<?php

require_once( dirname( __FILE__ ) . '/login-interstitial/class-itsec-login-interstitial-session.php' );
require_once( dirname( __FILE__ ) . '/login-interstitial/abstract-itsec-login-interstitial.php' );
require_once( dirname( __FILE__ ) . '/login-interstitial/class-itsec-login-interstitial-config-driven.php' );

/**
 * Class ITSEC_Lib_Login_Interstitial
 */
class ITSEC_Lib_Login_Interstitial {

	const SHOW_AFTER_LOGIN = 'itsec_after_interstitial';
	const AJAX = 'itsec-login-interstitial-ajax';

	const R_USER = 'itsec_interstitial_user';
	const R_TOKEN = 'itsec_interstitial_token';
	const R_SESSION = 'itsec_interstitial_session';
	const R_EXPIRED = 'itsec_interstitial_expired';
	const R_INTERSTITIAL = 'itsec_interstitial';
	const R_ASYNC_ACTION = 'itsec_interstitial_async_action';
	const R_GET_STATE = 'itsec_interstitial_get_state';
	const R_SAME_BROWSER_DENY = 'itsec_interstitial_browser_deny';

	const C_SAME_BROWSER = 'itsec_interstitial_browser';
	const SAME_BROWSER_PAYLOAD = 'same-browser';

	/** @var ITSEC_Login_Interstitial[] */
	private $registered = array();

	/** @var WP_Error */
	private $error;

	/** @var string */
	private $session_token;

	/** @var ITSEC_Login_Interstitial_Session|null */
	private $current_session;

	/**
	 * Initialize the module.
	 *
	 * This registers hooks and filters.
	 */
	public function run() {

		/**
		 * Fires when the Login Interstitial framework is initialized.
		 *
		 * @param ITSEC_Lib_Login_Interstitial
		 */
		do_action( 'itsec_login_interstitial_init', $this );

		if ( ! $this->registered ) {
			return;
		}

		uasort( $this->registered, array( $this, '_sort_interstitials' ) );

		add_action( 'login_enqueue_scripts', array( $this, 'enqueue' ) );
		add_action( 'wp_login', array( $this, 'wp_login' ), - 1000, 2 );
		add_action( 'wp_login_errors', array( $this, 'handle_token_expired' ) );
		add_action( 'login_init', array( $this, 'force_interstitial' ) );
		add_action( 'login_form', array( $this, 'ferry_after_login' ) );
		add_filter( 'auth_cookie', array( $this, 'capture_session_token' ), 10, 5 );

		add_action( 'wp_ajax_' . self::AJAX, array( $this, 'ajax_handler' ) );
		add_action( 'wp_ajax_nopriv_' . self::AJAX, array( $this, 'ajax_handler' ) );

		foreach ( $this->registered as $id => $interstitial ) {
			if ( $interstitial->has_async_action() ) {
				add_action( "login_form_itsec-{$id}", array( $this, 'async_action' ), 8 );
			}

			add_action( "login_form_itsec-{$id}", array( $this, 'submit' ), 9 );
			add_action( "login_form_itsec-{$id}", array( $this, 'display' ) );
		}
	}

	/**
	 * Register an interstitial.
	 *
	 * @api
	 *
	 * @param string                            $slug
	 * @param ITSEC_Login_Interstitial|callable $render_or_class
	 * @param array                             $opts
	 *
	 * @return bool
	 */
	public function register( $slug, $render_or_class, $opts = array() ) {

		if ( $render_or_class instanceof ITSEC_Login_Interstitial ) {
			$this->registered[ $slug ] = $render_or_class;

			return true;
		}

		$opts = wp_parse_args( $opts, array(
			'force_completion' => true, // Will logout the user's session before displaying the interstitial.
			'show_to_user'     => true, // Boolean or callable.
			'wp_login_only'    => false, // Only show the interstitial if the login form is submitted from wp-login.php,
			'submit'           => false, // Callable called with user when submitting the form.
			'async_action'     => false, // Callable called when a user clicks a link to perform an interstitial action.
			'info_message'     => false,
			'after_submit'     => false,
			'ajax_handler'     => false,
			'priority'         => 5,
		) );

