#
# Copyright (C) 2012-2014  Red Hat, Inc.
#
# This copyrighted material is made available to anyone wishing to use,
# modify, copy, or redistribute it subject to the terms and conditions of
# the GNU General Public License v.2, or (at your option) any later version.
# This program is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY expressed or implied, including the implied warranties 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, write to the
# Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
# 02110-1301, USA.  Any Red Hat trademarks that are incorporated in the
# source code or documentation are not subject to the GNU General Public
# License and may only be used or replicated with the express permission of
# Red Hat, Inc.
#

"""
This module include functions and classes for dealing with multiple layouts in
Anaconda. It wraps the libxklavier functionality to protect Anaconda from
dealing with its "nice" API that looks like a Lisp-influenced "good old C" and
also systemd-localed functionality.

It provides a XklWrapper class with several methods that can be used for listing
and various modifications of keyboard layouts settings.

"""

import gi
gi.require_version("GdkX11", "3.0")
gi.require_version("Xkl", "1.0")

from gi.repository import GdkX11, Xkl

import threading
import gettext
from collections import namedtuple

from pyanaconda.core.configuration.anaconda import conf
from pyanaconda.core.constants import DEFAULT_KEYBOARD
from pyanaconda.core.string import upcase_first_letter
from pyanaconda.keyboard import join_layout_variant, parse_layout_variant, \
    KeyboardConfigError, InvalidLayoutVariantSpec, normalize_layout_variant
from pyanaconda.core.async_utils import async_action_wait
from pyanaconda import localization


from pyanaconda.anaconda_loggers import get_module_logger
log = get_module_logger(__name__)

Xkb_ = lambda x: gettext.translation("xkeyboard-config", fallback=True).gettext(x)
iso_ = lambda x: gettext.translation("iso_639", fallback=True).gettext(x)

# namedtuple for information about a keyboard layout (its language and description)
LayoutInfo = namedtuple("LayoutInfo", ["lang", "desc"])


class XklWrapperError(KeyboardConfigError):
    """Exception class for reporting libxklavier-related problems"""

    pass


class XklWrapper(object):
    """
    Class wrapping the libxklavier functionality

    Use this class as a singleton class because it provides read-only data
    and initialization (that takes quite a lot of time) reads always the
    same data. It doesn't have sense to make multiple instances

    """

    _instance = None
    _instance_lock = threading.Lock()

    @staticmethod
    def get_instance():
        with XklWrapper._instance_lock:
            if not XklWrapper._instance:
                XklWrapper._instance = XklWrapper()

        return XklWrapper._instance

    def __init__(self):
        #initialize Xkl-related stuff
        display = GdkX11.x11_get_default_xdisplay()
        self._engine = Xkl.Engine.get_instance(display)

        self._rec = Xkl.ConfigRec()
        if not self._rec.get_from_server(self._engine):
            raise XklWrapperError("Failed to get configuration from server")

        #X is probably initialized to the 'us' layout without any variant and
        #since we want to add layouts with variants we need the layouts and
        #variants lists to have the same length. Add "" padding to variants.
        #See docstring of the add_layout method for details.
        diff = len(self._rec.layouts) - len(self._rec.variants)
        if diff > 0 and conf.system.can_activate_layouts:
            self._rec.set_variants(self._rec.variants + (diff * [""]))
            if not self._rec.activate(self._engine):
                # failed to activate layouts given e.g. by a kickstart (may be
                # invalid)
                lay_var_str = ",".join(map(join_layout_variant,
                                           self._rec.layouts,
                                           self._rec.variants))
                log.error("Failed to activate layouts: '%s', "
                          "falling back to default %s", lay_var_str, DEFAULT_KEYBOARD)
                self._rec.set_layouts([DEFAULT_KEYBOARD])
                self._rec.set_variants([""])

                if not self._rec.activate(self._engine):
                    # failed to activate even the default layout, something is
                    # really wrong
                    raise XklWrapperError("Failed to initialize layouts")

        #needed also for Gkbd.KeyboardDrawingDialog
        self.configreg = Xkl.ConfigRegistry.get_instance(self._engine)
        self.configreg.load(False)

        self._layout_infos = dict()
        self._layout_infos_lock = threading.RLock()
        self._switch_opt_infos = dict()
        self._switch_opt_infos_lock = threading.RLock()

        #this might take quite a long time
        self.configreg.foreach_language(self._get_language_variants, None)
        self.configreg.foreach_country(self._get_country_variants, None)

