# Copyright 2012 Nebula, Inc.
#
#    Licensed under the Apache License, Version 2.0 (the "License"); you may
#    not use this file except in compliance with the License. You may obtain
#    a copy of the License at
#
#         http://www.apache.org/licenses/LICENSE-2.0
#
#    Unless required by applicable law or agreed to in writing, software
#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
#    License for the specific language governing permissions and limitations
#    under the License.

from datetime import datetime  # noqa
from datetime import timedelta  # noqa
import string

import babel
import babel.dates
from django.conf import settings
from django import shortcuts
from django.utils import encoding
from django.utils import translation
from django.utils.translation import ugettext_lazy as _
import pytz

from horizon import forms
from horizon import messages


def _one_year():
    now = datetime.utcnow()
    return now + timedelta(days=365)


class UserSettingsForm(forms.SelfHandlingForm):
    language = forms.ChoiceField(label=_("Language"))
    timezone = forms.ChoiceField(label=_("Timezone"))
    pagesize = forms.IntegerField(label=_("Items Per Page"),
                                  min_value=1,
                                  max_value=getattr(settings,
                                                    'API_RESULT_LIMIT',
                                                    1000),
                                  help_text=_("Number of items to show per "
                                              "page (applies to the pages "
                                              "that have API supported "
                                              "pagination)"))
    instance_log_length = forms.IntegerField(
        label=_("Log Lines Per Instance"), min_value=1,
        help_text=_("Number of log lines to be shown per instance"))

    @staticmethod
    def _sorted_zones():
        d = datetime(datetime.today().year, 1, 1)
        zones = [(tz, pytz.timezone(tz).localize(d).strftime('%z'))
                 for tz in pytz.common_timezones]
        zones.sort(key=lambda zone: int(zone[1]))
        return zones

    def __init__(self, *args, **kwargs):
        super(UserSettingsForm, self).__init__(*args, **kwargs)

        # Languages
        def get_language_display_name(code, desc):
            try:
                desc = translation.get_language_info(code)['name_local']
                desc = string.capwords(desc)
            except KeyError:
                # If a language is not defined in django.conf.locale.LANG_INFO
                # get_language_info raises KeyError
                pass
            return "%s (%s)" % (desc, code)
        languages = [(k, get_language_display_name(k, v))
                     for k, v in settings.LANGUAGES]
        self.fields['language'].choices = languages

        # Timezones
        timezones = []
        language = translation.get_language()
        current_locale = translation.to_locale(language)
        babel_locale = babel.Locale.parse(current_locale)
        for tz, offset in self._sorted_zones():
            try:
                utc_offset = _("UTC %(hour)s:%(min)s") % {"hour": offset[:3],
                                                          "min": offset[3:]}
            except Exception:
                utc_offset = ""

            if tz == "UTC":
                tz_name = _("UTC")
            elif tz == "GMT":
                tz_name = _("GMT")
            else:
                tz_label = babel.dates.get_timezone_location(
                    tz, locale=babel_locale)
                # Translators:  UTC offset and timezone label
                tz_name = _("%(offset)s: %(label)s") % {"offset": utc_offset,
                                                        "label": tz_label}
            timezones.append((tz, tz_name))

        self.fields['timezone'].choices = timezones

    def handle(self, request, data):
        response = shortcuts.redirect(request.build_absolute_uri())
        # Language
        lang_code = data['language']
        if lang_code and translation.check_for_language(lang_code):
            if hasattr(request, 'session'):
                request.session['django_language'] = lang_code
            response.set_cookie(settings.LANGUAGE_COOKIE_NAME, lang_code,
                                expires=_one_year())

        # Timezone
        request.session['django_timezone'] = pytz.timezone(
            data['timezone']).zone
        response.set_cookie('django_timezone', data['timezone'],
                            expires=_one_year())

        request.session['horizon_pagesize'] = data['pagesize']
        response.set_cookie('horizon_pagesize', data['pagesize'],
                            expires=_one_year())

        request.session['instance_log_length'] = data['instance_log_length']
        response.set_cookie('instance_log_length',
                            data['instance_log_length'], expires=_one_year())

        with translation.override(lang_code):
            messages.success(request,
                             encoding.force_text(_("Settings saved.")))

        return response