( !$box->isAvailableTo($currentUser, $this->menuEditor) ) {
				remove_meta_box($box->getId(), $currentScreen, $box->getContext());
			}
		}
	}

	/**
	 * @param string $screenId
	 * @return ameMbeScreenSettings
	 */
	protected function getScreenSettings($screenId) {
		$this->loadSettings();

		if ( isset($this->settings[$screenId]) ) {
			return $this->settings[$screenId];
		}

		$collection = new ameMbeScreenSettings($screenId);
		$this->settings[$screenId] = $collection;
		return $collection;
	}

	/**
	 * Change the default list of hidden meta boxes.
	 *
	 * @param array $hidden
	 * @param WP_Screen $screen
	 * @return array
	 */
	public function filterDefaultHiddenBoxes($hidden, $screen) {
		if ( empty($screen) || !($screen instanceof WP_Screen) ) {
			return $hidden;
		}
		if ( isset($this->hiddenBoxCache[$screen->id]) ) {
			return $this->hiddenBoxCache[$screen->id];
		}

		$metaBoxes = $this->getScreenSettings($screen->id)->getMetaBoxes();

		static $isUpdateDone = false;
		if ( !$isUpdateDone ) {
			$changesDetected = $metaBoxes->setHiddenByDefault($hidden);
			if ( $changesDetected ) {
				$this->saveSettings();
			}
			$isUpdateDone = true;
		}

		$user = wp_get_current_user();
		$visible = array();

		foreach ($metaBoxes->getPresentBoxes() as $box) {
			if ( $box->isVisibleByDefaultFor($user, $this->menuEditor) ) {
				$visible[] = $box->getId();
			} else {
				$hidden[] = $box->getId();
			}
		}

		$hidden = array_unique(array_diff($hidden, $visible));

		//Note: It might be a good idea to cache intermediate results (i.e. only custom hidden & visible settings)
		//instead of the final result. Consider that if there are plugin compatibility issues.
		$this->hiddenBoxCache[$screen->id] = $hidden;

		return $hidden;
	}

	private function getUnmodifiedDefaultHiddenBoxes(WP_Screen $screen) {
		//This is a slightly modified excerpt from the get_hidden_meta_boxes() core function in screen.php.
		$hidden = array();
		if ( 'post' == $screen->base ) {
			if ( in_array($screen->post_type, array('post', 'page', 'attachment')) ) {
				$hidden = array(
					'slugdiv',
					'trackbacksdiv',
					'postcustom',
					'postexcerpt',
					'commentstatusdiv',
					'commentsdiv',
					'authordiv',
					'revisionsdiv',
				);
			} else {
				$hidden = array('slugdiv');
			}
		}
		return apply_filters('default_hidden_meta_boxes', $hidden, $screen);
	}

	/**
	 * @param WP_Screen $screen
	 */
	public function processPostTypeFeatures($screen = null) {
		if ( !isset($screen, $screen->post_type, $screen->id) || empty($screen->post_type) ) {
			return;
		}
		//Scan only the "Add Item" and "Edit Item" screens.
		//The "All Items" screen also has a post type, but it contains no editor boxes.
		if ( isset($screen->base) && ($screen->base !== 'post') ) {
			return;
		}

		$currentFeatures = get_all_post_type_supports($screen->post_type);
		if ( empty($currentFeatures) || !is_array($currentFeatures) ) {
			return;
		}

		$currentFeatures = array_intersect_key($currentFeatures, self::$supportedCptFeatures);

		$featureSettings = $this->getScreenSettings($screen->id)->getPostTypeFeatures();
		$changesDetected = $featureSettings->merge($currentFeatures);

		if ( $changesDetected && $this->userCanEditMetaBoxes() ) {
			$this->saveSettings();
		}

		//Remove disabled features.
		$currentUser = wp_get_current_user();
		foreach ($featureSettings->getFeatures() as $feature) {
			if ( !$feature->isAvailableTo($currentUser, $this->menuEditor) ) {
				remove_post_type_support($screen->post_type, $feature->getId());
			}
		}
	}

	public function userCanEditMetaBoxes() {
		return $this->menuEditor->current_user_can_edit_menu();
	}

	private function saveSettings() {
		$json = $this->settings->toJSON();
		$lock = ameFileLock::create(__FILE__);
		$lock->acquire(1);
		$this->setScopedOption(self::OPTION_NAME, $json);
		$lock->release();
	}

	private function loadSettings() {
		if ( isset($this->settings) ) {
			return $this->settings;
		}

