<?php

defined('ABSPATH') or exit;

// get old log filename
$upload_dir   = wp_upload_dir(null, false);
$old_filename = trailingslashit($upload_dir['basedir']) . 'mc4wp-debug.log';
$new_filename = trailingslashit($upload_dir['basedir']) . 'mc4wp-debug-log.php';

// check if old default log file exists
if (! file_exists($old_filename)) {
    return;
}

// rename to new file.
@rename($old_filename, $new_filename);

// if success, insert php exit tag as first line
if (file_exists($new_filename)) {
    $handle = fopen($new_filename, 'r+');

    if (is_resource($handle)) {
        // make sure first line of log file is a PHP tag + exit statement (to prevent direct file access)
        $line            = fgets($handle);
        $php_exit_string = '<?php exit; ?>';
        if (strpos($line, $php_exit_string) !== 0) {
            rewind($handle);
            fwrite($handle, $php_exit_string . PHP_EOL . $line);
        }

        fclose($handle);
    }
}