[SOLVED] Strange behaviour with catalog.php

<?php 

include("inc/functions.php");


$pageTitle = "Full Catalog";
$section = null;
$search = null;

/*Start Pagination*/ 
$items_per_page = 8;



if (isset($_GET["cat"])) {
    if ($_GET["cat"] == "books") {
        $pageTitle = "Books";
        $section = "books";
    } else if ($_GET["cat"] == "movies") {
        $pageTitle = "Movies";
        $section = "movies";
    } else if ($_GET["cat"] == "music") {
        $pageTitle = "Music";
        $section = "music";
    }
}


if(isset($_GET["s"])) {
    $search = filter_input(INPUT_GET, "s", FILTER_SANITIZE_STRING);

}

if(isset($_GET["pg"])) {
    $current_page = filter_input(INPUT_GET, "pg", FILTER_SANITIZE_NUMBER_INT);

}

if(empty($current_page)) {
    $current_page = 1;

}

$total_items = get_catalog_count($section, $search);

$total_pages = 1;
$offset = 0;

if($total_items > 0) {
    $total_pages = ceil($total_items / $items_per_page);

    //limit results in redirect
    $limit_results = "";

    /*if (!empty($section)) {
        $limit_results = "cat=" . $section . "&";
    }*/

    // redirect too-large page numbers to the last page
    if ($current_page > $total_pages) {
        header("location:catalog.php?"
            . $limit_results
            . "pg=".$total_pages);
    }

    // redirect too-small page numbers to the first page
    if ($current_page < 1) {
        header("location:catalog.php?"
            . $limit_results
            . "pg=1");
    }


    //determine the offset (number of items to skip) for the current page
    //for example: on page 3 with 8 item per page, the offset would be 16

    $offset = ($current_page - 1) * $items_per_page;

    $pagination = "<div class=\"pagination\">";
    $pagination .= "Pages: ";


    for ($i = 1;$i <= $total_pages;$i++) {
        if ($i == $current_page) {
            $pagination .= " <span>$i</span>";
        } else {
            $pagination .= " <a href='catalog.php?";
            if (!empty($search)) {

                //paginate across all the items in search term
                $pagination .= "s=" . $search .urlencode(htmlspecialchars($search))."&";
            } else/**/ if (!empty($section)) {
                $pagination .=  "cat=".$section."&";
            }
            $pagination .= "pg=$i'>$i</a>";
        }
    }

    $pagination .= "</div>";

}

$catalog = full_catalog_array(); //include catalog array

if(!empty($search)) {
  //set search equal to search_catalog_array(items per page, search, offset)
  $catalog = search_catalog_array($search, $items_per_page, $offset);    
} else if(empty($section)) {
  $catalog = full_catalog_array($items_per_page, $offset);
} else {
  $catalog = category_catalog_array($section, $items_per_page, $offset);
}



include("inc/header.php"); ?>

<div class="section catalog page">

    <div class="wrapper">

        <h1><?php
            if( $search != null) {
              echo "Search Results for \"" 
              . htmlspecialchars($search) 
              ."\"";

            } else {
              if($section != null) {
                echo "<a href=\"catalog.php\">Full Catalog</a> &gt; ";  
              }
               echo $pageTitle;
            }?>  </h1>          
        <?php
        if ($total_items < 1) {
            echo "<p>Sorry, No items were found matching that search term.</p>";
            echo "<p>Search Again or "
              . "<a href=\"catalog.php\">Browse the Full Catalog</a></p>";
        } else { 
            echo $pagination; ?>        
            <ul class="items">
                <?php
                foreach ($catalog as $item) {
                    echo get_item_html($item);
                }
                ?>
                </ul>

            <?php echo $pagination;  
            } ?>

    </div>
</div>




<?php include("inc/footer.php"); ?>