import json
import logging
from typing import Tuple

from django.conf import settings
from django.contrib.auth.models import AnonymousUser
from rest_framework import exceptions
from rest_framework.authentication import BaseAuthentication, get_authorization_header
from rest_framework.request import Request

from apps.api.permissions import RBACPermission, user_is_authorized
from apps.grafana_plugin.helpers.gcom import check_token
from apps.user_management.exceptions import OrganizationDeletedException, OrganizationMovedException
from apps.user_management.models import User
from apps.user_management.models.organization import Organization

from .constants import SCHEDULE_EXPORT_TOKEN_NAME, SLACK_AUTH_TOKEN_NAME
from .exceptions import InvalidToken
from .models import ApiAuthToken, PluginAuthToken, ScheduleExportAuthToken, SlackAuthToken, UserScheduleExportAuthToken

logger = logging.getLogger(__name__)
logger.setLevel(logging.DEBUG)


class ApiTokenAuthentication(BaseAuthentication):
    model = ApiAuthToken

    def authenticate(self, request):
        auth = get_authorization_header(request).decode("utf-8")
        user, auth_token = self.authenticate_credentials(auth)

        if not user_is_authorized(user, [RBACPermission.Permissions.API_KEYS_WRITE]):
            raise exceptions.AuthenticationFailed(
                "Only users with Admin permissions are allowed to perform this action."
            )

        return user, auth_token

    def authenticate_credentials(self, token):
        """
        Due to the random nature of hashing a  value, this must inspect
        each auth_token individually to find the correct one.
        """
        try:
            auth_token = self.model.validate_token_string(token)
        except InvalidToken:
            raise exceptions.AuthenticationFailed("Invalid token.")

        if auth_token.organization.is_moved:
            raise OrganizationMovedException(auth_token.organization)
        if auth_token.organization.deleted_at:
            raise OrganizationDeletedException(auth_token.organization)

        return auth_token.user, auth_token


class PluginAuthentication(BaseAuthentication):
    def authenticate_header(self, request):
        # Check parent's method comments
        return "Bearer"

    def authenticate(self, request: Request) -> Tuple[User, PluginAuthToken]:
        token_string = get_authorization_header(request).decode()

        if not token_string:
            raise exceptions.AuthenticationFailed("No token provided")

        return self.authenticate_credentials(token_string, request)

    def authenticate_credentials(self, token_string: str, request: Request) -> Tuple[User, PluginAuthToken]:
        context_string = request.headers.get("X-Instance-Context")
        if not context_string:
            raise exceptions.AuthenticationFailed("No instance context provided.")

        try:
            context = dict(json.loads(context_string))
        except (ValueError, TypeError):
            raise exceptions.AuthenticationFailed("Instance context must be JSON dict.")

        if "stack_id" not in context or "org_id" not in context:
            raise exceptions.AuthenticationFailed("Invalid instance context.")

        try:
            auth_token = check_token(token_string, context=context)
            if not auth_token.organization:
                raise exceptions.AuthenticationFailed("No organization associated with token.")
        except InvalidToken:
            raise exceptions.AuthenticationFailed("Invalid token.")

        user = self._get_user(request, auth_token.organization)
        return user, auth_token

    @staticmethod
    def _get_user(request: Request, organization: Organization) -> User:
        try:
            context = dict(json.loads(request.headers.get("X-Grafana-Context")))
        except (ValueError, TypeError):
            raise exceptions.AuthenticationFailed("Grafana context must be JSON dict.")

        if "UserId" not in context and "UserID" not in context:
            raise exceptions.AuthenticationFailed("Invalid Grafana context.")

        try:
            user_id = context["UserId"]
        except KeyError:
            user_id = context["UserID"]

        try:
            return organization.users.get(user_id=user_id)
        except User.DoesNotExist:
            logger.debug(f"Could not get user from grafana request. Context {context}")
            raise exceptions.AuthenticationFailed("Non-existent or anonymous user.")

