# Copyright (C) 2012 Canonical
#
# Authors:
#  Michael Vogt
#
# 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; version 3.
#
# 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, write to the Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

import dbus

from dbus.mainloop.glib import DBusGMainLoop
DBusGMainLoop(set_as_default=True)

import locale
import logging
import os
import xml.etree.ElementTree
from gettext import dgettext
from gettext import gettext as _

LOG = logging.getLogger(__name__)

# warning displayed if region does not match
REGION_WARNING_STRING = _("Sorry, this software is not available in your "
                          "region.")
# the prefix tag for regions that the software is most useful in
REGIONTAG = "iso3166::"

# blacklist this region
REGION_BLACKLIST_TAG = "blacklist-iso3166::"
# or whitelist it
REGION_WHITELIST_TAG = "whitelist-iso3166::"


def get_region_name(countrycode):
    """ return translated region name from countrycode using iso3166 """
    # find translated name
    if countrycode:
        for iso in ["iso_3166", "iso_3166_2"]:
            path = os.path.join("/usr/share/xml/iso-codes/", iso + ".xml")
            if os.path.exists(path):
                root = xml.etree.ElementTree.parse(path)
                xpath = ".//%s_entry[@alpha_2_code='%s']" % (iso, countrycode)
                match = root.find(xpath)
                if match is not None:
                    name = match.attrib.get("common_name")
                    if not name:
                        name = match.attrib["name"]
                    return dgettext(iso, name)
    return ""


# the first parameter of SetRequirements
class AccuracyLevel:
    NONE = 0
    COUNTRY = 1
    REGION = 2
    LOCALITY = 3
    POSTALCODE = 4
    STREET = 5
    DETAILED = 6


class AllowedResources:
    NONE = 0
    NETWORK = 1 << 0
    CELL = 1 << 1
    GPS = 1 << 2
    ALL = (1 << 10) - 1


class RegionDiscover(object):

    def get_region(self):
        """ return a dict with at least "county" and "countrycode" as
            keys - they may be empty if no region is found
        """
        res = {}
        # try geoclue first
        try:
            res = self._get_region_geoclue()
            if res:
                return res
        except Exception as e:
            LOG.warn("failed to use geoclue: '%s'" % e)
        # fallback
        res = self._get_region_dumb()
        return res

    def _get_region_dumb(self):
        """ return dict estimate about the current countrycode/country """
        res = {'countrycode': '',
               'country': '',
              }
        try:
            # use LC_MONETARY as the best guess
            loc = locale.getlocale(locale.LC_MONETARY)[0]
        except Exception as e:
            LOG.warn("Failed to get locale: '%s'" % e)
            return res
        if not loc:
            return res
        countrycode = loc.split("_")[1]
        res["countrycode"] = countrycode
        res["country"] = get_region_name(countrycode)
        return res

    def _get_region_geoclue(self):
        """ return the dict with at least countrycode,country from a geoclue
            provider
        """
        bus = dbus.SessionBus()
        master = bus.get_object(
            'org.freedesktop.Geoclue.Master',
            '/org/freedesktop/Geoclue/Master')
        client = bus.get_object(
            'org.freedesktop.Geoclue.Master', master.Create())
        client.SetRequirements(AccuracyLevel.COUNTRY,   # (i) accuracy_level
                               0,                       # (i) time
                               False,                   # (b) require_updates
                               AllowedResources.ALL)    # (i) allowed_resoures
        # this is crucial
        client.AddressStart()
        # now get the data
        time, address_res, accuracy = client.GetAddress()
        return address_res


my_region = None


def get_region_cached():
    global my_region
    if my_region is None:
        rd = RegionDiscover()
        my_region = rd.get_region()
    return my_region