# XMLRPC-specific code for SFA Client

from sfa.util.ssl import simple_ssl_context

import xmlrpc.client
import http.client

try:
    from sfa.util.sfalogging import logger
except:
    import logging
    logger = logging.getLogger('sfaserverproxy')

##
# ServerException, ExceptionUnmarshaller
#
# Used to convert server exception strings back to an exception.
#    from usenet, Raghuram Devarakonda


class ServerException(Exception):
    pass


class ExceptionUnmarshaller(xmlrpc.client.Unmarshaller):

    def close(self):
        try:
            return xmlrpc.client.Unmarshaller.close(self)
        except xmlrpc.client.Fault as e:
            raise ServerException(e.faultString)

##
# XMLRPCTransport
#
# A transport for XMLRPC that works on top of HTTPS

# targetting only python-2.7 we can get rid of some older code


class XMLRPCTransport(xmlrpc.client.Transport):

    def __init__(self, key_file=None, cert_file=None, timeout=None):
        xmlrpc.client.Transport.__init__(self)
        self.timeout = timeout
        self.key_file = key_file
        self.cert_file = cert_file

    def make_connection(self, host):
        # create a HTTPS connection object from a host descriptor
        # host may be a string, or a (host, x509-dict) tuple
        host, extra_headers, x509 = self.get_host_info(host)
        conn = http.client.HTTPSConnection(
            host, None, key_file=self.key_file,
            cert_file=self.cert_file, context=simple_ssl_context())

        # Some logic to deal with timeouts. It appears that some (or all) versions
        # of python don't set the timeout after the socket is created. We'll do it
        # ourselves by forcing the connection to connect, finding the socket, and
        # calling settimeout() on it. (tested with python 2.6)
        if self.timeout:
            if hasattr(conn, 'set_timeout'):
                conn.set_timeout(self.timeout)

            if hasattr(conn, "_conn"):
                # HTTPS is a wrapper around HTTPSConnection
                real_conn = conn._conn
            else:
                real_conn = conn
            conn.connect()
            if hasattr(real_conn, "sock") and hasattr(real_conn.sock, "settimeout"):
                real_conn.sock.settimeout(float(self.timeout))

        return conn

    def getparser(self):
        unmarshaller = ExceptionUnmarshaller()
        parser = xmlrpc.client.ExpatParser(unmarshaller)
        return parser, unmarshaller


class XMLRPCServerProxy(xmlrpc.client.ServerProxy):

    def __init__(self, url, transport, allow_none=True, verbose=False):
        # remember url for GetVersion
        # xxx not sure this is still needed as SfaServerProxy has this too
        self.url = url
        xmlrpc.client.ServerProxy.__init__(
            self, url, transport, allow_none=allow_none,
            context=simple_ssl_context(), verbose=verbose)

    def __getattr__(self, attr):
        logger.debug("xml-rpc %s method:%s" % (self.url, attr))
        return xmlrpc.client.ServerProxy.__getattr__(self, attr)

# the object on which we can send methods that get sent over xmlrpc


class SfaServerProxy:

    def __init__(self, url, keyfile, certfile, verbose=False, timeout=None):
        self.url = url
        self.keyfile = keyfile
        self.certfile = certfile
        self.verbose = verbose
        self.timeout = timeout
        # an instance of xmlrpc.client.ServerProxy
        transport = XMLRPCTransport(keyfile, certfile, timeout)
        self.serverproxy = XMLRPCServerProxy(
            url, transport, allow_none=True, verbose=verbose)

    # this is python magic to return the code to run when
    # SfaServerProxy receives a method call
    # so essentially we send the same method with identical arguments
    # to the server_proxy object
    def __getattr__(self, name):
        def func(*args, **kwds):
            return getattr(self.serverproxy, name)(*args, **kwds)
        return func