shop / different porto for products

[burna]

hy all!

i'm having troubles with a shopping-system.
the problem is that there are products with different porto-values which are also linked with a minimum quantity.

f.a.:
product 1 is only available if you take 2 pieces
product 2 is only available if you take 6 pieces
(the porto for product 1 is different as for product 2.)

i already have a working shoppingsystem which gives me the products in my cart back as an array:

Array
(
    [0] => Array
        (
            [item_id] => 1
            [title] => Apfelsaft 5l
            [price] => 9
            [qty] => 2
            [porto] => 6
        )

[1] => Array
    (
        [item_id] => 2
        [title] => Apfelsaft 1l
        [price] => 2
        [qty] => 1
        [porto] => 8
    )

)

so i need to count how often a product (1,5,7,9) is in the shopping-cart and for this i add the shipping costs one time. but how do i do that?

any help would be appreciated!!
greets, bernhard

[leatherback]

I would have the items in the cart using the item ID as array key in the shopping cart. Whenever you add an item you check whether the item is already in the cart. If so, you update the quantity.

Then you need to decide upon the logic for calculating the shipping cost; Something like:

// shipping cost based on shipping quantity batches. Round-up to the nearest batch size
$shippingcost = ceil($cart[$product]['qty']/$shipping_quantity[$product]) 
    * $shipping_cost_per_unit[$product];
// Shiping in set quantities, so round up to the nearest shipping quantity
$cart[$product]['qty'] = $cart[$product]['qty'] 
    + ($shipping_quantity[$product] -  $cart[$product]['qty'] % $shipping_quantity[$product]);

[burna]

hy leatherback,

thanks for your quick reply.
i solved the problem by dividing the minimum quantity (f.a. 2 pieces = /2). so i dont need to calculate the shipping-costs individually at the bottom.

BUT i already have one problem at least:
i hope you understand what i'm trying to (have to) do....

some product categories have a minimum quantity, so bottles can only be ordered in 6-packs.
the user could fill the cart like he wants, 1 apple, 1 orange, etc... each item has a individual ID and price.

the system must give an alert message when the product quantity isn't 6, 12, 18 etc.
oke, sounds easy. but i have a second product category where the quantity is another (2 pieces).

where should i begin to find the solution for my problem?
can you help me?

greets, bernard