<?php
/**
 * txt2tags-web
 *
 * A very small framework that let you build the static parts of your site
 * with t2t files without stress. ;-)
 *
 * The only requirement is a PHP environment.
 * It uses Google AppEngine to convert the t2t files to HTML. The files are
 * converted just on the first request and are cached for futher use. You
 * change the t2t files and just see the result on browser.
 *
 * @package		txt2tags-web
 * @author		Felipe Oliveira Carvalho
 * @copyright	Copyright (c) 2008, Felipe Oliveira Carvalho
 * @license		MIT License
 * @link
 */

/*
|---------------------------------------------------------------
| BASE URI
|---------------------------------------------------------------
|
| URI to the folder of this file.
| WITH trailing slash:
|
|   /
|   /my_site/
|
*/
	$BASE_URI = "/txt2tags-web/";

	$use_htaccess = TRUE;
	$URL_SUFFIX = 't2t';
	//$show_the_t2t_files = TRUE;
	$common_request_trigger = '__common_request_';

// -------------------------------------------------------------

/**
 * URI Class - Based on CodeIgniter URI_Class
 *
 * Parses URIs
 */
class URI
{
	public $base_uri;
	public $uri_string;
	public $query_string = '';
	public $segments = array();

	function URI()
	{
		// Sets the BASE_URI
		$this->_uri_safe_cpy($this->base_uri, $GLOBALS['BASE_URI']);

		// Gets the uri_string
		$this->uri_string = $this->_parse_request_uri();
	}

	/**
	 * Parse the REQUEST_URI
	 *
	 * Removes the base_uri and the query_string.
	 */
	private function _parse_request_uri()
	{
		if ( ! isset($_SERVER['REQUEST_URI']) OR $_SERVER['REQUEST_URI'] == '')
			return '';

		$this->_uri_safe_cpy($request_uri, $_SERVER['REQUEST_URI']);

		if ($request_uri == '')
			return '';

		// Grab the Query String
		if (strpos($request_uri, '?')) {
			$pieces = explode('?', $request_uri);
			$request_uri = $pieces[0];
			$query_string = $pieces[1];
			/* Removes the unecessary & */
			if ($query_string != '' AND $query_string[strlen($query_string) - 1] == '&')
				$this->query_string = substr($query_string, 0, -1);
		}

		// Explode the URI in segments
		$this->_explode_segments($request_uri);
		$segments = &$this->segments;

		// Removes the base_uri from the uri_string
		$i = 0;
		foreach(explode("/", $this->base_uri) as $segment) {
			if (isset($segments[$i]) AND $segment == $segment[$i])
				$i++;
		}
		// Removes the "index.php" from the URI if it exists
		if (isset($segments[$i] ) AND basename(__FILE__) == $segments[$i])
			$i++;
		$segments = array_slice($segments, $i);

		return implode('/', $segments);
	}

	/* Safe copy for URIs */
	private function _uri_safe_cpy(&$destinaton, $source)
	{
		$destinaton = preg_replace("|/(.*)|", "\\1", str_replace("\\", "/", $source));
	}

	/* Filter segments for malicious characters */
	private function _filter_uri($str)
	{
		if ($str != ''
		  AND ! preg_match("|^[a-z 0-9\?&\=~%\.\:_-]+$|i", $str)) {
			exit('The URI you submitted has disallowed characters.');
		}

		return $str;
	}

	/**
	 * Explode the URI Segments. The individual segments will
	 * be stored in the $this->segments array.
	 */
	private function _explode_segments($request_uri)
	{
		foreach(explode("/", preg_replace("|/*(.+?)/*$|", "\\1", $request_uri)) as $val) {
			// Filter segments for security
			$val = trim($this->_filter_uri($val));

			if ($val != '')
				$this->segments[] = $val;
		}
	}

	/* Returns the last segment of the URI */
	function basename()
	{
		return end($this->segments);
	}

