<?php
/**
 * THttpResponse class
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @link http://www.pradosoft.com/
 * @copyright Copyright &copy; 2005-2012 PradoSoft
 * @license http://www.pradosoft.com/license/
 * @version $Id$
 * @package System.Web
 */

/**
 * Includes the THttpResponse adapter.
 */
Prado::using('System.Web.THttpResponseAdapter');

/**
 * THttpResponse class
 *
 * THttpResponse implements the mechanism for sending output to client users.
 *
 * To output a string to client, use {@link write()}. By default, the output is
 * buffered until {@link flush()} is called or the application ends. The output in
 * the buffer can also be cleaned by {@link clear()}. To disable output buffering,
 * set BufferOutput property to false.
 *
 * To send cookies to client, use {@link getCookies()}.
 * To redirect client browser to a new URL, use {@link redirect()}.
 * To send a file to client, use {@link writeFile()}.
 *
 * By default, THttpResponse is registered with {@link TApplication} as the
 * response module. It can be accessed via {@link TApplication::getResponse()}.
 *
 * THttpResponse may be configured in application configuration file as follows
 *
 * <module id="response" class="System.Web.THttpResponse" CacheExpire="20" CacheControl="nocache" BufferOutput="true" />
 *
 * where {@link getCacheExpire CacheExpire}, {@link getCacheControl CacheControl}
 * and {@link getBufferOutput BufferOutput} are optional properties of THttpResponse.
 *
 * THttpResponse sends charset header if either {@link setCharset() Charset}
 * or {@link TGlobalization::setCharset() TGlobalization.Charset} is set.
 *
 * Since 3.1.2, HTTP status code can be set with the {@link setStatusCode StatusCode} property.
 *
 * Note: Some HTTP Status codes can require additional header or body information. So, if you use {@link setStatusCode StatusCode}
 * in your application, be sure to add theses informations.
 * E.g : to make an http authentication :
 * <code>
 *  public function clickAuth ($sender, $param)
 *  {
 *     $response=$this->getResponse();
 *     $response->setStatusCode(401);
 *     $response->appendHeader('WWW-Authenticate: Basic realm="Test"');
 *  }
 * </code>
 *
 * This event handler will sent the 401 status code (Unauthorized) to the browser, with the WWW-Authenticate header field. This
 * will force the browser to ask for a username and a password.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @version $Id$
 * @package System.Web
 * @since 3.0
 */
class THttpResponse extends TModule implements ITextWriter
{
	const DEFAULT_CONTENTTYPE	= 'text/html';
	const DEFAULT_CHARSET		= 'UTF-8';

	/**
	 * @var The differents defined status code by RFC 2616 {@link http://www.faqs.org/rfcs/rfc2616}
	 */
	private static $HTTP_STATUS_CODES = array(
		100 => 'Continue', 101 => 'Switching Protocols',
		200 => 'OK', 201 => 'Created', 202 => 'Accepted', 203 => 'Non-Authoritative Information', 204 => 'No Content', 205 => 'Reset Content', 206 => 'Partial Content',
		300 => 'Multiple Choices', 301 => 'Moved Permanently', 302 => 'Found', 303 => 'See Other', 304 => 'Not Modified', 305 => 'Use Proxy', 307 => 'Temporary Redirect',
		400 => 'Bad Request', 401 => 'Unauthorized', 402 => 'Payment Required', 403 => 'Forbidden', 404 => 'Not Found', 405 => 'Method Not Allowed', 406 => 'Not Acceptable', 407 => 'Proxy Authentication Required', 408 => 'Request Time-out', 409 => 'Conflict', 410 => 'Gone', 411 => 'Length Required', 412 => 'Precondition Failed', 413 => 'Request Entity Too Large', 414 => 'Request-URI Too Large', 415 => 'Unsupported Media Type', 416 => 'Requested range not satisfiable', 417 => 'Expectation Failed',
		500 => 'Internal Server Error', 501 => 'Not Implemented', 502 => 'Bad Gateway', 503 => 'Service Unavailable', 504 => 'Gateway Time-out', 505 => 'HTTP Version not supported'
	);

