How to make contact page with contact time restriction

[L222]

so my contact page looks like this \[code\]<?php include 'header.php'; foreach($_POST as $key => $value) {$posts[$key] = filter($value); } if(isset($posts['name'])) { if($posts['name'] == ""){ $error = "Please enter your real name!"; }else if(!isEmail($posts['email'])){ $error = "Please enter a valid email address!"; }else if($_POST['message'] == ""){ $error = "Please enter your message!"; }else{ $subject ="Contact"; $message="{$_POST['message']}"; $header="From: {$posts['name']} <{$posts['email']}>"; $to = $site->site_email; $send_contact=mail($to,$subject,$message,$header); $success = "Message Sent!"; } } ?> <div class="contentbox"> <div class="head">Contact</div>\[/code\]And I want to block spammers in this way......You can only send 1 email per hour. From this contact.php page Please help me with this and send me back this same code but edited with a time blocking code or something.Thanks