from rest_framework import serializers
from rest_framework import exceptions
from apps.inm.models import IProduct
from apps.inm.serializers import IProductListSerializer
from apps.mtm.serializers import MaterialSimpleSerializer
from apps.sam.models import Sale, SaleProduct
from apps.sam.serializers import CustomerSimpleSerializer, OrderSimpleSerializer
from django.db import transaction
from rest_framework.exceptions import ValidationError
class SaleCreateSerializer(serializers.ModelSerializer):
    iproducts = serializers.PrimaryKeyRelatedField(queryset=
    IProduct.objects.all(), many=True)
    class Meta:
        model = Sale
        fields = ['customer', 'order', 'product', 'iproducts', 
        'edelivery_date', 'trans_mode', 'receiver', 'receiver_phone'
        , 'receiver_address', 'remark']
    
    def validate(self, attrs):
        order = attrs.get('order', None)
        if order:
            if order.customer:
                attrs['customer'] = order.customer
            attrs['product'] = order.product
        ips = IProduct.objects.filter(id__in=[i.id for i in attrs['iproducts']])
        if ips.exclude(state=IProduct.SALE_OK).exists():
            raise exceptions.APIException('选取了非可用的产品')
        if ips.count() != ips.filter(material=attrs['product']).count():
            raise exceptions.APIException('产品选取错误')
        return super().validate(attrs)


class SaleListSerializer(serializers.ModelSerializer):
    customer_ = CustomerSimpleSerializer(source='customer', read_only=True)
    order_ = OrderSimpleSerializer(source='order', read_only=True)
    product_ = MaterialSimpleSerializer(source='product', read_only=True)
    class Meta:
        model = Sale
        fields = '__all__'

class SaleProductListSerializer(serializers.ModelSerializer):
    iproduct_ = IProductListSerializer(source='iproduct', read_only=True)
    class Meta:
        model = SaleProduct
        fields = '__all__'

class SaleProductCreateSerializer(serializers.ModelSerializer):
    class Meta:
        model = SaleProduct
        fields = ['sale', 'iproduct']

    def create(self, validated_data):
        with transaction.atomic():
            validated_data['number'] = validated_data['iproduct'].number
            instance = SaleProduct.objects.create(**validated_data)
            sale = instance.sale
            sale.count = SaleProduct.objects.filter(sale=instance.sale).count()
            sale.save()
            order = sale.order
            if order:
                if sale.count+order.delivered_count>order.count:
                    raise exceptions.APIException('超过订单所需数量')
        return instance