		$json = $this->getScopedOption(self::OPTION_NAME, null);

		if ( empty($json) ) {
			$this->settings = new ameMetaBoxSettings();
		} else {
			$this->settings = ameMetaBoxSettings::fromJSON($json);
		}

		return $this->settings;
	}

	public function exportSettings() {
		$this->loadSettings();
		if ( $this->settings->isEmpty() ) {
			return null;
		}
		return $this->settings->toArray();
	}

	public function importSettings($newSettings) {
		if ( empty($newSettings) || !is_array($newSettings) ) {
			return;
		}

		$settings = ameMetaBoxSettings::fromArray($newSettings);
		$settings->setFirstRefreshState(true);
		$this->settings = $settings;
		$this->saveSettings();
	}

	public function getExportOptionLabel() {
		return 'Meta boxes';
	}

	public function getExportOptionDescription() {
		return '';
	}

	public function enqueueTabScripts() {
		parent::enqueueTabScripts();
		$this->loadSettings();

		//Automatically refresh the list of available meta boxes.
		$query = $this->menuEditor->get_query_params();
		$this->shouldRefreshMetaBoxes = empty($query['ame-meta-box-refresh-done'])
			&& (
				$this->settings->isEmpty()
				|| (!empty($query[self::FORCE_REFRESH_PARAM]) && check_admin_referer(self::FORCE_REFRESH_PARAM))
				|| (!$this->settings->isFirstRefreshDone())
			);

		if ( $this->shouldRefreshMetaBoxes ) {
			$pagesWithMetaBoxes = array();
			if ( get_option('link_manager_enabled') ) {
				$pagesWithMetaBoxes[] = 'link-add.php';
			}
			$postTypes = get_post_types(array('public' => true, 'show_ui' => true), 'objects', 'or');
			foreach ($postTypes as $postType) {
				$pagesWithMetaBoxes[] = add_query_arg(
					array(
						'post_type'   => $postType->name,
						'ame_mb_rand' => rand(1, 10000),
					),
					self_admin_url('post-new.php')
				);
			}

			//Include Media/attachments. This post type doesn't have a standard "new post" screen,
			//so lets use the edit URL of the most recently uploaded image instead.
			$attachments = get_posts(array(
				'post_type'      => 'attachment',
				'post_mime_type' => 'image',
				'numberposts'    => 1,
				'post_status'    => null,
				'post_parent'    => 'any',
			));
			if ( $attachments && !empty($attachments) ) {
				$firstAttachment = reset($attachments);
				$pagesWithMetaBoxes[] = get_edit_post_link($firstAttachment->ID, 'raw');
			}

			wp_enqueue_auto_versioned_script(
				'ame-refresh-meta-boxes',
				plugins_url('refresh-meta-boxes.js', __FILE__),
				array('jquery')
			);

			wp_localize_script(
				'ame-refresh-meta-boxes',
				'wsMetaBoxRefresherData',
				array(
					'editorUrl'          => $this->getTabUrl(array('ame-meta-box-refresh-done' => 1)),
					'pagesWithMetaBoxes' => $pagesWithMetaBoxes,
				)
			);
			return;
		}

		wp_register_auto_versioned_script(
			'ame-meta-box-editor',
			plugins_url('metabox-editor.js', __FILE__),
			array(
				'ame-lodash',
				'knockout',
				'ame-actor-selector',
				'jquery',
				'ame-actor-manager',
			)
		);

		$settings = $this->loadSettings();
		wp_localize_script(
			'ame-meta-box-editor',
			'wsAmeMetaBoxEditorData',
			array(
				'settings'   => $settings->toArray(),
				'refreshUrl' => wp_nonce_url(
					$this->getTabUrl(array(
						self::FORCE_REFRESH_PARAM => 1,
						'ame-mb-random'           => rand(1, 10000),
					)),
					self::FORCE_REFRESH_PARAM
				),
			)
		);

		wp_enqueue_script('jquery-qtip');
		wp_enqueue_script('ame-meta-box-editor');

		wp_enqueue_auto_versioned_style(
			'ame-meta-box-editor-style',
			plugins_url('metabox-editor.css', __FILE__)
		);
	}

	public function handleFormSubmission($action, $post = array()) {
		//For debugging.
		if ( $action === 'ame_reset_meta_box_settings' && defined('WP_DEBUG') ) {
			$this->settings = new ameMetaBoxSettings();
			$this->saveSettings();
			return;
		}

