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import os
import threading
import warnings

from .authority import Authority
from . import argument
from .code_request import CodeRequest
from .token_request import TokenRequest
from .token_cache import TokenCache
from . import log
from .constants import OAuth2DeviceCodeResponseParameters

GLOBAL_ADAL_OPTIONS = {}

class AuthenticationContext(object):
    '''Retrieves authentication tokens from Azure Active Directory.

    For usages, check out the "sample" folder at:
        https://github.com/AzureAD/azure-activedirectory-library-for-python
    '''

    def __init__(
            self, authority, validate_authority=None, cache=None,
            api_version='1.0'):
        '''Creates a new AuthenticationContext object.

        By default the authority will be checked against a list of known Azure
        Active Directory authorities. If the authority is not recognized as 
        one of these well known authorities then token acquisition will fail.
        This behavior can be turned off via the validate_authority parameter
        below.

        :param str authority: A URL that identifies a token authority.
        :param bool validate_authority: (optional) Turns authority validation 
            on or off. This parameter default to true.
        :param TokenCache cache: (optional) Sets the token cache used by this 
            AuthenticationContext instance. If this parameter is not set, then
            a default is used. Cache instances is only used by that instance of
            the AuthenticationContext and are not shared unless it has been
            manually passed during the construction of other
            AuthenticationContexts.
        :param api_version: (optional) Specifies API version using on the wire.
            Historically it has a hardcoded default value as "1.0".
            Developers are now encouraged to set it as None explicitly,
            which means the underlying API version will be automatically chosen.
            In next major release, this default value will be changed to None.
        '''
        self.authority = Authority(authority, validate_authority is None or validate_authority)
        self._oauth2client = None
        self.correlation_id = None
        env_value = os.environ.get('ADAL_PYTHON_SSL_NO_VERIFY')
        if api_version is not None:
            warnings.warn(
                """The default behavior of including api-version=1.0 on the wire
                is now deprecated.
                Future version of ADAL will change the default value to None.

                To ensure a smooth transition, you are recommended to explicitly
                set it to None in your code now, and test out the new behavior.

                    context = AuthenticationContext(..., api_version=None)
                """, DeprecationWarning)
        self._call_context = {
            'options': GLOBAL_ADAL_OPTIONS,
            'api_version': api_version,
            'verify_ssl': None if env_value is None else not env_value # mainly for tracing through proxy
            }
        self._token_requests_with_user_code = {}
        self.cache = cache or TokenCache()
        self._lock = threading.RLock()

    @property
    def options(self):
        return self._call_context['options']

    @options.setter
    def options(self, val):
        self._call_context['options'] = val

    def _acquire_token(self, token_func):
        self._call_context['log_context'] = log.create_log_context(self.correlation_id)
        self.authority.validate(self._call_context)
        return token_func(self)

    def acquire_token(self, resource, user_id, client_id):
        '''Gets a token for a given resource via cached tokens.

        :param str resource: A URI that identifies the resource for which the
            token is valid.
        :param str user_id: The username of the user on behalf this application
            is authenticating.
        :param str client_id: The OAuth client id of the calling application.
        :returns: dic with several keys, include "accessToken" and
            "refreshToken".
        '''
        def token_func(self):
            token_request = TokenRequest(self._call_context, self, client_id, resource)
            return token_request.get_token_from_cache_with_refresh(user_id)

        return self._acquire_token(token_func)       

    def acquire_token_with_username_password(self, resource, username, password, client_id):
        '''Gets a token for a given resource via user credentails.
        
        :param str resource: A URI that identifies the resource for which the 
            token is valid.
        :param str username: The username of the user on behalf this
            application is authenticating.
        :param str password: The password of the user named in the username
            parameter.
        :param str client_id: The OAuth client id of the calling application.
        :returns: dict with several keys, include "accessToken" and
            "refreshToken".
        '''
        def token_func(self):
            token_request = TokenRequest(self._call_context, self, client_id, resource)
            return token_request.get_token_with_username_password(username, password)

        return self._acquire_token(token_func)

    def acquire_token_with_client_credentials(self, resource, client_id, client_secret):
        '''Gets a token for a given resource via client credentials.

        :param str resource: A URI that identifies the resource for which the 
            token is valid.
        :param str client_id: The OAuth client id of the calling application.
        :param str client_secret: The OAuth client secret of the calling application.
        :returns: dict with several keys, include "accessToken".
        '''
        def token_func(self):
            token_request = TokenRequest(self._call_context, self, client_id, resource)
            return token_request.get_token_with_client_credentials(client_secret)

        return self._acquire_token(token_func)

    def acquire_token_with_authorization_code(self, authorization_code, 
                                              redirect_uri, resource, 
                                              client_id, client_secret):
        '''Gets a token for a given resource via auhtorization code for a
        server app.
        
