from django.db import models
from django.contrib.admin import filters
from django.utils.translation import gettext_lazy as _
from django.utils.http import urlencode


__all__ = ('DateFieldFilter', 'DateTimeField')


class DateFieldFilter(filters.FieldListFilter):
    """ Display date input """
    template = 'admin/aircox/filters/date_filter.html'
    input_type = 'date'

    def __init__(self, field, request, params, model, model_admin, field_path):
        self.field_generic = '%s__' % field_path
        self.date_params = {k: v for k, v in params.items()
                                if k.startswith(self.field_generic)}

        # links as: (label, param, input_type|None, value)
        self.links = [(_('Exact'), self.field_generic + 'exact', self.input_type),
                      (_('Since'), self.field_generic + 'gte', self.input_type),
                      (_('Until'), self.field_generic + 'lte', self.input_type)]
        if field.null:
            self.links.insert(0, (_('None'), self.field_generic + 'isnull', None, '1'))
                      
        self.query_attrs = {k:v for k,v in request.GET.items()
                            if k not in self.date_params}
        self.query_string = urlencode(self.query_attrs)
        super().__init__(field, request, params, model, model_admin, field_path)

    def expected_parameters(self):
        return [link[1] for link in self.links]

    def choices(self, changelist):
        yield {'label': _('Any'),
               'type': None,
               'query_string': self.query_string}

        for link in self.links:
            value = len(link) > 3 and link[3] or self.date_params.get(link[1])
            yield {
                'label': link[0], 'name': link[1], 'value': value,
                'type': link[2],
                'query_attrs': self.query_attrs,
                'query_string': urlencode({link[1]: value}) + '&' + self.query_string
                                    if value else self.query_string,
            }


class DateTimeFieldFilter(DateFieldFilter):
    """ Display datetime input """
    input_type = 'datetime-local'


filters.FieldListFilter.register(
    lambda f: isinstance(f, models.DateField), DateFieldFilter, take_priority=True)

filters.FieldListFilter.register(
    lambda f: isinstance(f, models.DateTimeField), DateTimeFieldFilter, take_priority=True)