<?php
// SPDX-License-Identifier: GPL-3.0-or-later
declare(strict_types=1);

namespace Aiwend\Chat;

/**
 * Turns a filtered throttle limit into a safe number (Phase 87).
 *
 * A limit is a whole number of 1 or more. Anything else a filter returns (0, a negative number, a fraction, an empty or
 * non-numeric string, null, an array, a boolean) is a configuration mistake and falls back to the built-in default, so a
 * typo can never switch a throttle off. Disabling a throttle is a separate, explicit act: the scope's name must be listed
 * by the aiwend_throttles_disabled filter (see Rest\ChatController).
 */
final class LimitSetting
{
    /** Throttle scopes that can be disabled explicitly. */
    public const SCOPES = ['conversation', 'client', 'session_create'];

    /** @param mixed $value what the limit filter returned */
    public static function valid(mixed $value, int $default): int
    {
        if (is_int($value)) {
            return $value >= 1 ? $value : $default;
        }
        if (is_string($value) && preg_match('/^[1-9][0-9]{0,8}$/', $value) === 1) {
            return (int) $value;
        }
        if (is_float($value) && $value >= 1 && $value <= 999999999 && floor($value) === $value) {
            return (int) $value;
        }
        return $default;
    }

    /**
     * The limit to enforce: 0 (the limiter's "no limit") only when the scope is named in the explicit list, otherwise the valid
     * number or the default.
     *
     * @param mixed $value    what the limit filter returned
     * @param mixed $disabled what the disable filter returned (expected: a list of scope names)
     */
    public static function effective(string $scope, mixed $value, int $default, mixed $disabled): int
    {
        if (is_array($disabled) && in_array($scope, $disabled, true)) {
            return 0;
        }
        return self::valid($value, $default);
    }
}