		$opts['render'] = $render_or_class;

		try {
			$this->registered[ $slug ] = new ITSEC_Login_Interstitial_Config_Driven( $opts );
		} catch ( Exception $e ) {
			/** @noinspection ForgottenDebugOutputInspection */
			error_log( $e->getMessage() );

			return false;
		}

		return true;
	}

	/**
	 * Show the interstitial.
	 *
	 * @api
	 *
	 * @param ITSEC_Login_Interstitial_Session $session
	 *
	 * @return void
	 */
	public function show_interstitial( ITSEC_Login_Interstitial_Session $session ) {

		if ( ! isset( $this->registered[ $session->get_current_interstitial() ] ) ) {
			return;
		}

		$this->current_session = $session;

		$interstitial = $this->registered[ $session->get_current_interstitial() ];

		if ( $interstitial->is_completion_forced( $session ) ) {
			$this->destroy_session_token( $session->get_user() );
		}

		$this->login_html( $session );
		die;
	}

	/**
	 * Handle proceeding the session to the next interstitial.
	 *
	 * @api
	 *
	 * @param ITSEC_Login_Interstitial_Session $session
	 *
	 * @return bool
	 */
	public function proceed_to_next( ITSEC_Login_Interstitial_Session $session ) {

		$current = $session->get_current_interstitial();
		$session->add_completed_interstitial( $current );

		$session->set_current_interstitial( $this->get_next_interstitial( $session ) );

		return $session->save();
	}

	/**
	 * Get the current interstitial session.
	 *
	 * @api
	 *
	 * @return ITSEC_Login_Interstitial_Session|null
	 */
	public function get_current_session() {
		return $this->current_session;
	}

	/**
	 * Get the URL to an async action.
	 *
	 * @api
	 *
	 * @param ITSEC_Login_Interstitial_Session $session
	 * @param string                           $action
	 *
	 * @return string
	 */
	public function get_async_action_url( ITSEC_Login_Interstitial_Session $session, $action ) {

		$url = $this->get_base_wp_login_url();
		$url = add_query_arg( array(
			'action'             => "itsec-{$session->get_current_interstitial()}",
			self::R_USER         => $session->get_user()->ID,
			self::R_TOKEN        => $session->get_signature_for_payload( $action ),
			self::R_SESSION      => $session->get_id(),
			self::R_ASYNC_ACTION => $action,
		), $url );

		return $url;
	}

	/**
	 * Initialize the same browser functionality.
	 *
	 * This sets a cookie with a signature payload.
	 *
	 * @api
	 *
	 * @param ITSEC_Login_Interstitial_Session $session
	 */
	public function initialize_same_browser( ITSEC_Login_Interstitial_Session $session ) {
		ITSEC_Lib::set_cookie( self::C_SAME_BROWSER, $session->get_signature_for_payload( self::SAME_BROWSER_PAYLOAD ) );

		/**
		 * Fires when the login interstitial initializes the Same Browser API for async actions.
		 *
		 * @param ITSEC_Login_Interstitial_Session $session
		 */
		do_action( 'itsec_login_interstitial_initialize_same_browser', $session );
	}

	/**
	 * Register the interstitial helper script.
	 *
	 * @internal
	 */
	public function enqueue() {
		wp_register_script( 'itsec-login-interstitial-util', plugin_dir_url( __FILE__ ) . '/login-interstitial/util.js', array( 'jquery', 'wp-util' ), 1 );
		wp_add_inline_script( 'itsec-login-interstitial-util', '(function() { window.itsecLoginInterstitial = new ITSECLoginInterstitial(); window.itsecLoginInterstitial.init() })()' );
	}

	/**
	 * During the login process, check if we have any interstitials to display, and display them.
	 *
	 * @internal
	 *
	 * @param string  $username
	 * @param WP_User $user
	 */
	public function wp_login( $username, $user = null ) {
		$user = $user ? $user : wp_get_current_user();

		if ( ! $user || ! $user->exists() ) {
			return;
		}

		foreach ( $this->get_applicable_interstitials( $user ) as $action => $opts ) {
			$session = ITSEC_Login_Interstitial_Session::create( $user, $action );

			if ( is_wp_error( $session ) ) {
				wp_die( $session );
			}

			$session->initialize_from_global_state();

			if ( isset( $_REQUEST[ self::SHOW_AFTER_LOGIN ], $this->registered[ $_REQUEST[ self::SHOW_AFTER_LOGIN ] ] ) ) {
				$session->add_show_after( $_REQUEST[ self::SHOW_AFTER_LOGIN ] );
			}

			$session->save();

