#!/usr/bin/env python3
"""
Syncthing-GTK - 1st run wizard

Basically runs Syncthing daemon with -generate option and setups some
values afterwards.
"""


from gi.repository import GdkPixbuf, GLib, Gtk

from syncthing_gtk.configuration import Configuration
from syncthing_gtk.daemonoutputdialog import DaemonOutputDialog
from syncthing_gtk.daemonprocess import DaemonProcess
from syncthing_gtk.tools import _  # gettext function
from syncthing_gtk.tools import IS_WINDOWS, can_upgrade_binary, compare_version, get_config_dir, is_portable


try:
    from syncthing_gtk.stdownloader import StDownloader
except ImportError:
    StDownloader = None

import logging
import os
import platform
import random
import socket
import string
import traceback
from xml.dom import minidom

import bcrypt


log = logging.getLogger("Wizard")

DEFAULT_PORT = 8080
MAX_PORT = 8100


class Wizard(Gtk.Assistant):
    def __init__(self, uipath="/usr/share/syncthing-gtk",
                 iconpath="/usr/share/syncthing-gtk/icons", config=None):
        # Init
        Gtk.Assistant.__init__(self)
        if config is not None:
            self.config = config
        else:
            self.config = Configuration()
        self.uipath = uipath
        self.iconpath = iconpath
        self.syncthing_options = {}
        self.lines = []					# Daemon and wizard output,
        # maybe for error reports
        self.finished = False
        self.connect("prepare", self.prepare_page)
        # Find syncthing configuration directory
        self.st_configdir = os.path.join(get_config_dir(), "syncthing")
        self.st_configfile = os.path.join(
            get_config_dir(), "syncthing", "config.xml")
        # Window setup
        self.set_position(Gtk.WindowPosition.CENTER)
        self.set_size_request(720, -1)
        self.set_default_size(720, 300)
        self.set_deletable(True)
        if IS_WINDOWS:
            self.set_icon_list([GdkPixbuf.Pixbuf.new_from_file(
                "icons/32x32/apps/syncthing-gtk.png")])
        else:
            self.set_icon_name("syncthing-gtk")
        self.set_title("%s %s" % (_("Syncthing-GTK"), _("First run wizard")))
        # Add "Quit" button
        self.quit_button = Gtk.Button.new_from_stock("gtk-quit")
        self.add_action_widget(self.quit_button)
        self.quit_button.set_visible(True)
        self.quit_button.connect("clicked", lambda *a: self.emit("cancel"))
        # Pages
        self.add_page(IntroPage(self))
        self.add_page(FindDaemonPage())
        self.add_page(GenerateKeysPage())
        self.add_page(HttpSettingsPage())
        self.add_page(SaveSettingsPage())
        self.add_page(LastPage())

    def add_page(self, page):
        """ Adds page derived from custom Page class """
        index = self.append_page(page)
        page.parent = self
        self.set_page_type(page, page.TYPE)
        self.set_page_title(page, _(page.TITLE) + "  ")
        return index

    def insert(self, page):
        """
        Inserts new page after currently displayed.
        """
        index = self.get_current_page()
        index = self.insert_page(page, index + 1)
        page.parent = self
        self.set_page_type(page, page.TYPE)
        self.set_page_title(page, _(page.TITLE) + "  ")
        return index

    def insert_and_go(self, page):
        """
        Inserts new page after currently displayed
        and switches to it.
        """
        index = self.insert(page)
        self.set_current_page(index)
        return index

    def only_page(self, page):
        for r in range(1, page):
            self.remove_page(r)
        while self.get_n_pages() > 3:
            self.remove_page(self.get_n_pages() - 2)
        self.set_current_page(1)

    def prepare_page(self, another_self, page):
        """ Called before page is displayed """
        self.commit()  # Prevents back button from being displayed
        page.prepare()

    def find_widget(self, compare_fn, parent=None):
        """
        Recursively searches for widget, returning first one
        for which compare_fn(widget) returns True
        """
        if parent is None:
            parent = self
        for w in parent.get_children():
            if compare_fn(w):
                return w
            if isinstance(w, Gtk.Container):
                r = self.find_widget(compare_fn, w)
                if r is not None:
                    return r
        return None

    def output_line(self, line):
        """ Called for every line that wizard or daemon process outputs """
        self.lines.append(line)
        log.info(line)

