<?php
/**
 * Admin screens: links list, link details, settings, health and tools.
 *
 * @package LinkTender
 */

defined( 'ABSPATH' ) || exit;

require_once __DIR__ . '/class-linktender-list-table.php';

/**
 * Admin UI.
 */
class LinkTender_Admin {

	/**
	 * Plugin.
	 *
	 * @var LinkTender_Plugin
	 */
	private $plugin;

	/**
	 * Links page hook suffix.
	 *
	 * @var string
	 */
	private $links_hook = '';

	/**
	 * Hook suffixes of the LinkTender admin screens (filled in menu()).
	 *
	 * @var string[]
	 */
	private $hooks = array();

	/**
	 * List table instance.
	 *
	 * @var LinkTender_List_Table|null
	 */
	private $table = null;

	/**
	 * Constructor.
	 *
	 * @param LinkTender_Plugin $plugin Plugin.
	 */
	public function __construct( LinkTender_Plugin $plugin ) {
		$this->plugin = $plugin;
	}

	/**
	 * Registers hooks.
	 *
	 * @return void
	 */
	public function hooks() {
		add_action( 'admin_menu', array( $this, 'menu' ) );
		add_action( 'admin_init', array( $this, 'register_settings' ) );
		add_action( 'admin_enqueue_scripts', array( $this, 'assets' ) );
		add_action( 'admin_post_linktender_action', array( $this, 'handle_action' ) );
		add_action( 'admin_post_linktender_edit_url', array( $this, 'handle_edit_url' ) );
		add_action( 'admin_post_linktender_tool', array( $this, 'handle_tool' ) );
		add_action( 'admin_notices', array( $this, 'notices' ) );
		add_action( 'update_option_' . LinkTender_Settings::OPTION, array( $this, 'settings_changed' ), 10, 2 );
		add_filter( 'set-screen-option', array( $this, 'set_screen_option' ), 10, 3 );
		add_filter( 'plugin_action_links_' . plugin_basename( LINKTENDER_FILE ), array( $this, 'plugin_links' ) );
	}

	/**
	 * Menu entries.
	 *
	 * @return void
	 */
	public function menu() {
		$cap = LinkTender_Plugin::capability();

		// The menu title stays plain so the screen IDs are stable; the count bubble is added below.
		$this->links_hook = add_menu_page(
			__( 'Broken Links', 'linktender' ),
			__( 'LinkTender', 'linktender' ),
			$cap,
			'linktender',
			array( $this, 'render_links_page' ),
			'dashicons-admin-links',
			81
		);
		$this->hooks      = array( $this->links_hook );
		$this->hooks[]    = add_submenu_page( 'linktender', __( 'Broken Links', 'linktender' ), __( 'Links', 'linktender' ), $cap, 'linktender', array( $this, 'render_links_page' ) );
		$this->hooks[]    = add_submenu_page( 'linktender', __( 'LinkTender Settings', 'linktender' ), __( 'Settings', 'linktender' ), 'manage_options', 'linktender-settings', array( $this, 'render_settings_page' ) );
		$this->hooks[]    = add_submenu_page( 'linktender', __( 'LinkTender Health & Tools', 'linktender' ), __( 'Health & Tools', 'linktender' ), 'manage_options', 'linktender-tools', array( $this, 'render_tools_page' ) );

		add_action( 'load-' . $this->links_hook, array( $this, 'load_links_page' ) );

		/**
		 * Fires after the plugin's admin menu is registered. Add-ons add their pages here.
		 */
		do_action( 'linktender_admin_menu' );

		// Pages that add-ons registered under the LinkTender menu count as LinkTender screens too.
		global $submenu;
		if ( isset( $submenu['linktender'] ) && is_array( $submenu['linktender'] ) ) {
			foreach ( $submenu['linktender'] as $item ) {
				if ( isset( $item[2] ) ) {
					$this->hooks[] = get_plugin_page_hookname( $item[2], 'linktender' );
				}
			}
		}
		$this->hooks = array_values( array_unique( array_filter( $this->hooks ) ) );

		$this->add_count_bubble();
	}

	/**
	 * Adds the broken-link count to the top-level menu item.
	 *
	 * @return void
	 */
	private function add_count_bubble() {
		global $menu;
		if ( ! is_array( $menu ) || ! LinkTender_Install::checking_started() ) {
			return;
		}
		$broken = get_transient( 'linktender_broken_count' );
		if ( false === $broken ) {
			$counts = $this->plugin->links->status_counts();
			$broken = (int) $counts['broken'];
			set_transient( 'linktender_broken_count', $broken, 5 * MINUTE_IN_SECONDS );
		}
		$broken = (int) $broken;
		if ( $broken < 1 ) {
			return;
		}
		foreach ( $menu as $position => $item ) {
			if ( isset( $item[2] ) && 'linktender' === $item[2] ) {
				// phpcs:ignore WordPress.WP.GlobalVariablesOverride.Prohibited -- Appending a count bubble to our own menu item, as core does for comments and updates.
				$menu[ $position ][0] .= sprintf( ' <span class="awaiting-mod count-%1$d"><span class="pending-count">%2$s</span></span>', $broken, esc_html( number_format_i18n( $broken ) ) );
				break;
			}
		}
	}

	/**
	 * Whether a hook suffix or screen ID belongs to a LinkTender admin screen.
	 *
	 * @param string $hook Hook suffix (same as the screen ID for these pages).
	 * @return bool
	 */
	public function is_own_screen( $hook ) {
		/**
		 * Filters the hook suffixes of the LinkTender admin screens, where its CSS and JS load.
		 *
		 * @param string[] $hooks Hook suffixes.
		 */
		$hooks = (array) apply_filters( 'linktender_admin_screens', $this->hooks );
		return '' !== (string) $hook && in_array( (string) $hook, $hooks, true );
	}

	/**
	 * Settings link on the Plugins screen.
	 *
	 * @param array $links Links.
	 * @return array
	 */
	public function plugin_links( $links ) {
		$label = LinkTender_Install::checking_started() ? __( 'Broken links', 'linktender' ) : __( 'Start checking', 'linktender' );
		array_unshift( $links, '<a href="' . esc_url( admin_url( 'admin.php?page=linktender' ) ) . '">' . esc_html( $label ) . '</a>' );
		return $links;
	}

	/**
	 * Saves the per-page screen option.
	 *
	 * @param mixed  $status Status.
	 * @param string $option Option.
	 * @param mixed  $value  Value.
	 * @return mixed
	 */
	public function set_screen_option( $status, $option, $value ) {
		return 'linktender_per_page' === $option ? max( 5, min( 200, (int) $value ) ) : $status;
	}

	/**
	 * Styles and scripts on our pages only.
	 *
	 * @param string $hook Hook suffix.
	 * @return void
	 */
	public function assets( $hook ) {
		if ( ! $this->is_own_screen( $hook ) ) {
			return;
		}
		wp_enqueue_style( 'linktender-admin', LINKTENDER_URL . 'assets/css/admin.css', array(), LINKTENDER_VERSION );
		wp_enqueue_script( 'linktender-admin', LINKTENDER_URL . 'assets/js/admin.js', array(), LINKTENDER_VERSION, true );
	}

	/**
	 * Registers the settings option.
	 *
	 * @return void
	 */
	public function register_settings() {
		register_setting(
			'linktender_settings',
			LinkTender_Settings::OPTION,
			array(
				'type'              => 'array',
				'sanitize_callback' => array( 'LinkTender_Settings', 'sanitize' ),
				'default'           => array(),
			)
		);
	}

