<?php
require_once 'Zend/Oauth/Exception.php';
require_once 'Zend/Oauth/Http/Utility.php';
require_once 'Zend/Uri/Http.php';

/**
 *
 * Basic OAuth provider class
 */
class Zend_Oauth_Provider
{
    /**
     * OAuth result statuses
     */
    const OK = 0;
    const BAD_NONCE = 1;
    const BAD_TIMESTAMP = 2;
    const CONSUMER_KEY_UNKNOWN = 3;
    const CONSUMER_KEY_REFUSED = 4;
    const INVALID_SIGNATURE = 5;
    const TOKEN_USED = 6;
    const TOKEN_EXPIRED = 7;
    const TOKEN_REVOKED = 8;
    const TOKEN_REJECTED = 9;
    const PARAMETER_ABSENT = 10;
    const SIGNATURE_METHOD_REJECTED = 11;
    const OAUTH_VERIFIER_INVALID = 12;

    /**
     * Error names for error reporting
     * @var array
     */
    protected $errnames = array(
     self::BAD_NONCE => "nonce_used",
     self::BAD_TIMESTAMP => "timestamp_refused",
     self::CONSUMER_KEY_UNKNOWN => "consumer_key_unknown",
     self::CONSUMER_KEY_REFUSED => "consumer_key_refused",
     self::INVALID_SIGNATURE => "signature_invalid",
     self::TOKEN_USED => "token_used",
     self::TOKEN_EXPIRED => "token_expired",
     self::TOKEN_REVOKED => "token_revoked",
     self::TOKEN_REJECTED => "token_rejected",
     self::PARAMETER_ABSENT => "parameter_absent",
     self::SIGNATURE_METHOD_REJECTED => "signature_method_rejected",
     self::OAUTH_VERIFIER_INVALID => "verifier_invalid",
     );

    public $token;
    public $token_secret;
    public $consumer_key;
    public $consumer_secret;
    public $verifier;

    protected $problem;

    protected $tokenHandler;
    protected $consumerHandler;
    protected $nonceHandler;
    protected $oauth_params;

    protected $requestPath;
    /**
     * Current URL
     * @var Zend_Uri_Http
     */
    protected $url;
    /**
     *
     * Required OAuth parameters
     * @var array
     */
    protected $required = array("oauth_consumer_key", "oauth_signature", "oauth_signature_method", "oauth_nonce", "oauth_timestamp");

    /**
     * Set consumer key handler
     * @param string $callback
	 * @return Zend_Oauth_Provider
     */
    public function setConsumerHandler($callback)
    {
        $this->consumerHandler = $callback;
        return $this;
    }

    /**
     * Set nonce/ts handler
     * @param string $callback
	 * @return Zend_Oauth_Provider
     */
    public function setTimestampNonceHandler($callback)
    {
        $this->nonceHandler = $callback;
        return $this;
    }

    /**
     * Set token handler
     * @param string $callback
	 * @return Zend_Oauth_Provider
     */
    public function setTokenHandler($callback)
    {
        $this->tokenHandler = $callback;
        return $this;
    }

    /**
     * Set URL for requesting token (doesn't need token)
     * @param string $req_path
	 * @return Zend_Oauth_Provider
     */
    public function setRequestTokenPath($req_path)
	{
	    $this->requestPath = $req_path;
	    return $this;
	}

	/**
	 * Set this request as token endpoint
	 * @param string $request
	 * @return Zend_Oauth_Provider
	 */
	public function isRequestTokenEndpoint($request)
	{
	    $this->is_request = $request;
	    return $this;
	}

    /**
     * Report problem in OAuth as string
     * @param Zend_Oauth_Exception $e
     * @return string
     */
	public function reportProblem(Zend_Oauth_Exception $e)
	{
	    $code = $e->getCode();
	    if($code == self::PARAMETER_ABSENT) {
	        return "oauth_problem=parameter_absent&oauth_parameters_absent={$this->problem}";
	    }
	    if($code == self::INVALID_SIGNATURE) {
	        return "oauth_problem=signature_invalid&debug_sbs={$this->problem}";
	    }
	    if(isset($this->errnames[$code])) {
            return "oauth_problem=".$this->errnames[$code];
        }
        return "oauth_problem=unknown_problem&code=$code";
	}

