class OrderMeta
{
    const META_KEY = 'line_order_meta';
    const TRANSACTION_STATE_KEY = 'linepay_trans_state';

    /**
     * Welcart order ID
     *
     * @var int
     */
    private $orderid;

    /**
     * LINE Pay transaction ID
     *
     * @var string
     */
    private $transactionId;

    /**
     * Array of order meta data
     *
     * @var array
     */
    private $meta;

    /**
     * LINE Pay transaction state
     *
     * Default: `null`
     *
     * @var TransactionState|null
     */
    private $transactionState = null;

    /**
     * Constructs a LINE Pay order meta object from an existing Welcart transaction
     *
     * @author Evan D Shaw <evandanielshaw@gmail.com>
     * @param int $orderid
     * @return void
     */
    public function __construct($orderid) {
        global $usces;

        $this->orderid = (int)$orderid;
        $this->meta = unserialize($usces->get_order_meta_value(self::META_KEY, $orderid));
        $this->transactionId = $this->meta['transactionId'];
        $transactionState = $usces->get_order_meta_value(self::TRANSACTION_STATE_KEY, $orderid);
        if (!empty($transactionState)) {
            $transactionState = json_decode($transactionState, true);
            $this->transactionState = new TransactionState($this->transactionId, $transactionState['state']);
        }
    }

    /**
     * Saves LINE Pay order meta data on a successful Welcart order
     *
     * @author Evan D Shaw <evandanielshaw@gmail.com>
     * @global \usc_e_shop $usces
     * @param TransactionState $state
     * @param array            $meta
     * @param int              $orderid
     * @return void
     */
    public static function registerOrderMeta(TransactionState $state, array $meta, $orderid) {
        global $usces;

        $usces->set_order_meta_value('wc_trans_id', $state->getTransactionId(), $orderid);
        $usces->set_order_meta_value(self::META_KEY, serialize($meta), $orderid);
        $usces->set_order_meta_value(self::TRANSACTION_STATE_KEY, wp_json_encode($state), $orderid);
    }

    /**
     * Saves LINE Pay order meta data on a successful Welcart order
     *
     * @author Evan D Shaw <evandanielshaw@gmail.com>
     * @global \usc_e_shop $usces
     * @param TransactionState $state
     * @return OrderMeta
     */
    public function setTransactionState(TransactionState $state) {
        global $usces;

        $usces->set_order_meta_value(self::TRANSACTION_STATE_KEY, wp_json_encode($state), $this->orderid);
        return $this;
    }

    /**
     * Getter for `orderid`
     *
     * @author Evan D Shaw <evandanielshaw@gmail.com>
     * @return int
     */
    public function getOrderId() {
        return $this->orderid;
    }

    /**
     * Getter for `transactionId`
     *
     * @author Evan D Shaw <evandanielshaw@gmail.com>
     * @return string
     */
    public function getTransactionId() {
        return $this->transactionId;
    }

    /**
     * Getter for `meta`
     *
     * @author Evan D Shaw <evandanielshaw@gmail.com>
     * @return array
     */
    public function getMeta() {
        return $this->meta;
    }

    /**
     * Getter for `transactionState`
     *
     * @author Evan D Shaw <evandanielshaw@gmail.com>
     * @return TransactionState|null
     */
    public function getTransactionState() {
        return $this->transactionState;
    }
}