from django.db import transaction

from rest_framework import serializers

from core.apps.tasks.models.comment import Comment, CommentFile


class CommentCreatedBySerializer(serializers.Serializer):
    id = serializers.IntegerField()
    first_name = serializers.CharField()
    last_name = serializers.CharField()
    avatar = serializers.SerializerMethodField()

    def get_avatar(self, obj):
        request = self.context.get('request')
        if obj.avatar and request:
            return request.build_absolute_uri(obj.avatar.url)
        if obj.avatar:
            return obj.avatar.url
        return None


class CommentFileSerializer(serializers.ModelSerializer):
    file = serializers.SerializerMethodField()

    class Meta:
        model = CommentFile
        fields = ['id', 'file']

    def get_file(self, obj):
        request = self.context.get('request')
        if not obj.file:
            return None
        if request:
            return request.build_absolute_uri(obj.file.url)
        return obj.file.url


class CommentSerializer(serializers.ModelSerializer):
    created_by = CommentCreatedBySerializer(read_only=True)
    files = CommentFileSerializer(many=True, read_only=True)

    class Meta:
        model = Comment
        fields = [
            'id', 'message', 'type', 'created_by', 'created_at', 'files'
        ]


class CommentCreateSerializer(serializers.ModelSerializer):
    files = serializers.ListField(
        child=serializers.FileField(),
        required=False,
        write_only=True,
    )

    class Meta:
        model = Comment
        fields = [
            'id', 'message', 'type', 'task', 'files', 'created_at'
        ]
        read_only_fields = ['id', 'created_at']

    def create(self, validated_data):
        files = validated_data.pop('files', [])
        with transaction.atomic():
            comment = Comment.objects.create(
                created_by=self.context['request'].user,
                **validated_data
            )
            CommentFile.objects.bulk_create([
                CommentFile(comment=comment, file=f) for f in files
            ])
            return comment

    def update(self, instance, validated_data):
        files = validated_data.pop('files', None)
        with transaction.atomic():
            for attr, value in validated_data.items():
                setattr(instance, attr, value)
            instance.save()
            if files is not None:
                CommentFile.objects.bulk_create([
                    CommentFile(comment=instance, file=f) for f in files
                ])
            return instance

    def to_representation(self, instance):
        return CommentSerializer(instance, context=self.context).data