import typing
from httpx import AsyncClient, Auth, Request, Response
from authlib.oauth1 import (
    SIGNATURE_HMAC_SHA1,
    SIGNATURE_TYPE_HEADER,
)
from authlib.common.encoding import to_unicode
from authlib.oauth1 import ClientAuth
from authlib.oauth1.client import OAuth1Client as _OAuth1Client
from .utils import extract_client_kwargs
from ..base_client import OAuthError


class OAuth1Auth(Auth, ClientAuth):
    """Signs the httpx request using OAuth 1 (RFC5849)"""
    requires_request_body = True

    def auth_flow(self, request: Request) -> typing.Generator[Request, Response, None]:
        url, headers, body = self.prepare(
            request.method, str(request.url), request.headers, request.content)
        yield Request(method=request.method, url=url, headers=headers, data=body)


class AsyncOAuth1Client(_OAuth1Client, AsyncClient):
    auth_class = OAuth1Auth

    def __init__(self, client_id, client_secret=None,
                 token=None, token_secret=None,
                 redirect_uri=None, rsa_key=None, verifier=None,
                 signature_method=SIGNATURE_HMAC_SHA1,
                 signature_type=SIGNATURE_TYPE_HEADER,
                 force_include_body=False, **kwargs):

        _client_kwargs = extract_client_kwargs(kwargs)
        AsyncClient.__init__(self, **_client_kwargs)

        _OAuth1Client.__init__(
            self, None,
            client_id=client_id, client_secret=client_secret,
            token=token, token_secret=token_secret,
            redirect_uri=redirect_uri, rsa_key=rsa_key, verifier=verifier,
            signature_method=signature_method, signature_type=signature_type,
            force_include_body=force_include_body, **kwargs)

    async def fetch_access_token(self, url, verifier=None, **kwargs):
        """Method for fetching an access token from the token endpoint.

        This is the final step in the OAuth 1 workflow. An access token is
        obtained using all previously obtained credentials, including the
        verifier from the authorization step.

        :param url: Access Token endpoint.
        :param verifier: A verifier string to prove authorization was granted.
        :param kwargs: Extra parameters to include for fetching access token.
        :return: A token dict.
        """
        if verifier:
            self.auth.verifier = verifier
        if not self.auth.verifier:
            self.handle_error('missing_verifier', 'Missing "verifier" value')
        token = await self._fetch_token(url, **kwargs)
        self.auth.verifier = None
        return token

    async def _fetch_token(self, url, **kwargs):
        resp = await self.post(url, **kwargs)
        text = await resp.aread()
        token = self.parse_response_token(resp.status_code, to_unicode(text))
        self.token = token
        return token

    @staticmethod
    def handle_error(error_type, error_description):
        raise OAuthError(error_type, error_description)