# -*- coding: utf-8 -*-
# mainwindow.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/>.

"""
Main window for the leap client
"""
import os
import logging
import random
import keyring

from PySide import QtCore, QtGui

from ui_mainwindow import Ui_MainWindow
from leap.config.providerconfig import ProviderConfig
from leap.crypto.srpauth import SRPAuth
from leap.services.eip.vpn import VPN
from leap.services.eip.providerbootstrapper import ProviderBootstrapper
from leap.services.eip.eipbootstrapper import EIPBootstrapper
from leap.services.eip.eipconfig import EIPConfig
from leap.gui.wizard import Wizard
from leap.util.check import leap_assert
from leap.util.checkerthread import CheckerThread

logger = logging.getLogger(__name__)


class MainWindow(QtGui.QMainWindow):
    """
    Main window for login and presenting status updates to the user
    """

    # StackedWidget indexes
    LOGIN_INDEX = 0
    EIP_STATUS_INDEX = 1

    GEOMETRY_KEY = "Geometry"
    WINDOWSTATE_KEY = "WindowState"
    USER_KEY = "User"

    KEYRING_KEY = "leap_client"

    def __init__(self):
        QtGui.QMainWindow.__init__(self)

        self.CONNECTING_ICON = QtGui.QPixmap(":/images/conn_connecting.png")
        self.CONNECTED_ICON = QtGui.QPixmap(":/images/conn_connected.png")
        self.ERROR_ICON = QtGui.QPixmap(":/images/conn_error.png")

        self.LOGGED_OUT_ICON = QtGui.QPixmap(":/images/leap-gray-big.png")
        self.LOGGED_IN_ICON = QtGui.QPixmap(":/images/leap-color-big.png")

        self.ui = Ui_MainWindow()
        self.ui.setupUi(self)

        self.ui.lnPassword.setEchoMode(QtGui.QLineEdit.Password)

        self.ui.btnLogin.clicked.connect(self._login)
        self.ui.lnUser.returnPressed.connect(self._focus_password)
        self.ui.lnPassword.returnPressed.connect(self._login)

        self.ui.stackedWidget.setCurrentIndex(self.LOGIN_INDEX)

        self.ui.btnEipStartStop.setEnabled(False)
        self.ui.btnEipStartStop.clicked.connect(
            self._stop_eip)

        # This is loaded only once, there's a bug when doing that more
        # than once
        self._provider_config = ProviderConfig()
        self._eip_config = EIPConfig()
        # This is created once we have a valid provider config
        self._srp_auth = None

        self._checker_thread = CheckerThread()
        self._checker_thread.start()

        # This thread is always running, although it's quite
        # lightweight when it's done setting up provider
        # configuration and certificate.
        self._provider_bootstrapper = ProviderBootstrapper()

        # TODO: add sigint handler

        # Intermediate stages, only do something if there was an error
        self._provider_bootstrapper.name_resolution.connect(
            self._intermediate_stage)
        self._provider_bootstrapper.https_connection.connect(
            self._intermediate_stage)
        self._provider_bootstrapper.download_ca_cert.connect(
            self._intermediate_stage)

        # Important stages, loads the provider config and checks
        # certificates
        self._provider_bootstrapper.download_provider_info.connect(
            self._load_provider_config)
        self._provider_bootstrapper.check_api_certificate.connect(
            self._provider_config_loaded)

        # This thread is similar to the provider bootstrapper
        self._eip_bootstrapper = EIPBootstrapper()

        self._eip_bootstrapper.download_config.connect(
            self._intermediate_stage)
        self._eip_bootstrapper.download_client_certificate.connect(
            self._finish_eip_bootstrap)

        self._vpn = VPN()
        self._vpn.state_changed.connect(self._update_vpn_state)
        self._vpn.status_changed.connect(self._update_vpn_status)
        self._vpn.process_finished.connect(
            self._eip_finished)

