Send SKU instead of product ID for orders

replace-id-with-sku.php

function monsterinsights_custom_use_sku_instead_of_id( $body ) {

	$numbers = array();
	foreach ( $body as $key => $value ) {

		if ( 0 === strpos( $key, 'pr' ) ) {
			if ( preg_match( '/\d+/', $key, $matches ) ) {
				if ( isset( $matches[0] ) ) {
					$numbers[] = $matches[0];
				}
			}
		}
	}
	$numbers = array_unique( $numbers );

	foreach ( $numbers as $number ) {
		if ( isset( $body[ 'pr' . $number . 'id' ] ) ) {
			$id      = intval( $body[ 'pr' . $number . 'id' ] );
			$product = wc_get_product( $id );
			if ( $product->is_type( 'variable' ) && ! empty( $body[ 'pr' . $number . 'va' ] ) ) {
				// It's a variation, try to use that SKU.
				$variations = $product->get_children();
				if ( ! empty( $variations ) && is_array( $variations ) ) {
					foreach ( $variations as $variation_id ) {
						$variation = wc_get_product( $variation_id );
						if ( $body[ 'pr' . $number . 'va' ] === $variation->get_name() ) {
							$sku = $variation->get_sku();
						}
					}
				} else {
					$sku = $product->get_sku();
				}
			} 
			
			if ( ! empty( $sku ) ) {
				$body[ 'pr' . $number . 'id' ] = $sku;
			}
		}
	}

	return $body;
}

add_filter( 'monsterinsights_mp_api_call', 'monsterinsights_custom_use_sku_instead_of_id' );