# Login API Documentation

## Endpoint
```
POST /api/v1/auth/login
```

## Description
Login user with email or phone number. This endpoint authenticates users using either email address or phone number along with password.

## Current Implementation

### Frontend Code

**API Client** (`src/lib/api-client.ts`):
```typescript
export const adminApiHelpers = {
  // Auth - uses publicApi (no token required)
  login: (data: { email: string; password: string }) =>
    publicApi.post('/auth/login', data),
  // ...
}
```

**Login Page** (`src/pages/login/index.tsx`):
```typescript
const handleLogin = async (e: React.FormEvent) => {
  e.preventDefault()
  setIsLoading(true)

  try {
    const response = await adminApiHelpers.login({ email, password })
    const { access_token, user } = response.data

    // Check if user is admin
    if (user.role !== 'ADMIN') {
      toast.error("Access denied. Admin privileges required.")
      return
    }

    // Store credentials
    if (access_token) {
      localStorage.setItem('access_token', access_token)
    }
    localStorage.setItem('user', JSON.stringify(user))

    toast.success("Login successful!")
    navigate(from, { replace: true })
  } catch (error: any) {
    const message = error.response?.data?.message || "Invalid email or password"
    toast.error(message)
  } finally {
    setIsLoading(false)
  }
}
```

## Request

### Headers
```
Content-Type: application/json
```

### Body (JSON)

**Option 1: Email + Password**
```json
{
  "email": "admin@example.com",
  "password": "your-password"
}
```

**Option 2: Phone + Password** (if backend supports)
```json
{
  "phone": "+1234567890",
  "password": "your-password"
}
```

### Example Request
```bash
curl -X POST https://api.yourdomain.com/api/v1/auth/login \
  -H "Content-Type: application/json" \
  -d '{
    "email": "admin@example.com",
    "password": "password123"
  }'
```

## Response

### Success Response (200 OK)

**Option 1: With Access Token in Body** (localStorage fallback)
```json
{
  "access_token": "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9...",
  "refresh_token": "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9...",
  "user": {
    "id": "user-id-123",
    "email": "admin@example.com",
    "firstName": "John",
    "lastName": "Doe",
    "role": "ADMIN",
    "isActive": true,
    "createdAt": "2024-01-01T00:00:00.000Z"
  }
}
```

**Option 2: With httpOnly Cookies** (recommended)
```http
HTTP/1.1 200 OK
Set-Cookie: access_token=<jwt>; HttpOnly; Secure; SameSite=Strict; Path=/; Max-Age=900
Set-Cookie: refresh_token=<jwt>; HttpOnly; Secure; SameSite=Strict; Path=/auth/refresh; Max-Age=604800
Content-Type: application/json

{
  "user": {
    "id": "user-id-123",
    "email": "admin@example.com",
    "firstName": "John",
    "lastName": "Doe",
    "role": "ADMIN",
    "isActive": true,
    "createdAt": "2024-01-01T00:00:00.000Z"
  }
}
```

### Error Responses

**401 Unauthorized** - Invalid credentials
```json
{
  "message": "Invalid email or password",
  "statusCode": 401
}
```

**403 Forbidden** - Account inactive or not admin
```json
{
  "message": "Account is inactive",
  "statusCode": 403
}
```

**400 Bad Request** - Validation error
```json
{
  "message": "Validation failed",
  "errors": [
    {
      "field": "email",
      "message": "Invalid email format"
    }
  ],
  "statusCode": 400
}
```

**429 Too Many Requests** - Rate limit exceeded
```json
{
  "message": "Too many login attempts. Please try again later.",
  "statusCode": 429,
  "retryAfter": 900
}
```

**500 Internal Server Error** - Server error
```json
{
  "message": "Internal server error",
  "statusCode": 500
}
```

## Frontend Behavior

### 1. Form Validation
- Email: Required, valid email format
- Password: Required, minimum 8 characters
- Show/hide password toggle

### 2. Loading State
- Disable form during submission
- Show "Logging in..." button text
- Prevent multiple submissions

### 3. Success Flow
1. Validate response contains user data
2. Check if user.role === 'ADMIN'
3. Store access_token (if provided)
4. Store user data in localStorage
5. Show success toast
6. Redirect to dashboard or original destination

