<?php
/**
 * One-time admin notices carried across a redirect.
 *
 * @package LaunchList
 */

namespace LaunchList;

defined( 'ABSPATH' ) || exit;

/**
 * Notices an admin action leaves for the screen it redirects to, kept per user for a minute so a
 * redirect never carries the message (or anything in it) in the URL.
 */
class Notices {

	/** Notice types WordPress styles. */
	const TYPES = array( 'success', 'warning', 'error', 'info' );

	/**
	 * Leave a notice for the current user's next LaunchList screen.
	 *
	 * @param string $type    success, warning, error or info.
	 * @param string $message Plain text (escaped when shown).
	 * @return void
	 */
	public static function add( $type, $message ) {
		$user_id = get_current_user_id();

		if ( ! $user_id ) {
			return;
		}

		$notices   = self::peek( $user_id );
		$notices[] = array(
			'type'    => in_array( $type, self::TYPES, true ) ? $type : 'info',
			'message' => (string) $message,
		);

		set_transient( self::key( $user_id ), $notices, MINUTE_IN_SECONDS );
	}

	/**
	 * Take (and forget) the current user's notices.
	 *
	 * @return array<int, array{type: string, message: string}>
	 */
	public static function take() {
		$user_id = get_current_user_id();

		if ( ! $user_id ) {
			return array();
		}

		$notices = self::peek( $user_id );
		delete_transient( self::key( $user_id ) );

		return $notices;
	}

	/**
	 * The stored notices.
	 *
	 * @param int $user_id User ID.
	 * @return array<int, array{type: string, message: string}>
	 */
	private static function peek( $user_id ) {
		$notices = get_transient( self::key( $user_id ) );

		return is_array( $notices ) ? $notices : array();
	}

	/**
	 * The transient key.
	 *
	 * @param int $user_id User ID.
	 * @return string
	 */
	private static function key( $user_id ) {
		return 'launchlist_notices_' . (int) $user_id;
	}
}