	/**
	 * Check if this request needs token
	 * @return bool
	 */
	protected function needsToken()
	{
	    if(!empty($this->is_request)) {
	        return false;
	    }
	    if(empty($this->requestPath)) {
	        return true;
	    }
	    $GLOBALS['log']->debug("URLs: now: ".$this->url->getUri(). " req: {$this->requestPath}");
	    if($this->requestPath[0] == '/') {
	        return $this->url->getPath() != $this->requestPath;
	    }
	    return $this->url->getUri() != $this->requestPath;
	}

	/**
	 * Check if all required parameters are there
	 * @param array $params
	 * @throws Zend_Oauth_Exception
	 */
	protected function checkRequiredParams($params)
	{
        foreach($this->required as $param) {
            if(!isset($params[$param])) {
                $this->problem = $param;
                throw new Zend_Oauth_Exception("Missing parameter: $param", self::PARAMETER_ABSENT);
            }
        }
        if($this->needsToken() && !isset($params["oauth_token"])) {
            $this->problem = "oauth_token";
            throw new Zend_Oauth_Exception("Missing parameter: oauth_token", self::PARAMETER_ABSENT);
        }
        return true;
	}

	/**
	 * Check if signature method is supported
	 * @param string $signatureMethod
	 * @throws Zend_Oauth_Exception
	 */
	protected function checkSignatureMethod($signatureMethod)
	{
        $className = '';
        $hashAlgo  = null;
        $parts     = explode('-', $signatureMethod);
        if (count($parts) > 1) {
            $className = 'Zend_Oauth_Signature_' . ucfirst(strtolower($parts[0]));
        } else {
            $className = 'Zend_Oauth_Signature_' . ucfirst(strtolower($signatureMethod));
        }
        $filename = str_replace('_', '/', $className) . '.php';
        if(file_exists($filename)) {
            require_once $filename;
        }
        if(!class_exists($className)) {
            throw new Zend_Oauth_Exception("Invalid signature method", self::SIGNATURE_METHOD_REJECTED);
        }
	}

	/**
	 * Collect request parameters from the environment
	 * @param string $method HTTP method being used
	 * @param string $params Extra parameters
	 */
	protected function assembleParams($method, $params = array())
	{
	    $params = array_merge($_GET, $params);
	    if($method == 'POST') {
	        $params = array_merge($_POST, $params);
	    }
	    $auth = null;
	    if(function_exists('apache_request_headers')) {
	        $headers = apache_request_headers();
	        if(isset($headers['Authorization'])) {
	            $auth = $headers['Authorization'];
	        } elseif(isset($headers['authorization'])) {
	            $auth = $headers['authorization'];
	        }
	    }
	    if(empty($auth) && !empty($_SERVER['HTTP_AUTHORIZATION'])) {
	        $auth = $_SERVER['HTTP_AUTHORIZATION'];
	    }

	    if(!empty($auth) && substr($auth, 0, 6) == 'OAuth ') {
	        // import header data
	        if (preg_match_all('/(oauth_[a-z_-]*)=(:?"([^"]*)"|([^,]*))/', $auth, $matches)) {
              foreach ($matches[1] as $num => $header) {
                  if($header == 'realm') {
                      continue;
                  }
                  $params[$header] = urldecode(empty($matches[3][$num])? $matches[4][$num] : $matches[3][$num]);
              }
	        }
	    }
	    return $params;
	}

