<?php
/**
 * Plugin bootstrap.
 *
 * @package CodingCush\Tweaks
 */

namespace CodingCush\Tweaks;

defined( 'ABSPATH' ) || exit;

/**
 * Wires settings, tweaks and the admin screen together.
 */
final class Plugin {

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

	/**
	 * Settings store.
	 *
	 * @var Settings
	 */
	public $settings;

	/**
	 * Tweak registry.
	 *
	 * @var Registry
	 */
	public $registry;

	/**
	 * Booted tweak objects, keyed by id.
	 *
	 * @var array<string, Tweak>
	 */
	private $active = array();

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

	/**
	 * Activation: seed defaults once so the option autoloads from the first request.
	 *
	 * @return void
	 */
	public static function activate() {
		if ( false === get_option( CCTWEAKS_OPTION ) ) {
			add_option( CCTWEAKS_OPTION, Registry::defaults(), '', true );
		}
	}

	/**
	 * Boots the plugin.
	 *
	 * @return void
	 */
	private function boot() {
		$this->registry = new Registry();
		$this->settings = new Settings( $this->registry );

		// Only instantiate tweaks that are switched on: zero cost for everything else.
		foreach ( $this->registry->map() as $id => $def ) {
			if ( ! $this->settings->is_enabled( $id ) ) {
				continue;
			}
			$class = $def['class'];
			if ( class_exists( $class ) ) {
				$tweak = new $class( $id, $this->settings );
				$tweak->boot();
				$this->active[ $id ] = $tweak;
			}
		}

		if ( is_admin() ) {
			( new Admin\Admin( $this->registry, $this->settings ) )->boot();
		}
	}

	/**
	 * Returns ids of active tweaks.
	 *
	 * @return string[]
	 */
	public function active_ids() {
		return array_keys( $this->active );
	}
}