<?php
/**
 * Main plugin loader — singleton bootstrap.
 *
 * @package AI_SiteArk
 * Copyright (c) 2026 AtoZ INFOWAY INC.
 * Licensed under the GNU General Public License, version 2 or later.
 */

namespace AtoZ\SiteArk;

use AtoZ\SiteArk\Admin\Admin;

defined( 'ABSPATH' ) || exit;

/**
 * Class SiteArk
 *
 * Central loader. Boots the admin surface and the backup/restore controller
 * (which registers the AJAX step-runner and, later, the scheduled-backup cron).
 */
final class SiteArk {

	/**
	 * Singleton instance.
	 *
	 * @var SiteArk|null
	 */
	private static $instance = null;

	/**
	 * Get the singleton instance.
	 *
	 * @return SiteArk
	 */
	public static function instance() {
		if ( null === self::$instance ) {
			self::$instance = new self();
			self::$instance->run();
		}
		return self::$instance;
	}

	/**
	 * Private constructor (use instance()).
	 */
	private function __construct() {}

	/**
	 * Boot surfaces + controllers.
	 *
	 * @return void
	 */
	private function run() {
		// Move a pre-2.9 install's data onto the new `aisiteark_` names before anything reads it.
		Migrator::maybe_run();
		self::maybe_upgrade();

		if ( is_admin() ) {
			( new Admin() )->register();

			// What's New — in-dashboard release notes + post-update notice.
			if ( class_exists( '\\AtoZ\\SiteArk\\Modules\\Help\\Whats_New' ) ) {
				( new \AtoZ\SiteArk\Modules\Help\Whats_New() )->register();
			}
		}

		// Backup/restore controller (AJAX step-runner + admin-post handlers). Added
		// with the job engine; guarded so the scaffold loads before it exists.
		if ( class_exists( '\\AtoZ\\SiteArk\\Modules\\Backup\\Controller' ) ) {
			( new \AtoZ\SiteArk\Modules\Backup\Controller() )->register();
		}

		// WP-CLI commands (M2), only when running under WP-CLI.
		if ( defined( 'WP_CLI' ) && \WP_CLI && class_exists( '\\AtoZ\\SiteArk\\CLI\\CLI' ) ) {
			\AtoZ\SiteArk\CLI\CLI::register();
		}

		// Pro add-on (self-hosted builds only). The free core never references a Pro class;
		// Pro attaches through the extension-point hooks the core fires. The WordPress.org
		// build ships without includes/pro/, so this simply does nothing there — no locked
		// code, no gating. See docs/FREE-PRO-SPLIT.md.
		if ( is_readable( AISITEARK_DIR . 'includes/pro/class-pro.php' ) && class_exists( '\\AtoZ\\SiteArk\\Pro\\Pro' ) ) {
			\AtoZ\SiteArk\Pro\Pro::boot();
		}
	}

	/**
	 * Run dbDelta when the DB version changes (upgrades add tables/columns).
	 *
	 * @return void
	 */
	private static function maybe_upgrade() {
		if ( get_option( 'aisiteark_db_version' ) === AISITEARK_DB_VERSION ) {
			return;
		}
		if ( is_admin() ) {
			Activator::activate();
		}
	}
}