from django.core.exceptions import ValidationError
from django.db import models
from django.db.models.sql import constants
from django.utils.translation import ugettext_lazy as _

class ObjectManager(models.Manager):
    
    def filter_from_request(self, request):
        """
        Generic model filter from request GET data
        """
        qs = self.get_query_set()
        filters = dict()

        fields = [f.name for f in self.model._meta.fields]
        for p in request.GET:
            if constants.LOOKUP_SEP in p:
                field_name, field_qterm = p.split(constants.LOOKUP_SEP)
            else:
                field_name = p

            if field_qterm and field_qterm not in constants.QUERY_TERMS:
                continue
            if field_name in fields:
                if request.GET.get(p) != '':
                    filters[p] = request.GET.get(p)
        try:   
            qs = qs.filter(**filters)
        except ValueError, e:
            raise ValidationError(_(u'Error filter data'))
        return qs