	/**
	 * Get current request URL
	 */
	protected function getRequestUrl()
	{
	    $proto = "http";
	    if(empty($_SERVER['SERVER_PORT']) || empty($_SERVER['HTTP_HOST']) || empty($_SERVER['REQUEST_URI'])) {
	        return Zend_Uri_Http::fromString("http://localhost/");
	    }
	    if($_SERVER['SERVER_PORT'] == 443 || (!empty($_SERVER['HTTPS']) &&  $_SERVER['HTTPS'] == 'on')) {
	        $proto = 'https';
	    }
	    return Zend_Uri_Http::fromString("$proto://{$_SERVER['HTTP_HOST']}{$_SERVER['REQUEST_URI']}");
	}

	/**
     * Returns oauth parameters
     * @return array
     */
    public function getOAuthParams()
    {
        return $this->oauth_params;
    }

    /**
	 * Validate OAuth request
	 * @param Zend_Uri_Http $url Request URL, will use current if null
	 * @param array $params Additional parameters
	 * @return bool
	 * @throws Zend_Oauth_Exception
	 */
	public function checkOAuthRequest(Zend_Uri_Http $url = null, $params = array())
	{
	    if(empty($url)) {
	        $this->url = $this->getRequestUrl();
	    } else {
	        $this->url = clone $url;
	    }
	    // We'll ignore query for the pruposes of URL matching
	    $this->url->setQuery('');

	    if(isset($_SERVER['REQUEST_METHOD'])) {
	        $method = $_SERVER['REQUEST_METHOD'];
	    } elseif(isset($_SERVER['HTTP_METHOD'])) {
	        $method = $_SERVER['HTTP_METHOD'];
	    } else {
	        $method = 'GET';
	    }
        $params = $this->assembleParams($method, $params);
        $this->oauth_params = $params;
        $this->checkSignatureMethod($params['oauth_signature_method']);
        $this->checkRequiredParams($params);

        $this->timestamp = $params['oauth_timestamp'];
        $this->nonce = $params['oauth_nonce'];
        $this->consumer_key = $params['oauth_consumer_key'];

        if(!is_callable($this->nonceHandler)) {
            throw new Zend_Oauth_Exception("Nonce handler not callable", self::BAD_NONCE);
        }

        $res = call_user_func($this->nonceHandler, $this);
        if($res != self::OK) {
            throw new Zend_Oauth_Exception("Invalid request", $res);
        }

        if(!is_callable($this->consumerHandler)) {
            throw new Zend_Oauth_Exception("Consumer handler not callable", self::CONSUMER_KEY_UNKNOWN);
        }

        $res = call_user_func($this->consumerHandler, $this);
        // this will set $this->consumer_secret if OK
        if($res != self::OK) {
            throw new Zend_Oauth_Exception("Consumer key invalid", $res);
        }

        if($this->needsToken()) {
            $this->token = $params['oauth_token'];
            if(isset($params['oauth_verifier'])) {
                $this->verifier = $params['oauth_verifier'];
            }
            if(!is_callable($this->tokenHandler)) {
                throw new Zend_Oauth_Exception("Token handler not callable", self::TOKEN_REJECTED);
            }
            $res = call_user_func($this->tokenHandler, $this);
            // this will set $this->token_secret if OK
            if($res != self::OK) {
                throw new Zend_Oauth_Exception("Token invalid", $res);
            }
        }

        $util = new Zend_Oauth_Http_Utility();
        $req_sign = $params['oauth_signature'];
        unset($params['oauth_signature']);
        $our_sign = $util->sign($params, $params['oauth_signature_method'], $this->consumer_secret,
            $this->token_secret, $method, $this->url->getUri());
        if($req_sign != $our_sign) {
            // TODO: think how to extract signature base string
            $this->problem = $our_sign;
            $GLOBALS['log']->fatal("Bad signature: $req_sign != $our_sign");
            throw new Zend_Oauth_Exception("Invalid signature", self::INVALID_SIGNATURE);
        }

        return true;
	}

    /**
     * Generate new token
     * @param int $size How many characters?
     */
	public function generateToken($size)
	{
	    $str = '';
	    while(strlen($str) < $size) {
	        $str .= md5(uniqid(mt_rand(), true), true);
	    }
	    return substr($str, 0, $size);
	}
}