<?php

namespace MintyPHP\Module\Helpdesk\Service;

/**
 * OAuth2 client_credentials token service for BC OData access.
 *
 * This is a skeleton for V1. Basic Auth is the default and recommended
 * auth mode. OAuth2 support can be activated in settings but the full
 * token flow (request, cache, refresh) is deferred to a future version.
 */
class HelpdeskOAuthTokenService
{
    public function __construct(
        private readonly HelpdeskSettingsGateway $settingsGateway,
        private readonly HelpdeskTokenRepository $tokenRepository
    ) {
    }

    /**
     * Get a valid access token for BC API calls.
     *
     * @return string|null The bearer token, or null if unavailable.
     */
    public function getAccessToken(int $tenantId): ?string
    {
        if ($this->settingsGateway->getAuthMode() !== HelpdeskSettingsGateway::AUTH_MODE_OAUTH2) {
            return null;
        }

        // Check cache first
        $cached = $this->tokenRepository->findValidToken($tenantId);
        if ($cached !== null) {
            return $cached;
        }

        // Token request would go here in a future version.
        // For V1, return null to indicate OAuth2 is not yet fully implemented.
        return null;
    }
}