#!/usr/bin/env python

# Copyright (C) 2003-2007  Robey Pointer <robeypointer@gmail.com>
#
# This file is part of paramiko.
#
# Paramiko is free software; you can redistribute it and/or modify it under the
# terms of the GNU Lesser General Public License as published by the Free
# Software Foundation; either version 2.1 of the License, or (at your option)
# any later version.
#
# Paramiko 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 Paramiko; if not, write to the Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA.


import base64
from binascii import hexlify
import getpass
import os
import select
import socket
import sys
import time
import traceback

import paramiko

try:
    import interactive
except ImportError:
    from . import interactive


def agent_auth(transport, username):
    """
    Attempt to authenticate to the given transport using any of the private
    keys available from an SSH agent.
    """

    agent = paramiko.Agent()
    agent_keys = agent.get_keys()
    if len(agent_keys) == 0:
        return

    for key in agent_keys:
        print("Trying ssh-agent key %s" % hexlify(key.get_fingerprint()))
        try:
            transport.auth_publickey(username, key)
            print("... success!")
            return
        except paramiko.SSHException:
            print("... nope.")


def manual_auth(username, hostname):
    default_auth = "p"
    auth = input("Auth by (p)assword, (r)sa key, or (d)ss key? [%s] " % default_auth)
    if len(auth) == 0:
        auth = default_auth

    if auth == "r":
        default_path = os.path.join(os.environ["HOME"], ".ssh", "id_rsa")
        path = input("RSA key [%s]: " % default_path)
        if len(path) == 0:
            path = default_path
        try:
            key = paramiko.RSAKey.from_private_key_file(path)
        except paramiko.PasswordRequiredException:
            password = getpass.getpass("RSA key password: ")
            key = paramiko.RSAKey.from_private_key_file(path, password)
        t.auth_publickey(username, key)
    elif auth == "d":
        default_path = os.path.join(os.environ["HOME"], ".ssh", "id_dsa")
        path = input("DSS key [%s]: " % default_path)
        if len(path) == 0:
            path = default_path
        try:
            key = paramiko.DSSKey.from_private_key_file(path)
        except paramiko.PasswordRequiredException:
            password = getpass.getpass("DSS key password: ")
            key = paramiko.DSSKey.from_private_key_file(path, password)
        t.auth_publickey(username, key)
    else:
        pw = getpass.getpass("Password for %s@%s: " % (username, hostname))
        t.auth_password(username, pw)


# setup logging
paramiko.util.log_to_file("demo.log")

username = ""
if len(sys.argv) > 1:
    hostname = sys.argv[1]
    if hostname.find("@") >= 0:
        username, hostname = hostname.split("@")
else:
    hostname = input("Hostname: ")
if len(hostname) == 0:
    print("*** Hostname required.")
    sys.exit(1)
port = 22
if hostname.find(":") >= 0:
    hostname, portstr = hostname.split(":")
    port = int(portstr)

# now connect
try:
    sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    sock.connect((hostname, port))
except Exception as e:
    print("*** Connect failed: " + str(e))
    traceback.print_exc()
    sys.exit(1)

try:
    t = paramiko.Transport(sock)
    try:
        t.start_client()
    except paramiko.SSHException:
        print("*** SSH negotiation failed.")
        sys.exit(1)

    try:
        keys = paramiko.util.load_host_keys(os.path.expanduser("~/.ssh/known_hosts"))
    except IOError:
        try:
            keys = paramiko.util.load_host_keys(os.path.expanduser("~/ssh/known_hosts"))
        except IOError:
            print("*** Unable to open host keys file")
            keys = {}

    # check server's host key -- this is important.
    key = t.get_remote_server_key()
    if hostname not in keys:
        print("*** WARNING: Unknown host key!")
    elif key.get_name() not in keys[hostname]:
        print("*** WARNING: Unknown host key!")
    elif keys[hostname][key.get_name()] != key:
        print("*** WARNING: Host key has changed!!!")
        sys.exit(1)
    else:
        print("*** Host key OK.")

    # get username
    if username == "":
        default_username = getpass.getuser()
        username = input("Username [%s]: " % default_username)
        if len(username) == 0:
            username = default_username

    agent_auth(t, username)
    if not t.is_authenticated():
        manual_auth(username, hostname)
    if not t.is_authenticated():
        print("*** Authentication failed. :(")
        t.close()
        sys.exit(1)

    chan = t.open_session()
    chan.get_pty()
    chan.invoke_shell()
    print("*** Here we go!\n")
    interactive.interactive_shell(chan)
    chan.close()
    t.close()

except Exception as e:
    print("*** Caught exception: " + str(e.__class__) + ": " + str(e))
    traceback.print_exc()
    try:
        t.close()
    except:
        pass
    sys.exit(1)