    def error(self, page, title, message, display_bugreport_link):
        """
        Called from pages on error. Removes everything from page and
        creates error message.
        """
        for c in [] + page.get_children():
            page.remove(c)
        # Title
        l_title = WrappedLabel("<b>%s</b>" % (title,))
        l_title.props.margin_bottom = 15
        page.attach(l_title,	0, 0, 2, 1)
        # Message
        l_message = WrappedLabel(message)
        l_message.props.margin_bottom = 15
        page.attach(l_message,	0, 1, 2, 1)
        # Bugreport link
        if display_bugreport_link:
            github_link = '<a href="https://github.com/syncthing/syncthing-gtk/issues">GitHub</a>'
            l_bugreport = WrappedLabel(
                _("Please, check error log and fill bug report on %s.") % (
                    github_link,)
            )
            page.attach(l_bugreport, 0, 2, 2, 1)
            # 'Display error log' button
            button = Gtk.Button(_("Display error log"))
            button.props.margin_top = 25
            page.attach(button, 1, 3, 2, 1)
            button.connect("clicked", lambda *a: self.show_output())

        page.show_all()
        return page

    def show_output(self, *a):
        """
        Displays DaemonOutput window with error messages captured
        during key generation.
        """
        d = DaemonOutputDialog(self, None)
        d.show_with_lines(self.lines, self)

    def is_finished(self):
        """ Returns True if user finished entire wizard """
        return self.finished

    def run(self, *a):
        self.show()
        self.connect('cancel', Gtk.main_quit)
        self.connect('close', Gtk.main_quit)
        Gtk.main()


class WrappedLabel(Gtk.Label):
    def __init__(self, markup):
        Gtk.Label.__init__(self)
        self.set_justify(Gtk.Justification.LEFT)
        self.set_line_wrap(True)
        self.set_markup(markup)
        self.set_alignment(0, 0.5)

# @AbstractClass


class Page(Gtk.Grid):
    # TYPE = <needs to be defined in derived class>
    # TITLE = <needs to be defined in derived class>
    def __init__(self, dialog=None):
        Gtk.Grid.__init__(self)
        self.dialog = dialog
        self.parent = None
        self.init_page()
        self.show_all()

    def prepare(self):
        """ Sets page as complete by default """
        self.parent.set_page_complete(self, True)

    def init_page(self):
        """ Initialize the page """
        raise NotImplementedError()


class IntroPage(Page):
    TYPE = Gtk.AssistantPageType.INTRO
    TITLE = "Intro"

    def init_page(self):
        """ First, intro page. Just static text that explains what's going on """
        config_folder = "~/.config/syncthing"
        config_folder_link = '<a href="file://%s">%s</a>' % (
            os.path.expanduser(config_folder), config_folder)
        next_label = _("Next")
        try:
            # Hacky way to determine label on 'Next' button
            all_buttons = [b for b in self.dialog.quit_button.get_parent().get_children()
                           if isinstance(b, Gtk.Button) and b is not self.dialog.quit_button]
            # order is 'apply, next, back, finish, cancel'
            next_label = all_buttons[1].get_label().replace("_", "")
        except:
            pass
        # TODO: Temporal solution, remove later
        changed_line = _(
            "Continue this wizard to create a Syncthing configuration file or abort it to exit.")
        if "%s" in changed_line:
            changed_line = changed_line % (next_label,)

        self.attach(WrappedLabel(
            "<b>" + _("Welcome to Syncthing-GTK first run wizard!") + "</b>" +
            "\n\n" +
            _("It looks like you never have used Syncthing.") + " " +
            _("Initial configuration should be created.") + " " +
            changed_line + "\n\n" +
            (_("If you already had Syncthing daemon configured, please, "
               "exit this wizard and check your %s folder") % config_folder_link)
        ), 0, 0, 1, 1)


class FindDaemonPage(Page):
    # Next page, "Download Daemon" is displayed only if needed.
    # When that happens, it becomes page with longest title and wizard
    # window changes size to accommodate this change. And i don't like
    # that.
    # To prevent this 'window jumping', padding is added here, so
    # this page is always one with longest name.
    TITLE = "Find Daemon"
    TYPE = Gtk.AssistantPageType.PROGRESS

