<?php

/**
 * This program 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; under version 2
 * of the License (non-upgradable).
 *
 * This program 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 this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 *
 * Copyright (c) 2017 Open Assessment Technologies SA
 *
 */

namespace oat\tao\model\maintenance;

use oat\oatbox\service\ConfigurableService;
use oat\tao\model\metadata\exception\InconsistencyConfigException;

/**
 * Class Maintenance
 *
 * Service to manage platform maintenance
 *
 * @package oat\tao\model\maintenance
 */
class Maintenance extends ConfigurableService
{
    const SERVICE_ID = 'tao/maintenance';

    const OPTION_PERSISTENCE = 'persistence';

    /**
     * Storage to store platform state
     *
     * @var MaintenanceStorage
     */
    protected $storage;

    /**
     * Check if platform is ready, if $state is null, it is retrieved from storage
     *
     * @param MaintenanceState|null $state
     * @return bool
     */
    public function isPlatformReady(MaintenanceState $state = null)
    {
        if (is_null($state)) {
            $state = $this->getPlatformState();
        }
        return ($state->getBooleanStatus() === true);
    }

    /**
     * Enable the platform by updating storage
     */
    public function enablePlatform()
    {
        $this->setPlatformState(MaintenanceState::LIVE_MODE);
    }

    /**
     * Disable the platform by updating storage
     */
    public function disablePlatform()
    {
        $this->setPlatformState(MaintenanceState::OFFLINE_MODE);
    }

    /**
     * Get the current maintenance state of the platform
     *
     * @return MaintenanceState
     */
    public function getPlatformState()
    {
        try {
            return $this->getStorage()->getCurrentPlatformState();
        } catch (\common_exception_NotFound $e) {
            $this->enablePlatform();
            return new MaintenanceState(
                [MaintenanceState::STATUS => MaintenanceState::LIVE_MODE]
            );
        }
    }

    /**
     * Update platform state
     *
     * @param $status
     */
    protected function setPlatformState($status)
    {
        $state = new MaintenanceState([
            MaintenanceState::STATUS => $status
        ]);

        $this->getStorage()->setPlatformState($state);
    }

    /**
     * Get the maintenance storage
     *
     * @return MaintenanceStorage
     * @throws InconsistencyConfigException
     */
    public function getStorage()
    {
        if (! $this->storage) {
            if (! $this->hasOption(self::OPTION_PERSISTENCE)) {
                throw new InconsistencyConfigException(__('Maintenance service must have a persistence option.'));
            }
            $this->storage = new MaintenanceStorage(
                \common_persistence_Manager::getPersistence($this->getOption(self::OPTION_PERSISTENCE))
            );
        }
        return $this->storage;
    }
}