<?php

session_start();

class EpiOAuth

{

  public $version = '1.0';



  protected $requestTokenUrl;

  protected $accessTokenUrl;

  protected $authorizeUrl;

  protected $consumerKey;

  protected $consumerSecret;

  protected $token;

  protected $tokenSecret;

  protected $signatureMethod;



  public function getAccessToken()

  {

    $resp = $this->httpRequest('GET', $this->accessTokenUrl);

    return new EpiOAuthResponse($resp);

  }



  public function getAuthorizationUrl()

  {  

    $retval = "{$this->authorizeUrl}?";

    $token = $this->getRequestToken();

    return $this->authorizeUrl . '?oauth_token=' . $token->oauth_token;

  }



  public function getRequestToken()

  {

    $resp = $this->httpRequest('GET', $this->requestTokenUrl);

    return new EpiOAuthResponse($resp);

  }



  public function httpRequest($method = null, $url = null, $params = null)

  {

    if(empty($method) || empty($url))

      return false;



    if(empty($params['oauth_signature']))

      $params = $this->prepareParameters($method, $url, $params);



    switch($method)

    {

      case 'GET':

        return $this->httpGet($url, $params);

        break;

      case 'POST':

        return $this->httpPost($url, $params);

        break;

    }

  }



  public function setToken($token = null, $secret = null)

  {

    $params = func_get_args();

    $this->token = $token;

    $this->tokenSecret = $secret;

  } 



  public function encode($string)

  {

    return rawurlencode(utf8_encode($string));

  }



  protected function addOAuthHeaders(&$ch, $url, $oauthHeaders)

  {

    $_h = array('Expect:');

    $urlParts = parse_url($url);

    $oauth = 'Authorization: OAuth realm="' . $urlParts['path'] . '",';

    foreach($oauthHeaders as $name => $value)

    {

      $oauth .= "{$name}=\"{$value}\",";

    }

    $_h[] = substr($oauth, 0, -1);

  

    curl_setopt($ch, CURLOPT_HTTPHEADER, $_h); 

  }



  protected function generateNonce()

  {

    if(isset($this->nonce)) // for unit testing

      return $this->nonce;



    return md5(uniqid(rand(), true));

  }



  protected function generateSignature($method = null, $url = null, $params = null)

  {

    if(empty($method) || empty($url))

      return false;





    // concatenating

    $concatenatedParams = '';

    foreach($params as $k => $v)

    {

      $v = $this->encode($v);

      $concatenatedParams .= "{$k}={$v}&";

    }

    $concatenatedParams = $this->encode(substr($concatenatedParams, 0, -1));



    // normalize url

    $normalizedUrl = $this->encode($this->normalizeUrl($url));

    $method = $this->encode($method); // don't need this but why not?



    $signatureBaseString = "{$method}&{$normalizedUrl}&{$concatenatedParams}";

    return $this->signString($signatureBaseString);

  }



  protected function httpGet($url, $params = null)

  {

    if(count($params['request']) > 0)

    {

      $url .= '?';

      foreach($params['request'] as $k => $v)

      {

        $url .= "{$k}={$v}&";

      }

      $url = substr($url, 0, -1);

    }

    $ch = curl_init($url);

    $this->addOAuthHeaders($ch, $url, $params['oauth']);

    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);

    $resp  = $this->curl->addCurl($ch);



    return $resp;

  }



  protected function httpPost($url, $params = null)

  {

    $ch = curl_init($url);

    $this->addOAuthHeaders($ch, $url, $params['oauth']);

    curl_setopt($ch, CURLOPT_POST, 1);

    curl_setopt($ch, CURLOPT_POSTFIELDS, http_build_query($params['request']));

    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);

    $resp  = $this->curl->addCurl($ch);

    return $resp;

  }



  protected function normalizeUrl($url = null)

  {

    $urlParts = parse_url($url);

    $scheme = strtolower($urlParts['scheme']);

    $host   = strtolower($urlParts['host']);

    $port = intval($urlParts['port']);



    $retval = "{$scheme}://{$host}";

    if($port > 0 && ($scheme === 'http' && $port !== 80) || ($scheme === 'https' && $port !== 443))

    {

      $retval .= ":{$port}";

    }

    $retval .= $urlParts['path'];

    if(!empty($urlParts['query']))

    {

      $retval .= "?{$urlParts['query']}";

    }



    return $retval;

  }



  protected function prepareParameters($method = null, $url = null, $params = null)

  {

    if(empty($method) || empty($url))

      return false;



    $oauth['oauth_consumer_key'] = $this->consumerKey;

    $oauth['oauth_token'] = $this->token;

    $oauth['oauth_nonce'] = $this->generateNonce();

    $oauth['oauth_timestamp'] = !isset($this->timestamp) ? time() : $this->timestamp; // for unit test

    $oauth['oauth_signature_method'] = $this->signatureMethod;

    $oauth['oauth_version'] = $this->version;



    // encoding

    array_walk($oauth, array($this, 'encode'));

    if(is_array($params))

      array_walk($params, array($this, 'encode'));

    $encodedParams = array_merge($oauth, (array)$params);



    // sorting

    ksort($encodedParams);



    // signing

    $oauth['oauth_signature'] = $this->encode($this->generateSignature($method, $url, $encodedParams));

    return array('request' => $params, 'oauth' => $oauth);

  }



  protected function signString($string = null)

  {

    $retval = false;

    switch($this->signatureMethod)

    {

      case 'HMAC-SHA1':

        $key = $this->encode($this->consumerSecret) . '&' . $this->encode($this->tokenSecret);

        $retval = base64_encode(hash_hmac('sha1', $string, $key, true));

        break;

    }



    return $retval;

  }



  public function __construct($consumerKey, $consumerSecret, $signatureMethod='HMAC-SHA1')

  {

    $this->consumerKey = $consumerKey;

    $this->consumerSecret = $consumerSecret;

    $this->signatureMethod = $signatureMethod;

    $this->curl = EpiCurl::getInstance();

  }

}



class EpiOAuthResponse

{

  private $__resp;



  public function __construct($resp)

  {

    $this->__resp = $resp;

  }



  public function __get($name)

  {

    if($this->__resp->code < 200 || $this->__resp->code > 299)

      return false;



    parse_str($this->__resp->data, $result);

    foreach($result as $k => $v)

    {

      $this->$k = $v;

    }



    return $result[$name];

  }

}