        #'grp' means that we want layout (group) switching options
        self.configreg.foreach_option('grp', self._get_switch_option, None)

    def _get_lang_variant(self, c_reg, item, subitem, lang):
        if subitem:
            name = item.get_name() + " (" + subitem.get_name() + ")"
            description = subitem.get_description()
        else:
            name = item.get_name()
            description = item.get_description()

        #if this layout has already been added for some other language,
        #do not add it again (would result in duplicates in our lists)
        if name not in self._layout_infos:
            with self._layout_infos_lock:
                self._layout_infos[name] = LayoutInfo(lang, description)

    def _get_country_variant(self, c_reg, item, subitem, country):
        if subitem:
            name = item.get_name() + " (" + subitem.get_name() + ")"
            description = subitem.get_description()
        else:
            name = item.get_name()
            description = item.get_description()

        # if the layout was not added with any language, add it with a country
        if name not in self._layout_infos:
            with self._layout_infos_lock:
                self._layout_infos[name] = LayoutInfo(country, description)

    def _get_language_variants(self, c_reg, item, user_data=None):
        lang_name, lang_desc = item.get_name(), item.get_description()

        c_reg.foreach_language_variant(lang_name, self._get_lang_variant, lang_desc)

    def _get_country_variants(self, c_reg, item, user_data=None):
        country_name, country_desc = item.get_name(), item.get_description()

        c_reg.foreach_country_variant(country_name, self._get_country_variant,
                                      country_desc)

    def _get_switch_option(self, c_reg, item, user_data=None):
        """Helper function storing layout switching options in foreach cycle"""
        desc = item.get_description()
        name = item.get_name()

        with self._switch_opt_infos_lock:
            self._switch_opt_infos[name] = desc

    def get_current_layout(self):
        """
        Get current activated X layout and variant

        :return: current activated X layout and variant (e.g. "cz (qwerty)")

        """
        # ported from the widgets/src/LayoutIndicator.c code

        self._engine.start_listen(Xkl.EngineListenModes.TRACK_KEYBOARD_STATE)
        state = self._engine.get_current_state()
        cur_group = state.group
        num_groups = self._engine.get_num_groups()

        # BUG?: if the last layout in the list is activated and removed,
        #       state.group may be equal to n_groups
        if cur_group >= num_groups:
            cur_group = num_groups - 1

        layout = self._rec.layouts[cur_group] # pylint: disable=unsubscriptable-object
        try:
            variant = self._rec.variants[cur_group] # pylint: disable=unsubscriptable-object
        except IndexError:
            # X server may have forgotten to add the "" variant for its default layout
            variant = ""

        self._engine.stop_listen(Xkl.EngineListenModes.TRACK_KEYBOARD_STATE)

        return join_layout_variant(layout, variant)

    def get_available_layouts(self):
        """A list of layouts"""

        with self._layout_infos_lock:
            return list(self._layout_infos.keys())

    def get_common_layouts(self):
        """A list of common layouts"""

        return list(set(map(
            normalize_layout_variant, localization.get_common_keyboard_layouts()
        )).intersection(set(self.get_available_layouts())))

    def get_switching_options(self):
        """Method returning list of available layout switching options"""

        with self._switch_opt_infos_lock:
            return list(self._switch_opt_infos.keys())

    def get_layout_variant_description(self, layout_variant, with_lang=True, xlated=True):
        """
        Get description of the given layout-variant.

        :param layout_variant: layout-variant specification (e.g. 'cz (qwerty)')
        :type layout_variant: str
        :param with_lang: whether to include language of the layout-variant (if defined)
                          in the description or not
        :type with_lang: bool
        :param xlated: whethe to return translated or english version of the description
        :type xlated: bool
        :return: description of the layout-variant specification (e.g. 'Czech (qwerty)')
        :rtype: str

        """

        layout_info = self._layout_infos[layout_variant]

        # translate language and upcase its first letter, translate the
        # layout-variant description
        if xlated:
            lang = iso_(layout_info.lang)
            description = Xkb_(layout_info.desc)
        else:
            lang = upcase_first_letter(layout_info.lang)
            description = layout_info.desc

        if with_lang and lang and not description.startswith(lang):
            return "%s (%s)" % (lang, description)
        else:
            return description

    def get_switch_opt_description(self, switch_opt):
        """
        Get description of the given layout switching option.