	/**
	 * Starts a rescan when scan-related settings change.
	 *
	 * @param mixed $old_value Old.
	 * @param mixed $new_value New.
	 * @return void
	 */
	public function settings_changed( $old_value, $new_value ) {
		$keys = array( 'post_types', 'post_statuses', 'scan_menus', 'scan_widgets', 'scan_custom_fields', 'scan_excerpts', 'scan_comments', 'scan_comment_urls', 'check_images', 'check_media', 'check_internal', 'exclude_patterns' );
		$old  = is_array( $old_value ) ? $old_value : array();
		$new  = is_array( $new_value ) ? $new_value : array();
		foreach ( $keys as $key ) {
			$a = isset( $old[ $key ] ) ? $old[ $key ] : null;
			$b = isset( $new[ $key ] ) ? $new[ $key ] : null;
			if ( $a !== $b ) {
				LinkTender_Scanner::request_full_scan();
				return;
			}
		}
	}

	/**
	 * Labels for source types.
	 *
	 * @return array
	 */
	public static function source_labels() {
		/**
		 * Filters labels for source types (add-ons may register their own).
		 *
		 * @param array $labels Labels.
		 */
		return apply_filters(
			'linktender_source_labels',
			array(
				'post'    => __( 'Posts, pages & custom post types', 'linktender' ),
				'menu'    => __( 'Menus', 'linktender' ),
				'widget'  => __( 'Widgets', 'linktender' ),
				'comment' => __( 'Comments', 'linktender' ),
			)
		);
	}

	/**
	 * Labels for element types.
	 *
	 * @return array
	 */
	public static function element_labels() {
		return array(
			'a'         => __( 'Links', 'linktender' ),
			'img'       => __( 'Images', 'linktender' ),
			'iframe'    => __( 'Iframes', 'linktender' ),
			'video'     => __( 'Video', 'linktender' ),
			'audio'     => __( 'Audio', 'linktender' ),
			'source'    => __( 'Media sources', 'linktender' ),
			'embed'     => __( 'Embeds', 'linktender' ),
			'block'     => __( 'Block settings', 'linktender' ),
			'field'     => __( 'Custom field URLs', 'linktender' ),
			'menu'      => __( 'Menu items', 'linktender' ),
			'shortcode' => __( 'Shortcode settings', 'linktender' ),
			'author'    => __( 'Commenter website', 'linktender' ),
		);
	}

	/**
	 * URL of the details screen.
	 *
	 * @param int $link_id Link ID.
	 * @return string
	 */
	public static function details_url( $link_id ) {
		return add_query_arg(
			array(
				'page' => 'linktender',
				'link' => (int) $link_id,
			),
			admin_url( 'admin.php' )
		);
	}

	/**
	 * Nonce-protected single action URL.
	 *
	 * @param string $action  Action.
	 * @param int    $link_id Link ID.
	 * @return string
	 */
	public static function action_url( $action, $link_id ) {
		return wp_nonce_url(
			add_query_arg(
				array(
					'action'  => 'linktender_action',
					'do'      => $action,
					'link_id' => (int) $link_id,
				),
				admin_url( 'admin-post.php' )
			),
			'linktender_' . $action . '_' . (int) $link_id
		);
	}

	/**
	 * Status badge HTML.
	 *
	 * @param object $item Link row.
	 * @return string
	 */
	public static function status_badge( $item ) {
		$status = (int) $item->dismissed ? 'dismissed' : $item->status;
		$labels = array(
			'pending'    => __( 'Not checked yet', 'linktender' ),
			'ok'         => __( 'OK', 'linktender' ),
			'redirect'   => __( 'Redirected', 'linktender' ),
			'broken'     => __( 'Broken', 'linktender' ),
			'unverified' => __( 'Unverified', 'linktender' ),
			'dismissed'  => __( 'Marked as fine', 'linktender' ),
		);
		$label  = isset( $labels[ $status ] ) ? $labels[ $status ] : $status;
		$out    = '<span class="linktender-badge linktender-badge-' . esc_attr( $status ) . '">' . esc_html( $label ) . '</span>';

		$detail = '';
		if ( $item->http_code ) {
			$detail = (string) (int) $item->http_code;
			if ( 'redirect' === $item->status && $item->redirect_count ) {
				/* translators: %d: number of redirects. */
				$detail = sprintf( _n( '%d redirect', '%d redirects', (int) $item->redirect_count, 'linktender' ), (int) $item->redirect_count ) . ' &rarr; ' . (int) $item->http_code;
			}
		}
		$explain = self::explain( $item );
		if ( 'unverified' === $item->status && (int) $item->fail_count > 0 && ! (int) $item->dismissed ) {
			$retries = count( LinkTender_Queue::retry_intervals() );
			/* translators: 1: retry number, 2: total retries. */
			$explain .= ' ' . sprintf( __( 'Retry %1$d of %2$d scheduled. Only reported as broken if it keeps failing for 24 hours.', 'linktender' ), min( (int) $item->fail_count, $retries ), $retries );
		}
		if ( '' !== $detail || '' !== $explain ) {
			$out .= '<div class="linktender-detail">' . wp_kses( $detail, array() ) . ( '' !== $detail && '' !== $explain ? ' &middot; ' : '' ) . esc_html( $explain ) . '</div>';
		}
		return $out;
	}

	/**
	 * Formats a GMT MySQL datetime in the site's timezone and formats.
	 *
	 * @param string $gmt GMT datetime.
	 * @return string
	 */
	public static function format_gmt( $gmt ) {
		return wp_date( get_option( 'date_format' ) . ' ' . get_option( 'time_format' ), strtotime( $gmt . ' UTC' ) );
	}

	/**
	 * Plain-language explanation of a result.
	 *
	 * @param object $item Link row.
	 * @return string
	 */
	public static function explain( $item ) {
		switch ( $item->error_code ) {
			case 'bot_protection':
				return __( 'Blocked by bot protection. Probably fine; open it in your browser to confirm.', 'linktender' );
			case 'access_denied':
				if ( 999 === (int) $item->http_code ) {
					return __( 'The site blocks automated checks with code 999 (typical of LinkedIn). Not counted as broken.', 'linktender' );
				}
				return __( 'The site refused automated checks (login or firewall). Not counted as broken.', 'linktender' );
			case 'rate_limited':
				return __( 'The site asked us to slow down (rate limit). Will retry later.', 'linktender' );
			case 'client_error':
				if ( 400 === (int) $item->http_code ) {
					return __( 'Bad request (400). Some sites, such as Facebook, answer automated checks this way. Check it in a browser. Not counted as broken.', 'linktender' );
				}
				return __( 'The server rejected the check request. Not counted as broken.', 'linktender' );
			case 'loopback':
				return __( 'Your server could not connect to its own site (some hosts block this). Check the link in a browser. Not counted as broken.', 'linktender' );
			case 'offline':
				return __( 'Your server could not reach the internet when this was checked. Not counted as broken; it will be checked again.', 'linktender' );
			case 'dns':
				return __( 'Domain not found (DNS).', 'linktender' );
			case 'timeout':
				return __( 'Timed out.', 'linktender' );
			case 'refused':
				return __( 'Connection refused.', 'linktender' );
			case 'ssl':
				return __( 'SSL/TLS certificate problem.', 'linktender' );
			case 'server_error':
				return __( 'Server error.', 'linktender' );
			case 'redirect_loop':
				return __( 'Redirect loop.', 'linktender' );
			case 'too_many_redirects':
				return __( 'Too many redirects.', 'linktender' );
		}
		if ( 'broken' === $item->status && in_array( (int) $item->http_code, array( 404, 410 ), true ) ) {
			return 410 === (int) $item->http_code ? __( 'Gone', 'linktender' ) : __( 'Not found', 'linktender' );
		}
		return '';
	}