        QtCore.QCoreApplication.instance().connect(
            QtCore.QCoreApplication.instance(),
            QtCore.SIGNAL("aboutToQuit()"),
            self._vpn.set_should_quit)
        QtCore.QCoreApplication.instance().connect(
            QtCore.QCoreApplication.instance(),
            QtCore.SIGNAL("aboutToQuit()"),
            self._checker_thread.set_should_quit)

        self.ui.action_sign_out.setEnabled(False)
        self.ui.action_sign_out.triggered.connect(self._logout)
        self.ui.action_about_leap.triggered.connect(self._about)
        self.ui.action_quit.triggered.connect(self.quit)
        self.ui.action_wizard.triggered.connect(self._launch_wizard)

        # Used to differentiate between real quits and close to tray
        self._really_quit = False

        self._systray = None
        self._vpn_systray = None

        self._action_eip_status = QtGui.QAction(self.tr("Encryption is OFF"),
                                                self)
        self._action_eip_status.setEnabled(False)
        self._action_eip_stop = QtGui.QAction(self.tr("Stop"), self)
        self._action_eip_stop.triggered.connect(
            self._stop_eip)
        self._action_eip_write = QtGui.QAction(
            QtGui.QIcon(":/images/Arrow-Up-32.png"),
            "0.0 Kb", self)
        self._action_eip_write.setEnabled(False)
        self._action_eip_read = QtGui.QAction(
            QtGui.QIcon(":/images/Arrow-Down-32.png"),
            "0.0 Kb", self)
        self._action_eip_read.setEnabled(False)

        self._action_visible = QtGui.QAction(self.tr("Hide"), self)
        self._action_visible.triggered.connect(self._toggle_visible)

        self._center_window()
        self._wizard = None
        self._wizard_firstrun = False
        if self._first_run():
            self._wizard_firstrun = True
            self._wizard = Wizard(self._checker_thread)
            # Give this window time to finish init and then show the wizard
            QtCore.QTimer.singleShot(1, self._launch_wizard)
            self._wizard.accepted.connect(self._finish_init)
            self._wizard.rejected.connect(self._rejected_wizard)
        else:
            self._finish_init()

    def _rejected_wizard(self):
        if self._wizard_firstrun:
            self.quit()
        else:
            self._finish_init()

    def _launch_wizard(self):
        if self._wizard is None:
            self._wizard = Wizard(self._checker_thread)
        self._wizard.exec_()
        self._wizard = None

    def _finish_init(self):
        self.ui.cmbProviders.addItems(self._configured_providers())
        self._show_systray()
        self.show()
        if self._wizard:
            possible_username = self._wizard.get_username()
            if possible_username is not None:
                self.ui.lnUser.setText(possible_username)
                self._focus_password()
            self._wizard = None
        else:
            settings = QtCore.QSettings()
            saved_user = settings.value(self.USER_KEY, None)

            if saved_user is not None:
                self.ui.lnUser.setText(saved_user)
                self.ui.chkRemember.setChecked(True)
                saved_password = keyring.get_password(self.KEYRING_KEY,
                                                      saved_user
                                                      .encode("utf8"))
                self.ui.lnPassword.setText(saved_password.decode("utf8"))

    def _show_systray(self):
        """
        Sets up the systray icon
        """
        systrayMenu = QtGui.QMenu(self)
        systrayMenu.addAction(self._action_visible)
        systrayMenu.addAction(self.ui.action_sign_out)
        systrayMenu.addSeparator()
        systrayMenu.addAction(self.ui.action_quit)
        self._systray = QtGui.QSystemTrayIcon(self)
        self._systray.setContextMenu(systrayMenu)
        self._systray.setIcon(QtGui.QIcon(self.LOGGED_OUT_ICON))
        self._systray.setVisible(True)
        self._systray.activated.connect(self._toggle_visible)

