callback - php

<?php
$merchant_id = "a56e0-0a10c-73015-9f330";
$key = "";
// $jsoncfn = '{"statusCode":10011,"merchant_id":"a56e0-0a10c-73015-9f330","hash":"BPyctBr/2SBmF8zTt1fGrN1b0/fBO4xYEIPt4gSlUm8J6Gm26tVbZyWhvNEqQp8gmUKtYQicNmDvxqPGJVEI3Q==","data":{"symbol":"USDT","address":"0x2c949000D626A8C73A3e69054c0C60A8654ede31","msg":"Address timeout","timestamp":1594392362}}';
$jsoncfn = '{"statusCode":200,"merchant_id":"a56e0-0a10c-73015-9f330","hash":"EyBdBWHMSXtaecqzdouSWm9E+HqmUDlfuvhWwuWG9j6Y/4N9yynQnjHtnc8EpoF0+xXRlzbIk2f5Ix8RVjSu7Q==","data":{"symbol":"USDT","address":"0xCF68707fAbAbcaE21D9Cf3a1BD8BF4b2123d669E","block":10436505,"txid":"0xb17db1aae600f24c2a4d6cc48cc70ec31c1e53f7fdec2ae82b80edbfa2d28b0c","confirmation":16,"balance":1,"usd_balance":1,"timestamp":1594448100}}';
$res = json_decode($jsoncfn, true);
$data_hash = base64_encode(hash_hmac('sha512', json_encode($res['data']), $key,true));
if ($res['statusCode'] == 200 || $res['statusCode'] == 1001){
     //check hash
     //match merchant_id
     if ($res['merchant_id'] == $merchant_id && $data_hash == $res['hash']) {
         echo 'success';
         //do something
         return {code:0} // return success
     }else{
         echo 'error1';
         //do somehing
     }
} else {
    echo 'error2';
    //do somehing
}
?>