<?php

namespace Google\AuthHandler;

use Google\Auth\CredentialsLoader;
use Google\Auth\FetchAuthTokenCache;
use Google\Auth\HttpHandler\HttpHandlerFactory;
use Google\Auth\Subscriber\AuthTokenSubscriber;
use Google\Auth\Subscriber\ScopedAccessTokenSubscriber;
use Google\Auth\Subscriber\SimpleSubscriber;
use GuzzleHttp\Client;
use GuzzleHttp\ClientInterface;
use Psr\Cache\CacheItemPoolInterface;

/**
 * This supports Guzzle 5
 */
class Guzzle5AuthHandler
{
    protected $cache;
    protected $cacheConfig;

    public function __construct(CacheItemPoolInterface $cache = null, array $cacheConfig = [])
    {
        $this->cache = $cache;
        $this->cacheConfig = $cacheConfig;
    }

    public function attachCredentials(
        ClientInterface $http,
        CredentialsLoader $credentials,
        callable $tokenCallback = null
    ) {
        // use the provided cache
        if ($this->cache) {
            $credentials = new FetchAuthTokenCache(
                $credentials,
                $this->cacheConfig,
                $this->cache
            );
        }

        return $this->attachCredentialsCache($http, $credentials, $tokenCallback);
    }

    public function attachCredentialsCache(
        ClientInterface $http,
        FetchAuthTokenCache $credentials,
        callable $tokenCallback = null
    ) {
        // if we end up needing to make an HTTP request to retrieve credentials, we
        // can use our existing one, but we need to throw exceptions so the error
        // bubbles up.
        $authHttp = $this->createAuthHttp($http);
        $authHttpHandler = HttpHandlerFactory::build($authHttp);
        $subscriber = new AuthTokenSubscriber(
            $credentials,
            $authHttpHandler,
            $tokenCallback
        );

        $http->setDefaultOption('auth', 'google_auth');
        $http->getEmitter()->attach($subscriber);

        return $http;
    }

    public function attachToken(ClientInterface $http, array $token, array $scopes)
    {
        $tokenFunc = function ($scopes) use ($token) {
            return $token['access_token'];
        };

        $subscriber = new ScopedAccessTokenSubscriber(
            $tokenFunc,
            $scopes,
            $this->cacheConfig,
            $this->cache
        );

        $http->setDefaultOption('auth', 'scoped');
        $http->getEmitter()->attach($subscriber);

        return $http;
    }

    public function attachKey(ClientInterface $http, $key)
    {
        $subscriber = new SimpleSubscriber(['key' => $key]);

        $http->setDefaultOption('auth', 'simple');
        $http->getEmitter()->attach($subscriber);

        return $http;
    }

    private function createAuthHttp(ClientInterface $http)
    {
        return new Client([
            'base_url' => $http->getBaseUrl(),
            'defaults' => [
                'exceptions' => true,
                'verify' => $http->getDefaultOption('verify'),
                'proxy' => $http->getDefaultOption('proxy'),
            ]
        ]);
    }
}