    def init_page(self):
        """ Displayed while Syncthing binary is being searched for """
        self.label = WrappedLabel(
            "<b>" + _("Searching for Syncthing daemon.") + "</b>" +
            "\n\n" +
            _("Please wait...")
        )
        self.paths = []
        self.version_string = "v0.0"
        self.ignored_version = None
        self.attach(self.label, 0, 0, 1, 1)

    def prepare(self):
        default_path, default_binary = os.path.split(
            self.parent.config.get_default_value("syncthing_binary"))
        self.paths = []
        if default_path:
            self.paths += [default_path]
        self.paths += ["./"]
        self.paths += [os.path.expanduser("~/.local/bin")]
        self.paths += [self.parent.st_configdir]
        if is_portable():
            self.paths += [".\\data"]
        if StDownloader is None:
            self.binaries = ["syncthing"]
        else:
            suffix, trash = StDownloader.determine_platform()
            self.binaries = ["syncthing", "syncthing%s" % (suffix,)]
            if suffix == "x64":
                # Allow 32bit binary on 64bit
                self.binaries += ["syncthing.x86"]
            if default_binary not in self.binaries:
                self.binaries = [default_binary] + self.binaries
        if IS_WINDOWS:
            self.paths += ["c:/Program Files/syncthing",
                           "c:/Program Files (x86)/syncthing",
                           self.parent.st_configdir
                           ]
            self.binaries = ("syncthing.exe",)
        if "PATH" in os.environ:
            self.paths += os.environ["PATH"].split(":")
        log.info("Searching for syncthing binary...")
        GLib.idle_add(self.search)

    def search(self):
        """
        Called repeatedly through GLib.idle_add, until binary is found
        or all possible paths are tried.
        """
        try:
            path, self.paths = self.paths[0], self.paths[1:]
        except IndexError:
            # Out of possible paths. Not found
            if IS_WINDOWS:
                # On Windows, don't say anything and download Syncthing
                # directly
                self.parent.insert_and_go(DownloadSTPage())
                return False
            elif StDownloader is None:
                # On Linux with updater disabled, generate and
                # display error page
                title = _("Syncthing daemon not found.")
                message = _(
                    "Please, use package manager to install the Syncthing package.")
                page = self.parent.error(self, title, message, False)
                page.show_all()
                return False
            else:
                # On Linux with updater generate similar display error
                # and offer download
                from syncthing_gtk.app import MIN_ST_VERSION
                target_folder_link = '<a href="file://%s">%s</a>' % (
                    os.path.expanduser(StDownloader.get_target_folder()),
                    StDownloader.get_target_folder())
                dll_link = '<a href="https://github.com/syncthing/syncthing/releases">' + \
                    _('download latest binary') + '</a>'
                message, title = "", None
                if self.ignored_version is None:
                    # No binary was found
                    title = _("Syncthing daemon not found.")
                    message += _("Please, use package manager to install the Syncthing package "
                                 "or %(download_link)s from Syncthing page and save it to your "
                                 "%(target)s directory.") % {
                        'download_link': dll_link,
                        'target': target_folder_link
                    }
                else:
                    # Binary was found, but it was too old to be usable
                    title = _("Syncthing daemon is too old.")
                    message += _("Syncthing-GTK needs Syncthing daemon %(min)s or newer, but only %(actual)s were found.") % {
                        'min': MIN_ST_VERSION,
                        'actual': self.ignored_version
                    }
                    message += "\n"
                    message += _("Please, use package manager to install the Syncthing package "
                                 "or %(download_link)s from Syncthing page and save it to your "
                                 "%(target)s directory.") % {
                        'download_link': dll_link,
                        'target': target_folder_link
                    }
                message += "\n\n"
                message += _("Alternatively, Syncthing-GTK can download Syncthing binary") + " "
                message += _("to %s and keep it up-to-date, but this option is meant as") % \
                    (target_folder_link,) + " "
                message += _("last resort and generally not suggested.")
                page = self.parent.error(self, title, message, False)
                # Attach [ ] Download Syncthing checkbox
                cb = Gtk.CheckButton(
                    _("_Download Syncthing binary"), use_underline=True)
                cb.connect("toggled", lambda cb, *
                           a: self.parent.set_page_complete(page, cb.get_active()))
                page.attach(cb,	0, 2, 2, 1)
                # Attach [ ] Autoupdate checkbox
                cb = Gtk.CheckButton(
                    _("Auto_update downloaded binary"), use_underline=True)
                cb.connect("toggled", lambda cb, *
                           a: self.parent.config.set("st_autoupdate", cb.get_active()))
                page.attach(cb,	0, 3, 2, 1)
                page.show_all()
                # Add Download page
                self.parent.insert(DownloadSTPage())
                return False

