ViewCart.php

<?php // <--- do NOT put anything before this PHP tag

include('./functions.php');
include('./views/partials/head.php');
include('./views/partials/navbar.php');
// get the cookieMessage, this must be done before any HTML is sent to the browser.
// does the user have items in the shopping cart?
if (isset($_COOKIE['ShoppingCart']) && $_COOKIE['ShoppingCart'] != '') {

	// <===*** Quantity is passed along with id in cookie separated by '=' ***===>
	$map = [];

	foreach (explode(',', $_COOKIE['ShoppingCart']) as $pair) {
		[$id, $tag] = explode('=', $pair);
		$map[$id] = $tag; // This already removes any duplicates so no need for array_unique calls;
	}

	$ids = array_keys($map);
	$placeholders = implode(',', array_fill(0, count($ids), '?'));
	$dbh = connectToDatabase();

	// create a SQL statement to select the product and brand info about a given ProductID
	// this SQL statement will be very similar to the one in ViewProduct.php
	$statement = $dbh->prepare("
			
			SELECT * FROM Products AS P INNER JOIN Brands AS B ON P.BrandID = B.BrandID WHERE P.ProductID IN ($placeholders) ;
			
		");

	$statement->execute($ids);

	$rows = $statement->fetchAll(PDO::FETCH_ASSOC);

	// <===*** Using the famous spread operator (I borrowed it from my JS knowledge) ***===>
	// OUR SERVER DOESN'T SUPPORT THIS SPREAD OPERATOR....APPARENTLY THE VERSION IS OLDER THAN 7.4
	// $rows = array_map(fn($row) => [...$row, 'Quantity' => $map[$row['ProductID']], 'SubTotal' => $map[$row['ProductID']] * $row['Price']], $rows);
	$newRows = [];

	foreach ($rows as $row) {
		// Make a copy of the row
		$row['Quantity'] = $map[$row['ProductID']] ?? 0;
		$row['SubTotal'] = $row['Quantity'] * $row['Price'];

		$newRows[] = $row; // push the modified row
	}

	// Replace original rows array
	$rows = $newRows;
	// break reference

	// TODO: output the $totalPrice.
	$totalPrice = array_sum(array_column($rows, 'SubTotal'));
	// here array_column extracts values of a column (or key for associative array)
	// then array_sum performs mathematical sum
	$heading = 'Your Cart has ' . count($rows) . " items";
	$bannerMessage = 'Thank you for shopping with us. See you again soon!';
	include('./views/partials/banner.php');

	include './views/ViewCart.view.php';

	// you are allowed to stop and start the PHP tags so you don't need to use lots of echo statements.
} else {
	$heading = 'Your Cart Is Empty';
	include('./views/partials/banner.php');
	setCookieMessage("Checkout today's hot deals to get the best offers.");

	echo "
	<main class='ViewCart-main'>

    <div class='product-empty'>
        <p>Browse our <a class=\"Browse-products-link\" href=\"./ProductList.php\">products</a> and add items to your cart!</p>
    </div>

	</main>";
}