	/**
	 * Describes where an instance lives, with an edit link.
	 *
	 * @param object $instance Instance row.
	 * @return string HTML.
	 */
	public static function instance_label( $instance ) {
		$anchor = '' !== $instance->anchor ? ' <span class="linktender-anchor">&ldquo;' . esc_html( wp_html_excerpt( $instance->anchor, 60, '…' ) ) . '&rdquo;</span>' : '';
		$kind   = self::element_labels();
		$kind   = isset( $kind[ $instance->element ] ) ? $kind[ $instance->element ] : $instance->element;
		$kind   = '<span class="linktender-kind">' . esc_html( $kind ) . '</span>';

		switch ( $instance->source_type ) {
			case 'post':
				$post = get_post( (int) $instance->source_id );
				if ( ! $post ) {
					return esc_html__( '(deleted post)', 'linktender' );
				}
				$title = '' !== $post->post_title ? $post->post_title : __( '(no title)', 'linktender' );
				$type  = get_post_type_object( $post->post_type );
				$field = '';
				if ( '_elementor_data' === substr( $instance->source_field, 5 ) ) {
					$field = __( 'Elementor', 'linktender' );
				} elseif ( 0 === strpos( $instance->source_field, 'meta:' ) ) {
					/* translators: %s: custom field name. */
					$field = sprintf( __( 'field %s', 'linktender' ), substr( $instance->source_field, 5 ) );
				} elseif ( 'shortcode_output' === $instance->source_field ) {
					$field = __( 'shortcode output', 'linktender' );
				} elseif ( 'post_excerpt' === $instance->source_field ) {
					$field = __( 'excerpt', 'linktender' );
				}
				$edit = get_edit_post_link( $post->ID );
				$name = $edit ? '<a href="' . esc_url( $edit ) . '">' . esc_html( $title ) . '</a>' : esc_html( $title );
				return $kind . ' ' . $name . ' <span class="linktender-meta">(' . esc_html( $type ? $type->labels->singular_name : $post->post_type ) . ( '' !== $field ? ', ' . esc_html( $field ) : '' ) . ')</span>' . $anchor;

			case 'menu':
				$menus = wp_get_object_terms( (int) $instance->source_id, 'nav_menu' );
				$menu  = ( ! is_wp_error( $menus ) && $menus ) ? $menus[0] : null;
				$url   = $menu ? admin_url( 'nav-menus.php?action=edit&menu=' . (int) $menu->term_id ) : admin_url( 'nav-menus.php' );
				/* translators: %s: menu name. */
				$name = $menu ? sprintf( __( 'Menu: %s', 'linktender' ), $menu->name ) : __( 'Menu', 'linktender' );
				return $kind . ' <a href="' . esc_url( $url ) . '">' . esc_html( $name ) . '</a>' . $anchor;

			case 'comment':
				$comment = get_comment( (int) $instance->source_id );
				if ( ! $comment ) {
					return esc_html__( '(deleted comment)', 'linktender' );
				}
				$post_title = get_the_title( (int) $comment->comment_post_ID );
				/* translators: 1: comment author, 2: post title. */
				$name = sprintf( __( 'Comment by %1$s on %2$s', 'linktender' ), $comment->comment_author, '' !== $post_title ? $post_title : __( '(no title)', 'linktender' ) );
				$edit = admin_url( 'comment.php?action=editcomment&c=' . (int) $comment->comment_ID );
				return $kind . ' <a href="' . esc_url( $edit ) . '">' . esc_html( $name ) . '</a>' . $anchor;

			case 'widget':
				/* translators: %s: widget ID. */
				return $kind . ' <a href="' . esc_url( admin_url( 'widgets.php' ) ) . '">' . esc_html( sprintf( __( 'Widget %s', 'linktender' ), substr( $instance->source_field, 7 ) ) ) . '</a>' . $anchor;
		}

		/**
		 * Describes add-on source types.
		 *
		 * @param string $html     HTML.
		 * @param object $instance Instance.
		 */
		return (string) apply_filters( 'linktender_instance_label', esc_html( $instance->source_type ), $instance );
	}

	/**
	 * Prepares the list table and handles bulk actions.
	 *
	 * @return void
	 */
	public function load_links_page() {
		add_screen_option(
			'per_page',
			array(
				'default' => 30,
				'option'  => 'linktender_per_page',
			)
		);

		// phpcs:ignore WordPress.Security.NonceVerification.Recommended -- Only used to decide which screen to build.
		if ( isset( $_GET['link'] ) ) {
			return;
		}

		$this->table = new LinkTender_List_Table();
		$action      = $this->table->current_action();
		if ( $action ) {
			if ( ! isset( $_REQUEST['_wpnonce'] ) || ! wp_verify_nonce( sanitize_text_field( wp_unslash( $_REQUEST['_wpnonce'] ) ), 'bulk-links' ) ) {
				$this->deny( 'expired' );
			}
			$ids = isset( $_REQUEST['link_ids'] ) ? array_map( 'absint', (array) wp_unslash( $_REQUEST['link_ids'] ) ) : array();
			if ( $ids ) {
				$message = $this->run_action( $action, $ids );
				$this->notice( $message );
			}
			wp_safe_redirect( remove_query_arg( array( 'action', 'action2', 'link_ids', '_wpnonce', '_wp_http_referer' ), wp_get_referer() ? wp_get_referer() : admin_url( 'admin.php?page=linktender' ) ) );
			exit;
		}
		$this->table->prepare_items();
	}

	/**
	 * Runs one action on links. Returns a message.
	 *
	 * @param string $action Action.
	 * @param int[]  $ids    Link IDs.
	 * @return string
	 */
	private function run_action( $action, array $ids ) {
		delete_transient( 'linktender_broken_count' );
		$links  = $this->plugin->links;
		$editor = $this->plugin->editor;
		$count  = count( $ids );

		switch ( $action ) {
			case 'recheck':
				$links->recheck( $ids );
				/* translators: %d: number of links. */
				return sprintf( _n( '%d link will be rechecked in the next batch.', '%d links will be rechecked in the next batch.', $count, 'linktender' ), $count );

			case 'dismiss':
				$links->set_dismissed( $ids, true );
				/* translators: %d: number of links. */
				return sprintf( _n( '%d link marked as fine.', '%d links marked as fine.', $count, 'linktender' ), $count );

			case 'undismiss':
				$links->set_dismissed( $ids, false );
				$links->recheck( $ids );
				/* translators: %d: number of links. */
				return sprintf( _n( '%d link restored.', '%d links restored.', $count, 'linktender' ), $count );

			case 'unlink':
				$changed = 0;
				foreach ( $ids as $id ) {
					$result   = $editor->unlink( $id );
					$changed += $result['changed'];
				}
				$this->record_fix( $changed );
				/* translators: %d: number of places changed. */
				return sprintf( _n( 'Link removed in %d place.', 'Link removed in %d places.', $changed, 'linktender' ), $changed );

			case 'use_target':
				$changed = 0;
				foreach ( $ids as $id ) {
					$link = $links->get( $id );
					if ( $link && LinkTender_Links::final_url_is_usable( $link ) ) {
						$result   = $editor->replace_url( $id, $link->final_url );
						$changed += $result['changed'];
					}
				}
				$this->record_fix( $changed );
				/* translators: %d: number of places changed. */
				return sprintf( _n( 'Updated %d place to the final URL.', 'Updated %d places to the final URL.', $changed, 'linktender' ), $changed );

			case 'ignore_host':
				$hosts = array();
				foreach ( $ids as $id ) {
					$link = $links->get( $id );
					if ( $link && '' !== $link->host ) {
						$hosts[] = $link->host;
					}
				}
				$all = array_unique( array_merge( (array) LinkTender_Settings::get( 'ignored_hosts', array() ), $hosts ) );
				LinkTender_Settings::update( array( 'ignored_hosts' => $all ) );
				$links->set_dismissed( $this->ids_on_hosts( $hosts ), true );
				/* translators: %s: domain list. */
				return sprintf( __( 'Ignoring links on: %s', 'linktender' ), implode( ', ', $hosts ) );
		}