	/**
	 * @var boolean whether to buffer output
	 */
	private $_bufferOutput=true;
	/**
	 * @var boolean if the application is initialized
	 */
	private $_initialized=false;
	/**
	 * @var THttpCookieCollection list of cookies to return
	 */
	private $_cookies=null;
	/**
	 * @var integer response status code
	 */
	private $_status=200;
	/**
	 * @var string reason correspond to status code
	 */
	private $_reason='OK';
	/**
	 * @var string HTML writer type
	 */
	private $_htmlWriterType='System.Web.UI.THtmlWriter';
	/**
	 * @var string content type
	 */
	private $_contentType=null;
	/**
	 * @var string|boolean character set, e.g. UTF-8 or false if no character set should be send to client
	 */
	private $_charset='';
	/**
	 * @var THttpResponseAdapter adapter.
	 */
	private $_adapter;
	/**
	 * @var boolean whether http response header has been sent
	 */
	private $_httpHeaderSent;
	/**
	 * @var boolean whether content-type header has been sent
	 */
	private $_contentTypeHeaderSent;

	/**
	 * Destructor.
	 * Flushes any existing content in buffer.
	 */
	public function __destruct()
	{
		//if($this->_bufferOutput)
		//	@ob_end_flush();
	}

	/**
	 * @param THttpResponseAdapter response adapter
	 */
	public function setAdapter(THttpResponseAdapter $adapter)
	{
		$this->_adapter=$adapter;
	}

	/**
	 * @return THttpResponseAdapter response adapter, null if not exist.
	 */
	public function getAdapter()
	{
		return $this->_adapter;
	}

	/**
	 * @return boolean true if adapter exists, false otherwise.
	 */
	public function getHasAdapter()
	{
		return $this->_adapter!==null;
	}

	/**
	 * Initializes the module.
	 * This method is required by IModule and is invoked by application.
	 * It starts output buffer if it is enabled.
	 * @param TXmlElement module configuration
	 */
	public function init($config)
	{
		if($this->_bufferOutput)
			ob_start();
		$this->_initialized=true;
		$this->getApplication()->setResponse($this);
	}

	/**
	 * @return integer time-to-live for cached session pages in minutes, this has no effect for nocache limiter. Defaults to 180.
	 */
	public function getCacheExpire()
	{
		return session_cache_expire();
	}

	/**
	 * @param integer time-to-live for cached session pages in minutes, this has no effect for nocache limiter.
	 */
	public function setCacheExpire($value)
	{
		session_cache_expire(TPropertyValue::ensureInteger($value));
	}

	/**
	 * @return string cache control method to use for session pages
	 */
	public function getCacheControl()
	{
		return session_cache_limiter();
	}

	/**
	 * @param string cache control method to use for session pages. Valid values
	 *               include none/nocache/private/private_no_expire/public
	 */
	public function setCacheControl($value)
	{
		session_cache_limiter(TPropertyValue::ensureEnum($value,array('none','nocache','private','private_no_expire','public')));
	}

	/**
	 * @return string content type, default is text/html
	 */
	public function setContentType($type)
	{
		if ($this->_contentTypeHeaderSent)
			throw new Exception('Unable to alter content-type as it has been already sent');
		$this->_contentType = $type;
	}

	/**
	 * @return string current content type
	 */
	public function getContentType()
	{
		return $this->_contentType;
	}

	/**
	 * @return string|boolean output charset.
	 */
	public function getCharset()
	{
		return $this->_charset;
	}

	/**
	 * @param string|boolean output charset.
	 */
	public function setCharset($charset)
	{
		$this->_charset = (strToLower($charset) === 'false') ? false : (string)$charset;
	}

	/**
	 * @return boolean whether to enable output buffer
	 */
	public function getBufferOutput()
	{
		return $this->_bufferOutput;
	}

	/**
	 * @param boolean whether to enable output buffer
	 * @throws TInvalidOperationException if session is started already
	 */
	public function setBufferOutput($value)
	{
		if($this->_initialized)
			throw new TInvalidOperationException('httpresponse_bufferoutput_unchangeable');
		else
			$this->_bufferOutput=TPropertyValue::ensureBoolean($value);
	}

	/**
	 * @return integer HTTP status code, defaults to 200
	 */
	public function getStatusCode()
	{
		return $this->_status;
	}

