[FEAT] Implement Facebook OAuth Login for Users

[dhamolahedonist]

Description:

Implement functionality that allows users to log in via Facebook. This feature should ensure that users can authenticate using their Facebook accounts.

Acceptance Criteria:

API Endpoint Implementation:

• The endpoint should be accessible at /api/v1/auth/facebook.
• The endpoint should handle OAuth authentication via Facebook.

Authorization:

• Ensure that only valid Facebook users can log in.
• Validate the token received from Facebook to authenticate the user.

User Data Handling:

• On successful authentication, the user's Facebook profile should be retrieved.
• If the user is logging in for the first time, create a new user account in the database.
• If the user already exists, update their profile information accordingly.

Response:

On success: The API should return a 200 OK status code with the user's profile and a JWT token.
On failure: The API should return a 401 Unauthorized status code if the Facebook token is invalid, or a 500 Internal Server Error status code for unexpected errors.

Request Example:

GET /api/v1/auth/facebook
Authorization: Bearer <facebook_token>
Successful Response Example:

{
  "message": "Login successful",
  "status": 200,
  "token": "<jwt_token>",
  "data": {
    "user": {
      "id": "123",
      "name": "John Doe",
      "email": "john.doe@example.com"
     "facebook_id": "1234567890"
      "profile": {
        "id": "123",
        "first_name": "John",
        "last_name": "Doe",
        "phone_number": "1234567890",
        "avatarUrl": "https://example.com/avatar.jpg"
      }
    }
  }
}

Error Response Example:

{
    "message": "Invalid email. Email is required",
    "status_code": 400
}

or

{
  "message": "Authentication failed",
  "status": 401
}

or

{
  "message": "Internal server error",
  "status": 500
}

Purpose:

Enable users to log in using their Facebook accounts, providing a seamless authentication process.

Requirements:

Develop server-side logic to handle Facebook OAuth authentication.
Implement authorization checks to validate the Facebook token.
Ensure user data is properly handled during login and registration.
Expected Outcome:
Users can log in through Facebook, with their profile information being stored or updated in the system.

Status Codes:

200: User successfully authenticated,
401: Invalid email. Email is required,
500: Internal server error

Testing:

Write unit tests to verify that the endpoint correctly handles Facebook authentication.
Test authorization to ensure only valid Facebook users can log in.
Perform integration testing to confirm that user data is obtained and handled correctly during login and registration.