<?php
  include("database.php");

  session_start();
  if (!isset($_SESSION["sid"]) || !is_numeric($_SESSION["sid"])) {
    header("Location: index.php");
    exit();
  }
  $itemId = filter_input(INPUT_GET, "add", FILTER_VALIDATE_INT);
  if ($itemId) {
    $query = "SELECT id FROM carts WHERE user_id = ".$_SESSION["sid"]." AND item_id = ".$itemId;
    $result = mysqli_query($connection, $query);
    if (mysqli_num_rows($result) == 0) {
      $query = "INSERT INTO carts (id, user_id, item_id) VALUES (NULL, ".$_SESSION["sid"].", ".$itemId.")";
      mysqli_query($connection, $query);
    }
  }
  $query = "SELECT carts.id, items.name, items.price FROM carts INNER JOIN items ON carts.item_id = items.id WHERE carts.user_id = ".$_SESSION["sid"];
  $results = mysqli_query($connection, $query);
?>
<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <title>User Account</title>
</head>
<body>
  <section>
    <p>Shopping Cart</p>
    <?php
      if (mysqli_num_rows($results) > 0) {
        foreach($results as $item) {
          echo "<div>";
          echo "Item: ".$item["name"]." $".$item["price"];
          echo "</div>";
        }
      } else {
        echo "No Items in your Cart";
      }
    ?>
    <p><a href="index.php">Go Back</a></p>
  </section>
</body>
</html>