from rest_framework import serializers

from courses.models import Course, Lesson, Topic


class TopicSerializer(serializers.ModelSerializer):
    children = serializers.SerializerMethodField()

    class Meta:
        model = Topic
        exclude = ['id']

    @staticmethod
    def get_children(self):
        return [MiniLessonSerializer(i).data for i in self.lesson_set.all()]


class MiniLessonSerializer(serializers.ModelSerializer):

    class Meta:
        model = Lesson
        fields = ('title', 'free', 'token')


class LessonSerializer(MiniLessonSerializer):

    class Meta:
        model = Lesson
        exclude = ('id', 'topic', 'key')


class CourseInitSerializer(serializers.ModelSerializer):

    class Meta:
        model = Course
        fields = ['title', 'slug']


class CourseTreeSerializer(serializers.ModelSerializer):
    tree = serializers.SerializerMethodField()

    class Meta:
        model = Course
        fields = ('tree', 'slug')

    @staticmethod
    def get_tree(self):
        return [TopicSerializer(i).data for i in self.topic_set.all()]


class CourseDetailSerializer(serializers.ModelSerializer):
    level = serializers.SerializerMethodField()
    direction = serializers.SerializerMethodField()
    statistic = serializers.SerializerMethodField()

    class Meta:
        model = Course
        exclude = ('id', )

    @staticmethod
    def get_level(self):
        return self.get_level_display()

    @staticmethod
    def get_direction(self):
        return self.get_direction_display()

    @staticmethod
    def get_statistic(self):
        return self.get_statistic()