        vpn_systrayMenu = QtGui.QMenu(self)
        vpn_systrayMenu.addAction(self._action_eip_status)
        vpn_systrayMenu.addAction(self._action_eip_stop)
        vpn_systrayMenu.addAction(self._action_eip_read)
        vpn_systrayMenu.addAction(self._action_eip_write)
        self._vpn_systray = QtGui.QSystemTrayIcon(self)
        self._vpn_systray.setContextMenu(vpn_systrayMenu)
        self._vpn_systray.setIcon(QtGui.QIcon(self.ERROR_ICON))
        self._vpn_systray.setVisible(False)

    def _toggle_visible(self):
        """
        SLOT
        TRIGGER: self._systray.activated

        Toggles the window visibility
        """
        self.setVisible(not self.isVisible())
        action_visible_text = self.tr("Hide")
        if not self.isVisible():
            action_visible_text = self.tr("Show")
        self._action_visible.setText(action_visible_text)

    def _center_window(self):
        """
        Centers the mainwindow based on the desktop geometry
        """
        settings = QtCore.QSettings()
        geometry = settings.value(self.GEOMETRY_KEY, None)
        state = settings.value(self.WINDOWSTATE_KEY, None)
        if geometry is None:
            app = QtGui.QApplication.instance()
            width = app.desktop().width()
            height = app.desktop().height()
            window_width = self.size().width()
            window_height = self.size().height()
            x = (width / 2.0) - (window_width / 2.0)
            y = (height / 2.0) - (window_height / 2.0)
            self.move(x, y)
        else:
            self.restoreGeometry(geometry)

        if state is not None:
            self.restoreState(state)

    def _about(self):
        """
        Display the About LEAP dialog
        """
        QtGui.QMessageBox.about(
            self, self.tr("About LEAP"),
            self.tr("LEAP is a non-profit dedicated to giving "
                    "all internet users access to secure "
                    "communication. Our focus is on adapting "
                    "encryption technology to make it easy to use "
                    "and widely available. "
                    "<a href=\"https://leap.se\">More about LEAP"
                    "</a>"))

    def quit(self):
        self._really_quit = True
        if self._wizard:
            self._wizard.accept()
        self.close()

    def changeEvent(self, e):
        """
        Reimplements the changeEvent method to minimize to tray
        """
        if QtGui.QSystemTrayIcon.isSystemTrayAvailable() and \
                e.type() == QtCore.QEvent.WindowStateChange and \
                self.isMinimized():
            self._toggle_visible()
            e.accept()
            return
        QtGui.QMainWindow.changeEvent(self, e)

    def closeEvent(self, e):
        """
        Reimplementation of closeEvent to close to tray
        """
        if QtGui.QSystemTrayIcon.isSystemTrayAvailable() and \
                not self._really_quit:
            self._toggle_visible()
            e.ignore()
            return
        settings = QtCore.QSettings()
        settings.setValue(self.GEOMETRY_KEY, self.saveGeometry())
        settings.setValue(self.WINDOWSTATE_KEY, self.saveState())
        QtGui.QMainWindow.closeEvent(self, e)

    def _configured_providers(self):
        """
        Returns the available providers based on the file structure

        @rtype: list
        """
        providers = []
        try:
            providers = os.listdir(
                os.path.join(self._provider_config.get_path_prefix(),
                             "leap",
                             "providers"))
        except Exception as e:
            logger.debug("Error listing providers, assume there are none. %r"
                         % (e,))

        return providers

    def _first_run(self):
        """
        Returns True if there are no configured providers. False otherwise

        @rtype: bool
        """
        return len(self._configured_providers()) == 0

    def _focus_password(self):
        """
        Focuses in the password lineedit
        """
        self.ui.lnPassword.setFocus()

    def _set_status(self, status):
        """
        Sets the status label at the login stage to status

        @param status: status message
        @type status: str
        """
        self.ui.lblStatus.setText(status)

    def _set_eip_status(self, status):
        """
        Sets the status label at the VPN stage to status

