from rest_framework import serializers

from apps.announcements.models import Announcement
from apps.courses.models import Course


class AnnouncementSerializer(serializers.ModelSerializer):
    posted_by_name = serializers.CharField(source="posted_by.full_name", read_only=True, allow_null=True)

    class Meta:
        model = Announcement
        fields = ["id", "course", "body", "posted_by", "posted_by_name", "created_at", "updated_at"]
        read_only_fields = ["id", "posted_by", "posted_by_name", "created_at", "updated_at"]


class AnnouncementWriteSerializer(serializers.ModelSerializer):
    course = serializers.PrimaryKeyRelatedField(queryset=Course.objects.all())

    class Meta:
        model = Announcement
        fields = ["id", "course", "body"]
        read_only_fields = ["id"]