WooCommerce: Attach PDF Files To Customer Email in Multiple Product Categories

With this code snippet you can attach PDF files to e-mail plain and simply

But that was not good enough for me!

So I added this code with a little help from ChatGPT 🙂

First I wanted this only to fire up when the order is completed in WooCommerce. I did that with 'customer_completed_order' which is a standard WooCommerce Hook

After that I asked if they could make it with multiple PDF files. And also with custom category.
Here is what we ended up with - me and the mighty GPT, after several tries.

Example:
'sanketure' is a product category and sanketur.pdf is the PDF we want to send, if customer is buying something from that category.
And then it continues with 'oesters-safari' and 'svampeture'

add_filter('woocommerce_email_attachments', 'custom_attach_pdf_to_emails', 10, 4);

function custom_attach_pdf_to_emails($attachments, $email_id, $order, $email) {
    // Check if the email is customer completed order
    if ($email_id === 'customer_completed_order') {
        $upload_dir = wp_upload_dir();

        // Define the product category slugs and their corresponding PDF files
        $category_to_pdf = array(
            'sanketure' => 'sanketur.pdf',
            'oesters-safari' => 'osterssafari.pdf',
            'svampeture' => 'svampetur.pdf',
        );

        // Get the product categories for the order
        $product_categories = array();

        foreach ($order->get_items() as $item_id => $item) {
            $product_id = $item->get_product_id();
            $terms = get_the_terms($product_id, 'product_cat');

            if ($terms && !is_wp_error($terms)) {
                foreach ($terms as $term) {
                    $product_categories[] = $term->slug;
                }
            }
        }

        // Check if any of the product categories match the desired ones
        foreach ($product_categories as $category) {
            if (isset($category_to_pdf[$category])) {
                // Attach the corresponding PDF file
                $attachments[] = $upload_dir['basedir'] . "/2023/12/" . $category_to_pdf[$category];
            }
        }
    }

    return $attachments;
}