			$this->show_interstitial( $session );
		}

		if ( isset( $_REQUEST[ self::SHOW_AFTER_LOGIN ], $this->registered[ $_REQUEST[ self::SHOW_AFTER_LOGIN ] ] ) ) {
			$session = ITSEC_Login_Interstitial_Session::create( $user, $_REQUEST[ self::SHOW_AFTER_LOGIN ] );

			if ( is_wp_error( $session ) ) {
				wp_die( $session );
			}

			$session->initialize_from_global_state();
			$session->save();
			$this->show_interstitial( $session );
		}
	}

	/**
	 * Add a message that the interstitial expired.
	 *
	 * @internal
	 *
	 * @param WP_Error $errors
	 *
	 * @return WP_Error
	 */
	public function handle_token_expired( $errors ) {

		if ( isset( $_GET[ self::R_EXPIRED ] ) ) {
			$errors->add(
				'itsec-login-interstitial-invalid-token',
				esc_html__( 'Sorry, this request has expired. Please log in again.', 'better-wp-security' )
			);
		}

		return $errors;
	}

	/**
	 * Force the requested interstitial to be displayed if the user is already logged-in.
	 *
	 * @internal
	 */
	public function force_interstitial() {

		if ( empty( $_REQUEST[ self::SHOW_AFTER_LOGIN ] ) || ! isset( $this->registered[ $_REQUEST[ self::SHOW_AFTER_LOGIN ] ] ) ) {
			return;
		}

		$slug = $_REQUEST[ self::SHOW_AFTER_LOGIN ];

		if ( 'POST' === $_SERVER['REQUEST_METHOD'] ) {
			return;
		}

		if ( ! is_user_logged_in() ) {
			return;
		}

		$user         = wp_get_current_user();
		$interstitial = $this->registered[ $slug ];

		if ( ! $interstitial->show_to_user( $user, true ) ) {
			wp_safe_redirect( admin_url() );
			die;
		}

		$session = ITSEC_Login_Interstitial_Session::create( $user, $slug );
		$this->show_interstitial( $session );
	}

	/**
	 * Ferry the after login interstitial query var into the form.
	 *
	 * @internal
	 */
	public function ferry_after_login() {
		if ( ! empty( $_REQUEST[ self::SHOW_AFTER_LOGIN ] ) && isset( $this->registered[ $_REQUEST[ self::SHOW_AFTER_LOGIN ] ] ) ) {
			echo '<input type="hidden" name="' . esc_attr( self::SHOW_AFTER_LOGIN ) . '" value="' . esc_attr( $_REQUEST[ self::SHOW_AFTER_LOGIN ] ) . '">';
		}
	}

	/**
	 * Capture the session token to log out the user.
	 *
	 * @internal
	 *
	 * @param string $cookie
	 * @param int    $user_id
	 * @param int    $expiration
	 * @param string $scheme
	 * @param string $token
	 *
	 * @return string
	 */
	public function capture_session_token( $cookie, $user_id, $expiration, $scheme, $token ) {
		$this->session_token = $token;

		return $cookie;
	}

	/**
	 * Handle submitting the interstitial form.
	 *
	 * @internal
	 */
	public function submit() {
		$session = $this->get_and_verify_session();
		$slug    = $session->get_current_interstitial();

		// If we think we have all finished all the interstitials.
		// We need to check because another process may have moved the interstitial forward.
		if ( ! $slug ) {
			// Double check to ensure we are actually finished.
			if ( $next = $this->get_next_interstitial( $session ) ) {
				// If not, display the next interstitial.
				$session->set_current_interstitial( $next );
				$session->save();
			}

			$this->do_next_step( $session );
		}

		if ( 'POST' !== $_SERVER['REQUEST_METHOD'] || empty( $_POST['action'] ) ) {
			return;
		}

		if ( empty( $this->registered[ $slug ] ) ) {
			return;
		}

		$requested_slug = substr( $_POST['action'], strlen( 'itsec-' ) );

		if ( $slug !== $requested_slug ) {
			// If we have already completed the action that was requested, then just display
			// the new interstitial.
			if ( $session->is_interstitial_completed( $requested_slug ) ) {
				$this->show_interstitial( $session );
			} else {
				$this->redirect_invalid_token();
			}
		}

		$this->current_session = $session;

		$interstitial = $this->registered[ $slug ];

		if ( $interstitial->has_submit() ) {
			$maybe_error = $interstitial->submit( $session, $_POST );

			if ( is_wp_error( $maybe_error ) ) {
				$this->error = $maybe_error;

				return;
			}
		}

		$interstitial->after_submit( $session, $_POST );

