PHP Decode

<?php session_start();include(base64_decode('Y29uZmlnL2NvbmYucGhw'));if(isset($_SESSION[base64_decode('bG9nZ2Vk')])&&$_SESSION[base64_decode('bG9nZ2Vk')]===base64_decode('dHJ1ZQ==')){header(base64_decode('TG9jYXRpb246IGluZGV4LnBocA=='));exit();}else{$e0=$w1->c2(base64_decode('U0VMRUNUIHJlYWR5IEZST00gaW5mb3M='));$e0->r3();$v4=$e0->k5();if($v4[base64_decode('cmVhZHk=')]===base64_decode('MQ==')){header(base64_decode('TG9jYXRpb246IGluZGV4LnBocA=='));$q6=base64_decode('b2theSBJJ20gY29vbCwgSSBnaXZlIHlvdSB0aGUga2V5IGZvciBlbnRlciBpbiB0aGUgdGhlIDR0aCByYXAgY29udGVuZGVycyA6IGJyYWluc2hlbGw=');}}if(!isset($_GET[base64_decode('YWN0aW9u')])){header(base64_decode('TG9jYXRpb246IGhlbGxvLnBocD9hY3Rpb249Y29uZmlndXJl'));exit();}if(isset($_GET[base64_decode('YWN0aW9u')])){$j7=htmlspecialchars($_GET[base64_decode('YWN0aW9u')]);if($j7===base64_decode('cmVnaXN0ZXI=')){include(base64_decode('aW5jbHVkZS9yZWdpc3Rlci5waHA='));if(isset($_POST[base64_decode('dXNlcm5hbWU=')])){$w8=(isset($_POST[base64_decode('dXNlcm5hbWU=')])&&trim($_POST[base64_decode('dXNlcm5hbWU=')])!='')?htmlspecialchars($_POST[base64_decode('dXNlcm5hbWU=')]):null;$c9=(isset($_POST[base64_decode('cGFzc3dvcmQ=')])&&trim($_POST[base64_decode('cGFzc3dvcmQ=')])!='')?htmlspecialchars($_POST[base64_decode('cGFzc3dvcmQ=')]):null;if(isset($w8,$c9)){$e0=$w1->c2(base64_decode('SU5TRVJUIGludG8gdXNlcmluZm8gKHVzZXJuYW1lLCBwYXNzd29yZCkgVkFMVUVTICg6dXNlcm5hbWUsIDpwYXNzd29yZCk='));$e0->wa(base64_decode('OnVzZXJuYW1l'),$w8,PDO::PARAM_STR);$e0->wa(base64_decode('OnBhc3N3b3Jk'),md5(sha1($c9)),PDO::PARAM_STR);$e0->r3();$_SESSION[base64_decode('bG9nZ2Vk')]=base64_decode('dHJ1ZQ==');header(base64_decode('TG9jYXRpb246IGluZGV4LnBocA=='));}}}elseif($j7===base64_decode('Y29uZmlndXJl')){include(base64_decode('aW5jbHVkZS9jb25maWd1cmUucGhw'));if(isset($_POST[base64_decode('c3FscGF0aA==')])){$ib=base64_decode('TVJSREdNSldIQTJXQ09MR0c1UldFTVk9');$ec=htmlspecialchars($_POST[base64_decode('c3FscGF0aA==')]);if(isset($_POST[base64_decode('cHlwYXRo')])&$_POST[base64_decode('cHlwYXRo')]!=''){echo base64_decode('cHlwYXRoIDog').$_POST[base64_decode('cHlwYXRo')];$sd=htmlspecialchars($_POST[base64_decode('cHlwYXRo')]);$e0=$w1->c2(base64_decode('SU5TRVJUIGludG8gaW5mb3MgKHNxbHBhdGgsIG9zLCByZWFkeSwgcHJlc2V0LCBweXBhdGgpIFZBTFVFUyAoOnNxbHBhdGgsIDEsIDEsIDAsIDpweXBhdGgp'));$e0->wa(base64_decode('OnNxbHBhdGg='),$ec,PDO::PARAM_STR);$e0->wa(base64_decode('OnB5cGF0aA=='),$sd,PDO::PARAM_STR);$e0->r3();header(base64_decode('TG9jYXRpb246IGhlbGxvLnBocD9hY3Rpb249cmVnaXN0ZXI='));}else{$ke=0;$e0=$w1->c2(base64_decode('SU5TRVJUIGludG8gaW5mb3MgKHNxbHBhdGgsIG9zLCByZWFkeSwgcHJlc2V0LCBweXBhdGgpIFZBTFVFUyAoOnNxbHBhdGgsIDAsIDEsIDAsICcnKQ=='));$e0->wa(base64_decode('OnNxbHBhdGg='),$ec,PDO::PARAM_STR);$e0->r3();$lf=base64_decode('TUU0VEFNQlhHVTJXTVlKVUdSVEdJT0JYSEEyV0NZM0JIQTJXSU1BPQ==');header(base64_decode('TG9jYXRpb246IGhlbGxvLnBocD9hY3Rpb249cmVnaXN0ZXI='));}}}}?>