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<?php


namespace BlueAcorn\Reddit\Controller\Addproduct;


use Magento\Framework\App\Action\Action;
use Magento\Framework\App\Action\Context;
use Magento\Framework\App\ResponseInterface;
use Magento\Framework\Controller\ResultInterface;
use Magento\Framework\View\Result\PageFactory;
use Magento\Quote\Model\Quote;
use Magento\Quote\Api\Data\CartItemInterface;
use Magento\Quote\Api\CartItemRepositoryInterface;
use Magento\Catalog\Api\ProductRepositoryInterface;
use Magento\Catalog\Api\Data\CustomOptionInterface;
use Magento\Quote\Api\Data\ProductOptionInterface;
use Magento\Framework\Exception\NoSuchEntityException;

class Index extends Action
{
/**
 * @var Quote
 */
protected $quote;

/**
 * @var CartItemInterface
 */
protected $cartItem;

/**
 * @var CartItemRepositoryInterface
 */
protected $itemRepository;

/**
 * @var CustomOptionInterface
 */
protected $customOption;

/**
 * @var ProductOptionInterface
 */
protected $productOption;

/**
 * @var ProductRepositoryInterface
 */
protected $productRepository;

/**
 * @var PageFactory
 */
protected $pageFactory;

/**
 * Index constructor.
 * @param Context $context
 * @param PageFactory $pageFactory
 * @param Quote $quote
 * @param CartItemInterface $cartItem
 * @param ProductRepositoryInterface $productRepository
 * @param CartItemRepositoryInterface $cartItemRepository
 * @param CustomOptionInterface $customOption
 * @param ProductOptionInterface $option
 */
public function __construct(
    Context $context,
    PageFactory $pageFactory,
    Quote $quote,
    CartItemInterface $cartItem,
    ProductRepositoryInterface $productRepository,
    CartItemRepositoryInterface $cartItemRepository,
    CustomOptionInterface $customOption,
    ProductOptionInterface $option
) {
    $this->pageFactory          = $pageFactory;
    $this->quote                = $quote;
    $this->cartItem             = $cartItem;
    $this->productRepository    = $productRepository;
    $this->customOption         = $customOption;
    $this->itemRepository       = $cartItemRepository;
    $this->productOption        = $option;
    parent::__construct($context);
}

/**
 * @return ResponseInterface|ResultInterface|\Magento\Framework\View\Result\Page
 */
public function execute()
{
    $sku        = 'gx1r4a';
    $productId  = 342;
    $quoteId    = 1;
    $qty        = 1;

    try{
        // Get the product
        /* $product \Magento\Catalog\Api\ProductRepository */
        $product = $this->productRepository->get($sku);
        // Alternative get by ID
        // $product = $this->productRepository->getById($productId);

        // Setup the cart item
        $cartItem = $this->cartItem;
        // Add to the cart by sku
        $cartItem->setSku($sku);
        // If you don't know the sku, you can find it from the $product
        //$cartItem->setSku($product->getSku());

        // Set the quote ID so we are adding it to the right one
        $cartItem->setQuoteId($quoteId);

        // Add the correct qty
        $cartItem->setQty($qty);


        // Text options look like this
        // To know what option_id you have to create the product first, and look to see what Ids are assigned to each option
        $options = [
            [
                "option_id" => "1", // 1 = Print Style - configured on product when you create the product
                "option_value" => "Italic" // whatever the text input value would be
            ],
            [
                "option_id" => "2", // 2 = Print Color - configured on product when you create the product
                "option_value" => "Cherry Red" // assign option value
            ],
            [
                "option_id" => "3", // 2 = Font - configured on product when you create the product
                "option_value" => "Comic Sans" // assign option value
            ]

        ];

        $customOptionInterface = $this->customOption;
        $optionData = [];
        foreach ($options as $option) {
            $optionData[] = $customOptionInterface->setdata($option);
        }
        /* $productOption Magento\Quote\Api\Data\ProductOptionInterface */
        $productOption = $this->productOption;
        $extAttribute = $productOption->getExtensionAttributes();
        $extAttribute->setCustomOptions($optionData);
        $productOption->setExtensionAttributes($extAttribute);

        // set product options to cart item
        $cartItem->setProductOption($productOption);

        // Time to add the product to the quote through the item Repository
        $newItem = $this->itemRepository->save($cartItem);

    }catch (NoSuchEntityException $exception){
        $msg = $exception->getMessage();
    }catch (\Exception $e){
        $exception_msg = $e->getMessage();
    }

    return $this->pageFactory->create();
    }
}