<?php
declare(strict_types=1);

require_once __DIR__ . '/FreeTier.php';

/**
 * Tier-aware model routing for tools that expose the existing engine selector.
 *
 * Plus/trial users get the cost-controlled Azure mini path. Pro users get the
 * full Azure path. CaveauAI sessions keep the engine requested by their UI.
 */
final class ToolModels
{
    public static function engineForUser(int $userId, string $requestedEngine): string
    {
        $valid = ['nova_lite', 'azure_mini', 'azure_full', 'gpu', 'regex'];
        $requestedEngine = in_array($requestedEngine, $valid, true) ? $requestedEngine : 'azure_mini';

        if ($userId <= 0) {
            return $requestedEngine;
        }

        return match (FreeTier::tier($userId)) {
            'pro'   => $requestedEngine,
            'plus'  => $requestedEngine === 'azure_full' ? 'azure_mini' : $requestedEngine,
            default => in_array($requestedEngine, ['nova_lite', 'regex'], true) ? $requestedEngine : 'nova_lite',
        };
    }
}