		$this->proceed_to_next( $session );
		$this->do_next_step( $session );
	}

	/**
	 * Handle an async GET action to the interstitial.
	 *
	 * @internal
	 */
	public function async_action() {

		if ( empty( $_GET[ self::R_ASYNC_ACTION ] ) ) {
			return;
		}

		$session = $this->get_and_verify_session_for_async_action( true );

		if ( is_wp_error( $session ) ) {
			$this->display_wp_login_message( $session );
		}

		$action = $_GET[ self::R_ASYNC_ACTION ];
		$slug   = $session->get_current_interstitial();

		if ( empty( $this->registered[ $slug ] ) ) {
			$this->display_wp_login_message( new WP_Error( 'unsupported', esc_html__( 'Unsupported Interstitial. Please login again.', 'better-wp-security' ) ) );
		}

		$interstitial = $this->registered[ $slug ];

		if ( ! $interstitial->has_async_action() ) {
			$this->display_wp_login_message( new WP_Error( 'unsupported', esc_html__( 'Unsupported Interstitial. Please login again.', 'better-wp-security' ) ) );
		}

		if ( isset( $_REQUEST[ self::R_SAME_BROWSER_DENY ] ) ) {
			$session->delete();
			wp_redirect( wp_login_url() );
			die;
		}

		$args = array(
			'same_browser' => false,
		);

		if (
			isset( $_COOKIE[ self::C_SAME_BROWSER ] ) &&
			true === $session->verify_signature_for_payload( self::SAME_BROWSER_PAYLOAD, $_COOKIE[ self::C_SAME_BROWSER ] )
		) {
			$args['same_browser'] = true;
		}

		$this->current_session = $session;

		if ( ! $args['same_browser'] && 'GET' === $_SERVER['REQUEST_METHOD'] ) {
			$this->display_async_action_confirmation( $session, $action );
		}

		$result = $interstitial->handle_async_action( $session, $action, $args );

		if ( null === $result ) {
			$this->display_wp_login_message( new WP_Error( 'unsupported', esc_html__( 'Unsupported Interstitial. Please login again.', 'better-wp-security' ) ) );
		}

		if ( is_wp_error( $result ) ) {
			$this->display_wp_login_message( $result );
		}

		if ( true === $result ) {
			$result = array();
		}

		if ( $args['same_browser'] && empty( $result['allow_same_browser'] ) ) {
			$this->do_next_step( $session, array(
				'delete'        => false,
				'allow_interim' => false,
			) );
		}

		$result = wp_parse_args( $result, array(
			'message' => esc_html__( 'Action processed. Please continue in your original browser.', 'better-wp-security' ),
			'title'   => esc_html__( 'Action Processed', 'better-wp-security' ),
		) );

		$this->display_wp_login_message( $result );
	}

	/**
	 * Ajax Handler.
	 *
	 * @internal
	 */
	public function ajax_handler() {

		$session   = $this->get_and_verify_session( true );
		$get_state = ! empty( $_REQUEST[ self::R_GET_STATE ] );

		if ( is_wp_error( $session ) ) {
			if ( $get_state && is_user_logged_in() ) {
				wp_send_json_success( array(
					'logged_in' => true,
				) );
			}

			wp_send_json_error( array( 'message' => $session->get_error_message() ) );
		}

		if ( $get_state ) {
			wp_send_json_success( array(
				'current'   => $session->get_current_interstitial(),
				'completed' => $session->get_completed_interstitials(),
				'state'     => $session->get_state(),
			) );
		}

		$slug = $session->get_current_interstitial();

		if ( empty( $this->registered[ $slug ] ) ) {
			wp_send_json_error( array( 'message' => esc_html__( 'Invalid Interstitial Action', 'better-wp-security' ) ) );
		}

		$interstitial = $this->registered[ $slug ];

		if ( ! $interstitial->has_ajax_handlers() ) {
			wp_send_json_error( array( 'message' => esc_html__( 'Invalid Interstitial Action', 'better-wp-security' ) ) );
		}

		$data = $_POST;
		unset( $data[ self::R_USER ], $data[ self::R_TOKEN ], $data[ self::R_SESSION ] );

		$this->current_session = $session;
		$interstitial->handle_ajax( $session, $data );
	}

	/**
	 * Handle displaying the interstitial form.
	 *
	 * @internal
	 */
	public function display() {

