<?php
/**
 * Core WordPress events.
 *
 * @package PingPush
 */

defined( 'ABSPATH' ) || exit;

/**
 * Users, comments, posts, logins, plugins, mail, fatal errors and updates.
 */
class PingPush_Event_Core extends PingPush_Integration {

	/**
	 * Name.
	 *
	 * @return string
	 */
	public static function name() {
		return 'WordPress';
	}

	/**
	 * Register events.
	 */
	public function register_events() {
		$user_ph = array( 'user_login', 'user_name', 'user_email', 'user_role', 'ip' );

		PingPush_Events::register(
			'core_user_register',
			array(
				'label'        => __( 'New user registration', 'pingpush' ),
				'group'        => 'core',
				'title'        => __( 'New user: {user_login}', 'pingpush' ),
				'message'      => __( '{user_name} ({user_email}) registered as {user_role}.', 'pingpush' ),
				'enabled'      => true,
				'placeholders' => $user_ph,
			)
		);

		PingPush_Events::register(
			'core_new_comment',
			array(
				'label'        => __( 'New comment', 'pingpush' ),
				'description'  => __( 'Spam and trashed comments never notify.', 'pingpush' ),
				'group'        => 'core',
				'title'        => __( 'New comment on {post_title}', 'pingpush' ),
				'message'      => __( "{comment_author} ({comment_status}):\n{comment_excerpt}", 'pingpush' ),
				'enabled'      => true,
				'placeholders' => array( 'post_title', 'comment_author', 'comment_author_email', 'comment_excerpt', 'comment_status' ),
				'options'      => array(
					'scope' => array(
						'type'    => 'select',
						'label'   => __( 'Notify for', 'pingpush' ),
						'choices' => array(
							'all'      => __( 'Approved and pending comments', 'pingpush' ),
							'approved' => __( 'Approved comments only (pending ones notify once approved)', 'pingpush' ),
						),
						'default' => 'all',
					),
				),
			)
		);

		PingPush_Events::register(
			'core_password_reset',
			array(
				'label'        => __( 'Password reset requested', 'pingpush' ),
				'group'        => 'core',
				'title'        => __( 'Password reset requested', 'pingpush' ),
				'message'      => __( 'A password reset was requested for {user_login} ({user_email}) from {ip}.', 'pingpush' ),
				'placeholders' => $user_ph,
			)
		);

		$post_ph = array( 'post_title', 'post_type', 'post_url', 'author', 'old_status', 'new_status' );

		PingPush_Events::register(
			'core_post_published',
			array(
				'label'        => __( 'Post published', 'pingpush' ),
				'group'        => 'core',
				'title'        => __( '{post_type} published', 'pingpush' ),
				'message'      => __( '"{post_title}" by {author}', 'pingpush' ),
				'placeholders' => $post_ph,
				'options'      => array(
					'post_types' => array(
						'type'    => 'checkboxes',
						'label'   => __( 'Post types', 'pingpush' ),
						'choices' => array( __CLASS__, 'post_type_choices' ),
						'default' => array( 'post' ),
					),
				),
			)
		);

		PingPush_Events::register(
			'core_post_status',
			array(
				'label'        => __( 'Post status changed', 'pingpush' ),
				'description'  => __( 'For example, a post submitted for review.', 'pingpush' ),
				'group'        => 'core',
				'title'        => __( '{post_type} is now {new_status}', 'pingpush' ),
				'message'      => __( '"{post_title}" by {author}: {old_status} → {new_status}', 'pingpush' ),
				'placeholders' => $post_ph,
				'options'      => array(
					'statuses'   => array(
						'type'    => 'checkboxes',
						'label'   => __( 'When the new status is', 'pingpush' ),
						'choices' => array( __CLASS__, 'status_choices' ),
						'default' => array( 'pending' ),
					),
					'post_types' => array(
						'type'    => 'checkboxes',
						'label'   => __( 'Post types', 'pingpush' ),
						'choices' => array( __CLASS__, 'post_type_choices' ),
						'default' => array( 'post' ),
					),
				),
			)
		);

