cartFunctions.php

<?php 
session_start();

if (isset($_POST['action'])) {
 	switch ($_POST['action']) {
    	case 'add':
        	addItem();
            break;
        case 'update':
            updateItem();
            break;
		case 'remove':
            removeItem();
			break;
		case 'deliveryOption':
			deliveryOption();
			break;
    }
}

function addItem() {
	// Check if user logged in 
	if (! isset($_SESSION["ShopperID"])) {
		// redirect to login page if the session variable shopperid is not set
		header ("Location: login.php");
		exit;
	}
	// TO DO 1
	// Write code to implement: if a user clicks on "Add to Cart" button, insert/update the 
	// database and also the session variable for counting number of items in shopping cart.
	include_once("mysql_conn.php"); // Establish database connection handle: $conn
	// Check if a shopping cart exist, if not create a new shopping cart
	if(!isset($_SESSION["Cart"])){
		//create a shopping cart for the shopper
		$qry= "INSERT INTO Shopcart(ShopperID) VALUES(?)";
		$stmt=$conn->prepare($qry);
		$stmt->bind_param("i",$_SESSION["ShopperID"]);
		$stmt->execute();
		$stmt->close();
		$qry="SELECT LAST_INSERT_ID() AS ShopCartID";
		$result=$conn->query($qry);
		$row=$result->fetch_array();
		$_SESSION["Cart"]=$row["ShopCartID"]; 
	}
	
  	// If the ProductID exists in the shopping cart, 
	  // update the quantity, else add the item to the Shopping Cart.
	  $pid = $_POST["product_id"];
	  $quantity= $_POST["quantity"];
	  $qry="SELECT * FROM ShopCartItem WHERE ShopCartID=? AND ProductID=?";
	  $stmt=$conn->prepare($qry);
	  $stmt->bind_param("ii",$_SESSION["Cart"],$pid);
	  $stmt->execute();
	  $result=$stmt->get_result();
	  $stmt->close();
	  $addNewItem=0;

	  //if current item is already in the cart, increase quantity
	  if ($result->num_rows>0){
		$qry="UPDATE ShopCartItem SET Quantity=LEAST(Quantity+?,10) WHERE ShopCartID=? AND ProductID=?";
		$stmt=$conn->prepare($qry);
		$stmt->bind_param("iii",$quantity,$_SESSION["Cart"],$pid);
		$stmt->execute();
		$stmt->close();
	  }
	  //else, add the product to shopping cart
	  else{
		$qry= "INSERT INTO ShopCartItem(ShopCartID,ProductID,Price,Name,Quantity)SELECT ?,?,Price,ProductTitle,? FROM Product WHERE ProductID=?";
		
		$stmt=$conn->prepare($qry);
		$stmt->bind_param("iiii",$_SESSION["Cart"],$pid,$quantity,$pid);
		$stmt->execute();
		$stmt->close();
		$addNewItem=1;
	}
	$conn->close();

	if (isset($_SESSION["NumCartItem"])){
		$_SESSION["NumCartItem"]=$_SESSION["NumCartItem"]+$addNewItem;
	}
	else{
		$_SESSION["NumCartItem"]=1;
	}
	
	header("Location: shoppingCart.php");
  	
	exit;	
  	// Update session variable used for counting number of items in the shopping cart.
	
	// Redirect shopper to shopping cart page
	
}

function updateItem() {
	// Check if shopping cart exists 
	if (! isset($_SESSION["Cart"])) {
		// redirect to login page if the session variable cart is not set
		header ("Location: login.php");
		exit;
	}
	// TO DO 2
	// Write code to implement: if a user clicks on "Update" button, update the database
	// and also the session variable for counting number of items in shopping cart.

	$cartid=$_SESSION["Cart"];
	$pid=$_POST["product_id"];
	$quantity=$_POST["quantity"];
	include_once("mysql_conn.php");
	$qry="UPDATE ShopCartItem SET Quantity=? WHERE ProductID=? AND ShopCartID=?";
	$stmt=$conn->prepare($qry);
	$stmt->bind_param("iii",$quantity,$pid,$cartid);
	$stmt->execute();
	$stmt->close();
	$conn->close();
	header("Location: shoppingCart.php");
	exit;
	
}

function removeItem() {
	if (! isset($_SESSION["Cart"])) {
		// redirect to login page if the session variable cart is not set
		header ("Location: login.php");
		exit;
		
	}
	// TO DO 3
	// Write code to implement: if a user clicks on "Remove" button, update the database
	// and also the session variable for counting number of items in shopping cart.

	echo("ASDs");
	$cartid=$_SESSION["Cart"];
	$pid=$_POST["product_id"];
	$quantity=$_POST["quantity"];
	include_once("mysql_conn.php");
	$qry="DELETE FROM ShopCartItem  WHERE ProductID=? AND ShopCartID=?";
	$stmt=$conn->prepare($qry);
	$stmt->bind_param("ii",$pid,$cartid);
	$stmt->execute();
	$stmt->close();
	$conn->close();
	header("Location: shoppingCart.php");
	$_SESSION["NumCartItem"]=$_SESSION["NumCartItem"]-1;
	exit;
	
}

function deliveryOption(){
	if ($_POST["delivery"] == 'Normal'){
		$_SESSION["Delivery"] = "Normal";
		$_SESSION["ShipCharge"] = 5;
	}
	else{
		$_SESSION["Delivery"] = "Express";
		$_SESSION["ShipCharge"] = 10;

	}

	header ("Location: shoppingCart.php");
	exit;
}
?>