    @classmethod
    def is_user_from_request_present_in_organization(cls, request: Request, organization: Organization) -> User:
        try:
            cls._get_user(request, organization)
            return True
        except exceptions.AuthenticationFailed:
            return False


class GrafanaIncidentUser(AnonymousUser):
    @property
    def is_authenticated(self):
        # Always return True. This is a way to tell if
        # the user has been authenticated in permissions
        return True


class GrafanaIncidentStaticKeyAuth(BaseAuthentication):
    def authenticate_header(self, request):  # noqa
        # Check parent's method comments
        return "Bearer"

    def authenticate(self, request: Request) -> Tuple[GrafanaIncidentUser, None]:
        token_string = get_authorization_header(request).decode()

        if (
            not token_string == settings.GRAFANA_INCIDENT_STATIC_API_KEY
            or settings.GRAFANA_INCIDENT_STATIC_API_KEY is None
        ):
            raise exceptions.AuthenticationFailed("Wrong token")

        if not token_string:
            raise exceptions.AuthenticationFailed("No token provided")

        return self.authenticate_credentials(token_string, request)

    def authenticate_credentials(self, token_string: str, request: Request) -> Tuple[GrafanaIncidentUser, None]:
        try:
            user = GrafanaIncidentUser()
        except InvalidToken:
            raise exceptions.AuthenticationFailed("Invalid token.")

        return user, None


class SlackTokenAuthentication(BaseAuthentication):
    model = SlackAuthToken

    def authenticate(self, request) -> Tuple[User, SlackAuthToken]:
        auth = request.query_params.get(SLACK_AUTH_TOKEN_NAME)
        if not auth:
            raise exceptions.AuthenticationFailed("Invalid token.")
        user, auth_token = self.authenticate_credentials(auth)
        return user, auth_token

    def authenticate_credentials(self, token_string: str) -> Tuple[User, SlackAuthToken]:
        try:
            auth_token = self.model.validate_token_string(token_string)
        except InvalidToken:
            raise exceptions.AuthenticationFailed("Invalid token.")

        return auth_token.user, auth_token


class ScheduleExportAuthentication(BaseAuthentication):
    model = ScheduleExportAuthToken

    def authenticate(self, request) -> Tuple[User, ScheduleExportAuthToken]:
        auth = request.query_params.get(SCHEDULE_EXPORT_TOKEN_NAME)
        public_primary_key = request.parser_context.get("kwargs", {}).get("pk")
        if not auth:
            raise exceptions.AuthenticationFailed("Invalid token.")

        auth_token = self.authenticate_credentials(auth, public_primary_key)
        return auth_token

    def authenticate_credentials(
        self, token_string: str, public_primary_key: str
    ) -> Tuple[User, ScheduleExportAuthToken]:
        try:
            auth_token = self.model.validate_token_string(token_string)
        except InvalidToken:
            raise exceptions.AuthenticationFailed("Invalid token.")

        if auth_token.organization.is_moved:
            raise OrganizationMovedException(auth_token.organization)
        if auth_token.organization.deleted_at:
            raise OrganizationDeletedException(auth_token.organization)

        if auth_token.schedule.public_primary_key != public_primary_key:
            raise exceptions.AuthenticationFailed("Invalid schedule export token for schedule")

        if not auth_token.active:
            raise exceptions.AuthenticationFailed("Export token is deactivated")

        return auth_token.user, auth_token


class UserScheduleExportAuthentication(BaseAuthentication):
    model = UserScheduleExportAuthToken

    def authenticate(self, request) -> Tuple[User, UserScheduleExportAuthToken]:
        auth = request.query_params.get(SCHEDULE_EXPORT_TOKEN_NAME)
        public_primary_key = request.parser_context.get("kwargs", {}).get("pk")

        if not auth:
            raise exceptions.AuthenticationFailed("Invalid token.")

        auth_token = self.authenticate_credentials(auth, public_primary_key)
        return auth_token

    def authenticate_credentials(
        self, token_string: str, public_primary_key: str
    ) -> Tuple[User, UserScheduleExportAuthToken]:
        try:
            auth_token = self.model.validate_token_string(token_string)
        except InvalidToken:
            raise exceptions.AuthenticationFailed("Invalid token")

        if auth_token.organization.is_moved:
            raise OrganizationMovedException(auth_token.organization)
        if auth_token.organization.deleted_at:
            raise OrganizationDeletedException(auth_token.organization)

        if auth_token.user.public_primary_key != public_primary_key:
            raise exceptions.AuthenticationFailed("Invalid schedule export token for user")

        if not auth_token.active:
            raise exceptions.AuthenticationFailed("Export token is deactivated")

        return auth_token.user, auth_token