<?php
/**
 * WooCommerce events.
 *
 * Event names and fields follow the FullSession Shopify app, with a
 * `woocommerce_` prefix. All values are sent as strings.
 *
 * @package FullSession
 */

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

/**
 * Sends add to cart, checkout started and checkout completed events.
 *
 * Add to cart happens on the server, so the event is kept in the WooCommerce
 * session. For AJAX add to cart it comes back with the cart fragments;
 * otherwise it's sent on the next page load.
 */
class FullSession_WooCommerce {

	const SESSION_EVENTS   = 'fullsession_events';
	const SESSION_CHECKOUT = 'fullsession_checkout_started';
	const ORDER_META       = '_fullsession_tracked';
	const FRAGMENT_KEY     = 'div.fullsession-events';
	const MAX_QUEUED       = 20;

	/**
	 * Register hooks.
	 */
	public static function init() {
		add_action( 'before_woocommerce_init', array( __CLASS__, 'declare_compatibility' ) );
		add_action( 'woocommerce_add_to_cart', array( __CLASS__, 'on_add_to_cart' ), 10, 4 );
		add_filter( 'woocommerce_add_to_cart_fragments', array( __CLASS__, 'add_fragment' ) );
		add_filter( 'fullsession_page_events', array( __CLASS__, 'page_events' ) );
		add_action( 'wp_enqueue_scripts', array( __CLASS__, 'enqueue' ), 20 );
	}

	/**
	 * Whether WooCommerce is active.
	 *
	 * @return bool
	 */
	public static function is_active() {
		return class_exists( 'WooCommerce' );
	}

	/**
	 * Whether WooCommerce events are turned on.
	 *
	 * @return bool
	 */
	private static function is_enabled() {
		$settings = FullSession_Settings::get();
		return self::is_active() && $settings['woo_events'] && $settings['enabled'] && FullSession_Settings::is_connected();
	}

	/**
	 * Works with High-Performance Order Storage and the block-based cart and checkout.
	 */
	public static function declare_compatibility() {
		if ( class_exists( '\Automattic\WooCommerce\Utilities\FeaturesUtil' ) ) {
			\Automattic\WooCommerce\Utilities\FeaturesUtil::declare_compatibility( 'custom_order_tables', FULLSESSION_FILE, true );
			\Automattic\WooCommerce\Utilities\FeaturesUtil::declare_compatibility( 'cart_checkout_blocks', FULLSESSION_FILE, true );
		}
	}

	/**
	 * Queue an add to cart event.
	 *
	 * @param string $cart_item_key Cart item key.
	 * @param int    $product_id    Product ID.
	 * @param int    $quantity      Quantity added.
	 * @param int    $variation_id  Variation ID, 0 for simple products.
	 */
	public static function on_add_to_cart( $cart_item_key, $product_id, $quantity, $variation_id ) {
		if ( ! self::is_enabled() || ! WC()->session ) {
			return;
		}

		$product = wc_get_product( $variation_id ? $variation_id : $product_id );
		$parent  = $variation_id ? wc_get_product( $product_id ) : $product;
		if ( ! $product || ! $parent ) {
			return;
		}

		$data = array(
			'product_id'    => (string) $product_id,
			'product_title' => $parent->get_name(),
			'variant_id'    => $variation_id ? (string) $variation_id : '',
			'variant_title' => $variation_id ? wc_get_formatted_variation( $product, true, false, false ) : '',
			'variant_price' => (string) $product->get_price(),
			'quantity'      => (string) $quantity,
		);

		$events   = self::queued_events();
		$events[] = array(
			'name' => 'woocommerce_product_added_to_cart',
			'data' => $data,
		);
		WC()->session->set( self::SESSION_EVENTS, array_slice( $events, -self::MAX_QUEUED ) );
	}

	/**
	 * For AJAX add to cart, return the queued events with the cart fragments.
	 * fullsession-woocommerce.js picks them up from the `added_to_cart` event.
	 *
	 * @param array $fragments Cart fragments.
	 * @return array
	 */
	public static function add_fragment( $fragments ) {
		$is_add_to_cart = doing_action( 'wc_ajax_add_to_cart' )
			|| doing_action( 'wp_ajax_woocommerce_add_to_cart' )
			|| doing_action( 'wp_ajax_nopriv_woocommerce_add_to_cart' );

		if ( ! $is_add_to_cart || ! self::is_enabled() ) {
			return $fragments;
		}

		$events = self::take_queued_events();
		if ( $events ) {
			$fragments[ self::FRAGMENT_KEY ] = FullSession_Tracker::encode( $events );
		}
		return $fragments;
	}

