# -*- coding: utf-8 -*-
# initializers.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/>.
"""
Platform-dependant initialization code.
"""
import logging
import os
import platform
import stat
import subprocess
import tempfile

from PySide import QtGui, QtCore

from leap.bitmask.config import flags
from leap.bitmask.config.leapsettings import LeapSettings
from leap.bitmask.services.eip import get_vpn_launcher
from leap.bitmask.services.eip.darwinvpnlauncher import DarwinVPNLauncher
from leap.bitmask.util import first
from leap.bitmask.util.privilege_policies import LinuxPolicyChecker


logger = logging.getLogger(__name__)

# NOTE we could use a deferToThread here, but should
# be aware of this bug: http://www.themacaque.com/?p=1067

__all__ = ["init_platform"]

_system = platform.system()


class InitSignals(QtCore.QObject):
    """
    Signal container to communicate initialization events to differnt widgets.
    """
    eip_missing_helpers = QtCore.Signal()


init_signals = InitSignals()


def init_platform():
    """
    Run the right initializer for the platform we are running in.

    :return: whether the initializacion succeeded or not.
    :rtype: bool
    """
    initializer = None
    ok = False
    try:
        initializer = globals()[_system + "Initializer"]
    except:
        pass
    if initializer:
        logger.debug("Running initializer for %s" % (_system, ))
        ok = initializer()
    else:
        logger.debug("Initializer not found for %s" % (_system, ))

    return ok


#
# common utils
#

NOTFOUND_MSG = ("Tried to install %s, but %s "
                "not found inside this bundle.")
BADEXEC_MSG = ("Tried to install %s, but %s "
               "failed to %s.")

HELPERS_NOTFOUND_MSG = NOTFOUND_MSG % (
    "helper files", "those were")
HELPERS_BADEXEC_MSG = BADEXEC_MSG % (
    "helper files", "they", "be copied")


def get_missing_helpers_dialog():
    """
    Create a dialog for notifying of missing helpers.
    Returns that dialog.

    :rtype: QtGui.QMessageBox instance
    """
    WE_NEED_POWERS = ("To better protect your privacy, "
                      "Bitmask needs administrative privileges "
                      "to install helper files. Encrypted "
                      "Internet cannot work without those files. "
                      "Do you want to install them now?")
    msg = QtGui.QMessageBox()
    msg.setWindowTitle(msg.tr("Missing helper files"))
    msg.setText(msg.tr(WE_NEED_POWERS))
    # but maybe the user really deserve to know more
    # msg.setInformativeText(msg.tr(BECAUSE))
    msg.setStandardButtons(QtGui.QMessageBox.Yes | QtGui.QMessageBox.No)
    msg.addButton("No, don't ask again", QtGui.QMessageBox.RejectRole)
    msg.setDefaultButton(QtGui.QMessageBox.Yes)
    msg.setEscapeButton(QtGui.QMessageBox.No)
    return msg


def check_missing():
    """
    Check for the need of installing missing scripts, and
    raises a dialog to ask user for permission to do it.
    """
    config = LeapSettings()
    complain_missing = False
    alert_missing = config.get_alert_missing_scripts()

    if alert_missing and not flags.STANDALONE:
        # We refuse to install missing stuff if not running with standalone
        # flag. Right now we rely on the flag alone, but we can disable this
        # by overwriting some constant from within the debian package.
        alert_missing = False
        complain_missing = True

    launcher = get_vpn_launcher()
    missing_scripts = launcher.missing_updown_scripts()
    missing_other = launcher.missing_other_files()

    if missing_scripts:
        logger.warning("Missing scripts: %s" % (missing_scripts))
    if missing_other:
        logger.warning("Missing other files: %s" % (missing_other))

    missing_some = missing_scripts or missing_other
    if alert_missing and missing_some:
        msg = get_missing_helpers_dialog()
        ret = msg.exec_()

        if ret == QtGui.QMessageBox.Yes:
            install_missing_fun = globals().get(
                "_%s_install_missing_scripts" % (_system.lower(),),
                None)
            if not install_missing_fun:
                logger.warning(
                    "Installer not found for platform %s." % (_system,))
                return