		PingPush_Events::register(
			'core_login',
			array(
				'label'        => __( 'Successful login', 'pingpush' ),
				'group'        => 'core',
				'title'        => __( 'Login: {user_login}', 'pingpush' ),
				'message'      => __( '{user_name} ({user_role}) logged in from {ip}.', 'pingpush' ),
				'priority'     => -1,
				'placeholders' => $user_ph,
				'options'      => array(
					'scope' => array(
						'type'    => 'select',
						'label'   => __( 'Notify for', 'pingpush' ),
						'choices' => array(
							'admins' => __( 'Administrators only', 'pingpush' ),
							'all'    => __( 'All users', 'pingpush' ),
						),
						'default' => 'admins',
					),
				),
			)
		);

		PingPush_Events::register(
			'core_login_failed',
			array(
				'label'        => __( 'Failed login attempt', 'pingpush' ),
				'group'        => 'core',
				'title'        => __( 'Failed login', 'pingpush' ),
				'message'      => __( 'Failed login for "{username}" from {ip}.', 'pingpush' ),
				'priority'     => -1,
				'placeholders' => array( 'username', 'ip' ),
				'options'      => array(
					'throttle' => array(
						'type'    => 'select',
						'label'   => __( 'At most one alert per IP address every', 'pingpush' ),
						'choices' => array(
							'5'    => __( '5 minutes', 'pingpush' ),
							'15'   => __( '15 minutes', 'pingpush' ),
							'60'   => __( '1 hour', 'pingpush' ),
							'1440' => __( '24 hours', 'pingpush' ),
						),
						'default' => '15',
					),
				),
			)
		);

		PingPush_Events::register(
			'core_plugin_toggled',
			array(
				'label'        => __( 'Plugin activated or deactivated', 'pingpush' ),
				'group'        => 'core',
				'title'        => __( 'Plugin {action}', 'pingpush' ),
				'message'      => __( '{plugin_name} was {action} by {user_name}.', 'pingpush' ),
				'placeholders' => array( 'plugin_name', 'plugin_file', 'action', 'user_name' ),
			)
		);

		PingPush_Events::register(
			'core_role_changed',
			array(
				'label'        => __( 'User role changed', 'pingpush' ),
				'group'        => 'core',
				'title'        => __( 'Role changed: {user_login}', 'pingpush' ),
				'message'      => __( '{user_name}: {old_role} → {new_role}', 'pingpush' ),
				'placeholders' => array( 'user_login', 'user_name', 'user_email', 'old_role', 'new_role' ),
			)
		);

		PingPush_Events::register(
			'core_mail_failed',
			array(
				'label'        => __( 'Site email failed to send', 'pingpush' ),
				'group'        => 'core',
				'title'        => __( 'Email failed to send', 'pingpush' ),
				'message'      => __( "To: {to}\nSubject: {subject}\nError: {error}", 'pingpush' ),
				'enabled'      => true,
				'placeholders' => array( 'to', 'subject', 'error' ),
			)
		);

		PingPush_Events::register(
			'core_fatal_error',
			array(
				'label'        => __( 'Site error (fatal error / recovery mode)', 'pingpush' ),
				'description'  => __( 'Sent when WordPress detects a fatal error and enters recovery mode. WordPress limits this to about once a day per problem.', 'pingpush' ),
				'group'        => 'core',
				'title'        => __( 'Site error detected', 'pingpush' ),
				'message'      => __( "{error_message}\nFile: {error_file}:{error_line}", 'pingpush' ),
				'priority'     => 1,
				'enabled'      => true,
				'placeholders' => array( 'error_message', 'error_file', 'error_line' ),
			)
		);

		PingPush_Events::register(
			'core_updates',
			array(
				'label'        => __( 'Updates available', 'pingpush' ),
				'description'  => __( 'Checked twice a day. Each new version is reported only once.', 'pingpush' ),
				'group'        => 'core',
				'title'        => __( '{count} update(s) available', 'pingpush' ),
				'message'      => '{updates}',
				'priority'     => -1,
				'enabled'      => true,
				'placeholders' => array( 'count', 'updates' ),
				'options'      => array(
					'types' => array(
						'type'    => 'checkboxes',
						'label'   => __( 'Include', 'pingpush' ),
						'choices' => array(
							'core'    => __( 'WordPress core', 'pingpush' ),
							'plugins' => __( 'Plugins', 'pingpush' ),
							'themes'  => __( 'Themes', 'pingpush' ),
						),
						'default' => array( 'core', 'plugins', 'themes' ),
					),
				),
			)
		);
	}

