from rest_framework import serializers
from .models import Event
from users.serializers import UserSerializer


class EventSerializer(serializers.ModelSerializer):
    user = UserSerializer(read_only=True)
    linked_user = UserSerializer(read_only=True)

    class Meta:
        model = Event
        fields = [
            'id',
            'user',
            'linked_user',
            'start_date',
            'end_date',
            'start_time',
            'end_time',
            'color',
            'name',
            'description',
            'visibility',
            'created_at',
            'updated_at',
        ]
        read_only_fields = [
            'id',
            'user',
            'created_at',
            'updated_at',
        ]


class EventCreateSerializer(serializers.ModelSerializer):
    color = serializers.RegexField(r'^#[0-9a-fA-F]{6}$', required=False, allow_null=True, allow_blank=True)

    class Meta:
        model = Event
        fields = [
            'linked_user',
            'start_date',
            'end_date',
            'start_time',
            'end_time',
            'color',
            'name',
            'description',
            'visibility',
        ]

    def validate(self, attrs):
        values = {
            field: attrs.get(field, getattr(self.instance, field, None))
            for field in ('start_date', 'end_date', 'start_time', 'end_time')
        }
        if values['end_date'] < values['start_date']:
            raise serializers.ValidationError({'end_date': 'La fin doit suivre le début.'})
        if (values['start_date'] == values['end_date']
                and values['start_time'] is not None and values['end_time'] is not None
                and values['end_time'] <= values['start_time']):
            raise serializers.ValidationError({'end_time': 'La fin doit suivre le début.'})
        return attrs

    def create(self, validated_data):
        request = self.context.get('request')

        if request is None or not request.user.is_authenticated:
            raise serializers.ValidationError({
                'user': 'Un utilisateur authentifié est requis.'
            })

        validated_data['user'] = request.user

        return Event.objects.create(**validated_data)


class EventUpdateSerializer(EventCreateSerializer):
    class Meta:
        model = Event
        fields = [
            'linked_user',
            'start_date',
            'end_date',
            'start_time',
            'end_time',
            'color',
            'name',
            'description',
            'visibility',
        ]