# Authors:
#     Endi S. Dewata <edewata@redhat.com>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the Lesser GNU General Public License as published by
# the Free Software Foundation; either version 3 of the License or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
#  along with this program; if not, write to the Free Software Foundation,
# Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
#
# Copyright (C) 2013 Red Hat, Inc.
# All rights reserved.
#

from __future__ import absolute_import
from __future__ import print_function
import functools
import warnings

import requests
from requests.packages.urllib3.exceptions import InsecureRequestWarning


def catch_insecure_warning(func):
    """Temporary silence InsecureRequestWarning

    PKIConnection is not able to verify HTTPS connections yet. This decorator
    catches the warning.

    :see: https://fedorahosted.org/pki/ticket/1253
    """
    @functools.wraps(func)
    def wrapper(self, *args, **kwargs):
        with warnings.catch_warnings():
            warnings.simplefilter('ignore', InsecureRequestWarning)
            return func(self, *args, **kwargs)
    return wrapper


class PKIConnection:
    """
    Class to encapsulate the connection between the client and a Dogtag
    subsystem.
    """

    def __init__(self, protocol='http', hostname='localhost', port='8080',
                 subsystem='ca', accept='application/json',
                 trust_env=None):
        """
        Set the parameters for a python-requests based connection to a
        Dogtag subsystem.
        :param protocol: http or https
        :type protocol: str
        :param hostname: hostname of server
        :type hostname: str
        :param port: port of server
        :type port: str
        :param subsystem: ca, kra, ocsp, tks or tps
        :type subsystem: str
        :param accept: value of accept header.  Supported values are usually
           'application/json' or 'application/xml'
        :type accept: str
        :param trust_env: use environment variables for http proxy and other
           requests settings (default: yes)
        :type trust_env: bool, None
        :return: PKIConnection object.
        """

        self.protocol = protocol
        self.hostname = hostname
        self.port = port
        self.subsystem = subsystem

        self.serverURI = self.protocol + '://' + \
            self.hostname + ':' + self.port + '/' + \
            self.subsystem

        self.session = requests.Session()
        self.session.trust_env = trust_env
        if accept:
            self.session.headers.update({'Accept': accept})

    def authenticate(self, username=None, password=None):
        """
        Set the parameters used for authentication if username/password is to
        be used.  Both username and password must not be None.
        Note that this method only sets the parameters.  Actual authentication
        occurs when the connection is attempted,

        :param username: username to authenticate connection
        :param password: password to authenticate connection
        :return: None
        """
        if username is not None and password is not None:
            self.session.auth = (username, password)

    def set_authentication_cert(self, pem_cert_path, pem_key_path=None):
        """
        Set the path to the PEM file containing the certificate and private key
        for the client certificate to be used for authentication to the server,
        when client certificate authentication is required. The private key may
        optionally be stored in a different path.

        :param pem_cert_path: path to the PEM file
        :type pem_cert_path: str
        :param pem_key_path: path to the PEM-formatted private key file
        :type pem_key_path: str
        :return: None
        :raises: Exception if path is empty or None.
        """
        if pem_cert_path is None:
            raise Exception("No path for the certificate specified.")
        if len(str(pem_cert_path)) == 0:
            raise Exception("No path for the certificate specified.")
        if pem_key_path is not None:
            self.session.cert = (pem_cert_path, pem_key_path)
        else:
            self.session.cert = pem_cert_path

    @catch_insecure_warning
    def get(self, path, headers=None, params=None, payload=None):
        """
        Uses python-requests to issue a GET request to the server.

        :param path: path URI for the GET request
        :type path: str
        :param headers: headers for the GET request
        :type headers: dict
        :param params: Query parameters for the GET request
        :type params: dict or bytes
        :param payload: data to be sent in the body of the request
        :type payload: dict, bytes, file-like object
        :returns: request.response -- response from the server
        :raises: Exception from python-requests in case the GET was not
            successful, or returns an error code.
        """
        r = self.session.get(
            self.serverURI + path,
            verify=False,
            headers=headers,
            params=params,
            data=payload)
        r.raise_for_status()
        return r

    @catch_insecure_warning
    def post(self, path, payload, headers=None, params=None):
        """
        Uses python-requests to issue a POST request to the server.

        :param path: path URI for the POST request
        :type path: str
        :param payload: data to be sent in the body of the request
        :type payload: dict, bytes, file-like object
        :param headers: headers for the POST request
        :type headers: dict
        :param params: Query parameters for the POST request
        :type params: dict or bytes
        :returns: request.response -- response from the server
        :raises: Exception from python-requests in case the POST was not
            successful, or returns an error code.
        """
        r = self.session.post(
            self.serverURI + path,
            verify=False,
            data=payload,
            headers=headers,
            params=params)
        r.raise_for_status()
        return r

    @catch_insecure_warning
    def put(self, path, payload, headers=None):
        """
        Uses python-requests to issue a PUT request to the server.

        :param path: path URI for the PUT request
        :type path: str
        :param payload: data to be sent in the body of the request
        :type payload: dict, bytes, file-like object
        :param headers: headers for the PUT request
        :type headers: dict
        :returns: request.response -- response from the server
        :raises: Exception from python-requests in case the PUT was not
            successful, or returns an error code.
        """
        r = self.session.put(self.serverURI + path, payload, headers=headers)
        r.raise_for_status()
        return r

    @catch_insecure_warning
    def delete(self, path, headers=None):
        """
        Uses python-requests to issue a DEL request to the server.

        :param path: path URI for the DEL request
        :type path: str
        :param headers: headers for the DEL request
        :type headers: dict
        :returns: request.response -- response from the server
        :raises: Exception from python-requests in case the DEL was not
            successful, or returns an error code.
        """
        r = self.session.delete(self.serverURI + path, headers=headers)
        r.raise_for_status()
        return r


def main():
    """
    Test code for the PKIConnection class.
    :return: None
    """
    conn = PKIConnection()
    headers = {'Content-type': 'application/json',
               'Accept': 'application/json'}
    conn.set_authentication_cert('/root/temp4.pem')
    print(conn.get("", headers).json())

if __name__ == "__main__":
    main()