	/**
	 * Hooks.
	 */
	public function hooks() {
		add_action( 'user_register', array( $this, 'user_register' ), 20, 1 );
		add_action( 'comment_post', array( $this, 'comment_post' ), 20, 2 );
		add_action( 'comment_unapproved_to_approved', array( $this, 'comment_approved' ), 20, 1 );
		add_action( 'retrieve_password', array( $this, 'retrieve_password' ), 20, 1 );
		add_action( 'transition_post_status', array( $this, 'transition_post_status' ), 20, 3 );
		add_action( 'wp_login', array( $this, 'wp_login' ), 20, 2 );
		add_action( 'wp_login_failed', array( $this, 'wp_login_failed' ), 20, 1 );
		add_action( 'activated_plugin', array( $this, 'plugin_activated' ), 20, 1 );
		add_action( 'deactivated_plugin', array( $this, 'plugin_deactivated' ), 20, 1 );
		add_action( 'set_user_role', array( $this, 'set_user_role' ), 20, 3 );
		add_action( 'wp_mail_failed', array( $this, 'wp_mail_failed' ), 20, 1 );
		add_filter( 'recovery_mode_email', array( $this, 'recovery_mode_email' ), 20, 1 );
		add_action( 'pingpush_check_updates', array( $this, 'check_updates' ) );
		add_action( 'init', array( $this, 'ensure_update_cron' ) );
	}

	/* ---------- Choices ---------- */

	/**
	 * Post types with an admin UI, including custom post types.
	 *
	 * @return array<string,string>
	 */
	public static function post_type_choices() {
		$out = array();
		foreach ( get_post_types( array( 'show_ui' => true ), 'objects' ) as $type ) {
			if ( in_array( $type->name, array( 'attachment', 'wp_block', 'wp_navigation', 'wp_template', 'wp_template_part', 'wp_font_family', 'wp_font_face', 'shop_order', 'shop_order_refund', 'shop_coupon' ), true ) ) {
				continue;
			}
			$out[ $type->name ] = $type->labels->singular_name;
		}
		return $out;
	}

	/**
	 * Post statuses.
	 *
	 * @return array<string,string>
	 */
	public static function status_choices() {
		return array(
			'pending' => __( 'Pending review', 'pingpush' ),
			'draft'   => __( 'Draft', 'pingpush' ),
			'future'  => __( 'Scheduled', 'pingpush' ),
			'publish' => __( 'Published', 'pingpush' ),
			'private' => __( 'Private', 'pingpush' ),
			'trash'   => __( 'Trash', 'pingpush' ),
		);
	}

	/* ---------- Helpers ---------- */

	/**
	 * Visitor IP (REMOTE_ADDR only; proxy headers can be spoofed).
	 *
	 * @return string
	 */
	public static function ip() {
		$ip = isset( $_SERVER['REMOTE_ADDR'] ) ? sanitize_text_field( wp_unslash( $_SERVER['REMOTE_ADDR'] ) ) : '';
		return filter_var( $ip, FILTER_VALIDATE_IP ) ? $ip : __( 'unknown IP', 'pingpush' );
	}

	/**
	 * Translated role name.
	 *
	 * @param string $role Role slug.
	 * @return string
	 */
	private function role_name( $role ) {
		$roles = wp_roles()->get_names();
		return isset( $roles[ $role ] ) ? translate_user_role( $roles[ $role ] ) : ( $role ? $role : __( 'none', 'pingpush' ) );
	}

	/**
	 * User placeholders.
	 *
	 * @param WP_User $user User.
	 * @return array<string,string>
	 */
	private function user_data( $user ) {
		return array(
			'user_login' => $user->user_login,
			'user_name'  => $user->display_name ? $user->display_name : $user->user_login,
			'user_email' => $user->user_email,
			'user_role'  => implode( ', ', array_map( array( $this, 'role_name' ), (array) $user->roles ) ),
			'ip'         => self::ip(),
		);
	}

	/**
	 * Settings for an event.
	 *
	 * @param string $id Event id.
	 * @return array
	 */
	private function opt( $id ) {
		return PingPush_Events::settings_for( $id );
	}

