Meta Pixel – Purchase Event

/**

 * =============================================================================

 * META PIXEL — Purchase (WooCommerce Thank You) — Dedup ready for CAPI

 * =============================================================================

 * - Fires on thank-you page ONLY for paid orders (processing/completed)

 * - Uses variation_id when present

 * - Adds eventID = order_{order_id} for CAPI dedup

 * - Prevents repeats via order meta guard

 * =============================================================================

 */

add_action('woocommerce_thankyou', 'voelgoed_meta_pixel_purchase', 10, 1);

function voelgoed_meta_pixel_purchase($order_id) {

    if (empty($order_id) || is_admin() || wp_doing_ajax()) {

        return;

    }

    if ( ! function_exists('wc_get_order') ) {

        return;

    }

    $order = wc_get_order($order_id);

    if (!$order) {

        return;

    }

    // Only fire for PAID orders (prevents false purchases)

    $status = $order->get_status();

    if ( ! in_array($status, ['processing', 'completed'], true) ) {

        return;

    }

    // Prevent duplicates (page refresh / re-visits)

    if (get_post_meta($order_id, '_vg_meta_pixel_purchase_tracked', true)) {

        return;

    }

    $content_ids = [];

    $contents    = [];

    foreach ($order->get_items() as $item) {

        if (!is_a($item, 'WC_Order_Item_Product')) {

            continue;

        }

        $product_id   = (int) $item->get_product_id();

        $variation_id = (int) $item->get_variation_id();

        $id           = $variation_id ? $variation_id : $product_id;

        $qty = (int) $item->get_quantity();

        if ($id <= 0 || $qty <= 0) {

            continue;

        }

        // Unit price (ex tax) from line total / qty

        $line_total = (float) $item->get_total();

        $unit_price = $qty > 0 ? ($line_total / $qty) : 0.0;

        $content_ids[] = (string) $id;

        $contents[] = [

            'id'         => (string) $id,

            'quantity'   => $qty,

            'item_price' => round((float) $unit_price, 2),

        ];

    }

    $content_ids = array_values(array_unique($content_ids));

    $value    = (float) $order->get_total();

    $currency = $order->get_currency() ? $order->get_currency() : 'ZAR';

    // eventID must match server-side CAPI event_id for dedup

    $event_id = 'order_' . (string) $order_id;

    ?>

    <script>

    (function () {

        if (typeof fbq !== 'function') return;

        fbq('track', 'Purchase', {

            content_ids: <?php echo wp_json_encode($content_ids); ?>,

            content_type: 'product',

            contents: <?php echo wp_json_encode($contents); ?>,

            value: <?php echo wp_json_encode($value); ?>,

            currency: <?php echo wp_json_encode($currency); ?>

        }, {

            eventID: <?php echo wp_json_encode($event_id); ?>

        });

    })();

    </script>

    <?php

    // Mark tracked AFTER output (best possible server-side guard)

    update_post_meta($order_id, '_vg_meta_pixel_purchase_tracked', 1);

}