<?php
/**
 * Piwik - Open source web analytics
 *
 * @link http://piwik.org
 * @license http://www.gnu.org/licenses/gpl-3.0.html Gpl v3 or later
 * @version $Id$
 *
 * @category Piwik
 * @package Piwik
 */

/**
 * Class to retrieve absolute URL or URI components of the current URL,
 * and handle URL redirection.
 *
 * @package Piwik
 */
class Piwik_Url 
{
	/**
	 * If current URL is "http://example.org/dir1/dir2/index.php?param1=value1&param2=value2"
	 * will return "http://example.org/dir1/dir2/index.php?param1=value1&param2=value2"
	 *
	 * @return string
	 */
	static public function getCurrentUrl()
	{
		return self::getCurrentScheme() . '://'
			. self::getCurrentHost()
			. self::getCurrentScriptName() 
			. self::getCurrentQueryString();
	}

	/**
	 * If current URL is "http://example.org/dir1/dir2/index.php?param1=value1&param2=value2"
	 * will return "http://example.org/dir1/dir2/index.php"
	 *
	 * @return string
	 */
	static public function getCurrentUrlWithoutQueryString()
	{
		return self::getCurrentScheme() . '://'
			. self::getCurrentHost()
			. self::getCurrentScriptName();
	}

	/**
	 * If current URL is "http://example.org/dir1/dir2/index.php?param1=value1&param2=value2"
	 * will return "http://example.org/dir1/dir2/"
	 *
	 * @return string with trailing slash
	 */
	static public function getCurrentUrlWithoutFileName()
	{
		return self::getCurrentScheme() . '://'
			. self::getCurrentHost()
			. self::getCurrentScriptPath();
	}

	/**
	 * If current URL is "http://example.org/dir1/dir2/index.php?param1=value1&param2=value2"
	 * will return "/dir1/dir2/"
	 *
	 * @return string with trailing slash
	 */
	static public function getCurrentScriptPath()
	{
		$queryString = self::getCurrentScriptName() ;
		
		//add a fake letter case /test/test2/ returns /test which is not expected
		$urlDir = dirname ($queryString . 'x');
		$urlDir = str_replace('\\', '/', $urlDir);
		// if we are in a subpath we add a trailing slash
		if(strlen($urlDir) > 1)
		{
			$urlDir .= '/';
		}
		return $urlDir;
	}

	/**
	 * If current URL is "http://example.org/dir1/dir2/index.php?param1=value1&param2=value2"
	 * will return "/dir1/dir2/index.php"
	 *
	 * @return string
	 */
	static public function getCurrentScriptName()
	{
		$url = '';
		if( !empty($_SERVER['PATH_INFO']) ) 
		{ 
			$url = $_SERVER['PATH_INFO'];
		} 
		else if( !empty($_SERVER['REQUEST_URI']) ) 
		{
			$requestUri = $_SERVER['REQUEST_URI'];

			// strip http://host (Apache+Rails anomaly)
			if(preg_match('~^https?://[^/]+($|/.*)~', $requestUri, $matches))
			{
				$requestUri = $matches[1];
			}

			// strip parameters
			if( ($pos = strpos($requestUri, "?")) !== false ) 
			{
				$url = substr($requestUri, 0, $pos);
			} 
			else 
			{
				$url = $requestUri;
			}
		} 

	 	/**
		 * SCRIPT_NAME is our fallback, though it may not be set correctly
		 *
		 * @see http://php.net/manual/en/reserved.variables.php
		 */
		if(empty($url))
		{
			$url = $_SERVER['SCRIPT_NAME'];
		}

		if(!isset($url[0]) || $url[0] !== '/')
		{
			$url = '/' . $url;
		}
		return $url;
	}

	/**
	 * If the current URL is 'http://example.org/dir1/dir2/index.php?param1=value1&param2=value2"
	 * will return 'http'
	 *
	 * @return string 'https' or 'http'
	 */
	static public function getCurrentScheme()
	{
		if(isset($_SERVER['HTTPS'])
				&& ($_SERVER['HTTPS'] == 'on' || $_SERVER['HTTPS'] === true)
			)
		{
			return 'https';
		}
		return 'http';
	}

	/**
	 * If current URL is "http://example.org/dir1/dir2/index.php?param1=value1&param2=value2"
	 * will return "example.org"
	 *
	 * @return string
	 */
	static public function getCurrentHost()
	{
		if (!empty($_SERVER['HTTP_X_FORWARDED_HOST']))
		{
			return Piwik_Common::getFirstIpFromList($_SERVER['HTTP_X_FORWARDED_HOST']);
		}

		if(isset($_SERVER['HTTP_HOST']))
		{
			return $_SERVER['HTTP_HOST'];
		}

		return 'unknown';
	}

	/**
	 * If current URL is "http://example.org/dir1/dir2/index.php?param1=value1&param2=value2"
	 * will return "?param1=value1&param2=value2"
	 *
	 * @return string
	 */
	static public function getCurrentQueryString()
	{
		$url = '';	
		if(isset($_SERVER['QUERY_STRING'])
			&& !empty($_SERVER['QUERY_STRING']))
		{
			$url .= "?".$_SERVER['QUERY_STRING'];
		}
		return $url;
	}

