Single Item vendor box with age check

this has come up a cupple times in the last few weeks, and someone else contacted me inworld about it since i posted an age checker on another post...

so needing a break from my current heavy project i wrote this up, has fast pay, checks price, gives change, and if someone over the age limit it refuses service and refunds their money

//<--------------------------------------------------------------------------------------->//
//<------------------------------ Age checking basic 1 item vendor ----------------------->//
//<--------------------------------------------------------------------------------------->//

//Setup
integer age   = 91;   // Chceks with a GMT timestamp
integer price = 10;   // Sets the sale price
string  item_name = "object"; // must be inside of "" and exactly the same...
//as the item name inside the vending prim
//End Setup

key     user_key;
key    owner_key;
integer     paid;

string check_age(string data)       
{
    float av_total_days = do_math(data); 
     
    data = llGetDate();     
    
    float td_total_days = do_math(data); 
                   
    data = (string)llRound((td_total_days  - av_total_days) * 365);
    
    return data; 
} 

float do_math(string data)
{
    float data =(
                    ((float)llGetSubString(data,5,6)/12)+
                    ((float)llGetSubString(data,8,9)/365)+
                    ((float)llGetSubString(data,0,3))
                );                 
    return data;  
}


default //Starts things off by asking you for debit permissions
// later on this lets the object take money from you incase of mispayment or change
{
    // I use number values 2 is the same as PERMISSION_DEBIT, habbit ...
    state_entry()
    {
        llSetPayPrice(PAY_HIDE,[price,PAY_HIDE,PAY_HIDE,PAY_HIDE]);
        llRequestPermissions(llGetOwner(),2);
    }
    
    run_time_permissions(integer perm)
    {
        if (perm & 2) state online;
        else 
        {
            llOwnerSay("please grant the permission to continue");
            llRequestPermissions(llGetOwner(),2);
        }
    }
}

state online 
{
    on_rez(integer r) {llResetScript();}
    
    money(key id, integer amount)
    {
        user_key = id;
        paid = amount;
        state no_money;
    }        
}

state no_money //Blocks out money while info is processed 
{
    on_rez(integer r) {llResetScript();}
    state_entry(){llRequestAgentData(user_key,DATA_BORN);}
    
    dataserver(key kQueryid, string data)
    {
        data = check_age(data);
        if ((integer)data <= age)
        {
            if (paid == price) llGiveInventory(user_key,item_name);
            else if (paid > price) 
            {
                llGiveMoney(user_key,paid - price);
                llGiveInventory(user_key,item_name);
            }
            else 
            {
                llGiveMoney(user_key,paid);
                llInstantMessage(user_key,
                "you gave me "+(string)paid+"L$, but the item cost "+(string)price+"L$");
            }
        }
        else 
        {
            llInstantMessage(user_key, "im sorry but you are too old");
            llGiveMoney(user_key,paid);
        }
        state online;
    }
}