<?php
/**
 * ---------------------------------------------------------------------
 * GLPI - Gestionnaire Libre de Parc Informatique
 * Copyright (C) 2015-2020 Teclib' and contributors.
 *
 * http://glpi-project.org
 *
 * based on GLPI - Gestionnaire Libre de Parc Informatique
 * Copyright (C) 2003-2014 by the INDEPNET Development Team.
 *
 * ---------------------------------------------------------------------
 *
 * LICENSE
 *
 * This file is part of GLPI.
 *
 * GLPI is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * GLPI is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with GLPI. If not, see <http://www.gnu.org/licenses/>.
 * ---------------------------------------------------------------------
 */

namespace Glpi\System\Requirement;

if (!defined('GLPI_ROOT')) {
   die("Sorry. You can't access this file directly");
}

/**
 * @since 9.5.0
 */
abstract class AbstractRequirement implements RequirementInterface {

   /**
    * Flag that indicates if requirement check has already been done.
    *
    * @var bool
    */
   private $has_been_checked = false;

   /**
    * Flag that indicates if requirement is considered as optional.
    *
    * @var bool
    */
   protected $optional = false;

   /**
    * Flag that indicates if requirement is considered as out of context.
    *
    * @var bool
    */
   protected $out_of_context = false;

   /**
    * Requirement title.
    *
    * @var string
    */
   protected $title;

   /**
    * Flag that indicates if requirement is validated on system.
    *
    * @var bool
    */
   protected $validated;

   /**
    * Requirement validation message.
    *
    * @var string[]
    */
   protected $validation_messages = [];

   /**
    * Check requirement.
    *
    * This method will be called once before access to any RequirementInterface method
    * and should be used to compute  $validated and $validation_messages properties.
    *
    * @return void
    */
   abstract protected function check();

   /**
    * Run requirement check once.
    *
    * @return void
    */
   private function doCheck() {
      if (!$this->has_been_checked) {
         $this->check();
         $this->has_been_checked = true;
      }
   }

   public function getTitle(): string {
      $this->doCheck();

      return $this->title;
   }

   public function getValidationMessages(): array {
      $this->doCheck();

      return $this->validation_messages;
   }

   public function isMissing(): bool {
      $this->doCheck();

      return true !== $this->validated;
   }

   public function isOptional(): bool {
      $this->doCheck();

      return $this->optional;
   }

   public function isOutOfContext(): bool {
      $this->doCheck();

      return $this->out_of_context;
   }

   public function isValidated(): bool {
      $this->doCheck();

      return true === $this->validated;
   }

}