		/**
		 * Handles custom bulk/row actions registered by add-ons.
		 *
		 * @param string $message Message to show (empty if not handled).
		 * @param string $action  Action.
		 * @param int[]  $ids     Link IDs.
		 */
		return (string) apply_filters( 'linktender_bulk_action', '', $action, $ids );
	}

	/**
	 * IDs of links on the given hosts.
	 *
	 * @param string[] $hosts Hosts.
	 * @return int[]
	 */
	private function ids_on_hosts( array $hosts ) {
		$ids = array();
		foreach ( $hosts as $host ) {
			$result = $this->plugin->links->query(
				array(
					'view'     => 'all',
					'host'     => $host,
					'per_page' => 5000,
				)
			);
			$ids    = array_merge( $ids, wp_list_pluck( $result['items'], 'id' ) );
		}
		return array_map( 'intval', $ids );
	}

	/**
	 * Single-link action (row action links).
	 *
	 * @return void
	 */
	public function handle_action() {
		$action  = isset( $_GET['do'] ) ? sanitize_key( wp_unslash( $_GET['do'] ) ) : '';
		$link_id = isset( $_GET['link_id'] ) ? absint( $_GET['link_id'] ) : 0;
		if ( ! isset( $_GET['_wpnonce'] ) || ! wp_verify_nonce( sanitize_text_field( wp_unslash( $_GET['_wpnonce'] ) ), 'linktender_' . $action . '_' . $link_id ) ) {
			$this->deny( 'expired' );
		}
		if ( ! current_user_can( LinkTender_Plugin::capability() ) ) {
			$this->deny( 'capability' );
		}
		$this->notice( $this->run_action( $action, array( $link_id ) ) );
		$back = wp_get_referer();
		if ( ! $back || ( in_array( $action, array( 'unlink', 'use_target' ), true ) && false !== strpos( $back, 'link=' ) ) ) {
			$back = admin_url( 'admin.php?page=linktender' );
		}
		wp_safe_redirect( $back );
		exit;
	}

	/**
	 * Replace-URL form handler.
	 *
	 * @return void
	 */
	public function handle_edit_url() {
		$link_id = isset( $_POST['link_id'] ) ? absint( $_POST['link_id'] ) : 0;
		if ( ! isset( $_POST['_wpnonce'] ) || ! wp_verify_nonce( sanitize_text_field( wp_unslash( $_POST['_wpnonce'] ) ), 'linktender_edit_url_' . $link_id ) ) {
			$this->deny( 'expired' );
		}
		if ( ! current_user_can( LinkTender_Plugin::capability() ) ) {
			$this->deny( 'capability' );
		}
		$new_url = isset( $_POST['new_url'] ) ? trim( esc_url_raw( wp_unslash( $_POST['new_url'] ) ) ) : '';
		$link    = $this->plugin->links->get( $link_id );
		if ( ! $link || '' === $new_url ) {
			$this->notice( __( 'Please enter a valid URL.', 'linktender' ), 'error' );
		} elseif ( $new_url === $link->url ) {
			$this->notice( __( 'The URL is unchanged.', 'linktender' ), 'warning' );
		} else {
			$result = $this->plugin->editor->replace_url( $link_id, $new_url );
			$this->record_fix( $result['changed'] );
			if ( $result['changed'] ) {
				/* translators: 1: number of places, 2: new URL. */
				$this->notice( sprintf( _n( 'Replaced in %1$d place. The new URL %2$s will be checked shortly.', 'Replaced in %1$d places. The new URL %2$s will be checked shortly.', $result['changed'], 'linktender' ), $result['changed'], $new_url ) );
			} else {
				$this->notice( __( 'Nothing was changed. The link may be generated by a theme or plugin rather than stored in content.', 'linktender' ), 'warning' );
			}
		}
		wp_safe_redirect( admin_url( 'admin.php?page=linktender' ) );
		exit;
	}

	/**
	 * Tools (run now, rescan, pause, import).
	 *
	 * @return void
	 */
	public function handle_tool() {
		if ( ! isset( $_POST['_wpnonce'] ) || ! wp_verify_nonce( sanitize_text_field( wp_unslash( $_POST['_wpnonce'] ) ), 'linktender_tool' ) ) {
			$this->deny( 'expired' );
		}
		if ( ! current_user_can( 'manage_options' ) ) {
			$this->deny( 'capability' );
		}
		$tool = isset( $_POST['tool'] ) ? sanitize_key( wp_unslash( $_POST['tool'] ) ) : '';
		switch ( $tool ) {
			case 'start':
				LinkTender_Install::start_checking();
				$this->notice( __( 'Link checking started. Your content is scanned and links are checked in the background, in small batches.', 'linktender' ) );
				break;
			case 'run':
				if ( ! LinkTender_Install::checking_started() ) {
					$this->notice( __( 'Link checking has not been started yet.', 'linktender' ), 'warning' );
					break;
				}
				$summary = $this->plugin->queue->run( true );
				if ( $summary['locked'] ) {
					$this->notice( __( 'A batch is already running. Try again in a minute.', 'linktender' ), 'warning' );
				} else {
					/* translators: %d: number of links checked. */
					$this->notice( sprintf( _n( 'Batch finished: %d link checked.', 'Batch finished: %d links checked.', $summary['checked'], 'linktender' ), $summary['checked'] ) );
				}
				break;
			case 'rescan':
				LinkTender_Scanner::request_full_scan();
				$this->notice( __( 'A full content scan was started in the background.', 'linktender' ) );
				break;
			case 'recheck_all':
				global $wpdb;
				// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching -- Bulk update of the plugin's own table.
				$wpdb->query( $wpdb->prepare( "UPDATE %i SET next_check = '2000-01-01 00:00:00', fail_count = 0, first_failure = NULL WHERE dismissed = 0", LinkTender_Install::links_table() ) );
				$this->notice( __( 'All links are queued for a recheck.', 'linktender' ) );
				break;
			case 'pause':
				LinkTender_Settings::update( array( 'paused' => true ) );
				$this->notice( __( 'Checking is paused.', 'linktender' ) );
				break;
			case 'resume':
				LinkTender_Settings::update( array( 'paused' => false ) );
				$this->notice( __( 'Checking resumed.', 'linktender' ) );
				break;
			case 'import_blc':
				$importer = new LinkTender_Importer();
				$result   = $importer->import();
				/* translators: 1: number of settings, 2: number of dismissed links. */
				$this->notice( sprintf( __( 'Imported %1$d settings and %2$d links marked as fine from Broken Link Checker.', 'linktender' ), count( $result['settings'] ), $result['dismissed'] ) );
				LinkTender_Scanner::request_full_scan();
				break;
			default:
				/**
				 * Handles add-on tools posted to the tools form.
				 *
				 * @param string $tool Tool key.
				 */
				do_action( 'linktender_tool', $tool );
		}
		wp_safe_redirect( wp_get_referer() ? wp_get_referer() : admin_url( 'admin.php?page=linktender-tools' ) );
		exit;
	}