	/* ---------- Handlers ---------- */

	/**
	 * New user.
	 *
	 * @param int $user_id User id.
	 */
	public function user_register( $user_id ) {
		$user = get_userdata( $user_id );
		if ( ! $user ) {
			return;
		}
		PingPush_Events::trigger(
			'core_user_register',
			$this->user_data( $user ),
			array(
				'url'       => admin_url( 'user-edit.php?user_id=' . (int) $user_id ),
				'url_title' => __( 'View user', 'pingpush' ),
				'dedupe'    => (string) $user_id,
			)
		);
	}

	/**
	 * New comment.
	 *
	 * @param int        $comment_id Comment id.
	 * @param int|string $approved   1, 0, 'spam' or 'trash'.
	 */
	public function comment_post( $comment_id, $approved ) {
		if ( 'spam' === $approved || 'trash' === $approved ) {
			return;
		}
		$is_approved = 1 === (int) $approved;
		$scope       = $this->opt( 'core_new_comment' )['scope'] ?? 'all';
		if ( ! $is_approved && 'approved' === $scope ) {
			return; // Will notify on approval.
		}
		$this->notify_comment( $comment_id, $is_approved );
	}

	/**
	 * Pending comment approved.
	 *
	 * @param WP_Comment $comment Comment.
	 */
	public function comment_approved( $comment ) {
		if ( ! $comment instanceof WP_Comment ) {
			return;
		}
		$scope = $this->opt( 'core_new_comment' )['scope'] ?? 'all';
		if ( 'approved' !== $scope ) {
			return; // Already notified when it was posted.
		}
		$this->notify_comment( (int) $comment->comment_ID, true );
	}

	/**
	 * Send comment notification.
	 *
	 * @param int  $comment_id Comment id.
	 * @param bool $approved   Approved.
	 */
	private function notify_comment( $comment_id, $approved ) {
		$comment = get_comment( $comment_id );
		if ( ! $comment || in_array( $comment->comment_type, array( 'order_note', 'webhook_delivery', 'action_log' ), true ) ) {
			return;
		}
		PingPush_Events::trigger(
			'core_new_comment',
			array(
				'post_title'           => get_the_title( (int) $comment->comment_post_ID ),
				'comment_author'       => $comment->comment_author ? $comment->comment_author : __( 'Anonymous', 'pingpush' ),
				'comment_author_email' => $comment->comment_author_email,
				'comment_excerpt'      => wp_trim_words( wp_strip_all_tags( $comment->comment_content ), 40 ),
				'comment_status'       => $approved ? __( 'approved', 'pingpush' ) : __( 'pending', 'pingpush' ),
			),
			array(
				'url'        => $approved ? get_comment_link( $comment ) : admin_url( 'comment.php?action=editcomment&c=' . (int) $comment_id ),
				'url_title'  => $approved ? __( 'View comment', 'pingpush' ) : __( 'Moderate comment', 'pingpush' ),
				'dedupe'     => (string) $comment_id,
				'dedupe_ttl' => DAY_IN_SECONDS,
			)
		);
	}

	/**
	 * Password reset requested.
	 *
	 * @param string $user_login Login.
	 */
	public function retrieve_password( $user_login ) {
		$user = get_user_by( 'login', $user_login );
		if ( ! $user ) {
			return;
		}
		PingPush_Events::trigger(
			'core_password_reset',
			$this->user_data( $user ),
			array(
				'url'       => admin_url( 'user-edit.php?user_id=' . (int) $user->ID ),
				'url_title' => __( 'View user', 'pingpush' ),
				'dedupe'    => (string) $user->ID,
			)
		);
	}

	/**
	 * Post status transitions.
	 *
	 * @param string  $new_status New.
	 * @param string  $old_status Old.
	 * @param WP_Post $post       Post.
	 */
	public function transition_post_status( $new_status, $old_status, $post ) {
		if ( ! $post instanceof WP_Post || $new_status === $old_status || wp_is_post_revision( $post ) || wp_is_post_autosave( $post ) ) {
			return;
		}
		if ( in_array( $new_status, array( 'auto-draft', 'inherit' ), true ) ) {
			return;
		}