        for bin in self.binaries:
            bin_path = os.path.join(path, bin)
            log.info(" ... %s", bin_path)
            if os.path.isfile(bin_path):
                if os.access(bin_path, os.X_OK):
                    # File exists and is executable, run it and parse
                    # version string from output
                    log.info("Binary found in %s", bin_path)
                    if IS_WINDOWS:
                        bin_path = bin_path.replace("/", "\\")
                    p = DaemonProcess([bin_path, '-version'])
                    p.connect('line', self.cb_process_output)
                    p.connect('exit', self.cb_process_exit)
                    p.connect('failed', self.cb_process_exit)
                    p.start()
                    return False
                else:
                    log.info("Binary in %s is not not executable", bin_path)
        return True

    def cb_process_output(self, process, line):
        """
        Called when daemon binary outputs line while it's being asked
        for version string.
        """
        try:
            # Parse version string
            v = line.split(" ")[1]
            if v.startswith("v"):
                self.version_string = v
        except Exception:
            # Not line with version string, probably some other output
            pass

    def cb_process_exit(self, process, *a):
        """ Called after daemon binary outputs version and exits """
        from syncthing_gtk.app import MIN_ST_VERSION
        bin_path = process.get_commandline()[0]
        if compare_version(self.version_string, MIN_ST_VERSION):
            # Daemon binary exists, is executable and meets
            # version requirements. That's good, btw.
            self.parent.config["syncthing_binary"] = bin_path
            if not can_upgrade_binary(bin_path):
                # Don't try enable auto-update if binary is in
                # non-writable location (auto-update is enabled
                # by default on Windows only)
                self.parent.config["st_autoupdate"] = False
            self.parent.set_page_complete(self, True)
            self.label.set_markup(
                "<b>" + _("Syncthing daemon binary found.") + "</b>" +
                "\n\n" +
                _("Binary path:") + " " + bin_path + "\n" +
                _("Version:") + " " + self.version_string
            )
        else:
            # Found daemon binary too old to be usable.
            # Just ignore it and try to find better one.
            log.info("Binary in %s is too old", bin_path)
            self.ignored_version = self.version_string
            GLib.idle_add(self.search)


class DownloadSTPage(Page):
    TYPE = Gtk.AssistantPageType.PROGRESS
    TITLE = "Download Daemon"

    def init_page(self):
        """ Displayed while wizard downloads and extracts daemon """
        self.label = WrappedLabel(
            "<b>" + _("Downloading Syncthing daemon.") + "</b>")
        self.version = WrappedLabel(_("Please wait..."))
        self.pb = Gtk.ProgressBar()
        self.label.props.margin_bottom = 15
        self.target = None
        self.attach(self.label,		0, 0, 1, 1)
        self.attach(self.version,	0, 1, 1, 1)
        self.attach(self.pb,		0, 2, 1, 1)

    def prepare(self):
        # Determine which Syncthing to use
        suffix, tag = StDownloader.determine_platform()
        # Report error on unsupported platforms
        if suffix is None or tag is None:
            pd = "%s %s %s" % (
                platform.uname()[0], platform.uname()[2],  # OS, version
                platform.uname()[4])						# architecture
            self.parent.error(self,
                              _("Cannot download Syncthing daemon."),
                              _("This platform (%s) is not supported") % (pd,),
                              False)
            return
        # Determine target file & directory
        self.target = os.path.join(
            os.path.expanduser(StDownloader.get_target_folder()),
            "syncthing%s" % (suffix,)
        )
        # Create downloader and connect events
        self.sd = StDownloader(self.target, tag)
        self.sd.connect("error", self.on_download_error)
        self.sd.connect("version", self.on_version)
        self.sd.connect("download-progress", self.on_progress)
        self.sd.connect("download-finished", self.on_extract_start)
        self.sd.connect("extraction-progress", self.on_progress)
        self.sd.connect("extraction-finished", self.on_extract_finished)
        # Start downloading
        self.sd.get_version()

    def on_download_error(self, downloader, error, message):
        """
        Called when download fails. This is fatal for now, user can
        only observe message, cry and quit program.
        """
        message = "%s\n%s" % (
            str(error) if error is not None else "",
            message if message is not None else ""
        )
        self.parent.error(self,
                          _("Failed to download Syncthing daemon package."),
                          message, False)
        return

    def on_version(self, dowloader, version):
        self.version.set_markup("Downloading %s..." % (version, ))
        dowloader.download()

    def on_extract_start(self, *a):
        self.version.set_markup("Extracting...")