		$action = substr( current_action(), strlen( 'login_form_itsec-' ) );

		if ( empty( $this->registered[ $action ] ) ) {
			return;
		}

		$interstitial = $this->registered[ $action ];
		$session      = $this->get_and_verify_session();

		if ( ! $interstitial->show_to_user( $session->get_user(), $session->is_current_requested() ) ) {
			wp_safe_redirect( set_url_scheme( wp_login_url(), 'login_post' ) );
			die;
		}

		$this->login_html( $session );
		die;
	}

	/**
	 * Display an interstitial form during the login process.
	 *
	 * @internal
	 *
	 * @param ITSEC_Login_Interstitial_Session $session
	 */
	protected function login_html( ITSEC_Login_Interstitial_Session $session ) {

		$user         = $session->get_user();
		$action       = $session->get_current_interstitial();
		$interstitial = $this->registered[ $action ];

		$wp_login_url = $this->get_base_wp_login_url();
		$wp_login_url = add_query_arg( 'action', "itsec-{$action}", $wp_login_url );

		$interstitial->pre_render( $session );

		// Prevent JetPack from attempting to SSO the update password form.
		add_filter( 'jetpack_sso_allowed_actions', '__return_empty_array' );

		if ( ! function_exists( 'login_header' ) ) {
			require_once( dirname( __FILE__ ) . '/includes/function.login-header.php' );
		}

		login_header();

		wp_enqueue_script( 'itsec-login-interstitial-util' );
		?>

		<?php if ( $this->error && $this->error->get_error_data() === 'message' ) : ?>
			<p class="message"><?php echo $this->error->get_error_message(); ?></p>
		<?php elseif ( $this->error ): ?>
			<div id="login-error" class="message" style="border-left-color: #dc3232;">
				<?php echo $this->error->get_error_message(); ?>
			</div>
		<?php elseif ( $message = $interstitial->get_info_message( $session ) ): ?>
			<p class="message"><?php echo $message; ?></p>
		<?php endif; ?>

		<form name="itsec-<?php echo esc_attr( $action ); ?>" id="itsec-<?php echo esc_attr( $action ); ?>"
			  action="<?php echo esc_url( $wp_login_url ); ?>" method="post" autocomplete="off">

			<?php $interstitial->render( $session, compact( 'wp_login_url' ) ); ?>

			<input type="hidden" name="action" value="<?php echo esc_attr( "itsec-{$action}" ); ?>">

			<input type="hidden" name="<?php echo esc_attr( self::R_USER ) ?>" value="<?php echo esc_attr( $user->ID ); ?>">
			<input type="hidden" name="<?php echo esc_attr( self::R_TOKEN ) ?>" value="<?php echo esc_attr( $session->get_signature() ); ?>">
			<input type="hidden" name="<?php echo esc_attr( self::R_SESSION ) ?>" value="<?php echo esc_attr( $session->get_id() ); ?>">
		</form>

		<p id="backtoblog">
			<a href="<?php echo esc_url( home_url( '/' ) ); ?>" title="<?php esc_attr_e( 'Are you lost?', 'better-wp-security' ); ?>">
				<?php echo esc_html( sprintf( __( '&larr; Back to %s', 'better-wp-security' ), get_bloginfo( 'title', 'display' ) ) ); ?>
			</a>
		</p>

		</div>
		<?php do_action( 'login_footer' ); ?>
		<div class="clear"></div>
		</body>
		</html>
		<?php
	}

	/**
	 * Handle the interim login screen.
	 */
	private function interim_login() {

		if ( ! function_exists( 'login_header' ) ) {
			require_once( dirname( __FILE__ ) . '/includes/function.login-header.php' );
		}

		$GLOBALS['interim_login'] = 'success';
		$customize_login          = isset( $_REQUEST['customize-login'] );

		if ( $customize_login ) {
			wp_enqueue_script( 'customize-base' );
		}

		login_header( '', '<p class="message">' . __( 'You have logged in successfully.' ) . '</p>' );
		?>
		</div>
		<?php

		do_action( 'login_footer' ); ?>

		<?php if ( $customize_login ) : ?>
			<script type="text/javascript">
				setTimeout( function() {
					new wp.customize.Messenger( {
						url    : '<?php echo wp_customize_url(); ?>',
						channel: 'login',
					} ).send( 'login' );
				}, 1000 );
			</script>
		<?php endif; ?>

