# -*- coding: utf-8 -*-
"""
oauthlib.oauth1.rfc5849.endpoints.authorization
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

This module is an implementation of various logic needed
for signing and checking OAuth 1.0 RFC 5849 requests.
"""
from __future__ import absolute_import, unicode_literals

from oauthlib.common import Request, add_params_to_uri

from .. import errors
from .base import BaseEndpoint

try:
    from urllib import urlencode
except ImportError:
    from urllib.parse import urlencode


class AuthorizationEndpoint(BaseEndpoint):

    """An endpoint responsible for letting authenticated users authorize access
    to their protected resources to a client.

    Typical use would be to have two views, one for displaying the authorization
    form and one to process said form on submission.

    The first view will want to utilize ``get_realms_and_credentials`` to fetch
    requested realms and useful client credentials, such as name and
    description, to be used when creating the authorization form.

    During form processing you can use ``create_authorization_response`` to
    validate the request, create a verifier as well as prepare the final
    redirection URI used to send the user back to the client.

    See :doc:`/oauth1/validator` for details on which validator methods to implement
    for this endpoint.
    """

    def create_verifier(self, request, credentials):
        """Create and save a new request token.

        :param request: An oauthlib.common.Request object.
        :param credentials: A dict of extra token credentials.
        :returns: The verifier as a dict.
        """
        verifier = {
            'oauth_token': request.resource_owner_key,
            'oauth_verifier': self.token_generator(),
        }
        verifier.update(credentials)
        self.request_validator.save_verifier(
            request.resource_owner_key, verifier, request)
        return verifier

    def create_authorization_response(self, uri, http_method='GET', body=None,
                                      headers=None, realms=None, credentials=None):
        """Create an authorization response, with a new request token if valid.

        :param uri: The full URI of the token request.
        :param http_method: A valid HTTP verb, i.e. GET, POST, PUT, HEAD, etc.
        :param body: The request body as a string.
        :param headers: The request headers as a dict.
        :param credentials: A list of credentials to include in the verifier.
        :returns: A tuple of 3 elements.
                  1. A dict of headers to set on the response.
                  2. The response body as a string.
                  3. The response status code as an integer.

        If the callback URI tied to the current token is "oob", a response with
        a 200 status code will be returned. In this case, it may be desirable to
        modify the response to better display the verifier to the client.

        An example of an authorization request::

            >>> from your_validator import your_validator
            >>> from oauthlib.oauth1 import AuthorizationEndpoint
            >>> endpoint = AuthorizationEndpoint(your_validator)
            >>> h, b, s = endpoint.create_authorization_response(
            ...     'https://your.provider/authorize?oauth_token=...',
            ...     credentials={
            ...         'extra': 'argument',
            ...     })
            >>> h
            {'Location': 'https://the.client/callback?oauth_verifier=...&extra=argument'}
            >>> b
            None
            >>> s
            302

        An example of a request with an "oob" callback::

            >>> from your_validator import your_validator
            >>> from oauthlib.oauth1 import AuthorizationEndpoint
            >>> endpoint = AuthorizationEndpoint(your_validator)
            >>> h, b, s = endpoint.create_authorization_response(
            ...     'https://your.provider/authorize?foo=bar',
            ...     credentials={
            ...         'extra': 'argument',
            ...     })
            >>> h
            {'Content-Type': 'application/x-www-form-urlencoded'}
            >>> b
            'oauth_verifier=...&extra=argument'
            >>> s
            200
        """
        request = self._create_request(uri, http_method=http_method, body=body,
                                       headers=headers)

        if not request.resource_owner_key:
            raise errors.InvalidRequestError(
                'Missing mandatory parameter oauth_token.')
        if not self.request_validator.verify_request_token(
                request.resource_owner_key, request):
            raise errors.InvalidClientError()

        request.realms = realms
        if (request.realms and not self.request_validator.verify_realms(
                request.resource_owner_key, request.realms, request)):
            raise errors.InvalidRequestError(
                description=('User granted access to realms outside of '
                             'what the client may request.'))

        verifier = self.create_verifier(request, credentials or {})
        redirect_uri = self.request_validator.get_redirect_uri(
            request.resource_owner_key, request)
        if redirect_uri == 'oob':
            response_headers = {
                'Content-Type': 'application/x-www-form-urlencoded'}
            response_body = urlencode(verifier)
            return response_headers, response_body, 200
        else:
            populated_redirect = add_params_to_uri(
                redirect_uri, verifier.items())
            return {'Location': populated_redirect}, None, 302

    def get_realms_and_credentials(self, uri, http_method='GET', body=None,
                                   headers=None):
        """Fetch realms and credentials for the presented request token.

        :param uri: The full URI of the token request.
        :param http_method: A valid HTTP verb, i.e. GET, POST, PUT, HEAD, etc.
        :param body: The request body as a string.
        :param headers: The request headers as a dict.
        :returns: A tuple of 2 elements.
                  1. A list of request realms.
                  2. A dict of credentials which may be useful in creating the
                  authorization form.
        """
        request = self._create_request(uri, http_method=http_method, body=body,
                                       headers=headers)

        if not self.request_validator.verify_request_token(
                request.resource_owner_key, request):
            raise errors.InvalidClientError()

        realms = self.request_validator.get_realms(
            request.resource_owner_key, request)
        return realms, {'resource_owner_key': request.resource_owner_key}
