magento2 how to update tier price programmatically, including value type?

Question

I am able add tier prices using csv

$this->tierPrice->add($sku, $customerGroupId, $price, $qty);

but it is taking "value_type" as Fixed , i want to dynamically give the value for "value_type"

Answer 1

I done the same by doing

$product_obj = $this->_objectManager->create('Magento\Catalog\Model\Product')->load($prod_id);
    $tierPrices[] = array(
                                 'website_id'  => 0,
                                 'cust_group'  => 1,
                                 'price_qty'   => $qty,
                                 'price'       => $price,
                                 'percentage_value'  => $percentage);
                          $product_obj->setTierPrice($tierPrices);
                        $product_obj->save(); 
Here in the above array   `percentage_value` is given for the price range having discount type.         

Answer 2

I used Rakesh Jesadiya article information and done some debugging to create more "elegant" solution for percentage_value tier price type. Here is my code:

use Magento\Catalog\Api\Data\ProductTierPriceInterface;
use Magento\Catalog\Api\Data\ProductTierPriceInterfaceFactory;
use Magento\Catalog\Api\ScopedProductTierPriceManagementInterface;

class ProductPriceListsResolver
{
    /**
     * @var ScopedProductTierPriceManagementInterface
     */
    private $tierPriceManagement;
    /**
     * @var ProductTierPriceInterface
     */
    private $productTierPriceFactory;

    public function __construct(
        ScopedProductTierPriceManagementInterface $tierPriceManagement,
        ProductTierPriceInterfaceFactory $productTierPriceFactory
    ) {

        $this->tierPriceManagement = $tierPriceManagement;
        $this->productTierPriceFactory = $productTierPriceFactory;
    }

    public function resolve()
    {
        $sku = 'sku_83519'; //Product sku
        $customerGroupId = 6; //premium group id
        $price = 50.00;
        $qty = 1.00;

        /** @var ProductTierPriceInterface $productTierPrice */
        $productTierPrice = $this->productTierPriceFactory->create();
        $productTierPrice->setCustomerGroupId($customerGroupId)
            ->setQty($qty)
            ->setValue(20.00);

        $extensionAttributes = $productTierPrice->getExtensionAttributes();
        $extensionAttributes->setPercentageValue(20.00);
        $productTierPrice->setExtensionAttributes($extensionAttributes);
        try {
            $this->tierPriceManagement->add($sku, $productTierPrice);
        } catch (\Exception $e) {
            throw new $e;
        }
    }
}

Answer 3

I'm also looking for a solution to update tier price without call save() method.

So, I used @embed0 suggested solution but exception accured:

The data was invalid. Verify the data and try again. in /vendor/magento/module-catalog/Model/Product/TierPriceManagement.php:99

Can you please specified the expected result for $productTierPrice argument of add() method?