# coding: utf-8

# nslcd.py - functions for doing nslcd requests

#

# Copyright (C) 2013-2017 Arthur de Jong

#

# This library 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.

#

# This library 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 library; if not, write to the Free Software

# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA

# 02110-1301 USA

import fcntl

import os

import socket

import struct

import sys

import constants

# definition for reading and writing INT32 values

_int32 = struct.Struct('!i')

class NslcdClient(object):

    def __init__(self, action):

        # set up the socket (store in class to avoid closing it)

        self.sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)

        fcntl.fcntl(self.sock, fcntl.F_SETFD, fcntl.FD_CLOEXEC)

        # connect to nslcd

        self.sock.connect(constants.NSLCD_SOCKET)

        #self.sock.setblocking(1)

        self.fp = os.fdopen(self.sock.fileno(), 'r+b', 0)

        # write a request header with a request code

        self.action = action

        self.write_int32(constants.NSLCD_VERSION)

        self.write_int32(action)

    def write(self, value):

        self.fp.write(value)

    def write_int32(self, value):

        self.write(_int32.pack(value))

    def write_bytes(self, value):

        self.write_int32(len(value))

        self.write(value)

    def write_string(self, value):

        if sys.version_info[0] >= 3:

            value = value.encode('utf-8')

        self.write_bytes(value.encode('utf-8'))

    def write_ether(self, value):

        value = struct.pack('BBBBBB', *(int(x, 16) for x in value.split(':')))

        self.write(value)

    def write_address(self, af, value):

        self.write_int32(af)

        self.write_bytes(value)

    def read(self, size):

        value = b''

        while len(value) < size:

            data = self.fp.read(size - len(value))

            if not data:

                raise IOError('NSLCD protocol cut short')

            value += data

        return value

    def read_int32(self):

        return _int32.unpack(self.read(_int32.size))[0]

    def read_bytes(self):

        return self.read(self.read_int32())

    def read_string(self):

        value = self.read_bytes()

        if sys.version_info[0] >= 3:

            value = value.decode('utf-8')

        return value

    def read_stringlist(self):

        num = self.read_int32()

        return [self.read_string() for x in range(num)]

    def read_ether(self):

        value = self.fp.read(6)

        return ':'.join('%x' % x for x in struct.unpack('6B', value))

    def read_address(self):

        af = self.read_int32()

        return af, socket.inet_ntop(af, self.read_bytes())

    def read_addresslist(self):

        num = self.read_int32()

        return [self.read_address() for x in range(num)]

    def get_response(self):

        # complete the request if required and check response header

        if self.action:

            # flush the stream

            self.fp.flush()

            # read and check response version number

            if self.read_int32() != constants.NSLCD_VERSION:

                raise IOError('NSLCD protocol error')

            if self.read_int32() != self.action:

                raise IOError('NSLCD protocol error')

            # reset action to ensure that it is only the first time

            self.action = None

        # get the NSLCD_RESULT_* marker and return it

        return self.read_int32()

    def close(self):

        if hasattr(self, 'fp'):

            try:

                self.fp.close()

            except IOError:

                pass

    def __del__(self):

        self.close()

def usermod(username, asroot=False, password=None, args=None):

    # open a connection to nslcd

    con = NslcdClient(constants.NSLCD_ACTION_USERMOD)

    # write the request information

    con.write_string(username)

    con.write_int32(1 if asroot else 0)

    con.write_string(password)

    for k, v in args.items():

        con.write_int32(k)

        con.write_string(v)

    con.write_int32(constants.NSLCD_USERMOD_END)

    # read the response

    if con.get_response() != constants.NSLCD_RESULT_BEGIN:

        raise IOError('NSLCD protocol error')

    response = {}

    while True:

        key = con.read_int32()

        if key == constants.NSLCD_USERMOD_END:

            break

        response[key] = con.read_string()

    # return the response

    return response