		</body></html>
		<?php die;
	}

	/**
	 * Display a message on the WP-Login screen.
	 *
	 * @param WP_Error|array $message
	 */
	private function display_wp_login_message( $message ) {
		if ( ! function_exists( 'login_header' ) ) {
			require_once( dirname( __FILE__ ) . '/includes/function.login-header.php' );
		}

		login_header();

		?>
		<?php if ( is_wp_error( $message ) ) : ?>
			<div id="login-error" class="message" style="border-left-color: #dc3232;">
				<?php echo $message->get_error_message(); ?>
			</div>
		<?php elseif ( ! empty( $message['message'] ) ): ?>
			<p class="message"><?php echo $message['message']; ?></p>
		<?php endif; ?>

		<p id="backtoblog">
			<a href="<?php echo esc_url( home_url( '/' ) ); ?>" title="<?php esc_attr_e( 'Are you lost?', 'better-wp-security' ); ?>">
				<?php echo esc_html( sprintf( __( '&larr; Back to %s', 'better-wp-security' ), get_bloginfo( 'title', 'display' ) ) ); ?>
			</a>
		</p>

		</div>
		<?php do_action( 'login_footer' ); ?>
		<div class="clear"></div>
		</body>
		</html>
		<?php
		die;
	}

	/**
	 * Display a confirmation button for an async action.
	 *
	 * @param ITSEC_Login_Interstitial_Session $session
	 * @param string                           $action
	 */
	private function display_async_action_confirmation( ITSEC_Login_Interstitial_Session $session, $action ) {
		if ( ! function_exists( 'login_header' ) ) {
			require_once( dirname( __FILE__ ) . '/includes/function.login-header.php' );
		}

		$form_action = $this->get_async_action_url( $session, $action );

		login_header();
		?>
		<style type="text/css">
			.login h2 {
				margin-bottom: 10px;
				font-size: 14px;
			}

			.itsec-login-interstitial-confirm-async-action {
				vertical-align: top;
				display: block;
				text-decoration: none;
				height: 28px;
				margin: 0 0 15px 0;
				cursor: pointer;
				-webkit-appearance: none;
				border-radius: 3px;
				white-space: nowrap;
				box-sizing: border-box;
				background: #0083E3;
				color: #fff;
				text-shadow: none;
				padding: 20px 30px;
				line-height: 0;
				box-shadow: none;
				font-weight: 300;
				font-size: 1.2em;
				border: none;
				width: 100%;
				text-align: center;
			}
			.itsec-login-interstitial-confirm-async-action:last-child {
				margin-bottom: 0;
			}
			.itsec-login-interstitial-confirm-async-action:hover,
			.itsec-login-interstitial-confirm-async-action:focus {
				background: #006799;
				color: #fff;
			}
			.itsec-login-interstitial-confirm-async-action.itsec-login-interstitial-confirm-async-action--deny {
				background: #d54e21;
			}
			.itsec-login-interstitial-confirm-async-action.itsec-login-interstitial-confirm-async-action--deny:hover,
			.itsec-login-interstitial-confirm-async-action.itsec-login-interstitial-confirm-async-action--deny:focus {
				background: #983818;
			}
		</style>
		<form action="<?php echo esc_url( $form_action ); ?>" method="post" autocomplete="off">

			<h2><?php esc_html_e( 'Please Verify the Login Request', 'better-wp-security' ); ?></h2>

			<?php do_action( 'itsec_login_interstitial_async_action_confirmation_before_confirm', $session, $action ); ?>

			<button class="itsec-login-interstitial-confirm-async-action">
				<?php esc_html_e( 'Confirm Login', 'better-wp-security' ); ?>
			</button>
			<button name="<?php echo esc_attr( self::R_SAME_BROWSER_DENY ); ?>" class="itsec-login-interstitial-confirm-async-action itsec-login-interstitial-confirm-async-action--deny">
				<?php esc_html_e( 'Deny Login', 'better-wp-security' ); ?>
			</button>
		</form>

		<p id="backtoblog">
			<a href="<?php echo esc_url( home_url( '/' ) ); ?>" title="<?php esc_attr_e( 'Are you lost?', 'better-wp-security' ); ?>">
				<?php echo esc_html( sprintf( __( '&larr; Back to %s', 'better-wp-security' ), get_bloginfo( 'title', 'display' ) ) ); ?>
			</a>
		</p>

		</div>
		<?php do_action( 'login_footer' ); ?>
		<div class="clear"></div>
		</body>
		</html>
		<?php
		die;
	}