		$type_obj = get_post_type_object( $post->post_type );
		$author   = get_userdata( (int) $post->post_author );
		$data     = array(
			'post_title' => get_the_title( $post ),
			'post_type'  => $type_obj ? $type_obj->labels->singular_name : $post->post_type,
			'post_url'   => get_permalink( $post ),
			'author'     => $author ? $author->display_name : __( 'unknown', 'pingpush' ),
			'old_status' => $this->status_label( $old_status ),
			'new_status' => $this->status_label( $new_status ),
		);
		$edit_url = admin_url( 'post.php?post=' . (int) $post->ID . '&action=edit' );

		if ( 'publish' === $new_status ) {
			$opt = $this->opt( 'core_post_published' );
			if ( in_array( $post->post_type, (array) ( $opt['post_types'] ?? array() ), true ) ) {
				PingPush_Events::trigger(
					'core_post_published',
					$data,
					array(
						'url'        => (string) get_permalink( $post ),
						'url_title'  => __( 'View post', 'pingpush' ),
						'dedupe'     => (string) $post->ID,
						'dedupe_ttl' => 300,
					)
				);
			}
		}

		$opt = $this->opt( 'core_post_status' );
		if ( in_array( $new_status, (array) ( $opt['statuses'] ?? array() ), true ) && in_array( $post->post_type, (array) ( $opt['post_types'] ?? array() ), true ) ) {
			PingPush_Events::trigger(
				'core_post_status',
				$data,
				array(
					'url'       => $edit_url,
					'url_title' => __( 'Edit post', 'pingpush' ),
					'dedupe'    => $post->ID . ':' . $new_status,
				)
			);
		}
	}

	/**
	 * Status label.
	 *
	 * @param string $status Status.
	 * @return string
	 */
	private function status_label( $status ) {
		if ( 'new' === $status || 'auto-draft' === $status ) {
			return __( 'new', 'pingpush' );
		}
		$obj = get_post_status_object( $status );
		return $obj ? $obj->label : $status;
	}

	/**
	 * Successful login.
	 *
	 * @param string  $user_login Login.
	 * @param WP_User $user       User.
	 */
	public function wp_login( $user_login, $user ) {
		if ( ! $user instanceof WP_User ) {
			return;
		}
		$scope = $this->opt( 'core_login' )['scope'] ?? 'admins';
		if ( 'admins' === $scope && ! user_can( $user, 'manage_options' ) ) {
			return;
		}
		PingPush_Events::trigger(
			'core_login',
			$this->user_data( $user ),
			array(
				'url'       => admin_url( 'user-edit.php?user_id=' . (int) $user->ID ),
				'url_title' => __( 'View user', 'pingpush' ),
				'dedupe'    => $user->ID . ':' . self::ip(),
			)
		);
	}

	/**
	 * Failed login, throttled per IP.
	 *
	 * @param string $username Username tried.
	 */
	public function wp_login_failed( $username ) {
		$minutes = max( 1, (int) ( $this->opt( 'core_login_failed' )['throttle'] ?? 15 ) );
		PingPush_Events::trigger(
			'core_login_failed',
			array(
				'username' => sanitize_user( (string) $username ),
				'ip'       => self::ip(),
			),
			array(
				'url'        => admin_url( 'users.php' ),
				'url_title'  => __( 'Users', 'pingpush' ),
				'dedupe'     => self::ip(),
				'dedupe_ttl' => $minutes * MINUTE_IN_SECONDS,
			)
		);
	}

	/**
	 * Plugin activated.
	 *
	 * @param string $plugin Plugin file.
	 */
	public function plugin_activated( $plugin ) {
		$this->plugin_toggled( $plugin, __( 'activated', 'pingpush' ) );
	}

	/**
	 * Plugin deactivated.
	 *
	 * @param string $plugin Plugin file.
	 */
	public function plugin_deactivated( $plugin ) {
		if ( plugin_basename( PINGPUSH_FILE ) === $plugin ) {
			return; // Our queue is being torn down.
		}
		$this->plugin_toggled( $plugin, __( 'deactivated', 'pingpush' ) );
	}