	/**
	 * Remembers the first successful fix, which shows a one-time review prompt.
	 *
	 * @param int $changed Number of places changed.
	 * @return void
	 */
	private function record_fix( $changed ) {
		if ( $changed < 1 ) {
			return;
		}
		$review = get_option( 'linktender_review', array() );
		$review = is_array( $review ) ? $review : array();
		if ( empty( $review['fixed_at'] ) ) {
			$review['fixed_at'] = time();
			update_option( 'linktender_review', $review, false );
		}
	}

	/**
	 * Prints the review prompt once, right after the first successful fix.
	 *
	 * @return void
	 */
	private function maybe_review_prompt() {
		$review = get_option( 'linktender_review', array() );
		if ( ! is_array( $review ) || empty( $review['fixed_at'] ) || ! empty( $review['shown'] ) ) {
			return;
		}
		$review['shown'] = time();
		update_option( 'linktender_review', $review, false );
		printf(
			'<div class="notice notice-info is-dismissible linktender-review"><p>%1$s <a href="%2$s" target="_blank" rel="noopener noreferrer">%3$s</a></p></div>',
			esc_html__( 'Glad that worked. If LinkTender saved you some time, a short review on WordPress.org helps other site owners find it. We will not ask again.', 'linktender' ),
			esc_url( 'https://wordpress.org/support/plugin/linktender/reviews/#new-post' ),
			esc_html__( 'Leave a review', 'linktender' )
		);
	}

	/**
	 * Refuses a request whose nonce or capability check failed. Nothing is changed; the user is
	 * sent back with an explanation instead of an error page.
	 *
	 * @param string $reason "expired" (nonce) or "capability".
	 * @return void
	 */
	private function deny( $reason ) {
		if ( 'capability' === $reason ) {
			$this->notice( __( 'You are not allowed to do this, so nothing was changed. Ask an administrator of this site.', 'linktender' ), 'error' );
		} else {
			$this->notice( __( 'This link or form has expired, so nothing was changed. Please try again.', 'linktender' ), 'error' );
		}
		wp_safe_redirect( current_user_can( LinkTender_Plugin::capability() ) ? admin_url( 'admin.php?page=linktender' ) : admin_url() );
		exit;
	}

	/**
	 * Queues a notice for the current user's next page view.
	 *
	 * @param string $message Message.
	 * @param string $type    success|warning|error|info.
	 * @return void
	 */
	private function notice( $message, $type = 'success' ) {
		if ( '' === $message ) {
			return;
		}
		set_transient(
			'linktender_notice_' . get_current_user_id(),
			array(
				'message' => $message,
				'type'    => $type,
			),
			MINUTE_IN_SECONDS
		);
	}

	/**
	 * Shows queued notices on our screens.
	 *
	 * @return void
	 */
	public function notices() {
		$screen = get_current_screen();
		if ( ! $screen || ! $this->is_own_screen( $screen->id ) ) {
			return;
		}
		$key    = 'linktender_notice_' . get_current_user_id();
		$notice = get_transient( $key );
		if ( $notice ) {
			delete_transient( $key );
			printf( '<div class="notice notice-%1$s is-dismissible"><p>%2$s</p></div>', esc_attr( $notice['type'] ), esc_html( $notice['message'] ) );
			if ( 'success' === $notice['type'] ) {
				$this->maybe_review_prompt();
			}
		}
		if ( ! wp_http_supports() ) {
			printf( '<div class="notice notice-warning"><p>%s</p></div>', esc_html__( 'This server cannot send HTTP requests (PHP has neither the cURL extension nor working stream sockets), so links cannot be checked. Ask your host to enable cURL. Scanning your content still works.', 'linktender' ) );
		}
		if ( ! LinkTender_Install::checking_started() ) {
			// phpcs:ignore WordPress.Security.NonceVerification.Recommended -- Read-only: which screen is shown.
			$page = isset( $_GET['page'] ) ? sanitize_key( wp_unslash( $_GET['page'] ) ) : '';
			if ( 'linktender' !== $page ) {
				printf(
					'<div class="notice notice-info"><p>%1$s <a href="%2$s">%3$s</a></p></div>',
					esc_html__( 'Link checking has not been started yet.', 'linktender' ),
					esc_url( admin_url( 'admin.php?page=linktender' ) ),
					esc_html__( 'Start it on the Links screen.', 'linktender' )
				);
			}
		} elseif ( LinkTender_Settings::get( 'paused' ) ) {
			printf( '<div class="notice notice-warning"><p>%s</p></div>', esc_html__( 'Link checking is paused. Resume it under LinkTender → Health & Tools.', 'linktender' ) );
		}
	}

	/**
	 * Explains what checking does and asks an administrator to start it. Shown on the Links
	 * screen until checking was started. Nothing is requested from other servers before that.
	 *
	 * @return void
	 */
	private function render_start_panel() {
		echo '<div class="linktender-start">';
		echo '<h2>' . esc_html__( 'Start checking your links', 'linktender' ) . '</h2>';
		echo '<p>' . esc_html__( 'LinkTender has not contacted any other server yet. When you start it, it scans your content on this server and then checks each link it found by sending a request (HEAD, or GET when needed) to that link\'s address. This is how broken links are found. Requests run in the background in small batches, with a pause between requests to the same domain.', 'linktender' ) . '</p>';
		echo '<p>' . esc_html__( 'No data about your site or its visitors is sent to LinkTender or anyone else. You can pause checking at any time under Health & Tools.', 'linktender' ) . '</p>';
		if ( current_user_can( 'manage_options' ) ) {
			echo '<form method="post" action="' . esc_url( admin_url( 'admin-post.php' ) ) . '">';
			wp_nonce_field( 'linktender_tool' );
			echo '<input type="hidden" name="action" value="linktender_tool" /><input type="hidden" name="tool" value="start" />';
			submit_button( __( 'Start checking links', 'linktender' ), 'primary', 'submit', false );
			echo '</form>';
		} else {
			echo '<p><em>' . esc_html__( 'An administrator needs to start link checking.', 'linktender' ) . '</em></p>';
		}
		echo '</div>';
	}

