<?php
$subpage = isset($_GET["subpage"]) ? $_GET["subpage"] : "index";
$multipage = [
    "add-comment" => "comments/add-comment.php",
    "index" => "report/report-index.php",
    "kmom01" => "report/kmoms/kmom01.php",
    "kmom02" => "report/kmoms/kmom02.php",
    "kmom03" => "report/kmoms/kmom03.php",
    "kmom04" => "report/kmoms/kmom04.php",
    "kmom05" => "report/kmoms/kmom05.php",
    "kmom06" => "report/kmoms/kmom06.php",
    "kmom07" => "report/kmoms/kmom07.php"
];

if (isset($subpage) && array_key_exists($subpage, $multipage)) {
    $file = $multipage[$subpage];
} else {
    $subpage = "404";
    $file = "pages/404.php";
}

include($file);