	/**
	 * Set the HTTP status code for the response.
	 * The code and its reason will be sent to client using the currently requested http protocol version (see {@link THttpRequest::getHttpProtocolVersion})
	 * Keep in mind that HTTP/1.0 clients might not understand all status codes from HTTP/1.1
	 *
	 * @param integer HTTP status code
	 * @param string HTTP status reason, defaults to standard HTTP reasons
	 */
	public function setStatusCode($status, $reason=null)
	{
		if ($this->_httpHeaderSent)
			throw new Exception('Unable to alter response as HTTP header already sent');
		$status=TPropertyValue::ensureInteger($status);
		if(isset(self::$HTTP_STATUS_CODES[$status])) {
			$this->_reason=self::$HTTP_STATUS_CODES[$status];
		}else{
			if($reason===null || $reason==='') {
				throw new TInvalidDataValueException("response_status_reason_missing");
			}
			$reason=TPropertyValue::ensureString($reason);
			if(strpos($reason, "\r")!=false || strpos($reason, "\n")!=false) {
				throw new TInvalidDataValueException("response_status_reason_barchars");
			}
			$this->_reason=$reason;
		}
		$this->_status=$status;
	}

	/**
	 * @param string HTTP status reason
	 */
	public function getStatusReason() {
		return $this->_reason;
	}

	/**
	 * @return THttpCookieCollection list of output cookies
	 */
	public function getCookies()
	{
		if($this->_cookies===null)
			$this->_cookies=new THttpCookieCollection($this);
		return $this->_cookies;
	}

	/**
	 * Outputs a string.
	 * It may not be sent back to user immediately if output buffer is enabled.
	 * @param string string to be output
	 */
	public function write($str)
	{
		// when starting output make sure we send the headers first
		if (!$this->_bufferOutput and !$this->_httpHeaderSent)
			$this->ensureHeadersSent();
		echo $str;
	}

	/**
	 * Sends a file back to user.
	 * Make sure not to output anything else after calling this method.
	 * @param string file name
	 * @param string content to be set. If null, the content will be read from the server file pointed to by $fileName.
	 * @param string mime type of the content.
	 * @param array list of headers to be sent. Each array element represents a header string (e.g. 'Content-Type: text/plain').
	 * @param boolean force download of file, even if browser able to display inline. Defaults to 'true'.
	 * @param string force a specific file name on client side. Defaults to 'null' means auto-detect.
	 * @param integer size of file or content in bytes if already known. Defaults to 'null' means auto-detect.
	 * @throws TInvalidDataValueException if the file cannot be found
	 */
	public function writeFile($fileName,$content=null,$mimeType=null,$headers=null,$forceDownload=true,$clientFileName=null,$fileSize=null)
	{
		static $defaultMimeTypes=array(
			'css'=>'text/css',
			'gif'=>'image/gif',
			'png'=>'image/png',
			'jpg'=>'image/jpeg',
			'jpeg'=>'image/jpeg',
			'htm'=>'text/html',
			'html'=>'text/html',
			'js'=>'javascript/js',
			'pdf'=>'application/pdf',
			'xls'=>'application/vnd.ms-excel',
		);

		if($mimeType===null)
		{
			$mimeType='text/plain';
			if(function_exists('mime_content_type'))
				$mimeType=mime_content_type($fileName);
			else if(($ext=strrchr($fileName,'.'))!==false)
			{
				$ext=substr($ext,1);
				if(isset($defaultMimeTypes[$ext]))
					$mimeType=$defaultMimeTypes[$ext];
			}
		}

		if($clientFileName===null)
			$clientFileName=basename($fileName);
		else
			$clientFileName=basename($clientFileName);

		if($fileSize===null || $fileSize < 0)
			$fileSize = ($content===null?filesize($fileName):strlen($content));

		$this->sendHttpHeader();
		if(is_array($headers))
		{
			foreach($headers as $h)
				header($h);
		}
		else
		{
			header('Pragma: public');
			header('Expires: 0');
			header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
			header("Content-Type: $mimeType");
			$this->_contentTypeHeaderSent = true;
		}

		header('Content-Length: '.$fileSize);
		header("Content-Disposition: " . ($forceDownload ? 'attachment' : 'inline') . "; filename=\"$clientFileName\"");
		header('Content-Transfer-Encoding: binary');
		if($content===null)
			readfile($fileName);
		else
			echo $content;
	}

	/**
	 * Redirects the browser to the specified URL.
	 * The current application will be terminated after this method is invoked.
	 * @param string URL to be redirected to. If the URL is a relative one, the base URL of
	 * the current request will be inserted at the beginning.
	 */
	public function redirect($url)
	{
		if($this->getHasAdapter())
			$this->_adapter->httpRedirect($url);
		else
			$this->httpRedirect($url);
	}