	/**
	 * Summary cards above the list.
	 *
	 * @return void
	 */
	private function render_summary() {
		$counts = $this->plugin->links->status_counts();
		$state  = LinkTender_Scanner::state();
		$last   = get_option( LinkTender_Queue::LAST_RUN, array() );
		$cards  = array(
			'broken'     => __( 'Broken', 'linktender' ),
			'redirect'   => __( 'Redirected', 'linktender' ),
			'unverified' => __( 'Unverified', 'linktender' ),
			'ok'         => __( 'OK', 'linktender' ),
			'pending'    => __( 'Waiting', 'linktender' ),
		);
		echo '<div class="linktender-cards">';
		foreach ( $cards as $key => $label ) {
			printf(
				'<a class="linktender-card linktender-card-%1$s" href="%2$s"><span class="linktender-card-num">%3$s</span><span class="linktender-card-label">%4$s</span></a>',
				esc_attr( $key ),
				esc_url( admin_url( 'admin.php?page=linktender&view=' . $key ) ),
				esc_html( number_format_i18n( $counts[ $key ] ) ),
				esc_html( $label )
			);
		}
		echo '</div><p class="linktender-status-line">';
		if ( LinkTender_Scanner::is_running() ) {
			/* translators: %s: number of items. */
			echo esc_html( sprintf( __( 'Scanning content in the background (%s items so far).', 'linktender' ), number_format_i18n( (int) $state['parsed'] ) ) ) . ' ';
		}
		if ( ! empty( $last['time'] ) ) {
			/* translators: 1: time ago, 2: number of links. */
			echo esc_html( sprintf( __( 'Last batch %1$s ago checked %2$d links.', 'linktender' ), human_time_diff( (int) $last['time'] ), (int) $last['checked'] ) ) . ' ';
		}
		echo esc_html__( 'All checks run on this server. No account, no quota.', 'linktender' );
		echo '</p>';
		if ( current_user_can( 'manage_options' ) ) {
			echo '<form method="post" action="' . esc_url( admin_url( 'admin-post.php' ) ) . '" class="linktender-run-now">';
			wp_nonce_field( 'linktender_tool' );
			echo '<input type="hidden" name="action" value="linktender_tool" /><input type="hidden" name="tool" value="run" />';
			submit_button( __( 'Check a batch now', 'linktender' ), 'secondary', 'submit', false );
			echo '</form>';
		}
	}

	/**
	 * Links page (list or details).
	 *
	 * @return void
	 */
	public function render_links_page() {
		// phpcs:ignore WordPress.Security.NonceVerification.Recommended -- Read-only view switch.
		$link_id = isset( $_GET['link'] ) ? absint( $_GET['link'] ) : 0;
		if ( $link_id ) {
			$this->render_details( $link_id );
			return;
		}
		echo '<div class="wrap linktender-wrap">';
		echo '<h1 class="wp-heading-inline">' . esc_html__( 'Broken Links', 'linktender' ) . '</h1>';
		echo '<hr class="wp-header-end" />';
		if ( ! LinkTender_Install::checking_started() ) {
			$this->render_start_panel();
			echo '</div>';
			return;
		}
		$this->render_summary();
		$this->table->views();
		echo '<form method="get">';
		echo '<input type="hidden" name="page" value="linktender" />';
		$view = LinkTender_List_Table::arg( 'view' );
		if ( '' !== $view ) {
			echo '<input type="hidden" name="view" value="' . esc_attr( $view ) . '" />';
		}
		$this->table->search_box( __( 'Search URLs', 'linktender' ), 'linktender-search' );
		$this->table->display();
		echo '</form></div>';
	}

	/**
	 * Details screen for one link.
	 *
	 * @param int $link_id Link ID.
	 * @return void
	 */
	private function render_details( $link_id ) {
		$link = $this->plugin->links->get( $link_id );
		echo '<div class="wrap linktender-wrap">';
		echo '<p><a href="' . esc_url( admin_url( 'admin.php?page=linktender' ) ) . '">&larr; ' . esc_html__( 'Back to all links', 'linktender' ) . '</a></p>';
		if ( ! $link ) {
			echo '<h1>' . esc_html__( 'Link not found', 'linktender' ) . '</h1></div>';
			return;
		}
		$instances = $this->plugin->links->instances( $link_id );
		echo '<h1 class="linktender-details-title">' . esc_html( $link->url ) . '</h1>';
		echo '<table class="widefat striped linktender-facts"><tbody>';
		echo '<tr><th>' . esc_html__( 'Status', 'linktender' ) . '</th><td>' . wp_kses_post( self::status_badge( $link ) ) . '</td></tr>';
		if ( $link->final_url ) {
			echo '<tr><th>' . esc_html__( 'Ends at', 'linktender' ) . '</th><td><code>' . esc_html( $link->final_url ) . '</code></td></tr>';
		}
		if ( $link->message ) {
			echo '<tr><th>' . esc_html__( 'Server said', 'linktender' ) . '</th><td>' . esc_html( $link->message ) . '</td></tr>';
		}
		echo '<tr><th>' . esc_html__( 'Last checked', 'linktender' ) . '</th><td>' . esc_html( $link->last_checked ? self::format_gmt( $link->last_checked ) : '—' ) . '</td></tr>';
		echo '<tr><th>' . esc_html__( 'Next check', 'linktender' ) . '</th><td>' . esc_html( self::format_gmt( $link->next_check ) ) . '</td></tr>';
		echo '<tr><th>' . esc_html__( 'Checks / failures in a row', 'linktender' ) . '</th><td>' . (int) $link->check_count . ' / ' . (int) $link->fail_count . '</td></tr>';
		echo '</tbody></table>';

		echo '<h2>' . esc_html__( 'Replace this URL everywhere', 'linktender' ) . '</h2>';
		echo '<form method="post" action="' . esc_url( admin_url( 'admin-post.php' ) ) . '">';
		wp_nonce_field( 'linktender_edit_url_' . (int) $link->id );
		echo '<input type="hidden" name="action" value="linktender_edit_url" /><input type="hidden" name="link_id" value="' . (int) $link->id . '" />';
		echo '<label class="screen-reader-text" for="linktender-new-url">' . esc_html__( 'New URL', 'linktender' ) . '</label>';
		echo '<input type="url" class="large-text code" id="linktender-new-url" name="new_url" value="' . esc_attr( LinkTender_Links::final_url_is_usable( $link ) ? $link->final_url : $link->url ) . '" required />';
		submit_button( __( 'Replace everywhere', 'linktender' ) );
		echo '</form>';

		echo '<p class="linktender-actions">';
		echo '<a class="button" href="' . esc_url( self::action_url( 'recheck', (int) $link->id ) ) . '">' . esc_html__( 'Recheck', 'linktender' ) . '</a> ';
		echo '<a class="button linktender-confirm" data-confirm="' . esc_attr__( 'Remove this link everywhere it appears? The link text stays.', 'linktender' ) . '" href="' . esc_url( self::action_url( 'unlink', (int) $link->id ) ) . '">' . esc_html__( 'Unlink everywhere', 'linktender' ) . '</a> ';
		if ( (int) $link->dismissed ) {
			echo '<a class="button" href="' . esc_url( self::action_url( 'undismiss', (int) $link->id ) ) . '">' . esc_html__( 'Undo "mark as fine"', 'linktender' ) . '</a>';
		} else {
			echo '<a class="button" href="' . esc_url( self::action_url( 'dismiss', (int) $link->id ) ) . '">' . esc_html__( 'Mark as fine', 'linktender' ) . '</a>';
		}
		echo '</p>';

		/* translators: %d: number of places. */
		echo '<h2>' . esc_html( sprintf( _n( 'Found in %d place', 'Found in %d places', count( $instances ), 'linktender' ), count( $instances ) ) ) . '</h2>';
		echo '<ul class="linktender-found linktender-found-full">';
		foreach ( $instances as $instance ) {
			echo '<li>' . wp_kses_post( self::instance_label( $instance ) ) . '</li>';
		}
		echo '</ul>';

		/**
		 * Fires at the end of the link details screen.
		 *
		 * @param object $link Link row.
		 */
		do_action( 'linktender_link_details', $link );
		echo '</div>';
	}

