from rest_framework import serializers

from app.expenses.models import Category, Expense, Subcategory


class SubcategorySerializer(serializers.ModelSerializer):
	class Meta:
		model = Subcategory
		fields = ["id", "name", "order"]


class CategorySerializer(serializers.ModelSerializer):
	subcategories = SubcategorySerializer(many=True, read_only=True)

	class Meta:
		model = Category
		fields = ["id", "name", "order", "subcategories"]


class ExpenseReadSerializer(serializers.ModelSerializer):
	category = serializers.StringRelatedField()
	subcategory = serializers.StringRelatedField()

	class Meta:
		model = Expense
		fields = ["id", "concept", "amount", "category", "subcategory", "created_at"]


class ExpenseWriteSerializer(serializers.ModelSerializer):
	class Meta:
		model = Expense
		fields = ["concept", "amount", "category", "subcategory"]

	def validate(self, data):
		category = data.get("category")
		subcategory = data.get("subcategory")
		if subcategory and subcategory.category != category:
			raise serializers.ValidationError(
				{"subcategory": "Subcategory does not belong to the selected category."}
			)
		return data