from django.contrib.auth import get_user_model
from django.contrib.auth.backends import ModelBackend
from django.contrib.auth.hashers import check_password

from goodtimes import constants

from .models import IAmPrincipalOtp

class EmailBackend(ModelBackend):
    """
    Custom Authentication Backend for Email and Password Authentication.
    It extends Django's built-in 'ModelBackend'

    Methods:
    - authenticate(self, request, email=None, password=None, **kwargs): Authenticate a user.
    - get_user(self, user_id): Retrive a user by their user ID.

    Example:
    ```
    # Authenticate a user using their email and password
    user = EmailBackend.authenticate(request, email='user@example.com', password='password123')

    if user:
        # Authentication successful, user is logged in.
    else:
        # Authentication failed, user is not logged in.
    ```
    """
    UserModel = get_user_model()

    def authenticate(self, email=None, password=None, **kwargs):

        # Use a case-insensitive query for the email field
        try:
            user = self.UserModel.objects.get(email__iexact=email)
        except self.UserModel.DoesNotExist:
            return None

        # Use the user's `check_password` method to verify the password
        if user.check_password(password):
            return user
        return None

    def get_user(self, user_id):
        try:
            return self.UserModel.objects.get(pk=user_id)
        except self.UserModel.DoesNotExist:
            return None