_table_columns( $columns ) {
	}

	/**
	 * @param $manager \Groundhogg\Bulk_Jobs\Manager
	 */
	public function register_bulk_jobs( $manager ) {
	}

	/**
	 * @param $reports Report[]
	 *
	 * @return array
	 */
	public function register_reports( $reports ) {
		return $reports;
	}

	/**
	 * Add settings to the settings page
	 *
	 * @param $settings array[]
	 *
	 * @return array[]
	 */
	public function register_settings( $settings ) {
		return $settings;
	}

	/**
	 * Add settings sections to the settings page
	 *
	 * @param $sections array[]
	 *
	 * @return array[]
	 */
	public function register_settings_sections( $sections ) {
		return $sections;
	}

	/**
	 * Add settings tabs to the settings page
	 *
	 * @param $tabs array[]
	 *
	 * @return array[]
	 */
	public function register_settings_tabs( $tabs ) {
		return $tabs;
	}

	/**
	 * Register any proprietary DBS
	 *
	 * @param $db_manager Manager
	 */
	public function register_dbs( $db_manager ) {
	}

	/**
	 * Register any api endpoints.
	 *
	 * @param $api_manager
	 *
	 * @return void
	 */
	public function register_apis( $api_manager ) {
	}

	/**
	 * Register any api endpoints.
	 *
	 * @param $api_manager API_V4_HANDLER
	 *
	 * @return void
	 */
	public function register_v4_apis( $api_manager ) {
	}

	/**
	 * Register any new admin pages.
	 *
	 * @param $admin_menu Admin_Menu
	 *
	 * @return void
	 */
	public function register_admin_pages( $admin_menu ) {
	}

	/**
	 * Get the version #
	 *
	 * @return mixed
	 */
	abstract public function get_version();

	/**
	 * Get the ID number for the download in EDD Store
	 *
	 * @return int
	 */
	abstract public function get_download_id();

	protected $plugin_data = [];

	/**
	 * @param string $key
	 *
	 * @return string
	 */
	protected function get_plugin_data( $key = 'Name' ) {
		if ( empty( $this->plugin_data ) ) {
			$this->plugin_data = get_plugin_data( $this->get_plugin_file() );
		}

		return $this->plugin_data[ $key ];
	}

	/**
	 * @return string
	 */
	public function get_display_name() {
		return apply_filters( 'groundhogg/extension/name', $this->get_plugin_data( 'Name' ) );
	}

	/**
	 * @return string
	 */
	public function get_display_description() {
		return apply_filters( 'groundhogg/extension/description', $this->get_plugin_data( 'Description' ) );
	}

	/**
	 * @return string
	 */
	abstract public function get_plugin_file();

	/**
	 * Get details...
	 *
	 * @return array|false
	 */
	public function get_extension_details() {
		return get_array_var( get_option( 'gh_extensions', [] ), $this->get_download_id(), [] );
	}

	/**
	 * Get this extension's license key
	 *
	 * @return string|false
	 */
	public function get_license_key() {
		return get_array_var( $this->get_extension_details(), 'license' );
	}

	/**
	 * @return bool|string
	 */
	public function get_expiry() {

		if ( get_array_var( $this->get_extension_details(), 'expiry' ) === 'lifetime' ) {
			return false;
		}

		return date_i18n( get_option( 'date_format' ), strtotime( get_array_var( $this->get_extension_details(), 'expiry' ) ) );
	}

	/**
	 * Get the EDD updater.
	 *
	 * @return \GH_EDD_SL_Plugin_Updater
	 */
	public function get_edd_updater() {
		if ( ! class_exists( '\GH_EDD_SL_Plugin_Updater' ) ) {
			require_once __DIR__ . '/lib/edd/GH_EDD_SL_Plugin_Updater.php';
		}

		return new \GH_EDD_SL_Plugin_Updater( License_Manager::$storeUrl, $this->get_plugin_file(), [
			'version' => $this->get_version(),
			'license' => $this->get_license_key(),
			'item_id' => $this->get_download_id(),
			'author'  => $this->get_author(),
			'url'     => home_url(),
			'beta'    => is_option_enabled( 'gh_get_beta_versions' ),
		] );
	}

	/**
	 * Return the author string
	 *
	 * @return string
	 */
	protected function get_author() {
		if ( ! is_white_labeled() ) {
			return 'Groundhogg Inc.';
		} else {
			return white_labeled_name();
		}
	}

	final public function __clone() {
		trigger_error( "Singleton. No cloning allowed!", E_USER_ERROR );
	}

	final public function __wakeup() {
		trigger_error( "Singleton. No serialization allowed!", E_USER_ERROR );
	}

	/**
	 * Whether the license is valid
	 *
	 * @return bool
	 */
	public function license_is_valid() {
		$status = get_array_var( $this->get_extension_details(), 'status' );

		return $status === 'valid';
	}

	/**
	 * Return the license status string
	 */
	public function license_status() {
		$status  = get_array_var( $this->get_extension_details(), 'status' );
		$status  = html()->e( 'span', [ 'class' => 'status-' . $status ], $status === 'valid' ? __( 'valid', 'groundhogg' ) : __( 'invalid', 'groundhogg' ) );
		$expires = $this->get_expiry() ? sprintf( __( 'expires on <abbr title="%1$s">%1$s</abbr>', 'groundhogg' ), $this->get_expiry() ) : __( 'never expires', 'groundhogg' );

		return sprintf( __( "Your license is <b>%s</b> and %s.", 'groundhogg' ), $status, $expires );
	}

	/**
	 * @return string
	 */
	public function __toString() {
		$content = "<div class='gh-panel'>";
		$content .= "<div class='gh-panel-header'>";
		$content .= "<h2 class='hndle'>{$this->get_display_name()}</h2>";
		$content .= "</div>";
		$content .= "<div class=\"inside\">";
		$content .= "<p>" . $this->get_display_description() . "</p>";

		$content .= html()->input( [
			'placeholder' => __( 'License', 'groundhogg' ),
			'name'        => "license[{$this->get_download_id()}]",
			'value'       => $this->get_license_key(),
			'type'        => $this->get_license_key() ? 'password' : 'text'
		] );

		if ( $this->get_license_key() ) {
			$content .= "<p>";
			$content .= $this->license_status();
			$content .= "</p>";

			$content .= html()->wrap( [
				html()->wrap( __( 'Check', 'groundhogg' ), 'a', [
					'class' => 'gh-button secondary',
					'href'  => admin_url( wp_nonce_url( add_query_arg( [
						'action'    => 'check_license',
						'extension' => $this->get_download_id()
					], 'admin.php?page=gh_settings&tab=extensions' ) ) )
				] ),
				html()->wrap( __( 'Deactivate', 'groundhogg' ), 'a', [
					'class' => 'gh-button danger text',
					'href'  => admin_url( wp_nonce_url( add_query_arg( [
						'action'    => 'deactivate_license',
						'extension' => $this->get_download_id()
					], 'admin.php?page=gh_settings&tab=extensions' ) ) )
				] ),
			], 'div', [ 'class' => 'display-flex gap-10' ] );
		} else {
			$content .= html()->wrap( html()->input( [
				'type'  => 'submit',
				'name'  => 'activate_license',
				'class' => 'gh-button primary',
				'value' => __( 'Activate', 'groundhogg' ),
			] ), 'p' );
		}

		$content .= "</div>";
		$content .= "</div>";

		return $content;
	}

}