# -*- coding: utf-8 -*-
# vpn.py
# Copyright (C) 2013 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/>.

"""
VPN launcher and watcher thread
"""
import logging
import sys

from PySide import QtCore, QtGui
from subprocess import Popen, PIPE
from functools import partial

from leap.config.providerconfig import ProviderConfig
from leap.services.eip.vpnlaunchers import get_platform_launcher
from leap.services.eip.eipconfig import EIPConfig
from leap.services.eip.udstelnet import UDSTelnet
from leap.util.check import leap_assert, leap_assert_type

logger = logging.getLogger(__name__)
ON_POSIX = 'posix' in sys.builtin_module_names


# TODO: abstract the thread that can be asked to quit to another
# generic class that Fetcher and VPN inherit from
class VPN(QtCore.QThread):
    """
    VPN launcher and watcher thread. It will emit signals based on
    different events caught by the management interface
    """

    state_changed = QtCore.Signal(dict)
    status_changed = QtCore.Signal(dict)

    CONNECTION_RETRY_TIME = 1000
    POLL_TIME = 100

    TS_KEY = "ts"
    STATUS_STEP_KEY = "status_step"
    OK_KEY = "ok"
    IP_KEY = "ip"
    REMOTE_KEY = "remote"

    TUNTAP_READ_KEY = "tun_tap_read"
    TUNTAP_WRITE_KEY = "tun_tap_write"
    TCPUDP_READ_KEY = "tcp_udp_read"
    TCPUDP_WRITE_KEY = "tcp_udp_write"
    AUTH_READ_KEY = "auth_read"

    def __init__(self):
        QtCore.QThread.__init__(self)

        self._should_quit = False
        self._should_quit_lock = QtCore.QMutex()

        self._launcher = get_platform_launcher()
        self._subp = None
        self._started = False

        self._tn = None
        self._host = None
        self._port = None

        self._last_state = None
        self._last_status = None

    def get_should_quit(self):
        """
        Returns wether this thread should quit

        @rtype: bool
        @return: True if the thread should terminate itself, Flase otherwise
        """
        QtCore.QMutexLocker(self._should_quit_lock)
        return self._should_quit

    def set_should_quit(self):
        """
        Sets the should_quit flag to True so that this thread
        terminates the first chance it gets.
        Also terminates the VPN process and the connection to it
        """
        QtCore.QMutexLocker(self._should_quit_lock)
        self._should_quit = True
        if self._tn is None or self._subp is None:
            return

        try:
            self._disconnect()
            self._subp.terminate()
        except Exception as e:
            logger.debug("Could not terminate process, trying command " +
                         "signal SIGNINT: %r" % (e,))
            self._send_command("signal SIGINT")
        self._subp.wait()
        self.wait()
        self._started = False

    def start(self, eipconfig, providerconfig, socket_host, socket_port):
        """
        Launches OpenVPN and starts the thread to watch its output

        @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
        """
        leap_assert(eipconfig, "We need an eip config")
        leap_assert_type(eipconfig, EIPConfig)
        leap_assert(providerconfig, "We need a provider config")
        leap_assert_type(providerconfig, ProviderConfig)
        leap_assert(not self._started, "Starting process more than once!")

        logger.debug("Starting VPN...")

        with QtCore.QMutexLocker(self._should_quit_lock):
            self._should_quit = False

        command = self._launcher.get_vpn_command(eipconfig=eipconfig,
                                                 providerconfig=providerconfig,
                                                 socket_host=socket_host,
                                                 socket_port=socket_port)
        try:
            self._subp = Popen(command, stdout=PIPE, stderr=PIPE,
                               bufsize=1, close_fds=ON_POSIX)

            self._host = socket_host
            self._port = socket_port

            self._started = True

            QtCore.QThread.start(self)
        except Exception as e:
            logger.warning("Something went wrong while starting OpenVPN: %r" %
                           (e,))

    def _connect(self, socket_host, socket_port):
        """
        Connects to the specified socket_host socket_port
        @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
        """
        try:
            self._tn = UDSTelnet(socket_host, socket_port)

            # XXX make password optional
            # specially for win. we should generate
            # the pass on the fly when invoking manager
            # from conductor

            # self.tn.read_until('ENTER PASSWORD:', 2)
            # self.tn.write(self.password + '\n')
            # self.tn.read_until('SUCCESS:', 2)
            if self._tn:
                self._tn.read_eager()
        except Exception as e:
            logger.warning("Could not connect to OpenVPN yet: %r" % (e,))
            self._tn = None

    def _disconnect(self):
        """
        Disconnects the telnet connection to the openvpn process
        """
        logger.debug('Closing socket')
        self._tn.write("quit\n")
        self._tn.read_all()
        self._tn.close()
        self._tn = None

    def _send_command(self, command, until=b"END"):
        """
        Sends a command to the telnet connection and reads until END
        is reached