        @param status: status message
        @type status: str
        """
        self.ui.lblEIPStatus.setText(status)

    def _login_set_enabled(self, enabled=False):
        """
        Enables or disables all the login widgets

        @param enabled: wether they should be enabled or not
        @type enabled: bool
        """
        self.ui.lnUser.setEnabled(enabled)
        self.ui.lnPassword.setEnabled(enabled)
        self.ui.btnLogin.setEnabled(enabled)
        self.ui.chkRemember.setEnabled(enabled)
        self.ui.cmbProviders.setEnabled(enabled)

    def _download_provider_config(self):
        """
        Starts the bootstrapping sequence. It will download the
        provider configuration if it's not present, otherwise will
        emit the corresponding signals inmediately
        """
        provider = self.ui.cmbProviders.currentText()

        self._provider_bootstrapper.run_provider_select_checks(
            self._checker_thread,
            provider,
            download_if_needed=True)

    def _load_provider_config(self, data):
        """
        SLOT
        TRIGGER: self._provider_bootstrapper.download_provider_info

        Once the provider config has been downloaded, this loads the
        self._provider_config instance with it and starts the second
        part of the bootstrapping sequence

        @param data: result from the last stage of the
        run_provider_select_checks
        @type data: dict
        """
        if data[self._provider_bootstrapper.PASSED_KEY]:
            provider = self.ui.cmbProviders.currentText()
            if self._provider_config.loaded() or \
                    self._provider_config.load(os.path.join("leap",
                                                            "providers",
                                                            provider,
                                                            "provider.json")):
                self._provider_bootstrapper.run_provider_setup_checks(
                    self._checker_thread,
                    self._provider_config,
                    download_if_needed=True)
            else:
                self._set_status(
                    self.tr("Could not load provider configuration"))
                self._login_set_enabled(True)
        else:
            self._set_status(data[self._provider_bootstrapper.ERROR_KEY])
            self._login_set_enabled(True)

    def _login(self):
        """
        SLOT
        TRIGGERS:
          self.ui.btnLogin.clicked
          self.ui.lnPassword.returnPressed

        Starts the login sequence. Which involves bootstrapping the
        selected provider if the selection is valid (not empty), then
        start the SRP authentication, and as the last step
        bootstrapping the EIP service
        """
        leap_assert(self._provider_config, "We need a provider config")

        username = self.ui.lnUser.text()
        password = self.ui.lnPassword.text()
        provider = self.ui.cmbProviders.currentText()

        if len(provider) == 0:
            self._set_status(self.tr("Please select a valid provider"))
            return

        if len(username) == 0:
            self._set_status(self.tr("Please provide a valid username"))
            return

        if len(password) == 0:
            self._set_status(self.tr("Please provide a valid Password"))
            return

        self._set_status(self.tr("Logging in..."))
        self._login_set_enabled(False)

        if self.ui.chkRemember.isChecked():
            try:
                keyring.set_password(self.KEYRING_KEY,
                                     username.encode("utf8"),
                                     password.encode("utf8"))
                # Only save the username if it was saved correctly in
                # the keyring
                settings = QtCore.QSettings()
                settings.setValue(self.USER_KEY, username)
            except Exception as e:
                logger.error("Problem saving data to keyring. %r"
                             % (e,))

        self._download_provider_config()

    def _provider_config_loaded(self, data):
        """
        SLOT
        TRIGGER: self._provider_bootstrapper.check_api_certificate

        Once the provider configuration is loaded, this starts the SRP
        authentication
        """
        leap_assert(self._provider_config, "We need a provider config!")