	/**
	 * Plugin toggled.
	 *
	 * @param string $plugin Plugin file.
	 * @param string $action Action label.
	 */
	private function plugin_toggled( $plugin, $action ) {
		$name = $plugin;
		$path = WP_PLUGIN_DIR . '/' . $plugin;
		if ( file_exists( $path ) ) {
			if ( ! function_exists( 'get_plugin_data' ) ) {
				require_once ABSPATH . 'wp-admin/includes/plugin.php';
			}
			$info = get_plugin_data( $path, false, false );
			if ( ! empty( $info['Name'] ) ) {
				$name = $info['Name'];
			}
		}
		$current = wp_get_current_user();
		PingPush_Events::trigger(
			'core_plugin_toggled',
			array(
				'plugin_name' => $name,
				'plugin_file' => $plugin,
				'action'      => $action,
				'user_name'   => $current->exists() ? $current->display_name : __( 'the system', 'pingpush' ),
			),
			array(
				'url'        => admin_url( 'plugins.php' ),
				'url_title'  => __( 'Plugins', 'pingpush' ),
				'dedupe'     => $plugin . ':' . $action,
				'dedupe_ttl' => 30,
			)
		);
	}

	/**
	 * Role changed. Skips new users (no old roles).
	 *
	 * @param int      $user_id   User id.
	 * @param string   $role      New role.
	 * @param string[] $old_roles Old roles.
	 */
	public function set_user_role( $user_id, $role, $old_roles ) {
		if ( empty( $old_roles ) ) {
			return;
		}
		$user = get_userdata( $user_id );
		if ( ! $user ) {
			return;
		}
		PingPush_Events::trigger(
			'core_role_changed',
			array(
				'user_login' => $user->user_login,
				'user_name'  => $user->display_name,
				'user_email' => $user->user_email,
				'old_role'   => implode( ', ', array_map( array( $this, 'role_name' ), (array) $old_roles ) ),
				'new_role'   => $this->role_name( $role ),
			),
			array(
				'url'       => admin_url( 'user-edit.php?user_id=' . (int) $user_id ),
				'url_title' => __( 'View user', 'pingpush' ),
				'dedupe'    => $user_id . ':' . $role,
			)
		);
	}

	/**
	 * Mail failed.
	 *
	 * @param WP_Error $error Error.
	 */
	public function wp_mail_failed( $error ) {
		if ( ! is_wp_error( $error ) ) {
			return;
		}
		$data    = (array) $error->get_error_data();
		$to      = isset( $data['to'] ) ? implode( ', ', (array) $data['to'] ) : '';
		$subject = isset( $data['subject'] ) ? (string) $data['subject'] : '';
		$message = $error->get_error_message();

		PingPush_Events::trigger(
			'core_mail_failed',
			array(
				'to'      => $to,
				'subject' => $subject,
				'error'   => $message,
			),
			array(
				'url'        => admin_url(),
				'url_title'  => __( 'Open dashboard', 'pingpush' ),
				'dedupe'     => md5( $message . $to ),
				'dedupe_ttl' => 10 * MINUTE_IN_SECONDS,
			)
		);
	}

	/**
	 * Recovery mode email is about to be sent: a fatal error happened.
	 * Sends synchronously because the request is ending in an error.
	 *
	 * @param array $email Email args (returned unchanged).
	 * @return array
	 */
	public function recovery_mode_email( $email ) {
		$error = error_get_last();
		$file  = isset( $error['file'] ) ? str_replace( wp_normalize_path( ABSPATH ), '', wp_normalize_path( (string) $error['file'] ) ) : '';
		$msg   = isset( $error['message'] ) ? strtok( (string) $error['message'], "\n" ) : __( 'A fatal error occurred.', 'pingpush' );

		PingPush_Events::trigger(
			'core_fatal_error',
			array(
				'error_message' => $msg,
				'error_file'    => $file,
				'error_line'    => isset( $error['line'] ) ? (string) $error['line'] : '',
			),
			array(
				'url'        => admin_url( 'site-health.php' ),
				'url_title'  => __( 'Site Health', 'pingpush' ),
				'dedupe'     => md5( $file . $msg ),
				'dedupe_ttl' => HOUR_IN_SECONDS,
				'sync'       => true,
			)
		);
		return $email;
	}