        @param command: command to send
        @type command: str
        @param until: byte delimiter string for reading command output
        @type until: byte str
        @return: response read
        @rtype: list
        """
        leap_assert(self._tn, "We need a tn connection!")
        try:
            self._tn.write("%s\n" % (command,))
            buf = self._tn.read_until(until, 2)
            self._tn.read_eager()
            lines = buf.split("\n")
            return lines
        except Exception as e:
            logger.warning("Error sending command %s: %r" %
                           (command, e))
        return []

    def _parse_state_and_notify(self, output):
        """
        Parses the output of the state command and emits state_changed
        signal when the state changes

        @param output: list of lines that the state command printed as
        its output
        @type output: list
        """
        for line in output:
            stripped = line.strip()
            if stripped == "END":
                continue
            parts = stripped.split(",")
            if len(parts) < 5:
                continue
            ts, status_step, ok, ip, remote = parts

            state_dict = {
                self.TS_KEY: ts,
                self.STATUS_STEP_KEY: status_step,
                self.OK_KEY: ok,
                self.IP_KEY: ip,
                self.REMOTE_KEY: remote
            }

            if state_dict != self._last_state:
                self.state_changed.emit(state_dict)
                self._last_state = state_dict

    def _parse_status_and_notify(self, output):
        """
        Parses the output of the status command and emits
        status_changed signal when the status changes

        @param output: list of lines that the status command printed
        as its output
        @type output: list
        """
        tun_tap_read = ""
        tun_tap_write = ""
        tcp_udp_read = ""
        tcp_udp_write = ""
        auth_read = ""
        for line in output:
            stripped = line.strip()
            if stripped.endswith("STATISTICS") or stripped == "END":
                continue
            parts = stripped.split(",")
            if len(parts) < 2:
                continue
            if parts[0].strip() == "TUN/TAP read bytes":
                tun_tap_read = parts[1]
            elif parts[0].strip() == "TUN/TAP write bytes":
                tun_tap_write = parts[1]
            elif parts[0].strip() == "TCP/UDP read bytes":
                tcp_udp_read = parts[1]
            elif parts[0].strip() == "TCP/UDP write bytes":
                tcp_udp_write = parts[1]
            elif parts[0].strip() == "Auth read bytes":
                auth_read = parts[1]

        status_dict = {
            self.TUNTAP_READ_KEY: tun_tap_read,
            self.TUNTAP_WRITE_KEY: tun_tap_write,
            self.TCPUDP_READ_KEY: tcp_udp_read,
            self.TCPUDP_WRITE_KEY: tcp_udp_write,
            self.AUTH_READ_KEY: auth_read
        }

        if status_dict != self._last_status:
            self.status_changed.emit(status_dict)
            self._last_status = status_dict

    def run(self):
        """
        Main run loop for this thread
        """
        while True:
            if self.get_should_quit():
                logger.debug("Quitting VPN thread")
                return

            if self._tn is None:
                self._connect(self._host, self._port)
                QtCore.QThread.msleep(self.CONNECTION_RETRY_TIME)
            else:
                self._parse_state_and_notify(self._send_command("state"))
                self._parse_status_and_notify(self._send_command("status"))
                QtCore.QThread.msleep(self.POLL_TIME)


if __name__ == "__main__":
    app = QtGui.QApplication(sys.argv)

    import signal

    def sigint_handler(*args, **kwargs):
        logger.debug('SIGINT catched. shutting down...')
        vpn_thread = args[0]
        vpn_thread.set_should_quit()
        QtGui.QApplication.quit()

    def signal_tester(d):
        print d

    logger = logging.getLogger(name='leap')
    logger.setLevel(logging.DEBUG)
    console = logging.StreamHandler()
    console.setLevel(logging.DEBUG)
    formatter = logging.Formatter(
        '%(asctime)s '
        '- %(name)s - %(levelname)s - %(message)s')
    console.setFormatter(formatter)
    logger.addHandler(console)

    vpn_thread = VPN()

    sigint = partial(sigint_handler, vpn_thread)
    signal.signal(signal.SIGINT, sigint)

    eipconfig = EIPConfig()
    if eipconfig.load("leap/providers/bitmask.net/eip-service.json"):
        provider = ProviderConfig()
        if provider.load("leap/providers/bitmask.net/provider.json"):
            vpn_thread.start(eipconfig=eipconfig,
                             providerconfig=provider,
                             socket_host="/home/chiiph/vpnsock",
                             socket_port="unix")

    timer = QtCore.QTimer()
    timer.start(500)
    timer.timeout.connect(lambda: None)
    app.connect(app, QtCore.SIGNAL("aboutToQuit()"),
                vpn_thread.set_should_quit)
    w = QtGui.QWidget()
    w.resize(100, 100)
    w.show()

    vpn_thread.state_changed.connect(signal_tester)
    vpn_thread.status_changed.connect(signal_tester)

    sys.exit(app.exec_())