	/**
	 * Redirect the browser to another URL and exists the current application.
	 * This method is used internally. Please use {@link redirect} instead.
	 *
	 * @since 3.1.5
	 * You can set the set {@link setStatusCode StatusCode} to a value between 300 and 399 before
	 * calling this function to change the type of redirection.
	 * If not specified, StatusCode will be 302 (Found) by default
	 *
	 * @param string URL to be redirected to. If the URL is a relative one, the base URL of
	 * the current request will be inserted at the beginning.
	 */
	public function httpRedirect($url)
	{
		$this->ensureHeadersSent();

		if($url[0]==='/')
			$url=$this->getRequest()->getBaseUrl().$url;
		if ($this->_status >= 300 && $this->_status < 400)
			// The status code has been modified to a valid redirection status, send it
			header('Location: '.str_replace('&amp;','&',$url), true, $this->_status);
		else
			header('Location: '.str_replace('&amp;','&',$url));

		if(!$this->getApplication()->getRequestCompleted())
			$this->getApplication()->onEndRequest();

		exit();
	}

	/**
	 * Reloads the current page.
	 * The effect of this method call is the same as user pressing the
	 * refresh button on his browser (without post data).
	 **/
	public function reload()
	{
		$this->redirect($this->getRequest()->getRequestUri());
	}

	/**
	 * Flush the response contents and headers.
	 */
	public function flush($continueBuffering = true)
	{
		if($this->getHasAdapter())
			$this->_adapter->flushContent($continueBuffering);
		else
			$this->flushContent($continueBuffering);
	}

	/**
	 * Ensures that HTTP response and content-type headers are sent
	 */
	public function ensureHeadersSent()
	{
		$this->ensureHttpHeaderSent();
		$this->ensureContentTypeHeaderSent();
	}

	/**
	 * Outputs the buffered content, sends content-type and charset header.
	 * This method is used internally. Please use {@link flush} instead.
	 * @param boolean whether to continue buffering after flush if buffering was active
	 */
	public function flushContent($continueBuffering = true)
	{
		Prado::trace("Flushing output",'System.Web.THttpResponse');
		$this->ensureHeadersSent();
		if($this->_bufferOutput)
		{
			// avoid forced send of http headers (ob_flush() does that) if there's no output yet
			if (ob_get_length()>0)
			{
				if (!$continueBuffering)
				{
					$this->_bufferOutput = false;
					ob_end_flush();
				}
				else
					ob_flush();
				flush();
			}
		}
		else
			flush();
	}

	/**
	 * Ensures that the HTTP header with the status code and status reason are sent
	 */
	protected function ensureHttpHeaderSent()
	{
		if (!$this->_httpHeaderSent)
			$this->sendHttpHeader();
	}

	/**
	 * Send the HTTP header with the status code (defaults to 200) and status reason (defaults to OK)
	 */
	protected function sendHttpHeader()
	{
		if (($version=$this->getRequest()->getHttpProtocolVersion())==='')
			header (' ', true, $this->_status);
		else
			header($version.' '.$this->_status.' '.$this->_reason, true, $this->_status);
		$this->_httpHeaderSent = true;
	}

	/**
	 * Ensures that the HTTP header with the status code and status reason are sent
	 */
	protected function ensureContentTypeHeaderSent()
	{
		if (!$this->_contentTypeHeaderSent)
			$this->sendContentTypeHeader();
	}

	/**
	 * Sends content type header with optional charset.
	 */
	protected function sendContentTypeHeader()
	{
		$contentType=$this->_contentType===null?self::DEFAULT_CONTENTTYPE:$this->_contentType;
		$charset=$this->getCharset();
		if($charset === false) {
			$this->appendHeader('Content-Type: '.$contentType);
			return;
		}

		if($charset==='' && ($globalization=$this->getApplication()->getGlobalization(false))!==null)
			$charset=$globalization->getCharset();

		if($charset==='') $charset = self::DEFAULT_CHARSET;
		$this->appendHeader('Content-Type: '.$contentType.';charset='.$charset);

		$this->_contentTypeHeaderSent = true;
	}

	/**
	 * Returns the content in the output buffer.
	 * The buffer will NOT be cleared after calling this method.
	 * Use {@link clear()} is you want to clear the buffer.
	 * @return string output that is in the buffer.
	 */
	public function getContents()
	{
		Prado::trace("Retrieving output",'System.Web.THttpResponse');
		return $this->_bufferOutput?ob_get_contents():'';
	}

