<?php

/*
OneLobby
Copyright (C) 2007 Peter Goodman, Geoffrey Goodman

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
*/

//--------------------------------------------
// A little extension to make and deal with captcha
// images.
//--------------------------------------------

class Captcha extends FAExtension
{
	var $_font = 'Action Man Bold'; // make sure to exclude .ttf
	var $_captcha_length = 6;
	var $_reg_id = NULL;
	var $_use_captcha = FALSE;
	
	//--------------------------------------------
	// Constructor.
	//--------------------------------------------
	
	function Captcha()
	{
		$this->_reg_id = md5(uniqid(""));
		$this->_use_captcha = function_exists('imagecreate');
	}
	
	//--------------------------------------------
	// Create the captcha image itself. It is a JPEG.
	//--------------------------------------------
	
	function createCaptcha(&$reg, &$req)
	{
		//--------------------------------------------
		// Make sure that something is actually using this
		// captcha.
		//--------------------------------------------
		
		if(!$this->captchaIsRegistered($reg, $req) || !$this->_use_captcha)
		{
			header("HTTP/1.0 404 Not Found");
			exit();
		}
		
		//--------------------------------------------
		// Unregister this captcha.
		//--------------------------------------------
		
		$this->unregisterCaptcha($reg);
		
		//--------------------------------------------
		// Deal with the font path.
		//--------------------------------------------
		
		putenv('GDFONTPATH='. realpath(K4_BASE_DIR .'/fonts/'));
		
		//--------------------------------------------
		// Get the session.
		//--------------------------------------------
		
		$session = &$reg->get('session');
		
		//--------------------------------------------
		// Do all of the headers.
		//--------------------------------------------

		header("Content-type: image/jpeg");
		header(base64_decode("WC1DYXB0Y2hhOiBPbmVMb2JieSBodHRwOi8vd3d3Lm9uZWxvYmJ5LmNvbQ=="));
		header("Expires: Mon, 23 Jul 1993 05:00:00 GMT");
		header("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT");
		header("Cache-Control: no-store, no-cache, must-revalidate");
		header("Cache-Control: post-check=0, pre-check=0", false);
		header("Pragma: no-cache");

		//--------------------------------------------
		// Create the base image 130x40 px.
		//--------------------------------------------

		$create_fn = function_exists('imagecreatetruecolor') ? 'imagecreatetruecolor' : 'imagecreate';

		$final_image = $create_fn(95, 40);

		//--------------------------------------------
		// Add some nice background junk.
		//--------------------------------------------

		$background = imagecolorallocate($final_image, 255, 255, 255);
		imagefill($final_image, 0, 0, $background);
		imagecolordeallocate($final_image, $background);

		unset($background);

		//--------------------------------------------
		// Figure out the code.
		//--------------------------------------------

		$code = strtoupper(substr(md5(uniqid("")), 0, $this->_captcha_length));
		
		//--------------------------------------------
		// Add the code the session.
		//--------------------------------------------
		
		$session->set('captcha_code', k4_hash($code));
		
		//--------------------------------------------
		// Add the code in.
		//--------------------------------------------
		
		// stuff for the letter itself
		$letter_width = 14;
		$letter_height = 20;

		for($i = 0; $i < $this->_captcha_length; $i++) {
	
			// stuff for the letter itself
			$letter_text = $code{$i};
	
			// positioning
			$layer_x = ($i * $letter_width);
			$layer_y = 32 + rand(-7, 7);
	
			$font_color = imagecolorallocate($final_image, rand(0,150), rand(0,150), rand(0,150));
			imagettftext($final_image, 20, rand(-5, 5), $layer_x, $layer_y, $font_color, $this->_font, $letter_text);
			imagecolordeallocate($final_image, $font_color);
		}

		unset($font_color);
		
		//--------------------------------------------
		// Interlace the image for better output in the
		// browser.
		//--------------------------------------------
		
		imageinterlace($final_image, 1);

