<?php
/************************************************************************
 * This file is part of EspoCRM.
 *
 * EspoCRM – Open Source CRM application.
 * Copyright (C) 2014-2026 EspoCRM, Inc.
 * Website: https://www.espocrm.com
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program. If not, see <https://www.gnu.org/licenses/>.
 *
 * The interactive user interfaces in modified source and object code versions
 * of this program must display Appropriate Legal Notices, as required under
 * Section 5 of the GNU Affero General Public License version 3.
 *
 * In accordance with Section 7(b) of the GNU Affero General Public License version 3,
 * these Appropriate Legal Notices must retain the display of the "EspoCRM" word.
 ************************************************************************/

namespace Espo\Tools\OAuth;

use Espo\Core\Authentication\Oidc\PkceUtil;
use Espo\Core\Exceptions\Error;
use Espo\Core\Exceptions\Forbidden;
use Espo\Core\Session\Session;
use Espo\Entities\OAuthAccount;
use Espo\Entities\OAuthProvider;
use Espo\ORM\EntityManager;
use GuzzleHttp\Exception\GuzzleException;
use League\OAuth2\Client\Provider\Exception\IdentityProviderException;
use League\OAuth2\Client\Provider\GenericProvider;
use stdClass;

class ConnectionService
{
    public const string SESSION_KEY_CODE_VERIFIER = 'oauthCodeVerifier';

    public function __construct(
        private EntityManager $entityManager,
        private GenericProviderFactory $genericProviderFactory,
        private TokenSetter $tokenSetter,
        private Session $session,
        private ConfigDataProvider $configDataProvider,
    ) {}

    /**
     * @throws Forbidden
     * @throws Error
     */
    public function connect(OAuthAccount $account, string $code): void
    {
        $provider = $account->getProvider();

        if (!$provider->isActive()) {
            throw new Forbidden("Provider is not active.");
        }

        $genericProvider = $this->prepareGenericProvider($provider);

        try {
            $tokens = $genericProvider->getAccessToken('authorization_code', ['code' => $code]);
        } catch (GuzzleException $e) {
            throw new Error("Token request error.", 500, $e);
        } catch (IdentityProviderException $e) {
            throw new Error("Token request response error.", 500, $e);
        }

        $this->tokenSetter->set($account, $tokens);

        $this->entityManager->saveEntity($account);
    }

    public function disconnect(OAuthAccount $account): void
    {
        $account->setAccessToken(null);
        $account->setRefreshToken(null);
        $account->setExpiresAt(null);

        $this->entityManager->saveEntity($account);
    }

    private function prepareGenericProvider(OAuthProvider $provider): GenericProvider
    {
        $genericProvider = $this->genericProviderFactory->create($provider);

        if ($provider->useAuthorizationPkce()) {
            $codeVerifier = $this->session->get(self::SESSION_KEY_CODE_VERIFIER);

            $genericProvider->setPkceCode($codeVerifier);
        }

        return $genericProvider;
    }

    public function getAuthorizationData(OAuthAccount $account): stdClass
    {
        $provider = $account->getProvider();

        $scope = null;

        if ($provider->getScopes()) {
            $scope = implode($provider->getScopeSeparator() ?? ' ', $provider->getScopes());
        }

        $codeChallenge = $provider->useAuthorizationPkce() ? $this->prepareCodeChallenge() : null;

        return (object) [
            'endpoint' => $provider->getAuthorizationEndpoint(),
            'clientId' => $provider->getClientId(),
            'redirectUri' => $this->configDataProvider->getRedirectUri(),
            'scope' => $scope,
            'prompt' => $provider->getAuthorizationPrompt(),
            'params' => $provider->getAuthorizationParams(),
            'codeChallenge' => $codeChallenge,
            'codeChallengeMethod' => $codeChallenge ? 'S256' : null,
        ];
    }

    private function prepareCodeChallenge(): string
    {
        $codeVerifier = PkceUtil::generateCodeVerifier();

        $this->session->set(self::SESSION_KEY_CODE_VERIFIER, $codeVerifier);

        return PkceUtil::hashAndEncodeCodeVerifier($codeVerifier);
    }
}