<?php

namespace App\InvoiceRule;

use Doctrine\ORM\EntityManagerInterface;

use App\InvoiceRuleInterface;

use App\Ramcar\ServiceType;
use App\Ramcar\DiscountApply;

use App\Entity\Promo;

class DiscountType implements InvoiceRuleInterface
{
    protected $em;

    public function __construct(EntityManagerInterface $em)
    {
        $this->em = $em;
    }

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

    public function compute($criteria, &$total)
    {
        $items = [];

        $promos = $criteria->getPromos();

        if (empty($promos))
            return $items;

        // NOTE: only get first promo because only one is applicable anyway 
        $promo = $promos[0];

        $rate = $promo->getDiscountRate();
        $apply_to = $promo->getDiscountApply();

        switch ($apply_to)
        {
            case DiscountApply::SRP:
                $discount = bcmul($total['sell_price'], $rate, 2);
                break;
            case DiscountApply::OPL:
                // $discount = round($total['sell_price'] * 0.6 / 0.7 * $rate, 2);
                // $discount = round($total['sell_price'] * (1 - 1.5 / 0.7 * $rate), 2);
                $num1 = bcdiv(1.5, 0.7, 9);
                $num1_rate = bcmul($num1, $rate, 9);
                $multiplier = bcsub(1, $num1_rate, 9);

                $discount = bcmul($total['sell_price'], $multiplier, 2);
                break;
        }

        // if discount is higher than 0, add to items
        if ($discount > 0)
        {
            $qty = 1;
            $price = bcmul(-1, $discount, 2);

            $items[] = [
                'promo' => $promo,
                'title' => $this->getTitle(),
                'qty' => $qty,
                'price' => $price,
            ];
        }

        $total['discount'] = $discount;
        $total['total_price'] = bcsub($total['total_price'], $discount, 2);

        return $items;
    }

    public function validatePromo($criteria, $promo_id)
    {
        // return error if there's a problem, false otherwise
        // check service type
        $stype = $criteria->getServiceType();

        // discount/promo only applies for battery sales
        if ($stype != ServiceType::BATTERY_REPLACEMENT_NEW)
            return null;
        
        if (empty($promo_id))
        {
            return false;
        }

        // check if this is a valid promo
        $promo = $this->em->getRepository(Promo::class)->find($promo_id);

        if (empty($promo))
            return 'Invalid promo specified.';

        $criteria->addPromo($promo);
        return false;
    }

    public function validateInvoiceItems($criteria, $invoice_items)
    {
        return null;
    }

    protected function getTitle()
    {
        $title = 'Promo discount';

        return $title;
    }
}