from django.shortcuts import get_object_or_404
from rest_framework import serializers
from event.models import Event, ActivityTag, Place, ActivityTemplate


# Classes utilitaires
class EventSpecificSerializer(serializers.HyperlinkedModelSerializer):
    """
    Provide `update` and `create` methods  for nested view with an Event
    For example for Models which exetends EventSpecificMixin
    the event id has to be provided in the `save` method
    Works fine with view.EventSpecificViewSet
    """
    def update(self, instance, validated_data):
        """
        Note : does NOT change the event value of the instance
        """
        validated_data.pop('event_pk')
        [setattr(instance, key, value)
         for key, value in validated_data.items()]
        instance.save()
        return instance

    def create(self, validated_data):
        ModelClass = self.Meta.model
        event_pk = validated_data.pop('event_pk', None)
        event = event_pk and get_object_or_404(Event, id=event_pk) or None
        instance = ModelClass.objects.create(event=event, **validated_data)
        return instance


# Serializers
class EventSerializer(serializers.HyperlinkedModelSerializer):
    created_by = serializers.ReadOnlyField(source='created_by.username')

    class Meta:
        model = Event
        fields = ('url', 'id', 'title', 'slug', 'created_by', 'creation_date',
                  'description', 'beginning_date', 'ending_date')


# TODO rajouter des permissions
class PlaceSerializer(EventSpecificSerializer):
    event = EventSerializer(allow_null=True, read_only=True)

    class Meta:
        model = Place
        fields = ('url', 'id', 'name', 'description', 'event')



# TODO rajouter des permissions
class ActivityTagSerializer(EventSpecificSerializer):
    event = EventSerializer(allow_null=True, read_only=True)

    class Meta:
        model = ActivityTag
        fields = ('url', 'id', 'name', 'is_public', 'color', 'event')


# TODO rajouter des permissions
class ActivityTemplateSerializer(serializers.HyperlinkedModelSerializer):
    event = serializers.ReadOnlyField(source='event.title')
    tags = ActivityTagSerializer(many=True)

    class Meta:
        model = ActivityTemplate
        fields = ('url', 'id', 'title', 'event', 'is_public', 'has_perm',
                  'min_perm', 'max_perm', 'description', 'remarks', 'tags',)

    def update(self, instance, validated_data):
        tags_data = validated_data.pop('tags')
        [setattr(instance, key, value)
         for key, value in validated_data.items()]
        instance.save()
        tags = [ActivityTag.objects.get_or_create(**tag_data)[0]
                for tag_data in tags_data]
        instance.tags = tags
        return instance

    def create(self, validated_data):
        tags_data = validated_data.pop('tags')
        activity_template = ActivityTemplate.objects.create(**validated_data)
        tags = [ActivityTag.objects.get_or_create(**tag_data)[0]
                for tag_data in tags_data]
        activity_template.tags = tags
        return activity_template