	/**
	 * Events for the current page: queued add to cart, checkout started and order completed.
	 *
	 * @param array $events Events from other sources.
	 * @return array
	 */
	public static function page_events( $events ) {
		if ( ! self::is_enabled() ) {
			return $events;
		}

		$events = array_merge( $events, self::take_queued_events() );

		$checkout = self::checkout_started_event();
		if ( $checkout ) {
			$events[] = $checkout;
		}

		$completed = self::checkout_completed_event();
		if ( $completed ) {
			$events[] = $completed;
		}

		return $events;
	}

	/**
	 * Load the add to cart listener.
	 */
	public static function enqueue() {
		if ( ! self::is_enabled() || ! wp_script_is( FullSession_Tracker::HANDLE, 'enqueued' ) ) {
			return;
		}
		wp_enqueue_script( 'fullsession-woocommerce', FULLSESSION_URL . 'assets/js/fullsession-woocommerce.js', array( 'jquery', FullSession_Tracker::HANDLE ), FULLSESSION_VERSION, true );
		wp_add_inline_script( 'fullsession-woocommerce', 'window.fullsessionWooFragmentKey = ' . FullSession_Tracker::encode( self::FRAGMENT_KEY ) . ';', 'before' );
	}

	/**
	 * Checkout page opened. Sent once per cart, so reloading the page doesn't repeat it.
	 *
	 * @return array|null
	 */
	private static function checkout_started_event() {
		if ( ! is_checkout() || is_order_received_page() || ! WC()->cart || WC()->cart->is_empty() || ! WC()->session ) {
			return null;
		}

		$hash = WC()->cart->get_cart_hash();
		if ( WC()->session->get( self::SESSION_CHECKOUT ) === $hash ) {
			return null;
		}
		WC()->session->set( self::SESSION_CHECKOUT, $hash );

		return array(
			'name' => 'woocommerce_checkout_started',
			'data' => array(
				'checkout_total'      => (string) WC()->cart->get_total( 'edit' ),
				'checkout_currency'   => get_woocommerce_currency(),
				'checkout_item_count' => (string) count( WC()->cart->get_cart() ),
			),
		);
	}

	/**
	 * Thank-you page. Sent once per order.
	 *
	 * @return array|null
	 */
	private static function checkout_completed_event() {
		if ( ! is_order_received_page() ) {
			return null;
		}

		$order_id = absint( get_query_var( 'order-received' ) );
		// The order key in the URL is what WooCommerce itself uses to show this page.
		$key   = isset( $_GET['key'] ) ? sanitize_text_field( wp_unslash( $_GET['key'] ) ) : ''; // phpcs:ignore WordPress.Security.NonceVerification.Recommended
		$order = $order_id ? wc_get_order( $order_id ) : false;

		if ( ! $order || '' === $key || ! hash_equals( $order->get_order_key(), $key ) || $order->get_meta( self::ORDER_META ) ) {
			return null;
		}

		$order->update_meta_data( self::ORDER_META, 1 );
		$order->save();

		return array(
			'name' => 'woocommerce_checkout_completed',
			'data' => array(
				'order_id'          => (string) $order->get_id(),
				'checkout_total'    => (string) $order->get_total(),
				'checkout_currency' => $order->get_currency(),
			),
		);
	}

	/**
	 * Events waiting in the session.
	 *
	 * @return array
	 */
	private static function queued_events() {
		if ( ! WC()->session ) {
			return array();
		}
		$events = WC()->session->get( self::SESSION_EVENTS, array() );
		return is_array( $events ) ? $events : array();
	}

	/**
	 * Events waiting in the session, removed from it.
	 *
	 * @return array
	 */
	private static function take_queued_events() {
		$events = self::queued_events();
		if ( $events ) {
			WC()->session->set( self::SESSION_EVENTS, array() );
		}
		return $events;
	}
}