class Checkout extends CheckoutHooks
{
    /**
     * `GenericError` instance if checkout failed, `null` otherwise
     *
     * @var GenericError|null
     */
    private $error = null;

    /**
     * `Get Checkout Session` JSON decoded response object
     *
     * @var array|null
     */
    private $checkoutResponse = null;

    /**
     * `Get Charge` JSON decoded response object
     *
     * @var array|null
     */
    private $chargeResponse = null;

    /**
     * Handles a redirect from the `amazonPayRedirectUrl` returned by Amazon
     *
     * @author Evan D Shaw <evandanielshaw@gmail.com>
     * @global \usc_e_shop $usces
     * @return void
     */
    public function handleCheckoutResult() {
        global $usces;

        $sessionId = $_REQUEST['amazonCheckoutSessionId'];
        $result = (new API\CheckoutSession\Complete($this->module))->post($sessionId);
        if ($result instanceof GenericError) {
            $this->error = $result;
            $this->setToErrorPage();
            return;
        }

        $this->checkoutResponse = json_decode($result['response'], true);
        $details = $this->checkoutResponse['statusDetails'];
        $checkoutSessionState = new Models\CheckoutSession\State(
            $details['state'],
            $details['reasonCode'],
            $details['reasonDescription']
        );

        if ($checkoutSessionState->isCanceled()) {
            $this->error = $checkoutSessionState->getErrorResponseFromCanceledState();
            $this->setToErrorPage();
            return;
        }

        // deferred authorization
        if ($checkoutSessionState->isOpen()) {
            $res = $usces->order_processing();
            if (strtolower($res) === 'ordercompletion') {
                $this->setToCompletionPage();
            } else {
                $this->setToErrorPage();
            }
            return;
        }

        if ($checkoutSessionState->isCompleted()) {
            $getChargeRes = (new API\Charge\Get($this->module))->get($this->checkoutResponse['chargeId']);
            if ($getChargeRes instanceof GenericError) {
                $this->error = $getChargeRes;
                $this->setToErrorPage();
                return;
            }
            $this->chargeResponse = json_decode($getChargeRes['response'], true);

            $res = $usces->order_processing();
            if (strtolower($res) === 'ordercompletion') {
                $this->setToCompletionPage();
            } else {
                $this->setToErrorPage();
            }
            return;
        }

        $this->error = $this->module->errors->getErrorResponse(Errors\GenericErrorStore::UNKNOWN_ERROR);
        $this->setToErrorPage();
    }

    /**
     * Sets `$usces->page` to 'error' and adds redirect action
     *
     * @author Evan D Shaw <evandanielshaw@gmail.com>
     * @global \usc_e_shop $usces
     * @return void
     */
    public function setToErrorPage() {
        global $usces;

        $usces->page = 'error';
        add_filter('yoast-ga-push-after-pageview', 'usces_trackPageview_error');
        add_action('the_post', [$usces, 'action_cartFilter']);
        add_action('template_redirect', [$usces, 'template_redirect']);
    }

    /**
     * Sets `$usces->page` to 'ordercompletion' and adds redirect action
     *
     * @author Evan D Shaw <evandanielshaw@gmail.com>
     * @global \usc_e_shop $usces
     * @return void
     */
    public function setToCompletionPage() {
        global $usces;

        $usces->page = 'ordercompletion';
        add_filter('yoast-ga-push-after-pageview', 'usces_trackPageview_ordercompletion');
        add_action('the_post', [$usces, 'action_cartFilter']);
        add_action('template_redirect', [$usces, 'template_redirect']);
    }

    /**
     * Creates error HTML for error page
     *
     * @author Evan D Shaw <evandanielshaw@gmail.com>
     * @param string $html
     * @return string
     */
    protected function errorPageMessage($html) {
        if ($this->error === null) {
            return $html;
        }

        return (new Views\CartErrorPage\CartErrorPage())->getErrorPageHtml($html, $this->error);
    }

    /**
     * Saves AmazonPay order meta data
     *
     * @author Evan D Shaw <evandanielshaw@gmail.com>
     * @param array $args {
     *     Welcart `$_SESSION` variables
     *
     *     @type array  $cart
     *     @type array  $entry
     *     @type int    $order_id
     *     @type int    $member_id
     *     @type array  $payments
     *     @type string $charging_type
     *     @type array  $results
     * }
     * @return void
     */
    protected function registerOrderData($args) {
        if ($this->error === null) {
            $order = (new API\WelcartEntries())->getOrder();
            $chargeState = null;
            if ($this->chargeResponse !== null) {
                $chargeState = new Models\Charge\State(
                    $this->chargeResponse['statusDetails']['state'],
                    $this->chargeResponse['statusDetails']['reasonCode'],
                    $this->chargeResponse['statusDetails']['reasonDescription']
                );
            }
            OrderMeta::saveOrderMetaDataFromCheckoutSession(
                $this->checkoutResponse,
                (int)$args['order_id'],
                $order['total_full_price'],
                usces_crcode('return'),
                $chargeState
            );
        }
    }
}