import wagtail.api.v2.serializers as wagtail_serializers
from rest_framework.fields import SerializerMethodField

from vbv_lernwelt.course.models import CoursePage
from vbv_lernwelt.course.serializers import CourseCategorySerializer, CourseSerializer
from vbv_lernwelt.learnpath.utils import get_wagtail_type


def get_it_serializer_class(model, field_names):
    base_field_names = [
        "id",
        "title",
        "slug",
        "type",
        "translation_key",
        "frontend_url",
    ]
    return wagtail_serializers.get_serializer_class(
        model,
        field_names=base_field_names + field_names,
        meta_fields=[],
        base=ItBaseSerializer,
    )


class ItTypeField(wagtail_serializers.TypeField):
    def to_representation(self, obj):
        name = get_wagtail_type(obj)
        return name


class ItBaseSerializer(wagtail_serializers.BaseSerializer):
    type = ItTypeField(read_only=True)
    children = SerializerMethodField()
    course = SerializerMethodField()
    course_category = CourseCategorySerializer(read_only=True)
    frontend_url = SerializerMethodField()
    circles = SerializerMethodField()

    meta_fields = []

    def __init__(self, *args, **kwargs):
        self.descendants = kwargs.pop("descendants", None)
        super().__init__(*args, **kwargs)

    def get_children(self, obj):
        if not self.descendants:
            self.descendants = [p for p in obj.get_descendants().specific()]
        children = _get_children(self.descendants, obj)
        return [
            c.specific.get_serializer_class()(
                c.specific, descendants=self.descendants
            ).data
            for c in children
        ]

    def get_course(self, obj):
        if hasattr(obj, "course"):
            return CourseSerializer(obj.course).data
        else:
            course_parent_page = obj.get_ancestors().exact_type(CoursePage).last()
            if course_parent_page:
                return CourseSerializer(course_parent_page.specific.course).data
        return ""

    def get_circles(self, obj):
        course_parent_page = obj.get_ancestors().exact_type(CoursePage).last()

        if course_parent_page:
            from vbv_lernwelt.learnpath.models import Circle, LearningPath

            circles = (
                course_parent_page.get_children()
                .exact_type(LearningPath)
                .first()
                .get_children()
                .exact_type(Circle)
            )

            return [
                {"id": c.id, "title": c.title, "translation_key": c.translation_key}
                for c in circles
            ]

        return []

    def get_frontend_url(self, obj):
        if hasattr(obj, "get_frontend_url"):
            return obj.get_frontend_url()
        return ""


def _get_descendants(pages, obj):
    return [c for c in pages if c.path.startswith(obj.path) and c.depth >= obj.depth]


def _get_children(pages, obj):
    return [
        c for c in pages if c.path.startswith(obj.path) and obj.depth + 1 == c.depth
    ]