<?php
$verify_token = "samconnection";
  if ($_REQUEST['hub_verify_token'] == $verify_token) {
  echo $_REQUEST['hub_challenge'];
  }

require_once 'facebook_sdk/src/Facebook/autoload.php';
$input = json_decode(file_get_contents('php://input'), true);
if($input['entry'][0]['changes'][0]['value']['item'] == "comment" && !empty($input['entry'][0]['changes'][0]['value']['message'])){
$sender = $input['entry'][0]['changes'][0]['value']['from']['id'];
$page_id = $input['entry'][0]['id'];
if($sender != $page_id):
$accesstoken = '**************';
$post_id = $input['entry'][0]['changes'][0]['value']['post_id'];
$parent_id = $input['entry'][0]['changes'][0]['value']['parent_id'];
if($parent_id == $post_id):
$cid = $input['entry'][0]['changes'][0]['value']['comment_id'];
$message = "-";
    $fb = new Facebook\Facebook([
  'app_id' => '************',
  'app_secret' => '**********',
  'default_graph_version' => 'v5.0',
  ]);
if( !empty($input['entry'][0]['changes'][0]['value']['message'])):
try {
  // Returns a `Facebook\FacebookResponse` object
  $response = $fb->post(
    '/'.$cid.'/comments',
    array (
        'message' => '@['.$sender.'] welcome in our page'
        ),
    $accesstoken
  );
} catch(Facebook\Exceptions\FacebookResponseException $e) {
  echo 'Graph returned an error: ' . $e->getMessage();
} catch(Facebook\Exceptions\FacebookSDKException $e) {
  echo 'Facebook SDK returned an error: ' . $e->getMessage();
}
endif;
if(!empty($message)):
//$response = $fb->get('/'.$post_id.'/full_picture',$accesstoken);
//$pic =$response->getGraphNode();
$jsonData = '{
   "recipient":{
       "comment_id":"'.$cid.'"
   },
   "message": 'thank you for commenting'

}';

$url = 'https://graph.facebook.com/v5.0/me/messages?access_token='.$accesstoken;
$ch = curl_init($url);
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_POSTFIELDS, $jsonData);
curl_setopt($ch, CURLOPT_HTTPHEADER, array('Content-Type: application/json'));
if($r==true){
  $plan->UpdateRepliesCount($post_id,$count);
  $result = curl_exec($ch);
}
curl_close($ch);
endif;
endif;
endif;
?>