    def on_progress(self, dowloader, progress):
        self.pb.set_fraction(progress)

    def on_extract_finished(self, *a):
        """ Called after extraction is finished """
        # Everything done. Praise supernatural entities...
        self.label.set_markup("<b>" + _("Download finished.") + "</b>")
        self.parent.config["syncthing_binary"] = self.target
        self.version.set_markup(_("Binary path:") +
                                " " + self.target)
        self.pb.set_visible(False)
        self.parent.set_page_complete(self, True)


class GenerateKeysPage(Page):
    TYPE = Gtk.AssistantPageType.PROGRESS
    TITLE = "Generate Keys"

    def init_page(self):
        """ Displayed while Syncthing binary is being searched for """
        self.label = WrappedLabel(
            "<b>%s</b>\n\n%s" % (
                _("Syncthing is generating RSA key and certificate."),
                _("This may take a while...")
            )
        )
        self.attach(self.label, 0, 0, 1, 1)

    def prepare(self):
        GLib.idle_add(self.start_binary)

    def start_binary(self):
        """
        Starts Syncthing binary with -generate parameter and waits until
        key generation is finished
        """
        self.parent.output_line(
            "syncthing-gtk: Configuration directory: '%s'" % (self.parent.st_configdir,))
        # Create it, if needed
        try:
            os.makedirs(self.parent.st_configdir)
        except Exception as e:
            self.parent.output_line(
                "syncthing-gtk: Failed to create configuration directory")
            self.parent.output_line("syncthing-gtk: %s" % (str(e),))
        # Run syncthing -generate
        self.parent.output_line(
            "syncthing-gtk: Syncthing configuration directory: %s" % (self.parent.st_configdir,))
        self.process = DaemonProcess(
            [self.parent.config["syncthing_binary"], '-generate=%s' % self.parent.st_configdir])
        self.process.connect('line', lambda proc,
                             line: self.parent.output_line(line))
        self.process.connect('exit', self.cb_daemon_exit)
        self.process.connect('failed', self.cb_daemon_start_failed)
        self.process.start()
        return False

    def cb_daemon_start_failed(self, dproc, exception):
        self.parent.output_line("syncthing-gtk: Daemon startup failed")
        self.parent.output_line("syncthing-gtk: %s" % (str(exception),))
        self.cb_daemon_exit(dproc, -1)

    def cb_daemon_exit(self, dproc, exit_code):
        """ Called when Syncthing finishes """
        if exit_code == 0:
            # Finished without problem, advance to next page
            self.parent.set_page_complete(self, True)
            self.parent.next_page()
        else:
            self.parent.error(self,
                              _("Failed to generate keys"),
                              _("Syncthing daemon failed to generate RSA key or certificate."),
                              True)


class HttpSettingsPage(Page):
    TYPE = Gtk.AssistantPageType.CONTENT
    TITLE = "Setup WebUI"