        :param switch_opt: switching option name/ID (e.g. 'grp:alt_shift_toggle')
        :type switch_opt: str
        :return: description of the layout switching option (e.g. 'Alt + Shift')
        :rtype: str

        """

        # translate the description of the switching option
        return Xkb_(self._switch_opt_infos[switch_opt])

    @async_action_wait
    def activate_default_layout(self):
        """
        Activates default layout (the first one in the list of configured
        layouts).

        """

        self._engine.lock_group(0)

    def is_valid_layout(self, layout):
        """Return if given layout is valid layout or not"""

        return layout in self._layout_infos

    @async_action_wait
    def add_layout(self, layout):
        """
        Method that tries to add a given layout to the current X configuration.

        The X layouts configuration is handled by two lists. A list of layouts
        and a list of variants. Index-matching items in these lists (as if they
        were zipped) are used for the construction of real layouts (e.g.
        'cz (qwerty)').

        :param layout: either 'layout' or 'layout (variant)'
        :raise XklWrapperError: if the given layout is invalid or cannot be added

        """

        try:
            #we can get 'layout' or 'layout (variant)'
            (layout, variant) = parse_layout_variant(layout)
        except InvalidLayoutVariantSpec as ilverr:
            raise XklWrapperError("Failed to add layout: %s" % ilverr) from ilverr

        #do not add the same layout-variant combinanion multiple times
        if (layout, variant) in list(zip(self._rec.layouts, self._rec.variants)):
            return

        self._rec.set_layouts(self._rec.layouts + [layout])
        self._rec.set_variants(self._rec.variants + [variant])

        if not self._rec.activate(self._engine):
            raise XklWrapperError("Failed to add layout '%s (%s)'" % (layout,
                                                                      variant))

    @async_action_wait
    def remove_layout(self, layout):
        """
        Method that tries to remove a given layout from the current X
        configuration.

        See also the documentation for the add_layout method.

        :param layout: either 'layout' or 'layout (variant)'
        :raise XklWrapperError: if the given layout cannot be removed

        """

        #we can get 'layout' or 'layout (variant)'
        (layout, variant) = parse_layout_variant(layout)

        layouts_variants = list(zip(self._rec.layouts, self._rec.variants))

        if (layout, variant) not in layouts_variants:
            msg = "'%s (%s)' not in the list of added layouts" % (layout,
                                                                  variant)
            raise XklWrapperError(msg)

        idx = layouts_variants.index((layout, variant))
        new_layouts = self._rec.layouts[:idx] + self._rec.layouts[(idx + 1):] # pylint: disable=unsubscriptable-object
        new_variants = self._rec.variants[:idx] + self._rec.variants[(idx + 1):] # pylint: disable=unsubscriptable-object

        self._rec.set_layouts(new_layouts)
        self._rec.set_variants(new_variants)

        if not self._rec.activate(self._engine):
            raise XklWrapperError("Failed to remove layout '%s (%s)'" % (layout,
                                                                       variant))

    @async_action_wait
    def replace_layouts(self, layouts_list):
        """
        Method that replaces the layouts defined in the current X configuration
        with the new ones given.

        :param layouts_list: list of layouts defined as either 'layout' or
                             'layout (variant)'
        :raise XklWrapperError: if layouts cannot be replaced with the new ones

        """

        new_layouts = list()
        new_variants = list()

        for layout_variant in layouts_list:
            (layout, variant) = parse_layout_variant(layout_variant)
            new_layouts.append(layout)
            new_variants.append(variant)

        self._rec.set_layouts(new_layouts)
        self._rec.set_variants(new_variants)

        if not self._rec.activate(self._engine):
            msg = "Failed to replace layouts with: %s" % ",".join(layouts_list)
            raise XklWrapperError(msg)

    @async_action_wait
    def set_switching_options(self, options):
        """
        Method that sets options for layout switching. It replaces the old
        options with the new ones.

        :param options: layout switching options to be set
        :type options: list or generator
        :raise XklWrapperError: if the old options cannot be replaced with the
                                new ones

        """

        #preserve old "non-switching options"
        new_options = [opt for opt in self._rec.options if "grp:" not in opt] # pylint: disable=not-an-iterable
        new_options += options

        self._rec.set_options(new_options)

        if not self._rec.activate(self._engine):
            msg = "Failed to set switching options to: %s" % ",".join(options)
            raise XklWrapperError(msg)