	/**
	 * Do the next step for a session.
	 *
	 * If there are more steps, show the next step,  otherwise log the user in.
	 *
	 * @param ITSEC_Login_Interstitial_Session $session
	 * @param array                            $args
	 */
	private function do_next_step( ITSEC_Login_Interstitial_Session $session, array $args = array() ) {
		$args = wp_parse_args( $args, array(
			'delete'        => true,
			'allow_interim' => true,
		) );

		if ( $session->get_current_interstitial() ) {
			$this->show_interstitial( $session );
		} else {
			if ( true === $args['delete'] ) {
				$session->delete();
			}

			$this->handle_interstitials_completed( $session, $args );
		}
	}

	/**
	 * Handle when all of the interstitials have been processed.
	 *
	 * @param ITSEC_Login_Interstitial_Session $session
	 * @param array                            $args
	 */
	private function handle_interstitials_completed( ITSEC_Login_Interstitial_Session $session, array $args ) {

		$user   = $session->get_user();
		$secure = '';

		// If the user wants SSL but the session is not SSL, force a secure cookie.
		if ( ! force_ssl_admin() && get_user_option( 'use_ssl', $user->ID ) ) {
			$secure = true;
			force_ssl_admin( true );
		}

		if ( ! is_user_logged_in() ) {
			wp_set_auth_cookie( $user->ID, $session->is_remember_me(), $secure );

			remove_action( 'wp_login', array( $this, 'wp_login' ), - 1000 );
			do_action( 'wp_login', $user->user_login, $user );

			/**
			 * Fires when a user is re-logged back in after submitting an interstitial.
			 *
			 * @param WP_User $user
			 */
			do_action( 'itsec_login_interstitial_logged_in', $user );
		}

		if ( $args['allow_interim'] && $session->is_interim_login() ) {
			$this->interim_login();
		}

		if ( $session->get_redirect_to() ) {
			$redirect_to = $requested = $session->get_redirect_to();

			if ( $secure && false !== strpos( $redirect_to, 'wp-admin' ) ) {
				$redirect_to = preg_replace( '|^http://|', 'https://', $redirect_to );
			}
		} else {
			$redirect_to = admin_url();
			$requested   = '';
		}

		if ( ! $redirect_to || $redirect_to === 'wp-admin/' || $redirect_to === admin_url() ) {
			// If the user doesn't belong to a blog, send them to user admin. If the user can't edit posts, send them to their profile.
			if ( is_multisite() && ! get_active_blog_for_user( $user->ID ) && ! is_super_admin( $user->ID ) ) {
				$redirect_to = user_admin_url();
			} elseif ( is_multisite() && ! $user->has_cap( 'read' ) ) {
				$redirect_to = get_dashboard_url( $user->ID );
			} elseif ( ! $user->has_cap( 'edit_posts' ) ) {
				$redirect_to = $user->has_cap( 'read' ) ? admin_url( 'profile.php' ) : home_url();
			}
		}

		$redirect_to = apply_filters( 'login_redirect', $redirect_to, $requested, $user );
		wp_safe_redirect( $redirect_to );

		die;
	}

	/**
	 * Get the base wp login URL.
	 *
	 * @return string
	 */
	private function get_base_wp_login_url() {
		$wp_login_url = set_url_scheme( wp_login_url(), 'login_post' );

		if ( isset( $_GET['wpe-login'] ) && ! preg_match( '/[&?]wpe-login=/', $wp_login_url ) ) {
			$wp_login_url = add_query_arg( 'wpe-login', $_GET['wpe-login'], $wp_login_url );
		}

		return $wp_login_url;
	}

	/**
	 * Get the next interstitial to be displayed.
	 *
	 * @param ITSEC_Login_Interstitial_Session $session
	 *
	 * @return string|false
	 */
	private function get_next_interstitial( ITSEC_Login_Interstitial_Session $session ) {

		foreach ( $this->get_applicable_interstitials( $session->get_user() ) as $action => $interstitial ) {
			if ( ! $session->is_interstitial_completed( $action ) ) {
				return $action;

			}
		}

		foreach ( $session->get_show_after() as $action ) {
			if ( ! $session->is_interstitial_completed( $action ) ) {
				return $action;
			}
		}

		return false;
	}

	/**
	 * Get all handlers that are applicable to the given user.
	 *
	 * @param WP_User $user
	 *
	 * @return array
	 */
	private function get_applicable_interstitials( $user ) {