            # XXX maybe move constants to fun
            ok = install_missing_fun(HELPERS_BADEXEC_MSG, HELPERS_NOTFOUND_MSG)
            if not ok:
                msg = QtGui.QMessageBox()
                msg.setWindowTitle(msg.tr("Problem installing files"))
                msg.setText(msg.tr('Some of the files could not be copied.'))
                msg.setIcon(QtGui.QMessageBox.Warning)
                msg.exec_()

        elif ret == QtGui.QMessageBox.No:
            logger.debug("Not installing missing scripts, "
                         "user decided to ignore our warning.")
            init_signals.eip_missing_helpers.emit()

        elif ret == QtGui.QMessageBox.Rejected:
            logger.debug(
                "Setting alert_missing_scripts to False, we will not "
                "ask again")
            init_signals.eip_missing_helpers.emit()
            config.set_alert_missing_scripts(False)

    if complain_missing and missing_some:
        missing = missing_scripts + missing_other
        msg = _get_missing_complain_dialog(missing)
        ret = msg.exec_()

    # If there is some missing file and we don't want to complain, we emit the
    # 'missing helpers' signal so the eip status can show that some files are
    # missing.
    if missing_some and not alert_missing and not complain_missing:
        init_signals.eip_missing_helpers.emit()


def check_polkit():
    """
    Check if we have a running polkit agent and tries to launch an agent if
    needed.
    Show an error message if there is no agent and we couldn't run one.

    :return: True if we have a polkit running (or if we started one), False
             otherwise
    :rtype: bool
    """
    if LinuxPolicyChecker.is_up():
        return True

    try:
        LinuxPolicyChecker.maybe_pkexec()
    except Exception:
        logger.error("No polkit agent running.")

        msg = QtGui.QMessageBox()
        msg.setWindowTitle(msg.tr("No polkit agent running"))
        msg.setText(
            msg.tr('There is no polkit agent running and it is needed to run '
                   'the Bitmask services.<br>Take a look at the '
                   '<a href="https://leap.se/en/docs/client/known-issues">'
                   'known issues</a> page'))
        msg.setIcon(QtGui.QMessageBox.Critical)
        msg.exec_()

        return False


#
# windows initializers
#


def _windows_has_tap_device():
    """
    Loop over the windows registry trying to find if the tap0901 tap driver
    has been installed on this machine.
    """
    import _winreg as reg

    adapter_key = 'SYSTEM\CurrentControlSet\Control\Class' \
        '\{4D36E972-E325-11CE-BFC1-08002BE10318}'
    with reg.OpenKey(reg.HKEY_LOCAL_MACHINE, adapter_key) as adapters:
        try:
            for i in xrange(10000):
                key_name = reg.EnumKey(adapters, i)
                with reg.OpenKey(adapters, key_name) as adapter:
                    try:
                        component_id = reg.QueryValueEx(adapter,
                                                        'ComponentId')[0]
                        if component_id.startswith("tap0901"):
                            return True
                    except WindowsError:
                        pass
        except WindowsError:
            pass
    return False


def WindowsInitializer():
    """
    Raise a dialog in case that the windows tap driver has not been found
    in the registry, asking the user for permission to install the driver
    """
    if not _windows_has_tap_device():
        msg = QtGui.QMessageBox()
        msg.setWindowTitle(msg.tr("TAP Driver"))
        msg.setText(msg.tr("Bitmask needs to install the necessary drivers "
                           "for Encrypted Internet to work. Would you like to "
                           "proceed?"))
        msg.setInformativeText(msg.tr("Encrypted Internet uses VPN, which "
                                      "needs a TAP device installed and none "
                                      "has been found. This will ask for "
                                      "administrative privileges."))
        msg.setStandardButtons(QtGui.QMessageBox.Yes | QtGui.QMessageBox.No)
        msg.setDefaultButton(QtGui.QMessageBox.Yes)
        ret = msg.exec_()

        if ret == QtGui.QMessageBox.Yes:
            # XXX should do this only if executed inside bundle.
            # Let's assume it's the only way it's gonna be executed under win
            # by now.
            driver_path = os.path.join(os.getcwd(),
                                       "apps",
                                       "eip",
                                       "tap_driver")
            dev_installer = os.path.join(driver_path,
                                         "devcon.exe")
            if os.path.isfile(dev_installer) and \
                    stat.S_IXUSR & os.stat(dev_installer)[stat.ST_MODE] != 0:
                inf_path = os.path.join(driver_path,
                                        "OemWin2k.inf")
                cmd = [dev_installer, "install", inf_path, "tap0901"]
                ret = subprocess.call(cmd, stdout=subprocess.PIPE, shell=True)
            else:
                logger.error("Tried to install TAP driver, but the installer "
                             "is not found or not executable")

