# MODELS.PY
from django.db import models


class DataPoint(models.Model):
  # flat model
  label = models.CharField(max_length=50)
  x_coordinate = models.SmallIntegerField()
  y_coordinate = models.SmallIntegerField()


# ====================================================
class Coordinate(models.Model):
  x = models.SmallIntegerField()
  y = models.SmallIntegerField()


class DataPoint2(models.Model):
  # nested model
  label = models.CharField(max_length=50)
  coordinates = models.ForeignKey("Coordinate", on_delete=models.CASCADE)





# SERIALIZERS.PY

from rest_framework import serializers

from .models import *


###### NESTED at the SERIALIZER level

class NestedCoordinateSerializer(serializers.Serializer):
    x = serializers.IntegerField(source='x_coordinate')
    y = serializers.IntegerField(source='y_coordinate')


class DataPointSerializer(serializers.ModelSerializer):
    coordinates = NestedCoordinateSerializer(source='*')

    class Meta:
        model = DataPoint
        fields = ['label', 'coordinates']


########################################################
###### NESTED at the MODEL level

class CoordSerializer(serializers.ModelSerializer):
  class Meta:
    model = Coordinate
    fields = ["x", "y"]


class DataPoint2Serializer(serializers.ModelSerializer):
  coordinates = CoordSerializer()

  class Meta:
    model = DataPoint2
    fields = ["label", "coordinates"]