from rest_framework import serializers
from .models import Region


class RegionSerializer(serializers.ModelSerializer):
    """Serializer for Region model."""

    level_display = serializers.CharField(source='get_level_display', read_only=True)
    status_display = serializers.CharField(source='get_status_display', read_only=True)
    parent_name = serializers.CharField(source='parent.name', read_only=True, allow_null=True)
    children_count = serializers.SerializerMethodField()

    class Meta:
        model = Region
        fields = ('id', 'name', 'level', 'level_display', 'parent', 'parent_name',
                  'status', 'status_display', 'children_count', 'created_at', 'updated_at')
        read_only_fields = ('id', 'created_at', 'updated_at')

    def get_children_count(self, obj):
        return obj.children.count()


class RegionDetailSerializer(serializers.ModelSerializer):
    """Detailed serializer for Region model."""

    level_display = serializers.CharField(source='get_level_display', read_only=True)
    status_display = serializers.CharField(source='get_status_display', read_only=True)
    parent = RegionSerializer(read_only=True)
    children = RegionSerializer(many=True, read_only=True)
    full_path = serializers.SerializerMethodField()

    class Meta:
        model = Region
        fields = ('id', 'name', 'level', 'level_display', 'parent', 'children',
                  'status', 'status_display', 'full_path', 'created_at', 'updated_at')
        read_only_fields = ('id', 'created_at', 'updated_at')

    def get_full_path(self, obj):
        return obj.get_full_path()


class RegionTreeSerializer(serializers.ModelSerializer):
    """Serializer for Region tree structure."""

    children = serializers.SerializerMethodField()

    class Meta:
        model = Region
        fields = ('id', 'name', 'level', 'status', 'children')

    def get_children(self, obj):
        children = obj.get_children()
        return RegionTreeSerializer(children, many=True).data