<?php
/**
 * Server-side order attribution (DESIGN decision #23, §4.3).
 *
 * Fires on WooCommerce's `woocommerce_payment_complete` and posts a
 * `checkout_completed` event to the brain's server-to-server order endpoint:
 *
 *   POST {BRAIN}/api/storefront/order   header X-Aisthetix-Secret: <secretKey>
 *   { eventName:"checkout_completed", orderId, visitorKey|null, customerId|null,
 *     productIds:[...], value, currency }
 *
 * Server-side is the right place for the order event: it is ad-blocker-proof and
 * fires even if the shopper's tab is closed (unlike a client pixel). The brain
 * correlates it to prior try-ons by visitorKey + customerId + productId within the
 * 30-day attribution window. The secret key is server-only (never exposed to the
 * browser). Everything here is best-effort — a checkout must NEVER fail because the
 * brain is slow or unreachable.
 *
 * @package Aisthetix\TryOn
 */

namespace Aisthetix\TryOn;

defined( 'ABSPATH' ) || exit;

/**
 * Order attribution sender.
 */
class Attribution {

	/**
	 * Register hooks.
	 *
	 * @return void
	 */
	public function init() {
		// Fires once payment is captured for an order (the reliable "purchased" signal).
		add_action( 'woocommerce_payment_complete', array( $this, 'on_payment_complete' ), 20, 1 );
	}

	/**
	 * Build and send the checkout_completed event for a paid order.
	 *
	 * @param int $order_id WooCommerce order id.
	 * @return void
	 */
	public function on_payment_complete( $order_id ) {
		// Only when connected (we need the secret key to authenticate).
		if ( ! Plugin::is_connected() ) {
			return;
		}

		// Opt-in analytics: no server-side order event without the merchant's explicit
		// consent (default OFF). Mirrors the storefront cookie/event gate.
		if ( ! Plugin::analytics_enabled() ) {
			return;
		}

		$order_id = (int) $order_id;
		if ( $order_id <= 0 ) {
			return;
		}

		$order = wc_get_order( $order_id );
		if ( ! $order instanceof \WC_Order ) {
			return;
		}

		$payload = $this->build_payload( $order );

		// Fire-and-forget: non-blocking so checkout latency is unaffected. The brain
		// is idempotent on (storeId, order:<orderId>), so a retry can't double-count.
		wp_remote_post(
			Plugin::brain_url() . '/api/storefront/order',
			array(
				'timeout'  => 5,
				'blocking' => false,
				'headers'  => array(
					'Content-Type'       => 'application/json',
					'Accept'             => 'application/json',
					'X-Aisthetix-Secret' => Plugin::secret_key(),
				),
				'body'     => wp_json_encode( $payload ),
			)
		);
	}

	/**
	 * Assemble the order event payload (matches the shared contract exactly).
	 *
	 * @param \WC_Order $order Paid order.
	 * @return array
	 */
	private function build_payload( $order ) {
		$product_ids = array();
		foreach ( $order->get_items() as $item ) {
			if ( ! $item instanceof \WC_Order_Item_Product ) {
				continue;
			}
			// Canonical product id (not the variation id) — the join key the brain
			// matches against try-on / view anchors. The brain de-dupes productIds[].
			$pid = (int) $item->get_product_id();
			if ( $pid > 0 ) {
				$product_ids[] = (string) $pid;
			}
		}
		$product_ids = array_values( array_unique( $product_ids ) );

		// customerId: the logged-in WP user id on the order, or null for guests.
		$customer_id = (int) $order->get_customer_id();

		return array(
			'eventName'  => 'checkout_completed',
			'orderId'    => (string) $order->get_id(),
			'visitorKey' => $this->visitor_key_from_cookie(),
			'customerId' => $customer_id > 0 ? (string) $customer_id : null,
			'productIds' => $product_ids,
			// REVENUE BASIS (intentional): the order value is the GROSS order total —
			// get_total() includes tax and shipping. This is a deliberate choice for
			// parity with the Shopify attribution (which reports the order's total
			// price), so attributedRevenue means the same thing across platforms and
			// the brain's ROI numbers are comparable. It is NOT a bug to "fix" to a
			// net/subtotal basis; doing so would diverge from Shopify. If a net basis
			// is ever wanted it must be changed on BOTH platforms together.
			'value'      => (float) $order->get_total(),
			'currency'   => $order->get_currency(),
		);
	}

	/**
	 * Read the durable first-party visitor key from the `aisthetix_vid` cookie.
	 *
	 * The cookie is set by {@see Storefront::maybe_set_visitor_cookie()} on product
	 * pages and is sent on the same first-party domain at checkout, so it is the
	 * PRIMARY attribution key. Returns null when absent or malformed (a guest who
	 * never hit a product page, or a stripped cookie) — the brain still attributes
	 * via customerId for logged-in shoppers.
	 *
	 * @return string|null
	 */
	private function visitor_key_from_cookie() {
		if ( ! isset( $_COOKIE[ Storefront::VISITOR_COOKIE ] ) ) {
			return null;
		}
		// phpcs:ignore WordPress.Security.ValidatedSanitizedInput.InputNotSanitized -- validated by the strict regex below.
		$candidate = wp_unslash( $_COOKIE[ Storefront::VISITOR_COOKIE ] );
		if ( is_string( $candidate ) && preg_match( '/^[a-f0-9]{32}$/', $candidate ) ) {
			return $candidate;
		}
		return null;
	}
}