from rest_framework import serializers
from drf_spectacular.utils import extend_schema_field
from .models import Category, Product, ProductImage, DiscountCode, Order, OrderItem, Carrier

# NOTE: Carrier intentionally skipped per request (TODO below)

class CategorySerializer(serializers.ModelSerializer):
	class Meta:
		model = Category
		fields = ["id", "name", "url", "parent", "description", "image"]


class ProductImageSerializer(serializers.ModelSerializer):
	class Meta:
		model = ProductImage
		fields = ["id", "image", "alt_text", "is_main"]


class ProductSerializer(serializers.ModelSerializer):
	images = ProductImageSerializer(many=True, read_only=True)
	available = serializers.BooleanField(read_only=True)

	class Meta:
		model = Product
		fields = [
			"id","name","description","code","category","price","currency","url","stock","is_active","limited_to","default_carrier","available","images","created_at","updated_at"
		]
		read_only_fields = ["created_at","updated_at","available"]


class DiscountCodeSerializer(serializers.ModelSerializer):
	is_valid = serializers.SerializerMethodField()

	class Meta:
		model = DiscountCode
		fields = ["id","code","description","percent","amount","valid_from","valid_to","active","usage_limit","used_count","specific_products","specific_categories","is_valid"]
		read_only_fields = ["used_count","is_valid"]

	def get_is_valid(self, obj):
		return obj.is_valid()


class OrderItemSerializer(serializers.ModelSerializer):
	product = serializers.PrimaryKeyRelatedField(queryset=Product.objects.all())
	line_total = serializers.SerializerMethodField()

	class Meta:
		model = OrderItem
		fields = ["id","product","quantity","line_total"]
		read_only_fields = ["line_total"]

	def get_line_total(self, obj):
		# Uses existing model logic for discount via order context (kept minimal)
		# Since discount resolution logic is custom & currently incomplete, just returns base price * qty
		return obj.product.price * obj.quantity


class OrderSerializer(serializers.ModelSerializer):
	items = OrderItemSerializer(many=True)
	total_price = serializers.DecimalField(max_digits=10, decimal_places=2, read_only=True)

	class Meta:
		model = Order
		fields = [
			"id","user","status","total_price","currency","first_name","last_name","email","phone","address","city","postal_code","country","note","discount","items","created_at","updated_at"
		]
		read_only_fields = ["total_price","created_at","updated_at"]

	def create(self, validated_data):
		items_data = validated_data.pop("items", [])
		order = Order.objects.create(**validated_data)
		for item in items_data:
			OrderItem.objects.create(order=order, **item)
		order.total_price = order.calculate_total_price() if hasattr(order, "calculate_total_price") else order.total_price
		order.save()
		return order

	def update(self, instance, validated_data):
		items_data = validated_data.pop("items", None)
		for attr, value in validated_data.items():
			setattr(instance, attr, value)
		if items_data is not None:
			instance.items.all().delete()
			for item in items_data:
				OrderItem.objects.create(order=instance, **item)
		instance.total_price = instance.calculate_total_price() if hasattr(instance, "calculate_total_price") else instance.total_price
		instance.save()
		return instance

# TODO: CarrierSerializer (Carrier API not requested yet)