WP-import-all-product-stock-change.php

<?php 
function action__product_stock_change( $continue, $post_id, $data, $import_id ) {

    $firstImportId = 10;
    $supplierPrefix = "A-";

    $secondImportId = 20;

    // Set the input ID
    if ( $import_id === $firstImportId ) {
        // Change 'sku' to the column name that contains your SKU.
        $product_sku = $data['sku'];

        // if product sku doesn't start with the prefix return early
        if( ! substr( $product_sku, 0, strlen( $supplierPrefix ) ) === $supplierPrefix ){
          return false; 
        }

        // Change 'qty' to the column name that contains your QTY.
        $product_qty = ( $data['stock'] ? $data['stock'] : '0');

        $product_id_by_sku = wc_get_product_id_by_sku( $product_sku );
        
        // Set up WooCommerce product object
        $product = wc_get_product( $product_id_by_sku );

        // Process if product found
        if ( $product ) {
            $product_import = get_transient( 'product_import' );
            $product_import = ( $product_import ? $product_import : "" );
            // check if product and the product id by sku match,
            // if they don't, set the product qty to 0
            if ( $product->get_id() !== $product_id_by_sku ) {
                $product_qty = 0;
            }
            $array[] = $product->get_id();
            // Make changes to stock quantity and save
            $product->set_manage_stock( true );
            $product->set_stock_quantity( $product_qty );
            $product->save();
            $product_import .= $product->get_id() . ",";
            set_transient( 'product_import', $product_import, 3000 );
            return true;
        }
      // Don't update this post 
      return false;
    } else if ( $import_id == $secondImportId ) {

        // Change 'sku' to the column name that contains your SKU.
        $product_sku = $data['sku'];

        // if product sku starts with the prefix return early
        if( substr( $product_sku, 0, strlen( $supplierPrefix ) ) === $supplierPrefix ){
          return false; 
        }

        // Change 'qty' to the column name that contains your QTY.
        $product_qty = ( $data['stock'] ? $data['stock'] : '0');

        $product_id_by_sku = wc_get_product_id_by_sku( $product_sku );
        
        // Set up WooCommerce product object
        $product = wc_get_product( $product_id_by_sku );

        // Process if product found
        if ( $product ) {
            $product_import = get_transient( 'product_import' );
            $product_import = ( $product_import ? $product_import : "" );
            // check if product and the product id by sku match,
            // if they don't, set the product qty to 0
            if ( $product->get_id() !== $product_id_by_sku ) {
                $product_qty = 0;
            }
            $array[] = $product->get_id();
            // Make changes to stock quantity and save
            $product->set_manage_stock( true );
            $product->set_stock_quantity( $product_qty );
            $product->save();
            $product_import .= $product->get_id() . ",";
            set_transient( 'product_import', $product_import, 3000 );
            return true;
        }
      // Don't update this post 
      return false;
    }
}

add_filter( 'wp_all_import_is_post_to_update', 'action__product_stock_change', 10, 4 );


 function after_xml_import( $import_id, $import ) {

    $firstImportId = 10;
    $secondImportId = 20;
    
    // Only run if import ID is 5.
    if ( $import_id === $firstImportId || $import_id === $secondImportId  ) {

        $product_import = get_transient( 'product_import' );

        if ( $product_import ){
            $array = explode( ",",$product_import );
            $args = array(
                'limit' => -1,
            );
            $products = wc_get_products( $args );
            $count = count( $products );
            
            foreach( $products as $product ){
                if ( $product->get_type() === 'simple' && ! in_array( $product->get_id(), $array ) ) {
                    wc_update_product_stock( $product->get_id(), 0 );
                    wc_update_product_stock_status( $product->get_id(), 'outofstock' );
                }
            }
            delete_transient( 'product_import' );
        }
        
    }
}
add_action( 'pmxi_after_xml_import', 'after_xml_import', 10, 2 );