		$applicable = array();

		foreach ( $this->registered as $action => $interstitial ) {
			if ( $this->is_interstitial_applicable( $action, $user ) ) {
				$applicable[ $action ] = $interstitial;
			}
		}

		return $applicable;
	}

	/**
	 * Is the interstitial applicable to the given user.
	 *
	 * @param string  $action
	 * @param WP_User $user
	 *
	 * @return bool
	 */
	private function is_interstitial_applicable( $action, $user ) {

		$interstitial = $this->registered[ $action ];

		if ( ! $interstitial->show_to_user( $user, false ) ) {
			return false;
		}

		if ( ! did_action( 'login_init' ) && $interstitial->show_on_wp_login_only( $user ) ) {
			return false;
		}

		return true;
	}

	/**
	 * Get the active session.
	 *
	 * @param bool $return_error
	 *
	 * @return ITSEC_Login_Interstitial_Session|WP_Error
	 */
	private function get_and_verify_session( $return_error = false ) {

		$error = new WP_Error(
			'itsec-login-interstitial-invalid-token',
			esc_html__( 'Sorry, this request has expired. Please log in again.', 'better-wp-security' )
		);

		if ( ! isset( $_REQUEST[ self::R_USER ], $_REQUEST[ self::R_TOKEN ], $_REQUEST[ self::R_SESSION ] ) ) {
			return $return_error ? $error : $this->redirect_invalid_token();
		}

		$session = ITSEC_Login_Interstitial_Session::get( $_REQUEST[ self::R_SESSION ] );

		if ( is_wp_error( $session ) ) {
			return $return_error ? $error : $this->redirect_invalid_token();
		}

		$valid = $session->verify( (int) $_REQUEST[ self::R_USER ], $_REQUEST[ self::R_TOKEN ] );

		if ( true !== $valid ) {
			return $return_error ? $error : $this->redirect_invalid_token();
		}

		return $session;
	}

	/**
	 * Get the active session and verify for performing an async action.
	 *
	 * @param bool $return_error
	 *
	 * @return ITSEC_Login_Interstitial_Session|WP_Error
	 */
	private function get_and_verify_session_for_async_action( $return_error = false ) {

		$error = new WP_Error(
			'itsec-login-interstitial-invalid-token',
			esc_html__( 'Sorry, this request has expired. Please log in again.', 'better-wp-security' )
		);

		if ( ! isset( $_REQUEST[ self::R_USER ], $_REQUEST[ self::R_TOKEN ], $_REQUEST[ self::R_SESSION ], $_REQUEST[ self::R_ASYNC_ACTION ] ) ) {
			return $return_error ? $error : $this->redirect_invalid_token();
		}

		$session = ITSEC_Login_Interstitial_Session::get( $_REQUEST[ self::R_SESSION ] );

		if ( is_wp_error( $session ) ) {
			return $return_error ? $error : $this->redirect_invalid_token();
		}

		$valid = $session->verify_for_payload(
			$_REQUEST[ self::R_ASYNC_ACTION ],
			(int) $_REQUEST[ self::R_USER ],
			$_REQUEST[ self::R_TOKEN ]
		);

		if ( true !== $valid ) {
			return $return_error ? $error : $this->redirect_invalid_token();
		}

		return $session;
	}

	/**
	 * Redirect back to the login page with a message that the token is invalid.
	 */
	private function redirect_invalid_token() {

		if ( ! isset( $_REQUEST[ self::SHOW_AFTER_LOGIN ] ) && is_user_logged_in() ) {
			wp_safe_redirect( admin_url() );
			die;
		}

		$redirect = add_query_arg( self::R_EXPIRED, 1, wp_login_url() );
		wp_safe_redirect( set_url_scheme( $redirect, 'login_post' ) );
		die;
	}

	/**
	 * Destroy the session for a user.
	 *
	 * @param WP_User $user
	 */
	private function destroy_session_token( $user ) {
		WP_Session_Tokens::get_instance( $user->ID )->destroy( $this->session_token ? $this->session_token : wp_get_session_token() );
		wp_clear_auth_cookie();
	}

	/**
	 * Sort interstitials according to priority.
	 *
	 * @param ITSEC_Login_Interstitial $a
	 * @param ITSEC_Login_Interstitial $b
	 *
	 * @return int
	 */
	private function _sort_interstitials( $a, $b ) {
		return $a->get_priority() - $b->get_priority();
	}
}