	/**
	 * Make sure the update check is scheduled (e.g. after a plugin update that skipped activation).
	 */
	public function ensure_update_cron() {
		if ( ! wp_next_scheduled( 'pingpush_check_updates' ) ) {
			wp_schedule_event( time() + HOUR_IN_SECONDS, 'twicedaily', 'pingpush_check_updates' );
		}
	}

	/**
	 * Report new updates, each version only once.
	 */
	public function check_updates() {
		if ( ! PingPush_Events::is_enabled( 'core_updates' ) ) {
			return;
		}
		$types    = (array) ( $this->opt( 'core_updates' )['types'] ?? array() );
		$found    = $this->available_updates( $types );
		$notified = get_option( 'pingpush_notified_updates', array() );
		$notified = is_array( $notified ) ? $notified : array();

		$new = array();
		foreach ( $found as $key => $item ) {
			if ( ( $notified[ $key ] ?? '' ) !== $item['version'] ) {
				$new[ $key ] = $item;
			}
		}

		// Remember what is currently available; forget items that were updated.
		$remember = array();
		foreach ( $found as $key => $item ) {
			$remember[ $key ] = $item['version'];
		}
		update_option( 'pingpush_notified_updates', $remember, false );

		if ( empty( $new ) ) {
			return;
		}

		$lines = array();
		foreach ( $new as $item ) {
			$lines[] = $item['line'];
		}

		PingPush_Events::trigger(
			'core_updates',
			array(
				'count'   => (string) count( $new ),
				'updates' => implode( "\n", $lines ),
			),
			array(
				'url'       => admin_url( 'update-core.php' ),
				'url_title' => __( 'Open Updates', 'pingpush' ),
			)
		);
	}

	/**
	 * Read available updates from WordPress' update transients.
	 *
	 * @param string[] $types core|plugins|themes.
	 * @return array<string,array{version:string,line:string}>
	 */
	public function available_updates( array $types ) {
		$out = array();

		if ( in_array( 'core', $types, true ) ) {
			$core = get_site_transient( 'update_core' );
			if ( is_object( $core ) && ! empty( $core->updates ) ) {
				foreach ( $core->updates as $update ) {
					if ( isset( $update->response, $update->version ) && 'upgrade' === $update->response ) {
						$out['core'] = array(
							'version' => (string) $update->version,
							/* translators: 1: new version, 2: current version. */
							'line'    => sprintf( __( 'WordPress %1$s (installed: %2$s)', 'pingpush' ), $update->version, get_bloginfo( 'version' ) ),
						);
						break;
					}
				}
			}
		}

		if ( in_array( 'plugins', $types, true ) ) {
			$plugins = get_site_transient( 'update_plugins' );
			if ( is_object( $plugins ) && ! empty( $plugins->response ) ) {
				if ( ! function_exists( 'get_plugins' ) ) {
					require_once ABSPATH . 'wp-admin/includes/plugin.php';
				}
				$installed = get_plugins();
				foreach ( $plugins->response as $file => $update ) {
					$version = is_object( $update ) ? (string) ( $update->new_version ?? '' ) : '';
					if ( '' === $version ) {
						continue;
					}
					$name                     = $installed[ $file ]['Name'] ?? $file;
					$current                  = $installed[ $file ]['Version'] ?? '?';
					$out[ 'plugin:' . $file ] = array(
						'version' => $version,
						'line'    => sprintf( '%s %s → %s', $name, $current, $version ),
					);
				}
			}
		}

		if ( in_array( 'themes', $types, true ) ) {
			$themes = get_site_transient( 'update_themes' );
			if ( is_object( $themes ) && ! empty( $themes->response ) ) {
				foreach ( $themes->response as $stylesheet => $update ) {
					$version = is_array( $update ) ? (string) ( $update['new_version'] ?? '' ) : '';
					if ( '' === $version ) {
						continue;
					}
					$theme = wp_get_theme( $stylesheet );
					if ( ! $theme->exists() ) {
						continue; // Avoid alerts for themes that are not installed.
					}
					$out[ 'theme:' . $stylesheet ] = array(
						'version' => $version,
						/* translators: 1: theme name, 2: current version, 3: new version. */
						'line'    => sprintf( __( 'Theme %1$s %2$s → %3$s', 'pingpush' ), $theme->get( 'Name' ), $theme->get( 'Version' ), $version ),
					);
				}
			}
		}

		return $out;
	}
}