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<?php

    namespace Donut\Facebook;


    class FacebookApi
    {
        /** @var string */
        private $accountId;

        /** @var string */
        private $appId;

        /** @var string */
        private $appSecret;

        /** @var string */
        private $userAccessToken;

        /** @var string */
        private $accessToken;

        /** @var \Facebook\Facebook */
        private $facebook;


        public function __construct($accountId, $appId, $appSecret, $userAccessToken)
        {
            $this->accountId = $accountId;
            $this->appId = $appId;
            $this->appSecret = $appSecret;
            $this->userAccessToken = $userAccessToken;
        }


        public function getAccountId()
        {
            return $this->accountId;
        }


        public function getAccessToken()
        {
            if ($this->accessToken === NULL) {
                $facebook = $this->getFacebook();
                $response = $facebook->get('/' . $this->getAccountId() . '?fields=access_token', $this->userAccessToken);
                $body = $response->getDecodedBody();
                $this->accessToken = $body['access_token'];
            }
            return $this->accessToken;
        }


        /**
         * @return \Facebook\Facebook
         */
        public function getFacebook()
        {
            if (!$this->facebook) {
                $this->facebook = new \Facebook\Facebook(array(
                    'app_id' => $this->appId,
                    'app_secret' => $this->appSecret,
                ));
            }
            return $this->facebook;
        }
    }