"""Save or update a supply contract product discount."""
contract_id = params_kw.get('contract_id')
productid = params_kw.get('productid')
prodtypeid = params_kw.get('prodtypeid') or ''
new_discount = params_kw.get('discount') or '1.0'
old_discount = params_kw.get('old_discount') or '1.0'
item_id = params_kw.get('item_id')

userorgid = (await get_userorgid()) or '0'
dbname = get_module_dbname('supplychain')

async with DBPools().sqlorContext(dbname) as sor:
    if item_id:
        if new_discount == old_discount:
            pass
        elif float(new_discount) <= 0:
            await sor.D('supply_contract_items', {'id': item_id})
        else:
            await sor.U('supply_contract_items', {
                'id': item_id, 'discount': new_discount, 'updated_at': timestampstr()
            })
    elif float(new_discount) > 0 and new_discount != old_discount:
        now = timestampstr()
        await sor.C('supply_contract_items', {
            'id': getID(), 'contract_id': contract_id, 'resellerid': userorgid,
            'productid': productid, 'prodtypeid': prodtypeid,
            'discount': new_discount, 'created_at': now,
        })

status_text = '已设置' if float(new_discount) > 0 else '已删除'
return {
    'widgettype': 'Message',
    'options': {'title': '保存成功', 'message': f'折扣 {status_text}: {new_discount}', 'type': 'success', 'timeout': 2}
}