	/**
	 * If current URL is "http://example.org/dir1/dir2/index.php?param1=value1&param2=value2"
	 * will return 
	 *  array
	 *    'param1' => string 'value1'
	 *    'param2' => string 'value2'
	 * 
	 * @return array
	 */
	static function getArrayFromCurrentQueryString()
	{	
		$queryString = self::getCurrentQueryString();
		$urlValues = Piwik_Common::getArrayFromQueryString($queryString);
		return $urlValues;
	}

	/**
	 * Given an array of name-values, it will return the current query string 
	 * with the new requested parameter key-values;
	 * If a parameter wasn't found in the current query string, the new key-value will be added to the returned query string.  
	 *
	 * @param array $params array ( 'param3' => 'value3' )
	 * @return string ?param2=value2&param3=value3
	 */
	static function getCurrentQueryStringWithParametersModified( $params )
	{
		$urlValues = self::getArrayFromCurrentQueryString();
		foreach($params as $key => $value)
		{
			$urlValues[$key] = $value;
		}
		$query = self::getQueryStringFromParameters($urlValues);
		if(strlen($query) > 0)
		{
			return '?'.$query;
		}
		return '';
	}

	/**
	 * Given an array of parameters name->value, returns the query string.
	 * Also works with array values using the php array syntax for GET parameters.
	 *
	 * @param $parameters eg. array( 'param1' => 10, 'param2' => array(1,2))
	 * @return string eg. "param1=10&param2[]=1&param2[]=2"
	 */
	static public function getQueryStringFromParameters($parameters)
	{
		$query = '';
		foreach($parameters as $name => $value)
		{
			if(empty($value))
			{
				continue;
			}
			if(is_array($value))
			{
				foreach($value as $theValue)
				{
					$query .= $name . "[]=" . $theValue . "&";
				}
			}
			else
			{
				$query .= $name . "=" . $value . "&";
			}
		}
		$query = substr($query, 0, -1);
		return $query;
	}

	/**
	 * Redirects the user to the Referer if found. 
	 * If the user doesn't have a referer set, it redirects to the current URL without query string.
	 */
	static public function redirectToReferer()
	{
		$referer = self::getReferer();
		if($referer !== false)
		{	
			self::redirectToUrl($referer);
		}
		self::redirectToUrl(self::getCurrentUrlWithoutQueryString());
	}

	/**
	 * Redirects the user to the specified URL
	 *
	 * @param string $url
	 */
	static public function redirectToUrl( $url )
	{
		header("Location: $url");
		exit;
	}

	/**
	 * Returns the HTTP_REFERER header, false if not found.
	 *
	 * @return string|false
	 */
	static public function getReferer()
	{
		if(!empty($_SERVER['HTTP_REFERER']))
		{
			return $_SERVER['HTTP_REFERER'];
		}
		return false;
	}

	/**
	 * Is the URL on the same host and in the same script path?
	 *
	 * @param string $url
	 * @return bool True if local; false otherwise.
	 */
	static public function isLocalUrl($url)
	{
		// handle case-sensitivity differences
		$pathContains = Piwik_Common::isWindows() ? 'stripos' : 'strpos';

		// test the scheme/protocol portion of the reconstructed "current" URL
		if(stripos($url, 'http://') === 0 || stripos($url, 'https://') === 0)
		{
			// determine the offset to begin the comparison
			$offset = strpos($url, '://');
			$current = strstr(self::getCurrentUrlWithoutFileName(), '://');
			if($pathContains($url, $current, $offset) === $offset)
			{
				return true;
			}
		}

		return false;
	}

	/**
	 * Get local referer, i.e., on the same host and in the same script path.
	 *
	 * @return string|false
	 */
	static public function getLocalReferer()
	{
		// verify that the referer contains the current URL (minus the filename & query parameters), http://example.org/dir1/dir2/
		$referer = self::getReferer();
		if($referer !== false && self::isLocalUrl($referer)) {
			return $referer;
		}

		return false;
	}

	/**
	 * Get ORIGIN header, false if not found
	 *
	 * @return string|false
	 */
	static public function getOrigin()
	{
		if(!empty($_SERVER['HTTP_ORIGIN']))
		{
			return $_SERVER['HTTP_ORIGIN'];
		}
		return false;
	}

	/**
	 * Get acceptable origins
	 *
	 * @return array
	 */
	static public function getAcceptableOrigins()
	{
		$host = self::getCurrentHost();
		if($host == 'unknown')
		{
			return array();
		}

		// parse host:port
		$port = 80;
		if(preg_match('/^([^:]+):([0-9]+)$/', $host, $matches))
		{
			$host = $matches[1];
			$port = $matches[2];
		}

		// assume standard ports
		$origins = array(
			'http' => "http://$host",
			'https' => "https://$host",
		);

		// handle non-standard port
		if($port != 80 && $port != 443)
		{
			$scheme = self::getCurrentScheme();
			$origins[$scheme] = "$scheme://$host:$port";
		}

		return $origins;
	}
}