Too Many Redirects

<?php 
include("inc/functions.php");

$pageTitle = "Full Catalog";
$section = null;
$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["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);
$total_pages = ceil($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 pg 3 with 8 items per page, the offset would be 16
$offset = ($current_page - 1) * $items_per_page;


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 ($section != null) {
            echo "<a href='catalog.php'>Full Catalog</a> &gt; ";
        }
        echo $pageTitle; ?></h1>

        <ul class="items">
            <?php
            foreach ($catalog as $item) {
                echo get_item_html($item);
            }
            ?>
        </ul>

    </div>
</div>

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

<?php

function get_catalog_count($category = null) {
  $category = strtolower($category);
  include("connection.php");

  try {
    $sql = "SELECT COUNT(media_id) FROM Media";
    if (!empty($category)) {
      $results = $db->prepare(
        $sql
        . " WHERE LOWER(cateogry) = ?"
      );
      $results->bindParam(1,$category,PDO::PARAM_STR);
    } else {
      $results = $db->prepare($sql);
    }
      $results->execute();
  } catch (Exception $e) {
    echo "bad query"; 
  }

  $count = $results->fetchColumn(0);
  return $count;
}

function full_catalog_array($limit = null, $offset = 0) {
    include("connection.php");

    try {
       $sql = "SELECT media_id, title, category, img 
         FROM Media
         ORDER BY
         REPLACE(
          REPLACE(
            REPLACE(title,'The ',''),
          'An ', ''),
         'A ', '')";
        if (is_integer($limit)) {
          $results = $db->prepare($sql . " LIMIT ? OFFSET ?");
          $results->bindParam(1,$limit,PDO::PARAM_INT);
          $results->bindParam(2,$offset,PDO::PARAM_INT);
        } else {
          $results = $db->prepare($sql);
        }
        $results->execute();
      } catch (Exception $e) {
       echo "Unable to retrieve results";
       exit;
      }

      $catalog = ($results->fetchAll(PDO::FETCH_ASSOC));
      return $catalog;
}

function category_catalog_array($category, $limit = null, $offset = 0) {
    include("connection.php"); 
    $category = strtolower($category);
    try {
       $sql = "SELECT media_id, title, category, img
         FROM Media
         WHERE LOWER(category) = ?
         ORDER BY
         REPLACE(
          REPLACE(
            REPLACE(title,'The ',''),
          'An ', ''),
         'A ', '')";
       if (is_integer($limit)) {
          $results = $db->prepare($sql . " LIMIT ? OFFSET ?");            
          $results->bindParam(1,$category,PDO::PARAM_STR);
          $results->bindParam(2,$limit,PDO::PARAM_INT);
          $results->bindParam(3,$offset,PDO::PARAM_INT);
        } else {
          $results = $db->prepare($sql);
          $results->bindParam(1,$category,PDO::PARAM_STR);
        }
       $results->execute();
      } catch (Exception $e) {
       echo "Unable to retrieve results";
       exit;
      }

      $catalog = ($results->fetchAll(PDO::FETCH_ASSOC));
      return $catalog;
}

function random_catalog_array() {
    include("connection.php"); 

    try {
       $results = $db->query(
         "SELECT media_id, title, category, img 
         FROM Media
         ORDER BY RANDOM()
         LIMIT 4"
       ); 
      } catch (Exception $e) {
       echo "Unable to retrieve results";
       exit;
      }

      $catalog = ($results->fetchAll(PDO::FETCH_ASSOC));
      return $catalog;
}

function single_item_array($id) {
    include("connection.php"); 

    try {
       $results = $db->prepare(
         "SELECT title, category, img, format, year, genre, publisher, isbn
         FROM Media
         JOIN Genres ON Media.genre_id = Genres.genre_id
         LEFT OUTER JOIN Books ON Media.media_id = Books.media_id
         WHERE Media.media_id = ?"
       ); 
       $results->bindParam(1,$id, PDO::PARAM_INT);
       $results->execute();
      } catch (Exception $e) {
       echo "Unable to retrieve results";
       exit;
      }

      $item = ($results->fetch());
      if (empty($item)) return $item;
      try {
       $results = $db->prepare(
         "SELECT fullname, role
         FROM Media_People
         JOIN People ON Media_People.people_id = People.people_id
         WHERE Media_People.media_id = ?"
       ); 
       $results->bindParam(1,$id, PDO::PARAM_INT);
       $results->execute();
      } catch (Exception $e) {
       echo "Unable to retrieve results";
       exit;
      }
      while($row = $results->fetch(PDO::FETCH_ASSOC)) {
        $item[$row["role"]][] = $row["fullname"];
      } 
      return $item;
}

function get_item_html($item) {
    $output = "<li><a href='details.php?id="
        . $item["media_id"] . "'><img src='" 
        . $item["img"] . "' alt='" 
        . $item["title"] . "' />" 
        . "<p>View Details</p>"
        . "</a></li>";
    return $output;
}

function array_category($catalog,$category) {
    $output = array();

    foreach ($catalog as $id => $item) {
        if ($category == null OR strtolower($category) == strtolower($item["category"])) {
            $sort = $item["title"];
            $sort = ltrim($sort,"The ");
            $sort = ltrim($sort,"A ");
            $sort = ltrim($sort,"An ");
            $output[$id] = $sort;            
        }
    }

    asort($output);
    return array_keys($output);
}