from rest_framework import serializers
from apps.utils.serializers import CustomModelSerializer
from apps.sam.models import Customer, Contract, Order, OrderItem
from apps.utils.constants import EXCLUDE_FIELDS, EXCLUDE_FIELDS_BASE
from rest_framework.exceptions import ValidationError
from apps.mtm.serializers import MaterialSerializer

class CustomerSerializer(CustomModelSerializer):
    class Meta:
        model = Customer
        fields = '__all__'
        read_only_fields = EXCLUDE_FIELDS + ['belong_dept']


class ContractSerializer(CustomModelSerializer):
    class Meta:
        model = Contract
        fields = '__all__'
        read_only_fields = EXCLUDE_FIELDS + ['belong_dept', 'invoice']


class OrderSerializer(CustomModelSerializer):
    class Meta:
        model = Order
        fields = '__all__'
        read_only_fields = EXCLUDE_FIELDS + ['belong_dept', 'state']

    def validate(self, attrs):
        contract = attrs.get('contract', None)
        if contract:
            attrs['customer'] = contract.customer
        if attrs.get('customer', None) is None:
            raise ValidationError('未选择客户')
        return attrs
    
    def update(self, instance, validated_data):
        if instance.state != Order.ORDER_CREATE:
            raise ValidationError('订单信息不可编辑')
        return super().update(instance, validated_data)

class OrderItemSerializer(CustomModelSerializer):
    product_ = MaterialSerializer(source='product', read_only=True)
    order_ = OrderSerializer(source='order', read_only=True)
    class Meta:
        model = OrderItem
        fields = '__all__'
        read_only_fields = EXCLUDE_FIELDS_BASE + ['count_deliverd']

    def validate(self, attrs):
        order = attrs['order']
        if order.state != Order.ORDER_CREATE:
            raise ValidationError('该订单状态下不可创建')
        return attrs
    
    def create(self, validated_data):
        order = validated_data['order']
        product = validated_data['product']
        if OrderItem.objects.filter(order=order, product=product).exists():
            raise ValidationError('该产品已选择!')
        return super().create(validated_data)
    
    def update(self, instance, validated_data):
        validated_data.pop('product', None)
        validated_data.pop('order', None)
        return super().update(instance, validated_data)