<?php

declare(strict_types=1);

/**
 * Hoa
 *
 *
 * @license
 *
 * New BSD License
 *
 * Copyright © 2007-2017, Hoa community. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * Neither the name of the Hoa nor the names of its contributors may be
 *       used to endorse or promote products derived from this software without
 *       specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS AND CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

namespace Kitab;

/**
 * Configuration structure for the Kitab project.
 *
 * This structure contains all the configuration items used by Kitab.
 * All these items are public. Use it as a regular structure.
 *
 * # Examples
 *
 * Assuming the `foo` item is correctly declared:
 *
 * ```php
 * $configuration = new class () extends Kitab\Configuration {
 *     public $foo = null;
 * };
 * $configuration->foo = 'bar';
 *
 * assert('bar' === $configuration->foo);
 * ```
 */
abstract class Configuration
{
    /**
     * Get a configuration item value, or —if `null`— return a default value.
     * If the configuration item is not set, it will be considered as `null`.
     *
     * # Examples
     *
     * ```php
     * $configuration = new class () extends Kitab\Configuration {
     *     public $foo = null;
     * };
     *
     * assert($configuration->foo === null);
     * assert($configuration->getOr('foo', 'foobar') === 'foobar');
     * ```
     */
    public function getOr(string $item, $default)
    {
        if (null === $value = $this->$item) {
            return $default;
        }

        return $value;
    }
}