	/**
	 * Settings page.
	 *
	 * @return void
	 */
	public function render_settings_page() {
		$s     = LinkTender_Settings::all();
		$name  = LinkTender_Settings::OPTION;
		$types = LinkTender_Settings::available_post_types();
		?>
		<div class="wrap linktender-wrap">
			<h1><?php esc_html_e( 'LinkTender Settings', 'linktender' ); ?></h1>
			<form method="post" action="options.php">
				<?php settings_fields( 'linktender_settings' ); ?>
				<input type="hidden" name="<?php echo esc_attr( $name ); ?>[paused]" value="<?php echo $s['paused'] ? '1' : ''; ?>" />
				<h2><?php esc_html_e( 'What to scan', 'linktender' ); ?></h2>
				<table class="form-table" role="presentation">
					<tr>
						<th scope="row"><?php esc_html_e( 'Content types', 'linktender' ); ?></th>
						<td><fieldset>
						<?php
						foreach ( $types as $type ) {
							$object = get_post_type_object( $type );
							printf(
								'<label><input type="checkbox" name="%1$s[post_types][]" value="%2$s"%3$s /> %4$s</label><br />',
								esc_attr( $name ),
								esc_attr( $type ),
								checked( in_array( $type, (array) $s['post_types'], true ), true, false ),
								esc_html( $object ? $object->labels->name : $type )
							);
						}
						?>
						</fieldset></td>
					</tr>
					<tr>
						<th scope="row"><?php esc_html_e( 'Post statuses', 'linktender' ); ?></th>
						<td><fieldset>
						<?php
						$statuses = array(
							'publish' => __( 'Published', 'linktender' ),
							'private' => __( 'Private', 'linktender' ),
							'future'  => __( 'Scheduled', 'linktender' ),
							'draft'   => __( 'Drafts', 'linktender' ),
							'pending' => __( 'Pending review', 'linktender' ),
						);
						foreach ( $statuses as $status => $label ) {
							printf(
								'<label><input type="checkbox" name="%1$s[post_statuses][]" value="%2$s"%3$s /> %4$s</label><br />',
								esc_attr( $name ),
								esc_attr( $status ),
								checked( in_array( $status, (array) $s['post_statuses'], true ), true, false ),
								esc_html( $label )
							);
						}
						?>
						</fieldset></td>
					</tr>
					<tr>
						<th scope="row"><?php esc_html_e( 'Also scan', 'linktender' ); ?></th>
						<td><fieldset>
						<?php
						$bools = array(
							'scan_menus'         => __( 'Navigation menus (custom links)', 'linktender' ),
							'scan_widgets'       => __( 'Widgets', 'linktender' ),
							'scan_custom_fields' => __( 'Custom fields (incl. ACF text/URL fields and Elementor data)', 'linktender' ),
							'scan_excerpts'      => __( 'Excerpts', 'linktender' ),
							'scan_comments'      => __( 'Approved comments (links in the comment text)', 'linktender' ),
							'scan_comment_urls'  => __( 'Commenters\' website links (approved comments)', 'linktender' ),
							'check_images'       => __( 'Images', 'linktender' ),
							'check_media'        => __( 'Iframes, video, audio and embeds', 'linktender' ),
							'check_internal'     => __( 'Links to this site', 'linktender' ),
						);
						foreach ( $bools as $key => $label ) {
							printf(
								'<label><input type="checkbox" name="%1$s[%2$s]" value="1"%3$s /> %4$s</label><br />',
								esc_attr( $name ),
								esc_attr( $key ),
								checked( ! empty( $s[ $key ] ), true, false ),
								esc_html( $label )
							);
						}
						?>
						</fieldset></td>
					</tr>
					<tr>
						<th scope="row"><label for="linktender-exclude"><?php esc_html_e( 'Exclude URLs', 'linktender' ); ?></label></th>
						<td><textarea id="linktender-exclude" class="large-text code" rows="4" name="<?php echo esc_attr( $name ); ?>[exclude_patterns]"><?php echo esc_textarea( implode( "\n", (array) $s['exclude_patterns'] ) ); ?></textarea>
						<p class="description"><?php esc_html_e( 'One per line. URLs containing the text are skipped. Use * as a wildcard, e.g. https://example.com/private/*', 'linktender' ); ?></p></td>
					</tr>
					<tr>
						<th scope="row"><label for="linktender-hosts"><?php esc_html_e( 'Ignored domains', 'linktender' ); ?></label></th>
						<td><textarea id="linktender-hosts" class="large-text code" rows="3" name="<?php echo esc_attr( $name ); ?>[ignored_hosts]"><?php echo esc_textarea( implode( "\n", (array) $s['ignored_hosts'] ) ); ?></textarea>
						<p class="description"><?php esc_html_e( 'One domain per line. Subdomains are included.', 'linktender' ); ?></p></td>
					</tr>
				</table>

				<h2><?php esc_html_e( 'How to check', 'linktender' ); ?></h2>
				<table class="form-table" role="presentation">
					<?php
					$numbers = array(
						'recheck_hours' => array( __( 'Recheck working links every', 'linktender' ), __( 'hours', 'linktender' ) ),
						'batch_size'    => array( __( 'Links per batch', 'linktender' ), __( 'A batch runs every 5 minutes in the background, or every minute while there is a backlog.', 'linktender' ) ),
						'concurrency'   => array( __( 'Links checked at the same time', 'linktender' ), __( 'Each one goes to a different domain. Use 1 to check one link at a time.', 'linktender' ) ),
						'time_budget'   => array( __( 'Max seconds per batch', 'linktender' ), __( 'seconds. Keep this well under your PHP time limit.', 'linktender' ) ),
						'timeout'       => array( __( 'Request timeout', 'linktender' ), __( 'seconds', 'linktender' ) ),
						'host_delay'    => array( __( 'Pause between requests to the same domain', 'linktender' ), __( 'seconds', 'linktender' ) ),
						'max_redirects' => array( __( 'Follow up to', 'linktender' ), __( 'redirects', 'linktender' ) ),
					);
					foreach ( $numbers as $key => $labels ) {
						printf(
							'<tr><th scope="row"><label for="linktender-%1$s">%2$s</label></th><td><input type="number" min="0" class="small-text" id="linktender-%1$s" name="%3$s[%1$s]" value="%4$d" /> <span class="description">%5$s</span></td></tr>',
							esc_attr( $key ),
							esc_html( $labels[0] ),
							esc_attr( $name ),
							(int) $s[ $key ],
							esc_html( $labels[1] )
						);
					}
					?>
				</table>

				<table class="form-table" role="presentation">
					<tr>
						<th scope="row"><?php esc_html_e( 'Connectivity check', 'linktender' ); ?></th>
						<td><fieldset>
							<label><input type="checkbox" name="<?php echo esc_attr( $name ); ?>[connectivity_check]" value="1" <?php checked( ! empty( $s['connectivity_check'] ) ); ?> /> <?php esc_html_e( 'When checks fail at the network level, ask wordpress.org whether this server is online', 'linktender' ); ?></label>
							<p class="description"><?php esc_html_e( 'Off by default. When on, LinkTender sends at most one HEAD request to wordpress.org every 10 minutes, and only after a link check could not connect. No data is sent with it. When off, the server counts as offline after several different domains in a row could not be reached.', 'linktender' ); ?></p>
						</fieldset></td>
					</tr>
				</table>

