Update Custom product meta when order completed - php

Question

I am trying to update a product meta for all products of each order that gets completed. Can you have a look at my approach below? Any help on why it is not working will be appreciated. I am new to all this php customizing.
add_action( 'woocommerce_order_status_completed', 'update_product_meta', 20, 2 );
function update_product_meta ( $order_id, $order ) {
// GET USER ORDERS (COMPLETED + PROCESSING)
$args = array(
'post_status' => array('wc-completed')
);
$done_orders = wc_get_orders( $args );
// LOOP THROUGH ORDERS AND GET PRODUCT IDS
if ( $done_orders ) {
$product_ids = array();
foreach ( $done_orders as $done_order ) {
$order = wc_get_order( $done_order->ID );
$items = $order->get_items();
foreach ( $items as $item ) {
$product_id = $item->get_product_id();
}
}
add_action( 'woocommerce_process_product_meta', 'action_save_product_meta' );
function action_save_product_meta( $product_id ) {
update_post_meta($product_id, 'Stav', 'Vypůjčeno' );
}
}
}

Answer 1

Well you're pretty close, you just have to remove the nonsense at the end.
Something along the lines of:
<?php
add_action( 'woocommerce_order_status_completed', function ( $order_id, $order ) {
$args = array(
'post_status' => array('wc-completed')
);
$done_orders = wc_get_orders( $args );
if ( ! empty( $done_orders ) ) {
foreach ( $done_orders as $done_order ) {
$order = wc_get_order( $done_order->ID );
$items = $order->get_items();
foreach ( $items as $item ) {
$product_id = $item->get_product_id();
update_post_meta( $product_id, 'Stav', 'Vypůjčeno' );
};
};
};
}, 20, 2 );
You should think of limiting it to a specific amount because right now your query will request ALL items ever completed. be careful.