    def init_page(self):
        """ Permits user to set WebUI settings """
        # Wall of text
        label = WrappedLabel(
            "<b>" + _("WebUI setup") + "</b>" +
            "\n\n" +
            _("Syncthing can be managed remotely using WebUI and "
              "even if you are going to use Syncthing-GTK, WebUI needs "
              "to be enabled, as Syncthing-GTK uses it to communicate "
              "with the Syncthing daemon.") +
            "\n\n" +
            _("If you prefer to be able to manage Syncthing remotely, "
              "over the internet or on your local network, select <b>listen "
              "on all interfaces</b> and set username and password to "
              "protect Syncthing from unauthorized access.") +
            "\n" +
            _("Otherwise, select <b>listen on localhost</b>, so only "
              "users and programs on this computer will be able to "
              "interact with Syncthing.") +
            "\n"
        )
        # Radiobuttons
        lbl_radios = WrappedLabel("<b>" + _("WebUI Listen Addresses") + "</b>")
        self.rb_localhost = Gtk.RadioButton(label=_("Listen on _localhost"))
        self.rb_all_intfs = Gtk.RadioButton.new_from_widget(self.rb_localhost)
        self.rb_all_intfs.set_label(_("Listen on _all interfaces"))
        for x in (self.rb_localhost, self.rb_all_intfs):
            x.set_use_underline(True)
            x.set_property('margin-left', 15)
        # Username & password input boxes
        self.tx_username = Gtk.Entry()
        self.tx_password = Gtk.Entry()
        self.lbl_username = WrappedLabel(_("_Username"))
        self.lbl_password = WrappedLabel(_("_Password"))
        self.lbl_username.set_mnemonic_widget(self.tx_username)
        self.lbl_password.set_mnemonic_widget(self.tx_password)
        self.tx_password.set_visibility(False)
        self.tx_password.props.caps_lock_warning = True
        for x in (self.lbl_username, self.lbl_password):
            x.set_use_underline(True)
            x.set_property('margin-left', 45)
            x.set_property('margin-bottom', 5)
        for x in (self.tx_username, self.tx_password):
            x.set_property('margin-bottom', 5)
        # Connect signals
        for x in (self.rb_localhost, self.rb_all_intfs):
            x.connect("toggled", self.cb_stuff_changed)
        for x in (self.tx_username, self.tx_password):
            x.connect("changed", self.cb_stuff_changed)
            x.connect("delete-text", self.cb_stuff_changed)
            x.connect("insert-text", self.cb_stuff_changed)
        # Attach everything
        self.attach(label, 0, 0, 3, 1)
        self.attach(lbl_radios, 0, 1, 3, 1)
        self.attach(self.rb_localhost, 0, 2, 2, 1)
        self.attach(self.rb_all_intfs, 0, 3, 2, 1)
        self.attach(self.lbl_username, 0, 4, 1, 1)
        self.attach(self.lbl_password, 0, 5, 1, 1)
        self.attach(self.tx_username, 1, 4, 2, 1)
        self.attach(self.tx_password, 1, 5, 2, 1)

    def cb_stuff_changed(self, *a):
        """ Called every time user changes anything on this page """
        # Enable / disable username & password input boxes
        for x in (self.tx_username, self.tx_password, self.lbl_username, self.lbl_password):
            x.set_sensitive(self.rb_all_intfs.get_active())
        # Set page as 'complete' and store settings
        # if either localhost is selected, or username & password is filled
        values_ok = self.rb_localhost.get_active() or (len(self.tx_username.get_text().strip())
                                                       and len(self.tx_password.get_text().strip()))
        self.parent.set_page_complete(self, values_ok)
        if values_ok:
            if self.rb_localhost.get_active():
                self.parent.syncthing_options["listen_ip"] = "127.0.0.1"
            else:
                self.parent.syncthing_options["listen_ip"] = "0.0.0.0"
            self.parent.syncthing_options["user"] = str(
                self.tx_username.get_text())
            self.parent.syncthing_options["password"] = str(
                self.tx_password.get_text())

    def prepare(self):
        # Refresh UI
        self.cb_stuff_changed()


class SaveSettingsPage(Page):
    TYPE = Gtk.AssistantPageType.PROGRESS
    TITLE = "Save Settings"

    def init_page(self):
        """ Displayed while settings are being saved """
        self.label = WrappedLabel(
            "<b>" + _("Saving settings...") + "</b>" + "\n\n")
        self.status = Gtk.Label(_("Checking for available port..."))
        self.attach(self.label,		0, 0, 1, 1)
        self.attach(self.status,	0, 1, 1, 1)

    def prepare(self):
        GLib.idle_add(self.check_port, DEFAULT_PORT)

    def check_port(self, port):
        """
        Tries to open TCP port to check it availability.
        It this fails, checks next ports, until MAX_PORT is reached.
        When MAX_PORT is reached, it's safe to assume that something
        completely wrong is happening and an error should be displayed.
        """
        if port >= MAX_PORT:
            # Remove config.xml that I just created
            try:
                os.unlink(self.parent.st_configfile)
            except Exception as e:
                self.parent.output_line("syncthing-gtk: %s" % (str(e),))
            self.parent.error(self,
                              _("Failed to find unused port for listening."),
                              _("Please, check your firewall settings and try again."),
                              False)
            return
        s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        try:
            s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
            s.bind((self.parent.syncthing_options["listen_ip"], port))
            s.listen(0)
            s.close()
            # Good, port is available
            self.parent.output_line("syncthing-gtk: chosen port %s" % (port,))
            self.port = port
            self.parent.syncthing_options["port"] = str(port)
            self.status.set_markup(_("Saving..."))
            GLib.idle_add(self.save_settings)
        except socket.error:
            # Address already in use (or some crazy error)
            self.parent.output_line(
                "syncthing-gtk: port %s is not available" % (port,))
            GLib.idle_add(self.check_port, port + 1)
        finally:
            del s