#
# Darwin initializer functions
#


def _darwin_has_tun_kext():
    """
    Return True only if we found a directory under the system kext folder
    containing a kext named tun.kext, AND we found a startup item named 'tun'
    """
    # XXX we should be smarter here and use kextstats output.

    has_kext = os.path.isdir("/Library/Extensions/tun.kext")
    has_startup = os.path.isdir("/Library/StartupItems/tun")
    has_tun_and_startup = has_kext and has_startup
    logger.debug(
        'platform initializer check: has tun_and_startup = %s' %
        (has_tun_and_startup,))
    return has_tun_and_startup


def _darwin_install_missing_scripts(badexec, notfound):
    """
    Try to install the missing up/down scripts.

    :param badexec: error for notifying execution error during command.
    :type badexec: str
    :param notfound: error for notifying missing path.
    :type notfound: str
    :returns: True if the files could be copied successfully.
    :rtype: bool
    """
    # We expect to execute this from some way of bundle, since
    # the up/down scripts should be put in place by the installer.
    success = False
    installer_path = os.path.abspath(
        os.path.join(
            os.getcwd(), "..", "Resources", "openvpn"))
    launcher = DarwinVPNLauncher

    # XXX FIXME !!! call the bash script!
    if os.path.isdir(installer_path):
        fd, tempscript = tempfile.mkstemp(prefix="leap_installer-")
        try:
            scriptlines = launcher.cmd_for_missing_scripts(installer_path)
            with os.fdopen(fd, 'w') as f:
                f.write(scriptlines)
            st = os.stat(tempscript)
            os.chmod(tempscript, st.st_mode | stat.S_IEXEC | stat.S_IXUSR |
                     stat.S_IXGRP | stat.S_IXOTH)

            cmd, args = launcher().get_cocoasudo_installmissing_cmd()
            args.append(tempscript)
            cmdline = " ".join([cmd] + args)
            ret = subprocess.call(
                cmdline, stdout=subprocess.PIPE,
                shell=True)
            success = ret == 0
            if not success:
                logger.error("Install missing scripts failed.")
        except Exception as exc:
            logger.error(badexec)
            logger.error("Error was: %r" % (exc,))
        finally:
            try:
                os.remove(tempscript)
            except OSError as exc:
                logger.error("%r" % (exc,))
    else:
        logger.error(notfound)
        logger.debug('path searched: %s' % (installer_path,))

    return success


def DarwinInitializer():
    """
    Raise a dialog in case that the osx tuntap driver has not been found
    in the registry, asking the user for permission to install the driver
    """
    # XXX split this function into several

    TUNTAP_NOTFOUND_MSG = NOTFOUND_MSG % (
        "tuntaposx kext", "the installer")
    TUNTAP_BADEXEC_MSG = BADEXEC_MSG % (
        "tuntaposx kext", "the installer", "be launched")

    # TODO DRY this with other cases, and
    # factor out to _should_install() function.
    # Leave the dialog as a more generic thing.

    if not _darwin_has_tun_kext():
        msg = QtGui.QMessageBox()
        msg.setWindowTitle(msg.tr("TUN Driver"))
        msg.setText(msg.tr("Bitmask needs to install the necessary drivers "
                           "for Encrypted Internet to work. Would you like to "
                           "proceed?"))
        msg.setInformativeText(msg.tr("Encrypted Internet uses VPN, which "
                                      "needs a kernel extension for a TUN "
                                      "device installed, and none "
                                      "has been found. This will ask for "
                                      "administrative privileges."))
        msg.setStandardButtons(QtGui.QMessageBox.Yes | QtGui.QMessageBox.No)
        msg.setDefaultButton(QtGui.QMessageBox.Yes)
        ret = msg.exec_()