				<h2><?php esc_html_e( 'On your site', 'linktender' ); ?></h2>
				<table class="form-table" role="presentation">
					<tr>
						<th scope="row"><?php esc_html_e( 'Broken links in posts', 'linktender' ); ?></th>
						<td><fieldset>
							<label><input type="checkbox" name="<?php echo esc_attr( $name ); ?>[mark_broken]" value="1" <?php checked( $s['mark_broken'] ); ?> /> <?php esc_html_e( 'Show broken links with a strike-through', 'linktender' ); ?></label><br />
							<label><input type="checkbox" name="<?php echo esc_attr( $name ); ?>[nofollow_broken]" value="1" <?php checked( $s['nofollow_broken'] ); ?> /> <?php esc_html_e( 'Add rel="nofollow" to broken links', 'linktender' ); ?></label>
							<p class="description"><?php esc_html_e( 'Both are off by default. Your content is never changed by these options.', 'linktender' ); ?></p>
						</fieldset></td>
					</tr>
				</table>
				<?php
				/**
				 * Fires before the settings submit button. Add-ons can print their own fields.
				 *
				 * @param array $s Current settings.
				 */
				do_action( 'linktender_settings_fields', $s );
				submit_button();
				?>
			</form>
		</div>
		<?php
	}

	/**
	 * Health & tools page.
	 *
	 * @return void
	 */
	public function render_tools_page() {
		$stats    = $this->plugin->links->table_stats();
		$state    = LinkTender_Scanner::state();
		$last     = get_option( LinkTender_Queue::LAST_RUN, array() );
		$paused   = LinkTender_Settings::get( 'paused' );
		$importer = new LinkTender_Importer();
		$runner   = LinkTender_Queue::use_action_scheduler() ? __( 'Action Scheduler', 'linktender' ) : __( 'WP-Cron', 'linktender' );
		$next     = wp_next_scheduled( LinkTender_Queue::HOOK );
		?>
		<div class="wrap linktender-wrap">
			<h1><?php esc_html_e( 'Health & Tools', 'linktender' ); ?></h1>
			<h2><?php esc_html_e( 'Status', 'linktender' ); ?></h2>
			<table class="widefat striped linktender-facts"><tbody>
				<tr><th><?php esc_html_e( 'Checking', 'linktender' ); ?></th><td>
					<?php
					if ( ! LinkTender_Install::checking_started() ) {
						esc_html_e( 'Not started', 'linktender' );
					} else {
						echo $paused ? esc_html__( 'Paused', 'linktender' ) : esc_html__( 'Running', 'linktender' );
					}
					?>
				</td></tr>
				<tr><th><?php esc_html_e( 'Background runner', 'linktender' ); ?></th><td>
					<?php
					echo esc_html( $runner );
					if ( $next ) {
						/* translators: %s: time until next run. */
						echo ' &middot; ' . esc_html( sprintf( __( 'next run in %s', 'linktender' ), human_time_diff( $next ) ) );
					}
					if ( defined( 'DISABLE_WP_CRON' ) && DISABLE_WP_CRON ) {
						echo ' &middot; ' . esc_html__( 'DISABLE_WP_CRON is set: make sure a real cron job calls wp-cron.php.', 'linktender' );
					}
					?>
				</td></tr>
				<tr><th><?php esc_html_e( 'Content scan', 'linktender' ); ?></th><td>
					<?php
					if ( 'done' === $state['phase'] ) {
						/* translators: %s: time ago. */
						echo esc_html( $state['finished'] ? sprintf( __( 'Finished %s ago', 'linktender' ), human_time_diff( (int) $state['finished'] ) ) : __( 'Not started', 'linktender' ) );
					} else {
						/* translators: 1: phase, 2: number of items. */
						echo esc_html( sprintf( __( 'In progress (%1$s, %2$d items so far)', 'linktender' ), $state['phase'], (int) $state['parsed'] ) );
					}
					?>
				</td></tr>
				<tr><th><?php esc_html_e( 'Last batch', 'linktender' ); ?></th><td>
					<?php
					if ( ! empty( $last['time'] ) ) {
						/* translators: 1: time ago, 2: links, 3: seconds. */
						echo esc_html( sprintf( __( '%1$s ago: %2$d links checked in %3$s s', 'linktender' ), human_time_diff( (int) $last['time'] ), (int) $last['checked'], $last['seconds'] ) );
					} else {
						echo '&mdash;';
					}
					?>
				</td></tr>
				<tr><th><?php esc_html_e( 'Links due for a check', 'linktender' ); ?></th><td><?php echo esc_html( number_format_i18n( $this->plugin->links->count_due() ) ); ?></td></tr>
				<?php foreach ( $stats as $table => $info ) : ?>
					<tr><th><?php echo esc_html( $table ); ?></th><td>
						<?php
						/* translators: 1: rows, 2: size. */
						echo esc_html( sprintf( __( '%1$s rows, %2$s', 'linktender' ), number_format_i18n( $info['rows'] ), size_format( $info['bytes'] ) ? size_format( $info['bytes'] ) : '0 B' ) );
						?>
					</td></tr>
				<?php endforeach; ?>
			</tbody></table>
			<p class="description"><?php esc_html_e( 'LinkTender only uses its own two tables. It never alters WordPress core tables.', 'linktender' ); ?></p>

			<h2><?php esc_html_e( 'Tools', 'linktender' ); ?></h2>
			<form method="post" action="<?php echo esc_url( admin_url( 'admin-post.php' ) ); ?>" class="linktender-tools">
				<?php wp_nonce_field( 'linktender_tool' ); ?>
				<input type="hidden" name="action" value="linktender_tool" />
				<?php if ( LinkTender_Install::checking_started() ) : ?>
					<button class="button button-primary" name="tool" value="run"><?php esc_html_e( 'Check a batch now', 'linktender' ); ?></button>
				<?php else : ?>
					<button class="button button-primary" name="tool" value="start"><?php esc_html_e( 'Start checking links', 'linktender' ); ?></button>
				<?php endif; ?>
				<button class="button" name="tool" value="rescan"><?php esc_html_e( 'Rescan all content', 'linktender' ); ?></button>
				<button class="button" name="tool" value="recheck_all"><?php esc_html_e( 'Recheck all links', 'linktender' ); ?></button>
				<?php if ( $paused ) : ?>
					<button class="button" name="tool" value="resume"><?php esc_html_e( 'Resume checking', 'linktender' ); ?></button>
				<?php else : ?>
					<button class="button" name="tool" value="pause"><?php esc_html_e( 'Pause checking', 'linktender' ); ?></button>
				<?php endif; ?>
				<?php
				/**
				 * Prints extra tool buttons (name="tool").
				 */
				do_action( 'linktender_tools_buttons' );
				?>
			</form>

			<h2><?php esc_html_e( 'Switching from Broken Link Checker', 'linktender' ); ?></h2>
			<?php if ( $importer->available() ) : ?>
				<p><?php esc_html_e( 'Import exclusions, timing, front-end options and links you marked as fine (dismissed) from the "Broken Link Checker" plugin. Its data is only read, never changed.', 'linktender' ); ?></p>
				<form method="post" action="<?php echo esc_url( admin_url( 'admin-post.php' ) ); ?>">
					<?php wp_nonce_field( 'linktender_tool' ); ?>
					<input type="hidden" name="action" value="linktender_tool" />
					<button class="button" name="tool" value="import_blc"><?php esc_html_e( 'Import settings', 'linktender' ); ?></button>
				</form>
			<?php else : ?>
				<p><?php esc_html_e( 'No Broken Link Checker settings were found on this site.', 'linktender' ); ?></p>
			<?php endif; ?>
		</div>
		<?php
	}
}