        if data[self._provider_bootstrapper.PASSED_KEY]:
            username = self.ui.lnUser.text().encode("utf8")
            password = self.ui.lnPassword.text().encode("utf8")

            if self._srp_auth is None:
                self._srp_auth = SRPAuth(self._provider_config)
                self._srp_auth.authentication_finished.connect(
                    self._authentication_finished)
                self._srp_auth.logout_finished.connect(
                    self._done_logging_out)

            self._srp_auth.authenticate(username, password)
        else:
            self._set_status(data[self._provider_bootstrapper.ERROR_KEY])
            self._login_set_enabled(True)

    def _authentication_finished(self, ok, message):
        """
        SLOT
        TRIGGER: self._srp_auth.authentication_finished

        Once the user is properly authenticated, try starting the EIP
        service
        """
        self._set_status(message)
        if ok:
            self.ui.action_sign_out.setEnabled(True)
            # We leave a bit of room for the user to see the
            # "Succeeded" message and then we switch to the EIP status
            # panel
            QtCore.QTimer.singleShot(1000, self._switch_to_status)
        else:
            self._login_set_enabled(True)

    def _switch_to_status(self):
        """
        Changes the stackedWidget index to the EIP status one and
        triggers the eip bootstrapping
        """
        self.ui.stackedWidget.setCurrentIndex(self.EIP_STATUS_INDEX)
        self._systray.setIcon(self.LOGGED_IN_ICON)
        self._download_eip_config()

    def _start_eip(self):
        self._vpn.start(eipconfig=self._eip_config,
                        providerconfig=self._provider_config,
                        socket_host="localhost",
                        socket_port=str(random.randint(1000, 9999)))
        self._vpn_systray.setVisible(True)
        self.ui.btnEipStartStop.setEnabled(True)
        self.ui.btnEipStartStop.setText(self.tr("Stop EIP"))
        self.ui.btnEipStartStop.clicked.disconnect(
            self._start_eip)
        self.ui.btnEipStartStop.clicked.connect(
            self._stop_eip)

    def _stop_eip(self):
        self._vpn.set_should_quit()
        self._vpn_systray.setVisible(False)
        self._set_eip_status(self.tr("EIP has stopped"))
        self._set_eip_status_icon("error")
        self.ui.btnEipStartStop.setText(self.tr("Start EIP"))
        self.ui.btnEipStartStop.clicked.disconnect(
            self._stop_eip)
        self.ui.btnEipStartStop.clicked.connect(
            self._start_eip)

    def _download_eip_config(self):
        """
        Starts the EIP bootstrapping sequence
        """
        leap_assert(self._eip_bootstrapper, "We need an eip bootstrapper!")
        leap_assert(self._provider_config, "We need a provider config")

        self._set_eip_status(self.tr("Checking configuration, please wait..."))

        if self._provider_config.provides_eip():
            self._eip_bootstrapper.run_eip_setup_checks(
                self._checker_thread,
                self._provider_config,
                download_if_needed=True)
        else:
            self._set_eip_status(self.tr("%s does not support EIP") %
                                 (self._provider_config.get_domain(),))

    def _set_eip_status_icon(self, status):
        """
        Given a status step from the VPN thread, set the icon properly

        @param status: status step
        @type status: str
        """
        selected_pixmap = self.ERROR_ICON
        tray_message = self.tr("Encryption is OFF")
        if status in ("WAIT", "AUTH", "GET_CONFIG"):
            selected_pixmap = self.CONNECTING_ICON
        elif status in ("CONNECTED"):
            tray_message = self.tr("Encryption is ON")
            selected_pixmap = self.CONNECTED_ICON

        self.ui.lblVPNStatusIcon.setPixmap(selected_pixmap)
        self._vpn_systray.setIcon(QtGui.QIcon(selected_pixmap))
        self._action_eip_status.setText(tray_message)

    def _update_vpn_state(self, data):
        """
        SLOT
        TRIGGER: self._vpn.state_changed

