Php de yazılmış kodu asp ye dönüştürmek (kodun yorumlanması)

Php ile yazımış scriti asp ye dönüştürmek istiyorum.Fakat php kodunu tam olarak yorumlayamadım.Sizden isteğim php ile yazılmış aşağıdaki kodu satır satı asp ye dönüştürebileceğim şekilde yorumlama yapmanız.Teşekkür ederim.
<?php

define ('DBPATH','localhost');
define ('DBUSER','root');
define ('DBPASS','password');
define ('DBNAME','chat');

session_start();

global $dbh;
$dbh = mysql_connect(DBPATH,DBUSER,DBPASS);
mysql_selectdb(DBNAME,$dbh);

if ($_GET['action'] == "chatheartbeat") { chatHeartbeat(); }
if ($_GET['action'] == "sendchat") { sendChat(); }
if ($_GET['action'] == "closechat") { closeChat(); }
if ($_GET['action'] == "startchatsession") { startChatSession(); }

if (!isset($_SESSION['chatHistory'])) {
$_SESSION['chatHistory'] = array();
}

if (!isset($_SESSION['openChatBoxes'])) {
$_SESSION['openChatBoxes'] = array();
}

function chatHeartbeat() {

$sql = "select * from chat where (chat.to = '".mysql_real_escape_string($_SESSION['username'])."' AND recd = 0) order by id ASC";
$query = mysql_query($sql);
$items = '';

$chatBoxes = array();

while ($chat = mysql_fetch_array($query)) {

if (!isset($_SESSION['openChatBoxes'][$chat['from']]) && isset($_SESSION['chatHistory'][$chat['from']])) {
$items = $_SESSION['chatHistory'][$chat['from']];
}

$chat['message'] = sanitize($chat['message']);

$items .= <<<EOD
{
"s": "0",
"f": "{$chat['from']}",
"m": "{$chat['message']}"
},
EOD;

if (!isset($_SESSION['chatHistory'][$chat['from']])) {
$_SESSION['chatHistory'][$chat['from']] = '';
}

$_SESSION['chatHistory'][$chat['from']] .= <<<EOD
{
"s": "0",
"f": "{$chat['from']}",
"m": "{$chat['message']}"
},
EOD;

unset($_SESSION['tsChatBoxes'][$chat['from']]);
$_SESSION['openChatBoxes'][$chat['from']] = $chat['sent'];
}

if (!empty($_SESSION['openChatBoxes'])) {
foreach ($_SESSION['openChatBoxes'] as $chatbox => $time) {
if (!isset($_SESSION['tsChatBoxes'][$chatbox])) {
$now = time()-strtotime($time);
$time = date('g:iA M dS', strtotime($time));

$message = "Sent at $time";
if ($now > 180) {
$items .= <<<EOD
{
"s": "2",
"f": "$chatbox",
"m": "{$message}"
},
EOD;

if (!isset($_SESSION['chatHistory'][$chatbox])) {
$_SESSION['chatHistory'][$chatbox] = '';
}

$_SESSION['chatHistory'][$chatbox] .= <<<EOD
{
"s": "2",
"f": "$chatbox",
"m": "{$message}"
},
EOD;
$_SESSION['tsChatBoxes'][$chatbox] = 1;
}
}
}
}

$sql = "update chat set recd = 1 where chat.to = '".mysql_real_escape_string($_SESSION['username'])."' and recd = 0";
$query = mysql_query($sql);

if ($items != '') {
$items = substr($items, 0, -1);
}
header('Content-type: application/json');
?>
{
"items": [
<?php echo $items;?>
]
}

<?php
exit(0);
}

function chatBoxSession($chatbox) {

$items = '';

if (isset($_SESSION['chatHistory'][$chatbox])) {
$items = $_SESSION['chatHistory'][$chatbox];
}

return $items;
}

function startChatSession() {
$items = '';
if (!empty($_SESSION['openChatBoxes'])) {
foreach ($_SESSION['openChatBoxes'] as $chatbox => $void) {
$items .= chatBoxSession($chatbox);
}
}


if ($items != '') {
$items = substr($items, 0, -1);
}

header('Content-type: application/json');
?>
{
"username": "<?php echo $_SESSION['username'];?>",
"items": [
<?php echo $items;?>
]
}

<?php


exit(0);
}

function sendChat() {
$from = $_SESSION['username'];
$to = $_POST['to'];
$message = $_POST['message'];

$_SESSION['openChatBoxes'][$_POST['to']] = date('Y-m-d H:i:s', time());

$messagesan = sanitize($message);

if (!isset($_SESSION['chatHistory'][$_POST['to']])) {
$_SESSION['chatHistory'][$_POST['to']] = '';
}

$_SESSION['chatHistory'][$_POST['to']] .= <<<EOD
{
"s": "1",
"f": "{$to}",
"m": "{$messagesan}"
},
EOD;


unset($_SESSION['tsChatBoxes'][$_POST['to']]);

$sql = "insert into chat (chat.from,chat.to,message,sent) values ('".mysql_real_escape_string($from)."', '".mysql_real_escape_string($to)."','".mysql_real_escape_string($message)."',NOW())";
$query = mysql_query($sql);
echo "1";
exit(0);
}

function closeChat() {

unset($_SESSION['openChatBoxes'][$_POST['chatbox']]);

echo "1";
exit(0);
}

function sanitize($text) {
$text = htmlspecialchars($text, ENT_QUOTES);
$text = str_replace("\n\r","\n",$text);
$text = str_replace("\r\n","\n",$text);
$text = str_replace("\n","<br>",$text);
return $text;
}