# -*- test-case-name: twisted.conch.test.test_default -*-
# Copyright (c) Twisted Matrix Laboratories.
# See LICENSE for details.

"""
Accesses the key agent for user authentication.

Maintainer: Paul Swartz
"""

import os

from twisted.conch.ssh import agent, channel, keys
from twisted.internet import protocol, reactor
from twisted.python import log



class SSHAgentClient(agent.SSHAgentClient):

    def __init__(self):
        agent.SSHAgentClient.__init__(self)
        self.blobs = []


    def getPublicKeys(self):
        return self.requestIdentities().addCallback(self._cbPublicKeys)


    def _cbPublicKeys(self, blobcomm):
        log.msg('got %i public keys' % len(blobcomm))
        self.blobs = [x[0] for x in blobcomm]


    def getPublicKey(self):
        """
        Return a L{Key} from the first blob in C{self.blobs}, if any, or
        return C{None}.
        """
        if self.blobs:
            return keys.Key.fromString(self.blobs.pop(0))
        return None



class SSHAgentForwardingChannel(channel.SSHChannel):

    def channelOpen(self, specificData):
        cc = protocol.ClientCreator(reactor, SSHAgentForwardingLocal)
        d = cc.connectUNIX(os.environ['SSH_AUTH_SOCK'])
        d.addCallback(self._cbGotLocal)
        d.addErrback(lambda x:self.loseConnection())
        self.buf = ''


    def _cbGotLocal(self, local):
        self.local = local
        self.dataReceived = self.local.transport.write
        self.local.dataReceived = self.write


    def dataReceived(self, data):
        self.buf += data


    def closed(self):
        if self.local:
            self.local.loseConnection()
            self.local = None


class SSHAgentForwardingLocal(protocol.Protocol):
    pass