    def ct_textnode(self, xml, parent, name, value):
        """ Helper method """
        el = xml.createElement(name)
        text = xml.createTextNode(value)
        el.appendChild(text)
        parent.appendChild(el)

    def save_settings(self):
        """
        Loads&parses XML, changes some values and writes it back.
        No backup is created as this wizard is expected to be ran
        only if there is no config in first place.
        """
        # Generate API key
        self.apikey = "".join(random.choice(
            string.ascii_lowercase + string.digits) for _ in range(30))
        log.debug("Generated apikey %s", self.apikey)
        xml = None
        try:
            # Load XML file
            with open(self.parent.st_configfile, "r") as conf_file:
                config = conf_file.read()
            xml = minidom.parseString(config)
        except Exception as e:
            self.parent.output_line("syncthing-gtk: %s" %
                                    (traceback.format_exc(),))
            self.parent.error(self,
                              _("Failed to load Syncthing configuration"),
                              str(e),
                              True)
            return False
        try:
            # Prepare elements
            gui = xml.getElementsByTagName("configuration")[0] \
                .getElementsByTagName("gui")[0]
            au = xml.getElementsByTagName("configuration")[0] \
                .getElementsByTagName("options")[0] \
                .getElementsByTagName("autoUpgradeIntervalH")[0]
            while gui.firstChild is not None:
                gui.removeChild(gui.firstChild)
            # Update data
            self.ct_textnode(xml, gui, "address", "%s:%s" % (
                self.parent.syncthing_options["listen_ip"],
                self.parent.syncthing_options["port"],
            ))
            self.ct_textnode(xml, gui, "user",
                             self.parent.syncthing_options["user"])
            self.ct_textnode(xml, gui, "password", bcrypt.hashpw(
                self.parent.syncthing_options["password"].encode('utf8'),
                bcrypt.gensalt()
            ).decode('utf8'))
            self.ct_textnode(xml, gui, "apikey", self.apikey)
            gui.setAttribute("enabled", "true")
            gui.setAttribute("tls", "false")
            au.firstChild.replaceWholeText("0")
        except Exception as e:
            self.parent.output_line("syncthing-gtk: %s" %
                                    (traceback.format_exc(),))
            self.parent.error(self,
                              _("Failed to modify Syncthing configuration"),
                              str(e),
                              True)
            return False
        try:
            # Write XML back to file
            with open(self.parent.st_configfile, "w", encoding="utf-8") as f:
                f.write(xml.toxml())
        except Exception as e:
            self.parent.output_line("syncthing-gtk: %s" %
                                    (traceback.format_exc(),))
            self.parent.error(self,
                              _("Failed to save Syncthing configuration"),
                              str(e),
                              True)
            return False
        self.parent.set_page_complete(self, True)
        self.parent.next_page()
        return False


class LastPage(GenerateKeysPage):
    TYPE = Gtk.AssistantPageType.SUMMARY
    TITLE = "Finish"

    def init_page(self):
        """ Well, it's last page. """
        label = WrappedLabel(
            "<b>" + _("Done.") + "</b>" +
            "\n\n" +
            _("Syncthing has been successfully configured.") +
            "\n" +
            _("You can configure more details later, in "
              "<b>UI Settings</b> and <b>Daemon Settings</b> menus "
              "in main window of application.")
        )
        self.attach(label, 0, 0, 1, 1)

    def prepare(self):
        # Configure main app to manage Syncthing daemon by default
        self.parent.config["autostart_daemon"] = 1
        self.parent.config["autokill_daemon"] = 1
        self.parent.config["minimize_on_start"] = False
        if IS_WINDOWS:
            self.parent.config["use_old_header"] = True
        self.parent.quit_button.get_parent().remove(self.parent.quit_button)
        self.parent.finished = True