# -*- coding: utf-8 -*-
import operator

from django import forms
from django.conf import settings
from django.db.models import Q

from price.models import Good

class CustomSelect(forms.widgets.Select):
    """
    Custom Select widget that allow to define label for None choice.
    """

    def __init__(self, default_label, **kwargs):
        self.default_label = default_label
        super(self.__class__, self).__init__(**kwargs)
        
    def render(self, *args, **kwargs):
        self.choices = list(self.choices)
        self.choices[0] = (u'', self.default_label)
        return super(self.__class__, self).render(*args, **kwargs)


class SearchGoodsForm(forms.Form):
    query = forms.CharField(required=False, label='')
    firm = Good._meta.get_field('firm').formfield(required=False, label='',
                                                  widget=CustomSelect(default_label='Все фирмы'))

    def __init__(self, GET, *args, **kwargs):
        query = kwargs.pop('query', None)
        if not 'query' in GET:
            GET = GET.copy()
            GET['query'] = query
        super(SearchGoodsForm, self).__init__(GET, *args, **kwargs)


    def split_query(self, query):
        """
        Extract valid parts from search query.
        """

        return set([x for x in query.split()\
                   if len(x) >= settings.QUERY_PART_MIN_LENGTH])

    def clean_query(self):
        if 'query' in self.cleaned_data:
            query = self.cleaned_data['query']
            # Empty query is OK!
            if not query:
                return query
            if len(query) > settings.QUERY_SIZE_LIMIT:
                raise forms.ValidationError(u'Слишком длинный запрос')
            query = self.cleaned_data['query']
            query = self.split_query(query)
            if not query:
                raise forms.ValidationError(u'Слишком короткий запрос')
            elif len(query) > settings.QUERY_PART_NUMBER_LIMIT:
                raise forms.ValidationError(u'Слишком много подзапросов')
            return query


    def query_display(self):
        """
        Return human readable representation of parsed query.
        """

        if hasattr(self, 'cleaned_data') and 'query' in self.cleaned_data:
            return ' '.join(self.cleaned_data['query'])
        else:
            return ''


    def filter(self, paged_qs):
        """
        Filter QuerySet with parameters from form's fields.
        """

        if self.cleaned_data['query']:
            filters = [Q(name__icontains=x) for x in self.cleaned_data['query']]
            paged_qs = paged_qs.filter(reduce(operator.and_, filters))
        if self.cleaned_data['firm']:
            paged_qs = paged_qs.filter(firm=self.cleaned_data['firm'])
        return paged_qs