		//--------------------------------------------
		// Output the final image in very low quality.
		//--------------------------------------------

		imagejpeg($final_image, FALSE, 15);

		//--------------------------------------------
		// Clean up the memory
		//--------------------------------------------

		imagedestroy($final_image);
		unset($final_image);
	}
	
	//--------------------------------------------
	// Create all the HTML needed to use this captcha
	// so that we can just plunk in {$captcha_img},
	// etc. where it's stylish and everything
	// will work.
	//--------------------------------------------
	
	function drawCaptcha(&$reg, &$req, &$resp)
	{
		//--------------------------------------------
		// If a captcha has already been passed, we don't
		// need to display any others.
		//--------------------------------------------
		
		if($this->passedAlready($reg))
		{
			return;
		}
		
		//--------------------------------------------
		// Register the captcha.
		//--------------------------------------------
		
		$this->registerCaptcha($reg);
		
		//--------------------------------------------
		// Path to the image.
		//--------------------------------------------
		
		$url = k4_url('/captcha/'. $this->_reg_id .'/');
		
		//--------------------------------------------
		// Set the html to the templates.
		//--------------------------------------------
		
		$resp->assign('captcha_img', '<div style="width:95px;height:40px;background:url('. $url .') top left no-repeat;">&nbsp;</div>');
		$resp->assign('captcha_length', $this->_captcha_length);
		$resp->assign('captcha_name', 'captcha_input');
		$resp->assign('use_captcha', intval($this->_use_captcha));
	}
	
	//--------------------------------------------
	// Validate a the captcha image with the session.
	//--------------------------------------------
	
	function isValid(&$reg, &$req)
	{
		$session = &$reg->get('session');
		
		//--------------------------------------------
		// If we can't use captcha's then set the valid to
		// default to TRUE.
		//--------------------------------------------
		
		$valid = !$this->_use_captcha ? TRUE : FALSE;
		
		//--------------------------------------------
		// Validate the request variable against the
		// session variable.
		//--------------------------------------------
		
		if($session->get('captcha_code'))
		{
			if(k4_hash($req->get('captcha_input')) == $session->get('captcha_code'))
			{
				$valid = TRUE;
				
				$session->set('captcha_passed', $valid);
			}
		}
		
		//--------------------------------------------
		// Reset the value to nothing, which means that this
		// function can and should only be used once.
		//--------------------------------------------
		
		$session->set('captcha_code', $null = NULL);
		
		//--------------------------------------------
		// So... is it valid?
		//--------------------------------------------
		
		return $valid;
	}
	
	//--------------------------------------------
	// Register a captcha.
	//--------------------------------------------
	
	function registerCaptcha(&$reg)
	{
		$session = &$reg->get('session');
		$session->set('captcha_registered', $this->_reg_id);
	}
	
	//--------------------------------------------
	// Unregister a captcha.
	//--------------------------------------------
	
	function unregisterCaptcha(&$reg)
	{
		$session = &$reg->get('session');
		$session->set('captcha_registered', $false = FALSE);
	}
	
	//--------------------------------------------
	// Check to see if the captcha is in use, otherwise
	// we don't want to be able to see the image.
	//--------------------------------------------
	
	function captchaIsRegistered(&$reg, &$req)
	{
		$session = &$reg->get('session');
		
		$sess_reg_id = $session->get('captcha_registered') ? $session->get('captcha_registered') : FALSE;
		$req_reg_id = $req->get('reg_id') ? $req->get('reg_id') : FALSE;
		
		return ($sess_reg_id && $req_reg_id && $sess_reg_id == $req_reg_id);
	}
	
	//--------------------------------------------
	// Check to see if a captcha has been passed already.
	//--------------------------------------------
	
	function passedAlready(&$reg)
	{
		$session = &$reg->get('session');
		$passed = FALSE;
		
		if($session->get('captcha_passed'))
		{
			$passed = TRUE;
		}
		
		return $passed;
	}
}

?>