	/**
	 * Clears any existing buffered content.
	 */
	public function clear()
	{
		if($this->_bufferOutput)
			ob_clean();
		Prado::trace("Clearing output",'System.Web.THttpResponse');
	}

	/**
	 * @param integer|null Either {@link CASE_UPPER} or {@link CASE_LOWER} or as is null (default)
	 * @return array
	 */
	public function getHeaders($case=null)
	{
		$result = array();
		$headers = headers_list();
		foreach($headers as $header) {
			$tmp = explode(':', $header);
			$key = trim(array_shift($tmp));
			$value = trim(implode(':', $tmp));
			if(isset($result[$key]))
				$result[$key] .= ', ' . $value;
			else
				$result[$key] = $value;
		}

		if($case !== null)
			return array_change_key_case($result, $case);

		return $result;
	}

	/**
	 * Sends a header.
	 * @param string header
	 * @param boolean whether the header should replace a previous similar header, or add a second header of the same type
	 */
	public function appendHeader($value, $replace=true)
	{
		Prado::trace("Sending header '$value'",'System.Web.THttpResponse');
		header($value, $replace);
	}

	/**
	 * Writes a log message into error log.
	 * This method is simple wrapper of PHP function error_log.
	 * @param string The error message that should be logged
	 * @param integer where the error should go
	 * @param string The destination. Its meaning depends on the message parameter as described above
	 * @param string The extra headers. It's used when the message parameter is set to 1. This message type uses the same internal function as mail() does.
	 * @see http://us2.php.net/manual/en/function.error-log.php
	 */
	public function appendLog($message,$messageType=0,$destination='',$extraHeaders='')
	{
		error_log($message,$messageType,$destination,$extraHeaders);
	}

	/**
	 * Sends a cookie.
	 * Do not call this method directly. Operate with the result of {@link getCookies} instead.
	 * @param THttpCookie cook to be sent
	 */
	public function addCookie($cookie)
	{
		$request=$this->getRequest();
		if($request->getEnableCookieValidation())
		{
			$value=$this->getApplication()->getSecurityManager()->hashData($cookie->getValue());
			setcookie(
				$cookie->getName(),
				$value,
				$cookie->getExpire(),
				$cookie->getPath(),
				$cookie->getDomain(),
				$cookie->getSecure(),
				$cookie->getHttpOnly()
			);
		}
		else {
			setcookie(
				$cookie->getName(),
				$cookie->getValue(),
				$cookie->getExpire(),
				$cookie->getPath(),
				$cookie->getDomain(),
				$cookie->getSecure(),
				$cookie->getHttpOnly()
			);
		}
	}

	/**
	 * Deletes a cookie.
	 * Do not call this method directly. Operate with the result of {@link getCookies} instead.
	 * @param THttpCookie cook to be deleted
	 */
	public function removeCookie($cookie)
	{
		setcookie(
			$cookie->getName(),
			null,
			0,
			$cookie->getPath(),
			$cookie->getDomain(),
			$cookie->getSecure(),
			$cookie->getHttpOnly()
		);
	}

	/**
	 * @return string the type of HTML writer to be used, defaults to THtmlWriter
	 */
	public function getHtmlWriterType()
	{
		return $this->_htmlWriterType;
	}

	/**
	 * @param string the type of HTML writer to be used, may be the class name or the namespace
	 */
	public function setHtmlWriterType($value)
	{
		$this->_htmlWriterType=$value;
	}

	/**
	 * Creates a new instance of HTML writer.
	 * If the type of the HTML writer is not supplied, {@link getHtmlWriterType HtmlWriterType} will be assumed.
	 * @param string type of the HTML writer to be created. If null, {@link getHtmlWriterType HtmlWriterType} will be assumed.
	 */
	public function createHtmlWriter($type=null)
	{
		if($type===null)
			$type=$this->getHtmlWriterType();
		if($this->getHasAdapter())
			return $this->_adapter->createNewHtmlWriter($type, $this);
		else
			return $this->createNewHtmlWriter($type, $this);
	}

	/**
	 * Create a new html writer instance.
	 * This method is used internally. Please use {@link createHtmlWriter} instead.
	 * @param string type of HTML writer to be created.
	 * @param ITextWriter text writer holding the contents.
	 */
	public function createNewHtmlWriter($type, $writer)
	{
		return Prado::createComponent($type, $writer);
	}
}