: Zero client-side secrets, server-side validation

## 📁 File Structure

```
src/
├── pages/
│   ├── login.astro                    # Login page with Alpine.js
│   ├── api/
│   │   └── auth/
│   │       ├── login.ts              # OIDC initiation endpoint
│   │       ├── callback.ts           # OIDC callback handler
│   │       ├── logout.ts             # Session termination
│   │       └── profile.ts            # User profile API
│   └── admin/
│       └── [...protected].astro      # Protected admin routes
├── lib/
│   ├── auth/
│   │   ├── oidc-client.ts            # Authentik OIDC client
│   │   ├── session-manager.ts        # Session storage & validation
│   │   ├── role-mapper.ts            # Authentik group → role mapping
│   │   └── middleware.ts             # Authentication middleware
│   └── config/
│       └── authentik.ts              # Authentik configuration loader
└── components/
    ├── auth/
    │   ├── LoginButton.astro         # Alpine.js login component
    │   ├── UserProfile.astro         # User profile display
    │   └── ProtectedRoute.astro      # Route protection wrapper
    └── layouts/
        └── AuthenticatedLayout.astro  # Layout with auth state
```

## 🔐 Authentication Components

### **1. OIDC Client (`src/lib/auth/oidc-client.ts`)**
```typescript
interface AuthentikConfig {
  issuer: string;           // https://auth.company.com/application/o/heady/
  client_id: string;
  client_secret: string;
  redirect_uri: string;     // Auto-generated: {PUBLIC_URL}/api/auth/callback
  scope: string;            // "openid email profile groups" (auto-added)
}

interface AuthentikUser {
  sub: string;
  email: string;
  name: string;
  groups: string[];         // Authentik groups: ["admin", "heady-users", "network-ops"]
  picture?: string;
  authentik_groups?: string[]; // Fallback claim
}
```

### **2. Role Mapping (`src/lib/auth/role-mapper.ts`)**
```typescript
// Authentik-optimized role mapping
type HeadyRole = 'owner' | 'admin' | 'network_admin' | 'it_admin' | 'auditor' | 'member';

interface RoleMapping {
  // Environment variable mapping (highest priority)
  HEADY_OWNER_GROUPS: string[];      // "ceo,founders"
  HEADY_ADMIN_GROUPS: string[];      // "admin,administrators"
  HEADY_NETWORK_GROUPS: string[];    // "network,devops,sre"
  
  // Intelligent convention-based fallbacks
  mapByConvention(groups: string[]): HeadyRole;
}
```

### **3. Session Management (`src/lib/auth/session-manager.ts`)**
```typescript
interface HeadySession {
  sessionId: string;
  userId: string;
  email: string;
  role: HeadyRole;
  groups: string[];
  issuedAt: number;
  expiresAt: number;
  authentikSub: string;
}

// HTTP-only cookie storage
// Server-side session validation
// Automatic session refresh
```

## 🌐 API Routes

### **Login Flow (`/api/auth/login.ts`)**
```typescript
export const GET: APIRoute = async ({ url, redirect }) => {
  const authUrl = await oidcClient.createAuthUrl({
    redirect_uri: `${PUBLIC_URL}/api/auth/callback`,
    state: generateSecureState(),
    code_challenge: generatePKCE(),
  });
  
  return redirect(authUrl, 302);
};
```

### **Callback Handler (`/api/auth/callback.ts`)**
```typescript
export const GET: APIRoute = async ({ url, cookies, redirect }) => {
  // 1. Validate state & PKCE
  // 2. Exchange code for tokens
  // 3. Fetch user info from Authentik
  // 4. Map groups to roles
  // 5. Create secure session
  // 6. Set HTTP-only cookie
  // 7. Redirect to dashboard
};
```

## 🎨 Alpine.js Integration

### **Global Authentication State**
```javascript
// Global Alpine.js store
Alpine.store('auth', {
  user: null,
  role: null,
  isAuthenticated: false,
  
  async init() {
    // Check authentication status
    const response = await fetch('/api/auth/profile');
    if (response.ok) {
      const user = await response.json();
      this.user = user;
      this.role = user.role;
      this.isAuthenticated = true;
    }
  },
  
  async logout() {
    await fetch('/api/auth/logout', { method: 'POST' });
    this.user = null;
    this.role = null;
    this.isAuthenticated = false;
    window.location.href = '/login';
  }
});
```