        :param str authorization_code: An authorization code returned from a
            client.
        :param str redirect_uri: the redirect uri that was used in the
            authorize call.
        :param str resource: A URI that identifies the resource for which the
            token is valid.
        :param str client_id: The OAuth client id of the calling application.
        :param str client_secret: The OAuth client secret of the calling
            application.
        :returns: dict with several keys, include "accessToken" and
            "refreshToken".
        '''
        def token_func(self):
            token_request = TokenRequest(
                self._call_context, 
                self, 
                client_id, 
                resource, 
                redirect_uri)
            return token_request.get_token_with_authorization_code(
                authorization_code, 
                client_secret)

        return self._acquire_token(token_func)

    def acquire_token_with_refresh_token(self, refresh_token, client_id,
                                         resource, client_secret=None):
        '''Gets a token for a given resource via refresh tokens
        
        :param str refresh_token: A refresh token returned in a tokne response
            from a previous invocation of acquireToken.
        :param str client_id: The OAuth client id of the calling application.
        :param str resource: A URI that identifies the resource for which the
            token is valid.
        :param str client_secret: (optional)The OAuth client secret of the
            calling application.                 
        :returns: dict with several keys, include "accessToken" and
            "refreshToken".
        '''
        def token_func(self):
            token_request = TokenRequest(self._call_context, self, client_id, resource)
            return token_request.get_token_with_refresh_token(refresh_token, client_secret)

        return self._acquire_token(token_func)

    def acquire_token_with_client_certificate(self, resource, client_id, 
                                              certificate, thumbprint):
        '''Gets a token for a given resource via certificate credentials

        :param str resource: A URI that identifies the resource for which the
            token is valid.
        :param str client_id: The OAuth client id of the calling application.
        :param str certificate: A PEM encoded certificate private key.
        :param str thumbprint:  hex encoded thumbprint of the certificate.
        :returns: dict with several keys, include "accessToken".
        '''
        def token_func(self):
            token_request = TokenRequest(self._call_context, self, client_id, resource)
            return token_request.get_token_with_certificate(certificate, thumbprint)

        return self._acquire_token(token_func)

    def acquire_user_code(self, resource, client_id, language=None):
        '''Gets the user code info which contains user_code, device_code for
        authenticating user on device.
        
        :param str resource: A URI that identifies the resource for which the 
            device_code and user_code is valid for.
        :param str client_id: The OAuth client id of the calling application.
        :param str language: The language code specifying how the message
            should be localized to.
        :returns: dict contains code and uri for users to login through browser.
        '''
        self._call_context['log_context'] = log.create_log_context(self.correlation_id)
        self.authority.validate(self._call_context)
        code_request = CodeRequest(self._call_context, self, client_id, resource)
        return code_request.get_user_code_info(language)

    def acquire_token_with_device_code(self, resource, user_code_info, client_id):
        '''Gets a new access token using via a device code. 
        
        :param str resource: A URI that identifies the resource for which the
            token is valid.
        :param dict user_code_info: The code info from the invocation of
            "acquire_user_code"
        :param str client_id: The OAuth client id of the calling application.
        :returns: dict with several keys, include "accessToken" and
            "refreshToken".
        '''
        self._call_context['log_context'] = log.create_log_context(self.correlation_id)

        def token_func(self):
            token_request = TokenRequest(self._call_context, self, client_id, resource)

            key = user_code_info[OAuth2DeviceCodeResponseParameters.DEVICE_CODE]
            with self._lock:
                self._token_requests_with_user_code[key] = token_request

            token = token_request.get_token_with_device_code(user_code_info)
            
            with self._lock:
                self._token_requests_with_user_code.pop(key, None)
            
            return token

        return self._acquire_token(token_func)

    def cancel_request_to_get_token_with_device_code(self, user_code_info):
        '''Cancels the polling request to get token with device code. 

        :param dict user_code_info: The code info from the invocation of
            "acquire_user_code"
        :returns: None
        '''
        argument.validate_user_code_info(user_code_info)
        
        key = user_code_info[OAuth2DeviceCodeResponseParameters.DEVICE_CODE]
        with self._lock:
            request = self._token_requests_with_user_code.get(key)

            if not request:
                raise ValueError('No acquire_token_with_device_code existed to be cancelled')

            request.cancel_token_request_with_device_code()
            self._token_requests_with_user_code.pop(key, None)