# -*- coding: utf-8 -*-

from __future__ import unicode_literals

import datetime
import django

try:
    import pytz
except ImportError:
    pytz = None

try:
    import csp
except ImportError:
    csp = None

from collections import OrderedDict

from django import forms
from django.conf import settings
from django.contrib import admin
from django.utils.html import format_html
from django.utils import timezone
from django.template.defaultfilters import slugify
from django.templatetags.static import StaticNode
from django.utils.encoding import force_str
from django.contrib.admin.widgets import AdminDateWidget, AdminSplitDateTime as BaseAdminSplitDateTime

if django.VERSION >= (2, 0, 0):
    from django.utils.translation import gettext_lazy as _
else:
    from django.utils.translation import ugettext_lazy as _


class AdminSplitDateTime(BaseAdminSplitDateTime):
    def format_output(self, rendered_widgets):
        return format_html('<p class="datetime">{}</p><p class="datetime rangetime">{}</p>',
                           rendered_widgets[0],
                           rendered_widgets[1])


class DateRangeFilter(admin.filters.FieldListFilter):
    def __init__(self, field, request, params, model, model_admin, field_path):
        self.lookup_kwarg_gte = '{0}__range__gte'.format(field_path)
        self.lookup_kwarg_lte = '{0}__range__lte'.format(field_path)

        super(DateRangeFilter, self).__init__(field, request, params, model, model_admin, field_path)
        self.request = request
        self.form = self.get_form(request)

    def get_timezone(self, request):
        return timezone.get_default_timezone()

    @staticmethod
    def make_dt_aware(value, timezone):
        if settings.USE_TZ and pytz is not None:
            default_tz = timezone
            if value.tzinfo is not None:
                value = default_tz.normalize(value)
            else:
                value = default_tz.localize(value)
        return value

    def choices(self, cl):
        yield {
            # slugify converts any non-unicode characters to empty characters
            # but system_name is required, if title converts to empty string use id
            # https://github.com/silentsokolov/django-admin-rangefilter/issues/18
            'system_name': force_str(slugify(self.title) if slugify(self.title) else id(self.title)),
            'query_string': cl.get_query_string(
                {}, remove=self._get_expected_fields()
            )
        }

    def expected_parameters(self):
        return self._get_expected_fields()

    def queryset(self, request, queryset):
        if self.form.is_valid():
            validated_data = dict(self.form.cleaned_data.items())
            if validated_data:
                return queryset.filter(
                    **self._make_query_filter(request, validated_data)
                )
        return queryset

    def _get_expected_fields(self):
        return [self.lookup_kwarg_gte, self.lookup_kwarg_lte]

    def _make_query_filter(self, request, validated_data):
        query_params = {}
        date_value_gte = validated_data.get(self.lookup_kwarg_gte, None)
        date_value_lte = validated_data.get(self.lookup_kwarg_lte, None)

        if date_value_gte:
            query_params['{0}__gte'.format(self.field_path)] = self.make_dt_aware(
                datetime.datetime.combine(date_value_gte, datetime.time.min),
                self.get_timezone(request),
            )
        if date_value_lte:
            query_params['{0}__lte'.format(self.field_path)] = self.make_dt_aware(
                datetime.datetime.combine(date_value_lte, datetime.time.max),
                self.get_timezone(request),
            )

        return query_params

    def get_template(self):
        if django.VERSION[:2] <= (1, 8):
            return 'rangefilter/date_filter_1_8.html'
        else:
            if csp:
                return 'rangefilter/date_filter_csp.html'
            return 'rangefilter/date_filter.html'

    template = property(get_template)

    def get_form(self, request):
        form_class = self._get_form_class()
        return form_class(self.used_parameters)

    def _get_form_class(self):
        fields = self._get_form_fields()

        form_class = type(
            str('DateRangeForm'),
            (forms.BaseForm,),
            {'base_fields': fields}
        )
        form_class.media = self._get_media()
        # lines below ensure that the js static files are loaded just once
        # even if there is more than one DateRangeFilter in use
        request_key = 'DJANGO_RANGEFILTER_ADMIN_JS_SET'
        if (getattr(self.request, request_key, False)):
            form_class.js = []
        else:
            setattr(self.request, request_key, True)
            form_class.js = self.get_js()
        return form_class

    def _get_form_fields(self):
        return OrderedDict(
            (
                (self.lookup_kwarg_gte, forms.DateField(
                    label='',
                    widget=AdminDateWidget(attrs={'placeholder': _('From date')}),
                    localize=True,
                    required=False
                )),
                (self.lookup_kwarg_lte, forms.DateField(
                    label='',
                    widget=AdminDateWidget(attrs={'placeholder': _('To date')}),
                    localize=True,
                    required=False
                )),
            )
        )

    @staticmethod
    def get_js():
        return [
            StaticNode.handle_simple('admin/js/calendar.js'),
            StaticNode.handle_simple('admin/js/admin/DateTimeShortcuts.js'),
        ]

    @staticmethod
    def _get_media():
        js = [
            'calendar.js',
            'admin/DateTimeShortcuts.js',
        ]
        css = [
            'widgets.css',
        ]
        return forms.Media(
            js=['admin/js/%s' % url for url in js],
            css={'all': ['admin/css/%s' % path for path in css]}
        )


class DateTimeRangeFilter(DateRangeFilter):
    def _get_expected_fields(self):
        expected_fields = []
        for field in [self.lookup_kwarg_gte, self.lookup_kwarg_lte]:
            for i in range(2):
                expected_fields.append('{}_{}'.format(field, i))

        return expected_fields

    def _get_form_fields(self):
        return OrderedDict(
            (
                (self.lookup_kwarg_gte, forms.SplitDateTimeField(
                    label='',
                    widget=AdminSplitDateTime(attrs={'placeholder': _('From date')}),
                    localize=True,
                    required=False
                )),
                (self.lookup_kwarg_lte, forms.SplitDateTimeField(
                    label='',
                    widget=AdminSplitDateTime(attrs={'placeholder': _('To date')}),
                    localize=True,
                    required=False
                )),
            )
        )

    def _make_query_filter(self, request, validated_data):
        query_params = {}
        date_value_gte = validated_data.get(self.lookup_kwarg_gte, None)
        date_value_lte = validated_data.get(self.lookup_kwarg_lte, None)

        if date_value_gte:
            query_params['{0}__gte'.format(self.field_path)] = self.make_dt_aware(
                date_value_gte, self.get_timezone(request)
            )
        if date_value_lte:
            query_params['{0}__lte'.format(self.field_path)] = self.make_dt_aware(
                date_value_lte, self.get_timezone(request)
            )

        return query_params