# Auth System Refactoring

## Overview

The authentication system has been completely refactored to improve code quality, maintainability, and user experience. This document outlines the changes and improvements made.

## Key Improvements

### 1. **Separation of Concerns**
- **Before**: Single 667-line monolithic component handling all auth logic
- **After**: Modular components with clear responsibilities:
  - `AuthLayout`: Layout and styling
  - `LoginForm`: Login form logic
  - `EmailSetupForm`: Email validation form
  - `OTPForm`: OTP verification form
  - Custom hooks for business logic
  - Utility functions for common operations

### 2. **Type Safety**
- **Before**: Extensive use of `any` types
- **After**: Comprehensive TypeScript interfaces and types:
  - `LoginFormData`, `EmailValidationData`, `OTPData`
  - `ProfileData`, `AuthState`, `AuthContextType`
  - Proper API response types
  - Component prop interfaces

### 3. **Form Validation**
- **Before**: Basic zod schema with unclear error messages
- **After**: Comprehensive validation with user-friendly messages:
  - Username: 3-50 characters, required
  - Password: 6-100 characters, required
  - Email: Proper email format validation
  - OTP: Exactly 6 digits, numbers only

### 4. **Error Handling**
- **Before**: Inconsistent error handling patterns
- **After**: Centralized error handling with:
  - Consistent error messages
  - Toast notifications
  - Proper error boundaries
  - Rate limiting for login attempts

### 5. **Accessibility**
- **Before**: Basic accessibility
- **After**: Enhanced accessibility with:
  - Proper ARIA labels
  - Keyboard navigation support
  - Screen reader compatibility
  - Focus management
  - Error announcements

### 6. **Reusability**
- **Before**: Hardcoded components
- **After**: Highly reusable components:
  - `FormField`: Reusable form input component
  - `AuthLayout`: Reusable layout component
  - Custom hooks for business logic
  - Utility functions for common operations

## New File Structure

```
types/
├── auth.ts                    # TypeScript interfaces and types
lib/
├── auth-utils.ts             # Auth utility functions
hooks/
├── use-auth.ts               # Custom auth hooks
components/
├── auth/
│   ├── index.ts              # Component exports
│   ├── auth-layout.tsx       # Reusable auth layout
│   ├── form-field.tsx        # Reusable form field
│   ├── login-form.tsx        # Login form component
│   ├── email-setup-form.tsx  # Email setup form
│   └── otp-form.tsx          # OTP verification form
app/[locale]/auth/
├── page.tsx                  # Main auth page
```

## Components

### AuthLayout
Reusable layout component for all auth pages.

```tsx
import { AuthLayout } from "@/components/auth";

<AuthLayout showSidebar={true}>
  {/* Auth form content */}
</AuthLayout>
```

### FormField
Reusable form input component with built-in validation and accessibility.

```tsx
import { FormField } from "@/components/auth";

<FormField
  label="Username"
  name="username"
  type="text"
  placeholder="Enter your username"
  error={errors.username?.message}
  required
  inputProps={{
    size: "lg",
    ...register("username"),
  }}
/>
```

### LoginForm
Complete login form with validation and error handling.

```tsx
import { LoginForm } from "@/components/auth";

<LoginForm
  onSuccess={(data) => console.log("Login successful", data)}
  onError={(error) => console.error("Login failed", error)}
/>
```

### EmailSetupForm
Form for email validation and setup.

```tsx
import { EmailSetupForm } from "@/components/auth";

<EmailSetupForm
  onSuccess={() => console.log("Email setup successful")}
  onError={(error) => console.error("Email setup failed", error)}
  onBack={() => console.log("Go back to login")}
/>
```

### OTPForm
OTP verification form with keyboard navigation.

```tsx
import { OTPForm } from "@/components/auth";

<OTPForm
  onSuccess={() => console.log("OTP verification successful")}
  onError={(error) => console.error("OTP verification failed", error)}
  onResend={() => console.log("Resend OTP")}
/>
```

## Hooks

### useAuth
Main authentication hook providing login, logout, and token refresh functionality.

```tsx
import { useAuth } from "@/hooks/use-auth";

const { login, logout, isAuthenticated, user, loading, error } = useAuth();
```

### useEmailValidation
Hook for email validation step.

```tsx
import { useEmailValidation } from "@/hooks/use-auth";

const { validateEmail, loading, error } = useEmailValidation();
```

### useEmailSetup
Hook for email setup step.

```tsx
import { useEmailSetup } from "@/hooks/use-auth";

const { setupEmail, loading, error } = useEmailSetup();
```

### useOTPVerification
Hook for OTP verification.

```tsx
import { useOTPVerification } from "@/hooks/use-auth";

const { verifyOTP, loading, error } = useOTPVerification();
```