### **Login Page (`src/pages/login.astro`)**
```html
<Layout title="Login">
  <div class="login-container" x-data="loginPage()">
    <div class="login-card">
      <h1>🤠 Welcome to Heady</h1>
      <p>Strategic VPN management that's actually awesome</p>
      
      <button @click="login()" class="login-btn" :disabled="loading">
        <span x-show="!loading">Login with Authentik</span>
        <span x-show="loading">Connecting...</span>
      </button>
    </div>
  </div>

  <script>
    function loginPage() {
      return {
        loading: false,
        
        async login() {
          this.loading = true;
          window.location.href = '/api/auth/login';
        }
      };
    }
  </script>
</Layout>
```

## 🛡️ Security Features

### **Authentik-Specific Optimizations**
1. **Group Discovery**: Auto-detect `groups`, `ak_groups`, and `attributes.groups` claims
2. **Policy Integration**: Leverage Authentik policies for advanced access control
3. **Session Sync**: Optional session synchronization with Authentik
4. **Audit Integration**: Forward auth events to Authentik audit logs

### **Heady Security Enhancements**
1. **Role Hierarchy**: Owner > Admin > Network Admin > IT Admin > Auditor > Member
2. **Session Security**: HTTP-only cookies, secure flags, CSRF protection
3. **Route Protection**: Server-side route validation before page render
4. **Audit Logging**: All authentication events logged for compliance

## 🚀 Configuration

### **Environment Variables**
```bash
# Authentik Configuration
AUTHENTIK_ISSUER="https://auth.company.com/application/o/heady/"
AUTHENTIK_CLIENT_ID="heady-production"
AUTHENTIK_CLIENT_SECRET="your-secret-here"

# Public URLs
PUBLIC_URL="https://heady.company.com"
HEADY_URL="https://heady.company.com"  # Fallback

# Custom Role Mapping (Optional)
HEADY_OWNER_GROUPS="ceo,founders,executives"
HEADY_ADMIN_GROUPS="admin,administrators,managers"
HEADY_NETWORK_GROUPS="network,devops,sre,infrastructure"

# Session Configuration
SESSION_SECRET="your-32-char-secret-here"
SESSION_LIFETIME="24h"
```

### **Astro Configuration (`astro.config.mjs`)**
```javascript
export default defineConfig({
  output: 'hybrid',
  adapter: node({ mode: 'standalone' }),
  
  integrations: [
    tailwind({ applyBaseStyles: false })
  ],
  
  vite: {
    define: {
      // Expose public config to client-side
      PUBLIC_HEADY_VERSION: JSON.stringify(process.env.npm_package_version),
      PUBLIC_AUTH_ENABLED: JSON.stringify(!!process.env.AUTHENTIK_CLIENT_ID),
    }
  }
});
```

## 🎯 Implementation Strategy

### **Phase 1: Core Authentication**
1. ✅ OIDC client for Authentik
2. ✅ Session management system  
3. ✅ Login/logout API routes
4. ✅ Basic role mapping

### **Phase 2: UI Integration**
1. ✅ Login page with Alpine.js
2. ✅ Global authentication state
3. ✅ Protected route middleware
4. ✅ User profile components

### **Phase 3: Advanced Features**
1. ✅ Authentik policy integration
2. ✅ Advanced role mapping
3. ✅ Audit logging
4. ✅ Session synchronization

## 💡 Authentik Advantages

This architecture leverages Authentik's strengths:

1. **Modern OIDC**: Full standard compliance with advanced features
2. **Flexible Groups**: Multiple group sources and custom attributes  
3. **Policy Engine**: Advanced access control beyond simple roles
4. **Audit Ready**: Built-in audit trails and compliance features
5. **Self-Service**: User profile management and password reset flows

---

**🎯 Result**: Secure, maintainable, Authentik-optimized authentication that fits perfectly with Heady's "Security Through Simplicity" philosophy!