        Updates the displayed VPN state based on the data provided by
        the VPN thread
        """
        status = data[self._vpn.STATUS_STEP_KEY]
        self._set_eip_status_icon(status)
        if status == "AUTH":
            self._set_eip_status(self.tr("VPN: Authenticating..."))
        elif status == "GET_CONFIG":
            self._set_eip_status(self.tr("VPN: Retrieving configuration..."))
        elif status == "CONNECTED":
            self._set_eip_status(self.tr("VPN: Connected!"))
        elif status == "WAIT":
            self._set_eip_status(self.tr("VPN: Waiting to start..."))
        else:
            self._set_eip_status(status)

    def _update_vpn_status(self, data):
        """
        SLOT
        TRIGGER: self._vpn.status_changed

        Updates the download/upload labels based on the data provided
        by the VPN thread
        """
        upload = float(data[self._vpn.TUNTAP_WRITE_KEY])
        upload = upload / 1000.0
        upload_str = "%s Kb" % (upload,)
        self.ui.lblUpload.setText(upload_str)
        self._action_eip_write.setText(upload_str)
        download = float(data[self._vpn.TUNTAP_READ_KEY])
        download = download / 1000.0
        download_str = "%s Kb" % (download,)
        self.ui.lblDownload.setText(download_str)
        self._action_eip_read.setText(download_str)

    def _finish_eip_bootstrap(self, data):
        """
        SLOT
        TRIGGER: self._eip_bootstrapper.download_client_certificate

        Starts the VPN thread if the eip configuration is properly
        loaded
        """
        leap_assert(self._eip_config, "We need an eip config!")
        leap_assert(self._provider_config, "We need a provider config!")

        if self._eip_config.loaded() or \
                self._eip_config.load(os.path.join("leap",
                                                   "providers",
                                                   self._provider_config
                                                   .get_domain(),
                                                   "eip-service.json")):
                self._start_eip()
        # TODO: display a message if the EIP configuration cannot be
        # loaded

    def _logout(self):
        """
        SLOT
        TRIGGER: self.ui.action_sign_out.triggered

        Starts the logout sequence
        """
        self._set_eip_status_icon("error")
        self._set_eip_status(self.tr("Signing out..."))
        self._checker_thread.add_checks([self._srp_auth.logout])

    def _done_logging_out(self, ok, message):
        """
        SLOT
        TRIGGER: self._srp_auth.logout_finished

        Switches the stackedWidget back to the login stage after
        logging out
        """
        self._set_status(message)
        self._vpn_systray.setIcon(self.LOGGED_OUT_ICON)
        self.ui.action_sign_out.setEnabled(False)
        self.ui.stackedWidget.setCurrentIndex(self.LOGIN_INDEX)
        self.ui.lnPassword.setText("")
        self._login_set_enabled(True)
        self._set_status("")
        self._vpn.set_should_quit()
        self._vpn_systray.setVisible(False)

    def _intermediate_stage(self, data):
        """
        SLOT
        TRIGGERS:
          self._provider_bootstrapper.name_resolution
          self._provider_bootstrapper.https_connection
          self._provider_bootstrapper.download_ca_cert
          self._eip_bootstrapper.download_config

        If there was a problem, displays it, otherwise it does nothing.
        This is used for intermediate bootstrapping stages, in case
        they fail.
        """
        passed = data[self._provider_bootstrapper.PASSED_KEY]
        if not passed:
            self._login_set_enabled(True)
            self._set_status(data[self._provider_bootstrapper.ERROR_KEY])

    def _eip_finished(self, exitCode):
        """
        SLOT
        TRIGGERS:
          self._vpn.process_finished

        Triggered when the EIP/VPN process finishes to set the UI
        accordingly
        """
        logger.debug("Finished VPN with exitCode %s" % (exitCode,))
        self._stop_eip()

if __name__ == "__main__":
    import signal
    from functools import partial

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

    import sys

    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)

    app = QtGui.QApplication(sys.argv)
    mainwindow = MainWindow()
    mainwindow.show()

    timer = QtCore.QTimer()
    timer.start(500)
    timer.timeout.connect(lambda: None)

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

    sys.exit(app.exec_())