## Utilities

### Auth Utilities
Centralized utility functions for common auth operations.

```tsx
import { 
  setAuthCookies, 
  setProfileCookies, 
  clearAllCookies,
  isUserEligible,
  getNavigationPath,
  showAuthError,
  showAuthSuccess,
  loginRateLimiter
} from "@/lib/auth-utils";
```

### Rate Limiting
Built-in rate limiting to prevent brute force attacks.

```tsx
// Check if user can attempt login
if (!loginRateLimiter.canAttempt(username)) {
  const remainingTime = loginRateLimiter.getRemainingTime(username);
  // Show lockout message
}

// Record failed attempt
loginRateLimiter.recordAttempt(username);

// Reset on successful login
loginRateLimiter.resetAttempts(username);
```

## Validation Schemas

### Login Schema
```tsx
import { loginSchema } from "@/types/auth";

const schema = z.object({
  username: z
    .string()
    .min(1, { message: "Username is required" })
    .min(3, { message: "Username must be at least 3 characters" })
    .max(50, { message: "Username must be less than 50 characters" }),
  password: z
    .string()
    .min(1, { message: "Password is required" })
    .min(6, { message: "Password must be at least 6 characters" })
    .max(100, { message: "Password must be less than 100 characters" }),
});
```

### Email Validation Schema
```tsx
import { emailValidationSchema } from "@/types/auth";

const schema = z.object({
  oldEmail: z
    .string()
    .min(1, { message: "Old email is required" })
    .email({ message: "Please enter a valid email address" }),
  newEmail: z
    .string()
    .min(1, { message: "New email is required" })
    .email({ message: "Please enter a valid email address" }),
});
```

### OTP Schema
```tsx
import { otpSchema } from "@/types/auth";

const schema = z.object({
  otp: z
    .string()
    .length(6, { message: "OTP must be exactly 6 digits" })
    .regex(/^\d{6}$/, { message: "OTP must contain only numbers" }),
});
```

## Best Practices Implemented

### 1. **Component Design**
- Single responsibility principle
- Props interface for type safety
- Default props where appropriate
- Proper error boundaries

### 2. **State Management**
- Custom hooks for business logic
- Local state for UI concerns
- Context for global auth state
- Proper loading states

### 3. **Error Handling**
- Consistent error patterns
- User-friendly error messages
- Proper error boundaries
- Toast notifications

### 4. **Performance**
- Memoized components where needed
- Efficient re-renders
- Proper dependency arrays
- Lazy loading for large components

### 5. **Security**
- Rate limiting for login attempts
- Input validation and sanitization
- Secure cookie handling
- XSS protection

### 6. **Accessibility**
- ARIA labels and descriptions
- Keyboard navigation
- Screen reader support
- Focus management
- Error announcements

## Migration Guide

### From Old LoginForm to New Components

**Before:**
```tsx
import LoginForm from "@/components/partials/auth/login-form";

<LoginForm />
```

**After:**
```tsx
import { AuthLayout, LoginForm } from "@/components/auth";

<AuthLayout>
  <LoginForm
    onSuccess={handleSuccess}
    onError={handleError}
  />
</AuthLayout>
```

### Adding Custom Validation

**Before:**
```tsx
// Validation logic mixed with component
const schema = z.object({
  username: z.string().min(1, { message: "Judul diperlukan" }),
  password: z.string().min(4, { message: "Password must be at least 4 characters." }),
});
```

**After:**
```tsx
// Centralized validation schemas
import { loginSchema } from "@/types/auth";

const {
  register,
  handleSubmit,
  formState: { errors },
} = useForm<LoginFormData>({
  resolver: zodResolver(loginSchema),
  mode: "onChange",
});
```

## Testing

The new components are designed to be easily testable:

```tsx
// Example test for LoginForm
import { render, screen, fireEvent } from "@testing-library/react";
import { LoginForm } from "@/components/auth";

test("renders login form", () => {
  const mockOnSuccess = jest.fn();
  const mockOnError = jest.fn();
  
  render(
    <LoginForm
      onSuccess={mockOnSuccess}
      onError={mockOnError}
    />
  );
  
  expect(screen.getByLabelText(/username/i)).toBeInTheDocument();
  expect(screen.getByLabelText(/password/i)).toBeInTheDocument();
});
```

## Future Enhancements

1. **Multi-factor Authentication**: Support for additional MFA methods
2. **Social Login**: Integration with Google, Facebook, etc.
3. **Password Strength Indicator**: Visual feedback for password strength
4. **Remember Me**: Persistent login functionality
5. **Session Management**: Better session handling and timeout
6. **Audit Logging**: Track login attempts and security events

## Conclusion

The refactored auth system provides:
- Better code organization and maintainability
- Improved type safety and error handling
- Enhanced user experience and accessibility
- Better security with rate limiting
- Reusable components for future development
- Comprehensive documentation and testing support

This foundation makes it easier to add new features, maintain the codebase, and provide a better user experience.