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

from django.core.exceptions import ValidationError

from p4l.models import Record

from rest_framework import serializers

import logging

from rest_framework.serializers import NestedValidationError

import copy

from django.db.models.fields.related import ForeignKey

logger = logging.getLogger(__name__)

class ThesaurusSerializer(serializers.SlugRelatedField):

    def __init__(self, *args, **kwargs):

        kwargs.update({                       

            'read_only': False,

        })

        serializers.SlugRelatedField.__init__(self, *args, **kwargs)

    def from_native(self, data):

        if self.queryset is None:

            raise Exception('Writable related fields must include a `queryset` argument')

        try:

            res, _ = self.queryset.get_or_create(**{self.slug_field: data})

            return res

        except (TypeError, ValueError):

            msg = self.error_messages['invalid']

            raise ValidationError(msg)

class P4lModelSerializer(serializers.ModelSerializer):

    def get_nested_field(self, model_field, related_model, to_many):

        field_exclude = ()

        if model_field is None:

            fk = [f.name for f in related_model._meta.fields if (isinstance(f, ForeignKey) and f.rel.to == Record)][0]

            field_exclude = ('id', fk)

        class NestedModelSerializer(P4lModelSerializer):

            class Meta:

                model = related_model

                depth = self.opts.depth - 1

                exclude = field_exclude

        return NestedModelSerializer(many=to_many)

    def field_from_native(self, data, files, field_name, into):

        """

        Override default so that the serializer can be used as a writable

        nested field across relationships.

        """        

        if self.read_only:

            return

        try:

            value = data[field_name]

        except KeyError:

            if self.default is not None and not self.partial:

                # Note: partial updates shouldn't set defaults

                value = copy.deepcopy(self.default)

            else:

                if self.required:

                    raise ValidationError(self.error_messages['required'])

                return

        # Set the serializer object if it exists

        obj = getattr(self.parent.object, field_name) if self.parent.object else None

        if self.source == '*':

            if value:

                into.update(value)

        else:

            if value in (None, ''):

                into[(self.source or field_name)] = None

            elif self.many and hasattr(value, '__iter__'):

                if obj is not None:

                    obj.all().delete()

                nested_items = []

                for val in value:

                    kwargs = {

                        'instance': None,

                        'data': val,

                        'context': self.context,

                        'partial': self.partial,

                        'many': False

                    }

                    serializer = self.__class__(**kwargs)

                    nested_items.append(serializer.from_native(val, files))

                into[self.source or field_name] = nested_items

            else:

                kwargs = {

                    'instance': obj,

                    'data': value,

                    'context': self.context,

                    'partial': self.partial,

                    'many': self.many

                }

                serializer = self.__class__(**kwargs)

                if serializer.is_valid():

                    into[self.source or field_name] = serializer.object

                else:

                    # Propagate errors up to our parent

                    raise NestedValidationError(serializer.errors)

#class RecordSerializer(serializers.ModelSerializer):

class RecordSerializer(P4lModelSerializer):

    '''

    Serializer for record

    '''

    language = ThesaurusSerializer(many=False, required=False, slug_field='uri') 

    otherLanguages = ThesaurusSerializer(many=True, required=False, slug_field='uri')

    subjects = ThesaurusSerializer(many=True, required=False, slug_field='uri')

    themes = ThesaurusSerializer(many=True, required=False, slug_field='uri')

    countries = ThesaurusSerializer(many=True, required=False, slug_field='uri')

    projectNames = ThesaurusSerializer(many=True, required=False, slug_field='uri')

    subjectCorporateBodies = ThesaurusSerializer(many=True, required=False, slug_field='uri') 

    corporateAuthors = ThesaurusSerializer(many=True, required=False, slug_field='uri')

    audiences = ThesaurusSerializer(many=True, required=False, slug_field='uri')

    class Meta:

        model = Record

        depth = 1

        fields = ("identifier", "uri", "subjects", "notes", "otherLanguages",

                  "language", "editionStatement", "recordType", "isDocumentPart",

                  "hidden", "restricted", "themes", "countries", "projectNames", 

                  "subjectCorporateBodies", "corporateAuthors", "corporateAuthorLabel", 

                  "imprints", "titles", "addedTitles", "issns", "isbns", "documentCodes",

                  "abstracts", "titlesMainDocument", "collations", "volumeIssues",

                  "periodicals", "meetings", "subjectMeetings", "series",

                  "authors", "subjectPersons", "urls", "audiences")