### 4. Error Handling
- Display user-friendly error messages
- Show toast notification
- Keep form enabled for retry
- Don't expose sensitive error details

### 5. Security Features
- HTTPS only in production
- httpOnly cookies support
- CSRF protection (SameSite cookies)
- Automatic token refresh
- Role-based access control

## Backend Requirements

### Must Implement
1. **Password Hashing**: bcrypt with salt rounds >= 12
2. **Rate Limiting**: 5 attempts per 15 minutes per IP
3. **Account Lockout**: Lock after 5 failed attempts
4. **Role Verification**: Ensure user.role === 'ADMIN'
5. **Active Status Check**: Verify user.isActive === true
6. **Token Generation**: JWT with proper expiration
7. **Audit Logging**: Log all login attempts

### Recommended
1. **httpOnly Cookies**: Store tokens in cookies, not response body
2. **Refresh Tokens**: Long-lived tokens for session renewal
3. **2FA Support**: Two-factor authentication
4. **IP Whitelisting**: Restrict admin access by IP
5. **Session Management**: Track active sessions
6. **Email Notifications**: Alert on new login

## Testing

### Manual Testing
```bash
# Test with valid credentials
curl -X POST http://localhost:3000/api/v1/auth/login \
  -H "Content-Type: application/json" \
  -d '{"email":"admin@example.com","password":"password123"}'

# Test with invalid credentials
curl -X POST http://localhost:3000/api/v1/auth/login \
  -H "Content-Type: application/json" \
  -d '{"email":"admin@example.com","password":"wrong"}'

# Test with non-admin user
curl -X POST http://localhost:3000/api/v1/auth/login \
  -H "Content-Type: application/json" \
  -d '{"email":"user@example.com","password":"password123"}'
```

### Automated Testing
See `src/pages/login/__tests__/index.test.tsx` for component tests.

## Environment Variables

### Development (`.env`)
```env
VITE_BACKEND_API_URL=http://localhost:3000/api/v1
```

### Production (`.env.production`)
```env
VITE_BACKEND_API_URL=https://api.yourdomain.com/api/v1
```

## API Client Configuration

The login endpoint uses the `publicApi` instance which:
- Does NOT require authentication
- Does NOT send Authorization header
- DOES send cookies (`withCredentials: true`)
- DOES handle CORS properly

## Flow Diagram

```
User enters credentials
        ↓
Form validation
        ↓
POST /api/v1/auth/login
        ↓
Backend validates credentials
        ↓
Backend checks role === 'ADMIN'
        ↓
Backend generates tokens
        ↓
Backend returns user + tokens
        ↓
Frontend checks role === 'ADMIN'
        ↓
Frontend stores tokens
        ↓
Frontend redirects to dashboard
```

## Security Checklist

Backend:
- [ ] Passwords hashed with bcrypt
- [ ] Rate limiting enabled
- [ ] Account lockout implemented
- [ ] HTTPS enforced
- [ ] CORS configured properly
- [ ] httpOnly cookies used
- [ ] Audit logging enabled
- [ ] Input validation
- [ ] SQL injection prevention

Frontend:
- [x] HTTPS only in production
- [x] Cookie support enabled
- [x] Role verification
- [x] Error handling
- [x] Loading states
- [x] Form validation
- [x] Token storage
- [x] Automatic token refresh

## Troubleshooting

### Issue: "Network Error"
**Solution:** Check API URL in environment variables

### Issue: "CORS Error"
**Solution:** Backend must allow credentials and specific origin

### Issue: "Invalid credentials" for valid user
**Solution:** Check backend password hashing and comparison

### Issue: "Access denied" for admin user
**Solution:** Verify user.role === 'ADMIN' in database

### Issue: Token not persisting
**Solution:** Check if backend is setting httpOnly cookies or returning access_token

## Related Documentation

- [Authentication Setup](./AUTHENTICATION.md)
- [API Standards](./API_STANDARDS.md)
- [Security Checklist](./SECURITY_CHECKLIST.md)
- [Backend Requirements](./SECURITY_CHECKLIST.md#backend-security)

## Support

For issues with login:
1. Check browser console for errors
2. Check network tab for API response
3. Verify environment variables
4. Check backend logs
5. Test with curl/Postman