<?php
/**
 * Plugin container.
 *
 * Holds the shared services, boots them in order, then hands control to the
 * module registry. This file names no module.
 *
 * @package PageCore
 */

namespace PageCore;

defined( 'ABSPATH' ) || exit;

/**
 * The single plugin instance.
 */
final class Plugin {

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

	/**
	 * Instantiated services, keyed by short name.
	 *
	 * @var array
	 */
	private $services = array();

	/**
	 * Whether boot() has run.
	 *
	 * @var bool
	 */
	private $booted = false;

	/**
	 * Get or create the instance.
	 *
	 * @return Plugin
	 */
	public static function instance() {
		if ( null === self::$instance ) {
			self::$instance = new self();
		}

		return self::$instance;
	}

	/**
	 * Schedule the boot.
	 */
	private function __construct() {
		add_action( 'plugins_loaded', array( $this, 'boot' ), 5 );
	}

	/**
	 * Construct the services, then boot the modules.
	 *
	 * @return void
	 */
	public function boot() {
		if ( $this->booted ) {
			return;
		}

		$this->booted = true;

		$this->services['settings']       = new Settings();
		$this->services['assets']         = new Assets();
		$this->services['http']           = new Http();
		$this->services['filesystem']     = new Filesystem();
		$this->services['modules']        = new Modules();
		$this->services['modules_screen'] = new Modules_Screen();
		$this->services['admin_menu']     = new Admin_Menu();

		if ( is_admin() ) {
			$this->services['admin_menu']->register();
		}

		$modules_rest = new Modules_Rest();
		$modules_rest->register();

		$svg_rest = new Svg_Rest();
		$svg_rest->register();

		$theme_rest = new Theme_Rest();
		$theme_rest->register();

		$settings_rest = new Settings_Rest();
		$settings_rest->register();

		Color_Schemes::register();

		$this->services['modules']->discover();
		$this->services['modules']->boot_enabled();
	}

	/**
	 * Settings store.
	 *
	 * @return Settings
	 */
	public function settings() {
		return $this->service( 'settings' );
	}

	/**
	 * Asset loader.
	 *
	 * @return Assets
	 */
	public function assets() {
		return $this->service( 'assets' );
	}

	/**
	 * Remote request helper.
	 *
	 * @return Http
	 */
	public function http() {
		return $this->service( 'http' );
	}

	/**
	 * Filesystem helper.
	 *
	 * @return Filesystem
	 */
	public function filesystem() {
		return $this->service( 'filesystem' );
	}

	/**
	 * Module registry.
	 *
	 * @return Modules
	 */
	public function modules() {
		return $this->service( 'modules' );
	}

	/**
	 * The Modules screen renderer.
	 *
	 * @return Modules_Screen
	 */
	public function modules_screen() {
		return $this->service( 'modules_screen' );
	}

	/**
	 * The admin menu builder.
	 *
	 * @return Admin_Menu
	 */
	public function admin_menu() {
		return $this->service( 'admin_menu' );
	}

	/**
	 * Fetch a service, booting the plugin first if something asked early.
	 *
	 * @param string $name Service key.
	 * @return mixed
	 */
	private function service( $name ) {
		if ( ! $this->booted ) {
			$this->boot();
		}

		return isset( $this->services[ $name ] ) ? $this->services[ $name ] : null;
	}

	/**
	 * Singletons are not cloned.
	 *
	 * @return void
	 */
	private function __clone() {}

	/**
	 * Singletons are not unserialised.
	 *
	 * @return void
	 * @throws \Exception Always.
	 */
	public function __wakeup() {
		throw new \Exception( 'PageCore\\Plugin cannot be unserialised.' );
	}
}