<?php
// Include WordPress bootstrap file
require_once('wp-load.php');

// Get global database object
global $wpdb;

// Function to generate SKU for variations
function generate_variation_sku($parent_sku, $attributes) {
    $sku = $parent_sku;
    foreach ($attributes as $attribute) {
        $sku .= '-' . strtoupper($attribute);
    }
    return $sku;
}

// Get all published parent products
$parent_products = $wpdb->get_results("
    SELECT ID, post_title
    FROM {$wpdb->posts}
    WHERE post_type = 'product'
    AND post_status = 'publish'
");

if ($parent_products) {
    $count = 1; // SKU counter
    foreach ($parent_products as $parent_product) {
        $parent_id = $parent_product->ID;

        // Get parent SKU
        $parent_sku = get_post_meta($parent_id, '_sku', true);

        // If parent SKU is empty or not set, assign a new SKU
        if (empty($parent_sku)) {
            $parent_sku = sprintf('%03d', $count); // Format SKU as 001, 002, etc.
            update_post_meta($parent_id, '_sku', $parent_sku);

            // Get variations for the parent product
            $variations = get_posts(array(
                'post_type' => 'product_variation',
                'post_status' => 'publish',
                'post_parent' => $parent_id,
                'fields' => 'ids'
            ));

            if ($variations) {
                foreach ($variations as $variation_id) {
                    // Get attributes for the variation
                    $variation_attributes = wc_get_product_variation_attributes($variation_id);

                    // Generate SKU for the variation
                    $variation_sku = generate_variation_sku($parent_sku, array_values($variation_attributes));

                    // Update SKU for the variation
                    update_post_meta($variation_id, '_sku', $variation_sku);
                }
            }

            $count++; // Increment SKU counter
        }
    }
    echo 'SKUs assigned successfully!';
} else {
    echo 'No parent products found.';
}