        if ret == QtGui.QMessageBox.Yes:
            installer_path = os.path.abspath(
                os.path.join(
                    os.getcwd(),
                    "..",
                    "Resources",
                    "tuntap-installer.app"))
            if os.path.isdir(installer_path):
                cmd = ["open '%s'" % (installer_path,)]
                try:
                    ret = subprocess.call(
                        cmd, stdout=subprocess.PIPE,
                        shell=True)
                except:
                    logger.error(TUNTAP_BADEXEC_MSG)
            else:
                logger.error(TUNTAP_NOTFOUND_MSG)

    # Second check, for missing scripts.
    check_missing()
    return True


#
# Linux initializers
#


def _get_missing_complain_dialog(stuff):
    """
    Create a dialog for notifying about missing helpers (but doing nothing).
    Used from non-standalone runs.

    :param stuff: list of missing items to display
    :type stuff: list
    :rtype: QtGui.QMessageBox instance
    """
    msgstr = QtCore.QObject()
    msgstr.NO_HELPERS = msgstr.tr(
        "Some essential helper files are missing in your system.")
    msgstr.EXPLAIN = msgstr.tr(
        "Reinstall your debian packages, or make sure you place them by hand.")

    class ComplainDialog(QtGui.QDialog):

        def __init__(self, parent=None):
                super(ComplainDialog, self).__init__(parent)

                label = QtGui.QLabel(msgstr.NO_HELPERS)
                label.setAlignment(QtCore.Qt.AlignLeft)

                label2 = QtGui.QLabel(msgstr.EXPLAIN)
                label2.setAlignment(QtCore.Qt.AlignLeft)

                textedit = QtGui.QTextEdit()
                textedit.setText("\n".join(stuff))

                ok = QtGui.QPushButton()
                ok.setText(self.tr("Ok, thanks"))
                self.ok = ok
                self.ok.clicked.connect(self.close)

                mainLayout = QtGui.QGridLayout()
                mainLayout.addWidget(label, 0, 0)
                mainLayout.addWidget(label2, 1, 0)
                mainLayout.addWidget(textedit, 2, 0)
                mainLayout.addWidget(ok, 3, 0)

                self.setLayout(mainLayout)

    msg = ComplainDialog()
    msg.setWindowTitle(msg.tr("Missing Bitmask helpers"))
    return msg


def _linux_install_missing_scripts(badexec, notfound):
    """
    Try to install the missing helper files.

    :param badexec: error for notifying execution error during command.
    :type badexec: str
    :param notfound: error for notifying missing path.
    :type notfound: str
    :returns: True if the files could be copied successfully.
    :rtype: bool
    """
    success = False
    installer_path = os.path.abspath(
        os.path.join(os.getcwd(), "apps", "eip", "files"))

    install_helper = "leap-install-helper.sh"
    install_helper_path = os.path.join(installer_path, install_helper)

    install_opts = ("--from-path %s --install-bitmask-root YES "
                    "--install-polkit-file YES --install-openvpn YES "
                    "--remove-old-files YES" % (installer_path,))

    if os.path.isdir(installer_path):
        try:
            policyChecker = LinuxPolicyChecker()
            pkexec = first(policyChecker.maybe_pkexec())
            cmdline = ["%s %s %s" % (
                pkexec, install_helper_path, install_opts)]

            ret = subprocess.call(
                cmdline, stdout=subprocess.PIPE,
                shell=True)
            success = ret == 0
            if not success:
                logger.error("Install of helpers failed.")
        except Exception as exc:
            logger.error(badexec)
            logger.error("Error was: %r" % (exc,))
    else:
        logger.error(notfound)
        logger.debug('path searched: %s' % (installer_path,))

    return success


def LinuxInitializer():
    """
    Raise a dialog if needed files are missing.

    Missing files can be either bitmask-root policykit file.
    The dialog will also be raised if some of those files are
    found to have incorrect permissions.

    :return: whether the operations went ok or not, if False, it's recommended
    not to continue with the app run.
    :rtype: bool
    """
    if not check_polkit():
        return False

    check_missing()
    return True