CODEWITHSUNDEEP
phpopencart
Qchmqs
Qchmqs

Reputation: 1805

how price calculation is done in opencart

In open cart I was building a module and I needed to know how price calculations are done, and I came across this code 

$price = $this->currency->format($this->tax->calculate($result['price'], 
        $result['tax_class_id'], $this->config->get('config_tax')));
if ((float)$result['special']) {
    $special = $this->currency->format($this->tax->calculate(
        $result['special'], 
        $result['tax_class_id'], $this->config->get('config_tax')));
} else {
    $special = false;
}                       
if ($this->config->get('config_tax')) {
    $tax = $this->currency->format((float)$result['special'] ? 
           $result['special'] : $result['price']);
} else {
    $tax = false;
}

Actually I didn't get the idea what really happening here as I can see there is really no difference between the $price and the $special and the $tax but there should be a reason why it is implemented this way.

I am sure i am missing something here any one explain to me how the price calculation is done in opencart?

Upvotes: 1

Views: 9053

Answers (2)

Jay Gilford
Jay Gilford

Reputation: 15151

Just a quick note for Mr Trick's answer. The three parameters of $this->tax->calculate() are

$value, $tax_class_id, $calculate = true

The third of which is not necessary, but in the original code, it gets the global config value of whether or not tax should be applied (since you can disable it in the settings). It's worth also noting that the tax object has changed between versions (I think it was 1.5.1.2 that it changed last) so if you're wanting to make it backward compatible, it's something to consider

Upvotes: 2

MrTrick
MrTrick

Reputation: 1957

From reading the source, this is what I understand: $price, $special and $tax are variables that are passed to the view to display. 

$price = $this->currency->format($this->tax->calculate($result['price'], 
        $result['tax_class_id'], $this->config->get('config_tax')));

Every item has a price, so $price is always set. $price is ; the base price, with the applicable tax classes and tax applied.

if ((float)$result['special']) {
    $special = $this->currency->format($this->tax->calculate(
        $result['special'], 
        $result['tax_class_id'], $this->config->get('config_tax')));
} else {
    $special = false;
}

An item might be on special. If it is, then $special is set to the base special price, with the same set of tax calculations applied to it. (so that the view code can display both the original and the SPECIAL! price side-by-side) 

if ($this->config->get('config_tax')) {
    $tax = $this->currency->format((float)$result['special'] ? 
           $result['special'] : $result['price']);
} else {
    $tax = false;
}

Not all installations have a tax configured. If it is, then $tax is set to be the base or base special price. (so that the view code can display how much the item cost before tax. (it's a little bit illogical that $tax is the price without any tax on it)

Make sense? If you need to know more about how price is calculated, look more closely at tax->calculate(). Otherwise it's 

$taxed_price = $special ? $special : $price; 
$untaxed_price = (float)$result['special'] ? $result['special'] : $result['price'];

Upvotes: 4

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