	/* Grab the file extension of the URI */
	function get_file_extension()
	{
		$x = explode('.', $this->basename());
		if (count($x) > 0)
			return end($x);
		return '';
	}

	/* Returns the entire Request URI without index.php inside */
	function get_request_uri()
	{
		return '/'.$this->base_uri.$this->uri_string.$this->query_string;
	}
}

/**
 * Request class
 *
 * This class receives an URI obect and performs the request.
 */
class Request
{
	public $uri;

	function Request(URI $uri)
	{
		$this->uri = $uri;

		$uri_string = $uri->uri_string;
		if ($uri_string == '') {
			if (file_exists('./index.t2t')) {
				$this->render_t2t_file_as_html('./index.t2t');
			} else {
				/* Avoiding infinite redirect */
				if (__FILE__ == 'index.php')
					exit('index.t2t Not Found');
				else
					$this->common_request();
			}
		} else {
			$extension = $uri->get_file_extension();
			if ($extension == 'html' ) {
				$this->html_request();
			} else if ($extension == 't2t') {
				$this->t2t_request();
			} else if (@is_dir($uri->uri_string)) {
				$this->directory_request();
			} else {
				$this->common_request();
			}
		}
	}

	/**
	 * Looks for a t2t file with the same name of the HTML file in URI and
	 * render it converted to HTML. If the HTML file exists it will be rendered.
	 */
	private function html_request()
	{
		if (file_exists($this->uri->uri_string)) {
			$this->render_html_file($this->uri->uri_string);
		} else {
			/* Try to render the file using the extension .t2t instead .html */
			$file = substr($this->uri->uri_string, 0, -4);
			$file .= 't2t';
			if (file_exists($file)) {
				$this->render_t2t_file_as_html($file);
			} else if (@is_dir($this->uri->uri_string)) {
				$this->directory_request();
			} else {
				$this->show_404();
			}
		}
	}

	private function t2t_request()
	{
		if (file_exists($this->uri->uri_string) AND $GLOBALS['show_the_t2t_files']) {
			echo file_get_contents($this->uri->uri_string);
		} else {
			$this->show_404();
		}
	}

	/* Looks for a index.t2t -> index.html file */
	private function directory_request()
	{
		$dir = './'.$this->uri->uri_string;
		if (file_exists($dir.'/index.html')) {
			$this->render_html_file($dir.'/index.html');
		} else if (file_exists($dir.'/index.t2t')) {
			$this->render_t2t_file_as_html($dir.'/index.t2t');
		} else if ($dir == './') {
			/* Avoiding Infinite Redirect on root dir */
			$this->show_404();
		} else {
			$this->common_request();
		}
	}

	/**
	 * The common behavior for a request.
	 * Just let the Web Server care about the request.
	 */
	private function common_request()
	{
		$request_uri = $this->uri->get_request_uri();

		/* If the user uses .htaccess to redirect things to index.php we have to
		 * tell the .htaccess to not redirect. We use common_request_trigger as a
		 * variable in the Query String */
		if ($GLOBALS['use_htaccess']) {
			$query_string = $this->uri->query_string;
			if ($query_string == '')
				$request_uri .= '?';
			else
				$request_uri .= '&';
			$request_uri .= $GLOBALS['common_request_trigger'];
		}

		header('Location: '.$request_uri);
	}

	// -------------------------------------------------------------

	private function render_html_file($file)
	{
		echo file_get_contents($file);
	}

	/* The magic! */
	private function render_t2t_file_as_html($file)
	{
		echo 't2t converted';
		return;
		$txt2tags = new Txt2tags($file);
		echo $txt2tags->get_html();
	}

	// -------------------------------------------------------------

	private function show_404()
	{
		header("HTTP/1.1 404 Not Found");
		exit("404 Not Found");
	}
}

/* Here we go! */
function main()
{
	$uri = new URI();
	new Request(&$uri);
	//print_r($uri);
}

main();
?>