"""
Shipment API 序列化器
"""
from rest_framework import serializers


class SalesItemSerializer(serializers.Serializer):
    """
    销售品序列化器（只读）
    
    用于返回销售品数据
    """
    id = serializers.IntegerField(read_only=True)
    name = serializers.CharField(read_only=True)
    quantity = serializers.DecimalField(max_digits=12, decimal_places=2, read_only=True)
    unit = serializers.IntegerField(read_only=True)
    unit_display = serializers.SerializerMethodField()
    position = serializers.CharField(read_only=True)
    remark = serializers.CharField(read_only=True)
    printing_job_id = serializers.IntegerField(read_only=True)
    customer_id = serializers.IntegerField(read_only=True)
    shipment_id = serializers.IntegerField(source='shipment.id', read_only=True, allow_null=True)
    shipment_date = serializers.DateField(source='shipment.shipment_date', read_only=True, allow_null=True)
    created_at = serializers.DateTimeField(read_only=True)
    created_by_id = serializers.IntegerField(source='created_by.id', read_only=True, allow_null=True)
    created_by_name = serializers.SerializerMethodField()
    
    def get_unit_display(self, obj):
        return obj.get_unit_display()
    
    def get_created_by_name(self, obj):
        if obj.created_by:
            employee = getattr(obj.created_by, 'employee', None)
            if employee:
                return employee.name
            return obj.created_by.username
        return None