from django.contrib.auth import (
    login as django_login,
    logout as django_logout
)
from django.conf import settings
from django.core.exceptions import ObjectDoesNotExist
from django.utils.translation import ugettext_lazy as _

from rest_framework import status
from rest_framework.views import APIView
from rest_framework.response import Response
from rest_framework.generics import GenericAPIView
from rest_framework.permissions import IsAuthenticated, AllowAny
from rest_framework.generics import RetrieveUpdateAPIView

from allauth.account import app_settings as allauth_settings

from .app_settings import (
    TokenSerializer, UserDetailsSerializer, LoginSerializer,
    PasswordResetSerializer, PasswordResetConfirmSerializer,
    PasswordChangeSerializer, JWTSerializer, create_token
)
from .models import TokenModel

from .utils import jwt_encode


class LoginView(GenericAPIView):

    """
    Check the credentials and return the REST Token
    if the credentials are valid and authenticated.
    Calls Django Auth login method to register User ID
    in Django session framework

    Accept the following POST parameters: username, password
    Return the REST Framework Token Object's key.
    """
    permission_classes = (AllowAny,)
    serializer_class = LoginSerializer
    token_model = TokenModel

    def process_login(self):
        django_login(self.request, self.user)

    def get_response_serializer(self):
        if getattr(settings, 'REST_USE_JWT', False):
            response_serializer = JWTSerializer
        else:
            response_serializer = TokenSerializer
        return response_serializer

    def login(self):
        self.user = self.serializer.validated_data['user']

        if getattr(settings, 'REST_USE_JWT', False):
            self.token = jwt_encode(self.user)
        else:
            self.token = create_token(self.token_model, self.user, self.serializer)

        if getattr(settings, 'REST_SESSION_LOGIN', True):
            self.process_login()

    def get_response(self):
        serializer_class = self.get_response_serializer()

        if getattr(settings, 'REST_USE_JWT', False):
            data = {
                'user': self.user,
                'token': self.token
            }
            serializer = serializer_class(instance=data, context={'request': self.request})
        else:
            serializer = serializer_class(instance=self.token, context={'request': self.request})

        return Response(serializer.data, status=status.HTTP_200_OK)

    def post(self, request, *args, **kwargs):
        self.request = request
        self.serializer = self.get_serializer(data=self.request.data)
        self.serializer.is_valid(raise_exception=True)

        self.login()
        return self.get_response()


class LogoutView(APIView):

    """
    Calls Django logout method and delete the Token object
    assigned to the current User object.

    Accepts/Returns nothing.
    """
    permission_classes = (AllowAny,)

    def get(self, request, *args, **kwargs):
        try:
            if allauth_settings.LOGOUT_ON_GET:
                response = self.logout(request)
            else:
                response = self.http_method_not_allowed(request, *args, **kwargs)
        except Exception as exc:
            response = self.handle_exception(exc)

        return self.finalize_response(request, response, *args, **kwargs)

    def post(self, request):
        return self.logout(request)

    def logout(self, request):
        try:
            request.user.auth_token.delete()
        except (AttributeError, ObjectDoesNotExist):
            pass

        django_logout(request)

        return Response({"success": _("Successfully logged out.")},
                        status=status.HTTP_200_OK)


class UserDetailsView(RetrieveUpdateAPIView):
    """
    Returns User's details in JSON format.

    Accepts the following GET parameters: token
    Accepts the following POST parameters:
        Required: token
        Optional: email, first_name, last_name and UserProfile fields
    Returns the updated UserProfile and/or User object.
    """
    serializer_class = UserDetailsSerializer
    permission_classes = (IsAuthenticated,)

    def get_object(self):
        return self.request.user


class PasswordResetView(GenericAPIView):

    """
    Calls Django Auth PasswordResetForm save method.

    Accepts the following POST parameters: email
    Returns the success/fail message.
    """

    serializer_class = PasswordResetSerializer
    permission_classes = (AllowAny,)

    def post(self, request, *args, **kwargs):
        # Create a serializer with request.data
        serializer = self.get_serializer(data=request.data)
        serializer.is_valid(raise_exception=True)

        serializer.save()
        # Return the success message with OK HTTP status
        return Response(
            {"success": _("Password reset e-mail has been sent.")},
            status=status.HTTP_200_OK
        )


class PasswordResetConfirmView(GenericAPIView):
    """
    Password reset e-mail link is confirmed, therefore this resets the user's password.

    Accepts the following POST parameters: new_password1, new_password2
    Accepts the following Django URL arguments: token, uid
    Returns the success/fail message.
    """

    serializer_class = PasswordResetConfirmSerializer
    permission_classes = (AllowAny,)

    def post(self, request):
        serializer = self.get_serializer(data=request.data)
        serializer.is_valid(raise_exception=True)
        serializer.save()
        return Response({"success": _("Password has been reset with the new password.")})


class PasswordChangeView(GenericAPIView):
    """
    Calls Django Auth SetPasswordForm save method.

    Accepts the following POST parameters: new_password1, new_password2
    Returns the success/fail message.
    """

    serializer_class = PasswordChangeSerializer
    permission_classes = (IsAuthenticated,)

    def post(self, request):
        serializer = self.get_serializer(data=request.data)
        serializer.is_valid(raise_exception=True)
        serializer.save()
        return Response({"success": _("New password has been saved.")})