magento-packagingweight/Plugin/MatrixRatePlugin.php

<?php
/**
 * Copyright James Oakley 2025. https://git.oakleys.org/
 *
 * This file is part of Jro_PackagingWeight.
 *
 * Jro_PackagingWeight is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by the
 * Free Software Foundation, either version 3 of the License, or (at your
 * option) any later version.

 * Jro_PackagingWeight is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
 * Public License for more details.

 * You should have received a copy of the GNU General Public License along with
 * Jro_PackagingWeight. If not, see https://www.gnu.org/licenses/.
 */

namespace Jro\PackagingWeight\Plugin;

use Magento\Quote\Model\Quote\Address\RateRequest;
use WebShopApps\MatrixRate\Model\Carrier\Matrixrate;
use Magento\Framework\App\Config\ScopeConfigInterface;
use Magento\Store\Model\ScopeInterface;
use Magento\Shipping\Model\Rate\Result as RateResult;
use Magento\Quote\Model\Quote\Address\RateResult\Method as RateMethod;

class MatrixRatePlugin
{
    private const XML_PATH_1_5   = 'carriers/matrixrate/packaging_weight_1_5';
    private const XML_PATH_6_10  = 'carriers/matrixrate/packaging_weight_6_10';
    private const XML_PATH_11_PLUS = 'carriers/matrixrate/packaging_weight_11_plus';
    private const XML_PATH_PRICE_ADJ_1_5     = 'carriers/matrixrate/packaging_cost_1_5';
    private const XML_PATH_PRICE_ADJ_6_10    = 'carriers/matrixrate/packaging_cost_6_10';
    private const XML_PATH_PRICE_ADJ_11_PLUS = 'carriers/matrixrate/packaging_cost_11_plus';

    /**
     * @var \Magento\Framework\App\Config\ScopeConfigInterface
     */
    private $scopeConfig;

    /**
     * @var \Magento\Quote\Model\Quote\Address\RateRequest
     */
    private ?RateRequest $rateRequest = null;

    /**
     * Constructor, using DI.
     *
     * @param \Magento\Framework\App\Config\ScopeConfigInterface $scopeConfig
     */
    public function __construct(ScopeConfigInterface $scopeConfig)
    {
        $this->scopeConfig = $scopeConfig;
    }

    /**
     * Plugin for before collectRates method.
     *
     * @param \WebShopApps\MatrixRate\Model\Carrier\Matrixrate $subject
     * @param \Magento\Quote\Model\Quote\Address\RateRequest $request
     */
    public function beforeCollectRates(Matrixrate $subject, RateRequest $request)
    {
        // Store the RateRequest, so we can use it in afterCollectRates.
        $this->rateRequest = $request;

        $itemQty = (int) $request->getPackageQty();

        if ($itemQty <= 0) {
            return [$request];
        }

        $weightToAdd = 0;

        if ($itemQty >= 1 && $itemQty <= 5) {
            $weightToAdd = (float) $this->scopeConfig->getValue(self::XML_PATH_1_5, ScopeInterface::SCOPE_STORE);
        } elseif ($itemQty >= 6 && $itemQty <= 10) {
            $weightToAdd = (float) $this->scopeConfig->getValue(self::XML_PATH_6_10, ScopeInterface::SCOPE_STORE);
        } elseif ($itemQty > 10) {
            $weightToAdd = (float) $this->scopeConfig->getValue(self::XML_PATH_11_PLUS, ScopeInterface::SCOPE_STORE);
        }

        if ($weightToAdd <= 0) {
            return [$request];
        }

        $originalWeight = $request->getPackageWeight();
        $adjustedWeight = $originalWeight + $weightToAdd;

        $request->setPackageWeight($adjustedWeight);
        $request->setData('package_weight', $adjustedWeight);
        $request->setFreeMethodWeight($adjustedWeight);
        $request->setData('weight', $adjustedWeight);
        if (method_exists($request, 'setWeight')) {
            $request->setWeight($adjustedWeight);
        }

        return [$request];
    }

    /**
     * Plugin for after collectRates method.
     *
     * @param \WebShopApps\MatrixRate\Model\Carrier\Matrixrate $subject
     * @param \Magento\Shipping\Model\Rate\Result $result
     */
    public function afterCollectRates(Matrixrate $subject, $result)
    {
        if (!$result instanceof \Magento\Shipping\Model\Rate\Result) {
            return $result;
        }
        if (!$this->rateRequest instanceof RateRequest) {
            return $result;
        }

        $itemCount = (int) $this->rateRequest->getPackageQty();

        if ($itemCount <= 0) {
            return $result;
        }

        // Determine correct per-item adjustment based on quantity
        if ($itemCount >= 1 && $itemCount <= 5) {
            $adjustment = (float) $this->scopeConfig
                ->getValue(self::XML_PATH_PRICE_ADJ_1_5, ScopeInterface::SCOPE_STORE);
        } elseif ($itemCount >= 6 && $itemCount <= 10) {
            $adjustment = (float) $this->scopeConfig
                ->getValue(self::XML_PATH_PRICE_ADJ_6_10, ScopeInterface::SCOPE_STORE);
        } else {
            $adjustment = (float) $this->scopeConfig
                ->getValue(self::XML_PATH_PRICE_ADJ_11_PLUS, ScopeInterface::SCOPE_STORE);
        }

        if ($adjustment <= 0) {
            return $result;
        }

        foreach ($result->getAllRates() as $method) {
            $originalPrice = $method->getPrice();
            $originalCost = $method->getCost();

            $method->setPrice($originalPrice + $adjustment);
            $method->setCost($originalCost + $adjustment);
        }

        return $result;
    }
}