		//Note: We don't need to check user permissions here because plugin core already did.
		if ( $action === 'ame_save_meta_boxes' ) {
			check_admin_referer($action);

			//Save settings.
			$settings = ameMetaBoxSettings::fromJSON($post['settings']);
			$settings->setFirstRefreshState(true);
			$this->settings = $settings;
			$this->saveSettings();

			wp_redirect($this->getTabUrl(array('updated' => 1)));
			exit;
		}
	}

	public function displaySettingsPage() {
		$this->loadSettings();
		if ( $this->shouldRefreshMetaBoxes ) {
			if ( !$this->settings->isFirstRefreshDone() ) {
				//Let's update the initial refresh flag before the refresh actually happens.
				//This helps prevent an infinite loop when the initial refresh fails.
				$this->settings->setFirstRefreshState(true);
				$this->saveSettings();
			}
			$this->outputTemplate('box-refresh');
		} else {
			parent::displaySettingsPage();
		}
	}

	public function clearCache() {
		$this->hiddenBoxCache = array();
		$this->settings = null;
	}

	/**
	 * Add a script that will remove Gutenberg document panels that correspond to hidden meta boxes.
	 */
	public function enqueueGutenbergScripts() {
		//Some plugins load the Gutenberg editor outside the admin dashboard in which case
		//the get_current_screen() function might not be available.
		if ( !function_exists('get_current_screen') ) {
			return;
		}
		$currentScreen = get_current_screen();
		if ( empty($currentScreen) ) {
			return;
		}
		$currentUser = wp_get_current_user();

		$boxesToPanels = array(
			'slugdiv'          => 'post-link',
			'postexcerpt'      => 'post-excerpt',
			'postimagediv'     => 'featured-image',
			'commentstatusdiv' => 'discussion-panel',
			'categorydiv'      => 'taxonomy-panel-category',
			'pageparentdiv'    => 'page-attributes',
		);

		$boxesToSelectors = array(
			'submitdiv' => '#editor .edit-post-post-schedule',
			'formatdiv' => '#editor .editor-post-format, #editor .edit-post-post-schedule + .components-panel__row',
		);

		$panelsToRemove = array();
		$selectorsToHide = array();
		$metaBoxes = $this->getScreenSettings($currentScreen->id)->getMetaBoxes();
		$presentBoxes = $metaBoxes->getPresentBoxes();
		foreach ($presentBoxes as $box) {
			if ( $box->isAvailableTo($currentUser, $this->menuEditor) ) {
				continue;
			}

			//What's the panel name for this box?
			$boxId = $box->getId();
			if ( isset($boxesToPanels[$boxId]) ) {
				$panelsToRemove[] = $boxesToPanels[$boxId];
			} else if ( preg_match('/^tagsdiv-(?P<taxonomy>.++)$/', $boxId, $matches) ) {
				$panelsToRemove[] = 'taxonomy-panel-' . $matches['taxonomy'];
			} else if ( isset($boxesToSelectors[$boxId]) ) {
				$selectorsToHide[] = $boxesToSelectors[$boxId];
			}
			//We deliberately skip non-core boxes. For now, the remove_meta_box() call
			//in processMetaBoxes() seems to remove them effectively.
		}

		if ( empty($panelsToRemove) && empty($selectorsToHide) ) {
			return;
		}

		wp_enqueue_auto_versioned_script(
			'ame-hide-gutenberg-panels',
			plugins_url('hide-gutenberg-panels.js', __FILE__),
			array('wp-data', 'wp-blocks', 'wp-edit-post', 'jquery')
		);

		wp_localize_script(
			'ame-hide-gutenberg-panels',
			'wsAmeGutenbergPanelData',
			array(
				'panelsToRemove'  => $panelsToRemove,
				'selectorsToHide' => $selectorsToHide,
			)
		);
	}
}