index.php

<?php

use Facebook\Facebook;
use Service\ConfigProvider;

include(__DIR__ . '/vendor/autoload.php');

$configProvider = new ConfigProvider(__DIR__ . '/config.json');

if (isset($_REQUEST['hub_challenge'])) {
    $challenge = $_REQUEST['hub_challenge'];
    if ($_REQUEST['hub_verify_token'] === $configProvider->getParameter('verify_token')) {
        echo $challenge;
        die();
    }
}

$input = json_decode(file_get_contents('php://input'), true);

if ($input === null) {
    exit;
}

$message = $input['entry'][0]['messaging'][0]['message']['text'];
$sender = $input['entry'][0]['messaging'][0]['sender']['id'];


$fb = new Facebook([
    'app_id' => $configProvider->getParameter('app_id'),
    'app_secret' => $configProvider->getParameter('app_secret'),
]);


if($message=="Labas")
{
    $data = [
        'messaging_type' => 'RESPONSE',
        'recipient' => [
            'id' => $sender,
        ],
        'message' => [
            'text' => 'Sveiki, kuo galiu padeti?' ,
        ]
    ];
}

$response = $fb->post('/me/messages', $data, $configProvider->getParameter('access_token'));