<?php

namespace App\Invoice;

use App\InvoiceInterface;

class Tax implements InvoiceInterface
{
    const TAX_RATE              = 0.12;

    public function check($criteria)
    {
        if (!empty($criteria->isTaxable()))
            return true;

        return false;

    }

    public function getTemplate()
    {
        return 'invoice/tax.html.twig';
    }

    public function getID()
    {
        return 'tax';
    }

    public function compute($items, &$total)
    {
        foreach ($items as $item)
        {
            $price = $item['price'];
            $qty = $item['qty'];

            if (isset($items['service_type']))
            {
                if ($items['service_type'] == 'battery_new')
                {
                    // battery purchase
                    if (isset($item['battery']))
                    {
                        // battery purchase
                        $vat = $this->getTaxAmount($price);
 
                        $qty_price = bcmul($price, $qty, 2);
                        $price_minus_vat = bcsub($price, $vat, 2);
                        $qty_price_minus_vat = bcmul($price_minus_vat, $qty, 2);

                        $total['sell_price'] = bcadd($total['sell_price'], $qty_price, 2);
                        $total['vat'] = bcadd($total['vat'], $qty_price, 2);
                        $total['vat_ex_price'] = bcadd($total['vat_ex_price'], $qty_price_minus_vat, 2);

                        $total['total_price'] = bcadd($total['total_price'], $qty_price, 2);
                    }
                }
                    
            }
            else
            {
                // everything else
            }
        }
    }

    protected function getTaxAmount($price)
    {
        $vat_ex_price = $this->getTaxExclusivePrice($price);
        $tax_amount = bcsub($price, $vat_ex_price, 2);

        return $tax_amount;
    }

    protected function getTaxExclusivePrice($price)
    {
        $tax_ex_price = bcdiv($price, bcadd(1, self::TAX_RATE, 2), 2);
        return $tax_ex_price;
    }

}