Duplicate items when adding in my order in the cart - php

Question

I have a problem with my shopping cart functionality of my restaurant website.
For example, if i add an item to the cart, then i add another item, then if I delete the one I added last and add it again, it's adding itself doubled in the session. Here I have the functions for adding and removing the items in the shopping cart:
function AddProd($id_prod, $quant) {
if(isset($_SESSION['cart'])){
$_SESSION['cart'].=$id_prod.'>'.$quant.",";
} else {
$_SESSION['cart']=$id_prod.'>'.$quant.",";
}
}
function RemoveFromCart($id_prod) {
if(isset($_SESSION['cart'])) {
$n = $_SESSION['cart'];
$prod_id = substr($n, 0, -1);
$ids = explode(',', $prod_id);
$prods = '';
foreach ($ids as $id) {
$i = explode('>', $id);
if($i[0] != $id_prod) $prods = $prods.''.$id.',';
}
$_SESSION['cart'] = $prods;
}
}
Here i have the function which sets the quantity of the item:
function SetCartNumber($conn) {
if(isset($_SESSION['cart'])) {
$n = $_SESSION['cart'];
$prod_id = substr($n, 0, -1);
$ids = array_map('trim', explode(',', $prod_id));
foreach ($ids as $id) {
$i = explode('>', $id);
$total = $total + $i[1];
}
return $total;
}
return 0;
}
Here it inserts into databse:
function LastId($conn, $tbl){
$s = 'SELECT `id` FROM `'.$tbl.'` ORDER BY `id` DESC LIMIT 1';
if ($r = mysqli_query($conn, $s)) {
$rowd = mysqli_fetch_array($r, MYSQLI_NUM);
return $rowd[0];
}
return -1;
}
$t_price = (empty(GetPromotion($connect))) ? $total_price : '<span style="color: white; font-weight: bold;">'.SetPromotion($connect).'</span> <span style="text-decoration: line-through; color: red;">'.$total_price.'</span>';
if(isset($_POST['delete_prod'])) {
RemoveFromCart($_POST['delete_prod']);
echo '<script type="text/JavaScript"> setTimeout("location.href = \'cart\';",100); </script>';
}
if(isset($_POST['decrease_prod'])) {
ProdsDecrease($_POST['decrease_prod']);
echo '<script type="text/JavaScript"> setTimeout("location.href = \'cart\';",100); </script>';
}
if(isset($_POST['increase_prod'])) {
ProdsIncrease($_POST['increase_prod']);
echo '<script type="text/JavaScript"> setTimeout("location.href = \'cart\';",100); </script>';
}
if (!empty($_POST['trimite']))
{
$str_name = ($str_name[strlen($str_name)-2] == ',') ? substr($str_name, 0, -2) : $str_name;
$str_name2 = ($str_name2[strlen($str_name2)-2] == ',') ? substr($str_name2, 0, -2) : $str_name2;
$price = (empty(SetPromotion($connect))) ? SetCartPrice($connect) : SetPromotion($connect);
$price = (!empty(GetPromotion($connect))) ? $price.' lei(Promotie activa: '.GetPromotion($connect).'%)' : $price;
$prods = MailProds($connect);
$quantity = SetCartNumber($connect);
$price1 = (empty(SetPromotion($connect))) ? SetCartPrice($connect) : SetPromotion($connect);
$price1 = floatval($price1);
$quantity = floatval($quantity);
$email = filter_input(INPUT_POST, 'email');
$telefon = filter_input(INPUT_POST, 'telefon');
$mentiuni = filter_input(INPUT_POST, 'mentiuni');
$tacamuri = filter_input(INPUT_POST, 'tacamuri');
if(!empty(get())) { $email = getEmail($connect); }
$sql = "INSERT INTO `comenzi`(`name`, `pret`, `cantitate`, `adresa_mail`, `nr_telefon`, `mentiuni`, `tacamuri`) VALUES ('$prods', '$price1', '$quantity', '$email', '$telefon', '$mentiuni', '$tacamuri')";
How could I solve the issue?

Answer 1

the problem is in addProd funtion function. you session must contains unique prodId values. but when you are adding the same product again. you are not deleting the first then you will face the problem.
so you should check if the product is already is in session or not, before adding it.
or you should update it.