Having trouble adding a 24 hour voting system?

Question

There is a script that triggers the code below

I want to disallow executing the script more than once per 24 hours.

I wanted this script to store the last visit time in a table against the user id in a database, then do a time calculation and back them out until the 24 hour expiry time.

Can someone explain how to do this? It would be greatly appreciated if someone could help me with this?

<?php
//Input correct values into this section
$dbhost = '888888';
$dbuser = '888888';
$dbpass = '888888';
$dbname = '888888';
$dbtable = 'redeem';
$dbtable2 = 'playersthatvoted';
//------------------------------------
$input = 'diamond 12';
$player = $_POST['Player'];
$time = time();
if(!isset($_COOKIE['24Hourvote'])){
   //---- This is the connection
   $conn = mysql_connect ($dbhost, $dbuser, $dbpass) or die ('Error: ' . mysql_error());
   mysql_select_db($dbname);
   $query1 = "INSERT INTO `".$dbname."`.`".$dbtable."` (`player`, `item`) VALUES ('".$player."', '".$input."')";
   $query2 = "INSERT INTO `".$dbname."`.`".$dbtable2."` (`player`, `time`) VALUES ('".$player."', '".$time."')";
   mysql_query($query1);
   mysql_query($query2);
   $query= 'SELECT `player` FROM `playersthatvoted` ASC LIMIT 0, 10 ';
   $result = mysql_query($query);
   mysql_close($conn);
   echo 'Done! Type /redeem in-game to get your diamonds.';
   $ip=@$REMOTE_ADDR;
   setcookie ("24Hourvote",$ip,time()+86400,'/',true,…
} else {
   echo 'You have already voted today! Come back later...'; }
?>

EDIT: and could I make it so that it displays the time left until the user can vote again?