# -*- coding: utf-8 -*-
# darwin.py
# Copyright (C) 2013-2017 LEAP
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the 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 General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

"""
Darwin VPN launcher implementation.
"""

import commands
import getpass
import os
import socket
import sys

from twisted.logger import Logger

from leap.bitmask.vpn.launcher import VPNLauncher
from leap.bitmask.vpn.launcher import VPNLauncherException
from leap.common.config import get_path_prefix


logger = Logger()


class HelperCommand(object):

    SOCKET_ADDR = '/tmp/bitmask-helper.socket'

    def __init__(self):
        pass

    def _connect(self):
        self._sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
        try:
            self._sock.connect(self.SOCKET_ADDR)
        except socket.error, msg:
            raise RuntimeError(msg)

    def send(self, cmd, args=''):
        # TODO check cmd is in allowed list
        self._connect()
        sock = self._sock
        data = ""

        command = cmd + ' ' + args + '/CMD'

        try:
            sock.sendall(command)
            while '\n' not in data:
                data += sock.recv(32)
        finally:
            sock.close()

        return data


class NoTunKextLoaded(VPNLauncherException):
    pass


class DarwinVPNLauncher(VPNLauncher):
    """
    VPN launcher for the Darwin Platform
    """
    UP_SCRIPT = None
    DOWN_SCRIPT = None

    # TODO -- move this to bitmask-helper

    # Hardcode the installation path for OSX for security, openvpn is
    # run as root
    INSTALL_PATH = "/Applications/Bitmask.app/"
    INSTALL_PATH_ESCAPED = os.path.realpath(os.getcwd() + "/../../")
    OPENVPN_BIN = 'openvpn.leap'
    OPENVPN_PATH = "%s/Contents/Resources/openvpn" % (INSTALL_PATH,)
    OPENVPN_PATH_ESCAPED = "%s/Contents/Resources/openvpn" % (
        INSTALL_PATH_ESCAPED,)
    OPENVPN_BIN_PATH = "%s/Contents/Resources/%s" % (INSTALL_PATH,
                                                     OPENVPN_BIN)
    OTHER_FILES = []

    @classmethod
    def is_kext_loaded(kls):
        """
        Checks if the needed kext is loaded before launching openvpn.

        :returns: True if kext is loaded, False otherwise.
        :rtype: bool
        """
        loaded = bool(commands.getoutput(
            'kextstat | grep "net.sf.tuntaposx.tun"'))
        if not loaded:
            logger.error("tuntaposx extension not loaded!")
        return loaded

    @classmethod
    def _get_icon_path(kls):
        """
        Returns the absolute path to the app icon.

        :rtype: str
        """
        resources_path = os.path.abspath(
            os.path.join(os.getcwd(), "../../Contents/Resources"))

        return os.path.join(resources_path, "bitmask.tiff")

    @classmethod
    def get_vpn_command(kls, vpnconfig, providerconfig, socket_host,
                        remotes, socket_port="unix", openvpn_verb=1):
        """
        Returns the OSX implementation for the vpn launching command.

        Might raise:
            NoTunKextLoaded,
            OpenVPNNotFoundException,
            VPNLauncherException.

        :param eipconfig: eip configuration object
        :type eipconfig: EIPConfig
        :param providerconfig: provider specific configuration
        :type providerconfig: ProviderConfig
        :param socket_host: either socket path (unix) or socket IP
        :type socket_host: str
        :param socket_port: either string "unix" if it's a unix socket,
                            or port otherwise
        :type socket_port: str
        :param openvpn_verb: the openvpn verbosity wanted
        :type openvpn_verb: int

        :return: A VPN command ready to be launched.
        :rtype: list
        """
        if not kls.is_kext_loaded():
            raise NoTunKextLoaded('tun kext is needed, but was not found')

        # we use `super` in order to send the class to use
        command = super(DarwinVPNLauncher, kls).get_vpn_command(
            vpnconfig, providerconfig, socket_host, socket_port, remotes,
            openvpn_verb)
        command.extend(['--setenv', "LEAPUSER", getpass.getuser()])

        return command

    # TODO ship statically linked binary and deprecate.
    @classmethod
    def get_vpn_env(kls):
        """
        Returns a dictionary with the custom env for the platform.
        This is mainly used for setting LD_LIBRARY_PATH to the correct
        path when distributing a standalone client

        :rtype: dict
        """
        ld_library_path = os.path.join(get_path_prefix(), "..", "lib")
        ld_library_path.encode(sys.getfilesystemencoding())
        return {
            "DYLD_LIBRARY_PATH": ld_library_path
        }