<?php
// CONFIG: Enable debug mode. This means we'll log requests into 'ipn.log' in the same directory.
// Especially useful if you encounter network errors or other intermittent problems with IPN (validation).
// Set this to 0 once you go live or don't require logging.
define("DEBUG", 1);
// Set to 0 once you're ready to go live
define("USE_SANDBOX", 1);
define("LOG_FILE", "ipn.log");
// Read POST data
// reading posted data directly from $_POST causes serialization
// issues with array data in POST. Reading raw POST data from input stream instead.
$raw_post_data = file_get_contents('php://input');
$raw_post_array = explode('&', $raw_post_data);
$myPost = array();
foreach ($raw_post_array as $keyval) {
	$keyval = explode ('=', $keyval);
	if (count($keyval) == 2)
		$myPost[$keyval[0]] = urldecode($keyval[1]);
}
// read the post from PayPal system and add 'cmd'
$req = 'cmd=_notify-validate';
if(function_exists('get_magic_quotes_gpc')) {
	$get_magic_quotes_exists = true;
}
foreach ($myPost as $key => $value) {
	if($get_magic_quotes_exists == true && get_magic_quotes_gpc() == 1) {
		$value = urlencode(stripslashes($value));
	} else {
		$value = urlencode($value);
	}
	$req .= "&$key=$value";
}
// Post IPN data back to PayPal to validate the IPN data is genuine
// Without this step anyone can fake IPN data
if(USE_SANDBOX == true) {
	$paypal_url = "https://www.sandbox.paypal.com/cgi-bin/webscr";
} else {
	$paypal_url = "https://www.paypal.com/cgi-bin/webscr";
}
$ch = curl_init($paypal_url);
if ($ch == FALSE) {
	return FALSE;
}
curl_setopt($ch, CURLOPT_HTTP_VERSION, CURL_HTTP_VERSION_1_1);
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_RETURNTRANSFER,1);
curl_setopt($ch, CURLOPT_POSTFIELDS, $req);
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, 1);
curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 2);
curl_setopt($ch, CURLOPT_FORBID_REUSE, 1);
if(DEBUG == true) {
	curl_setopt($ch, CURLOPT_HEADER, 1);
	curl_setopt($ch, CURLINFO_HEADER_OUT, 1);
}
// CONFIG: Optional proxy configuration
//curl_setopt($ch, CURLOPT_PROXY, $proxy);
//curl_setopt($ch, CURLOPT_HTTPPROXYTUNNEL, 1);
// Set TCP timeout to 30 seconds
curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 30);
curl_setopt($ch, CURLOPT_HTTPHEADER, array('Connection: Close'));
// CONFIG: Please download 'cacert.pem' from "http://curl.haxx.se/docs/caextract.html" and set the directory path
// of the certificate as shown below. Ensure the file is readable by the webserver.
// This is mandatory for some environments.
//$cert = __DIR__ . "./cacert.pem";
//curl_setopt($ch, CURLOPT_CAINFO, $cert);
$res = curl_exec($ch);
if (curl_errno($ch) != 0) // cURL error
	{
	if(DEBUG == true) {	
		error_log(date('[Y-m-d H:i e] '). "Can't connect to PayPal to validate IPN message: " . curl_error($ch) . PHP_EOL, 3, LOG_FILE);
	}
	curl_close($ch);
	exit;
} else {
		// Log the entire HTTP response if debug is switched on.
		if(DEBUG == true) {
			error_log(date('[Y-m-d H:i e] '). "HTTP request of validation request:". curl_getinfo($ch, CURLINFO_HEADER_OUT) ." for IPN payload: $req" . PHP_EOL, 3, LOG_FILE);
			error_log(date('[Y-m-d H:i e] '). "HTTP response of validation request: $res" . PHP_EOL, 3, LOG_FILE);
		}
		curl_close($ch);
}
// Inspect IPN validation result and act accordingly
// Split response headers and payload, a better way for strcmp
$tokens = explode(PHP_EOL.PHP_EOL, trim($res)); 
$res = trim(end($tokens));

$item_name = $_POST['item_name'];
$item_number = $_POST['item_number'];
$payment_status = $_POST['payment_status'];
$payment_amount = $_POST['mc_gross'];
$payment_currency = $_POST['mc_currency'];
$txn_id = $_POST['txn_id'];
$receiver_email = $_POST['receiver_email'];
$payer_email = $_POST['payer_email'];

error_log(date('[Y-m-d H:i e] '). $payment_status. ' ' . $txn_id. ' '.$item_name . PHP_EOL, 3, LOG_FILE);

die();

if (strcmp ($res, "VERIFIED") == 0) {
	// assign posted variables to local variables
	$item_name = $_POST['item_name'];
	$item_number = $_POST['item_number'];
	$payment_status = $_POST['payment_status'];
	$payment_amount = $_POST['mc_gross'];
	$payment_currency = $_POST['mc_currency'];
	$txn_id = $_POST['txn_id'];
	$receiver_email = $_POST['receiver_email'];
	$payer_email = $_POST['payer_email'];
	
	include("DBController.php");
	$db = new DBController();
	
	// check whether the payment_status is Completed
	$isPaymentCompleted = false;
	if($payment_status == "Completed") {
		$isPaymentCompleted = true;
	}
	// check that txn_id has not been previously processed
	$isUniqueTxnId = false; 
	$param_type="s";
	$param_value_array = array($txn_id);
	$result = $db->runQuery("SELECT * FROM payment WHERE txn_id = ?",$param_type,$param_value_array);
	if(empty($result)) {
        $isUniqueTxnId = true;
	}	
	// check that receiver_email is your PayPal email
	// check that payment_amount/payment_currency are correct
	if($isPaymentCompleted) {
	    $param_type = "sssdss";
	    $param_value_array = array($item_number, $item_name, $payment_status, $payment_amount, $payment_currency, $txn_id);
	    $payment_id = $db->insert("INSERT INTO payment(item_number, item_name, payment_status, payment_amount, payment_currency, txn_id) VALUES(?, ?, ?, ?, ?, ?)", $param_type, $param_value_array);
	    error_log(date('[Y-m-d H:i e] '). "Vdddddddddddderified IPN: $req ". PHP_EOL, 3, LOG_FILE);
	} 
	// process payment and mark item as paid.
	
	
	if(DEBUG == true) {
		error_log(date('[Y-m-d H:i e] '). "Verified IPN: $req ". PHP_EOL, 3, LOG_FILE);
	}
	
} else if (strcmp ($res, "INVALID") == 0) {
	// log for manual investigation
	// Add business logic here which deals with invalid IPN messages
	if(DEBUG == true) {
		error_log(date('[Y-m-d H:i e] '). "Invalid IPN: $req" . PHP_EOL, 3, LOG_FILE);
	}
}
?>