<?php

namespace App\Content;

/**
 * The arithmetic every paged list needs, in one place.
 *
 * A fixed upper limit is not pagination: it shows the first thirty entries and says nothing about
 * the rest. This makes "there are more, here is how to reach them" cheap enough that no list has
 * to settle for a cap.
 */
final class Pagination
{
    /**
     * @return array{page: int, pages: int, offset: int, perPage: int, total: int}
     */
    public static function of(int $page, int $total, int $perPage): array
    {
        $perPage = max(1, min(200, $perPage));
        $pages = max(1, (int) ceil($total / $perPage));
        // A page beyond the end shows the last one rather than an empty screen.
        $page = max(1, min($page, $pages));

        return [
            'page' => $page,
            'pages' => $pages,
            'offset' => ($page - 1) * $perPage,
            'perPage' => $perPage,
            'total' => $total,
        ];
    }
}