block.phpmeow.class.php

<?php

/*
 * phpMeow - A Cute and Fuzzy Alternative to CAPTCHA
 * Created by Kris Craig.  April - July, 2011.
 * 
 * phpMeow is the first fully-functional, secure 
 * implementation of KittenAuth in PHP.
 * 
 * This software is open-source and you're free to 
 * use and/or distribute it as you see fit.  See 
 * LICENSE file for more information.
 * 
 * Get the latest version at:  http://www.github.com/sirkris/phpmeow
 */

class phpmeow_block
{
	/* Determine which animals to allocate to a block, depending on whether it's been designated as a correct answer or not.  --Kris */
	function allocate( $whichblock, $correct_blocks, $required, $animarr )
	{
		require( "config.phpmeow.php" );
		
		$allocation = array();
		
		$correct = FALSE;
		foreach ( $correct_blocks as $ckey => $cval )
		{
			if ( $whichblock == $cval )
			{
				$correct = TRUE;
				break;
			}
		}
		
		$total = 4;
		if ( $correct == TRUE )
		{
			foreach ( $required as $rkey => $requirement )
			{
				foreach ( $requirement as $creature => $quantity )
				{
					for ( $qloop = 1; $qloop <= $quantity; $qloop++ )
					{
						$allocation[$total] = $creature;
						$total--;
					}
				}
			}
		}
		
		/* Random animals/junk to fill any remaining squares.  --Kris */
		do
		{
			for ( $picloop = 1; $picloop <= $total; $picloop++ )
			{
				do
				{
					$allocation[$picloop] = mt_rand( 0, count( $animarr ) - 1 );
					
					$dup = FALSE;
					for ( $subloop = 1; $subloop < $picloop; $subloop++ )
					{
						if ( $allocation[$picloop] == $allocation[$subloop] )
						{
							$dup = TRUE;
							break;
						}
					}
				} while ( $dup == TRUE );
				
				$allocation[$picloop] = $animarr[$allocation[$picloop]];
			}
			
			/* If not intended to be correct, make sure it isn't correct anyway by random chance.  If it is, regenerate.  --Kris */
			$invalid = FALSE;
			if ( $correct == FALSE )
			{
				$invalid = TRUE;
				foreach ( $required as $rkey => $requirement )
				{
					foreach ( $requirement as $creature => $quantity )
					{
						if ( count( array_keys( $allocation, $creature ) ) < $quantity )
						{
							$invalid = FALSE;
							break;
						}
					}
				}
			}
			/* If it is intended to be correct, make sure the randomness didn't screw up the quantity.  --Kris */
			else
			{
				foreach ( $required as $rkey => $requirement )
				{
					foreach ( $requirement as $creature => $quantity )
					{
						if ( count( array_keys( $allocation, $creature ) ) != $quantity )
						{
							$invalid = TRUE;
							break;
						}
					}
				}
			}
		} while ( $invalid == TRUE );
		
		shuffle( $allocation );
		
		return $allocation;
	}
	
	/* Randomly select an image from each specified category.  --Kris */
	function assign_animals( $allocation, $animals )
	{
		require( "config.phpmeow.php" );
		
		$images = array();
		
		foreach ( $allocation as $akey => $aval )
		{
			do
			{
				$newimage = $animals[$aval][mt_rand( 0, count( $animals[$aval] ) - 1 )];
				
				$dup = FALSE;
				foreach ( $images as $ikey => $ival )
				{
					if ( strcmp( $newimage, $ival ) == 0 )
					{
						$dup = TRUE;
						break;
					}
				}
			} while ( $dup == TRUE );
			
			$images[] = $newimage;
		}
		
		return $images;
	}
	
	/* Put the animals into their respective cages.  Make sure they have plenty of air and water.  --Kris */
	function boxify_images( $images, $animal )
	{
		require( "config.phpmeow.php" );
		
		$left_mod = mt_rand( ($phpmeow_animal_width / 5) * -1, $phpmeow_animal_width / 5 );
		$top_mod = mt_rand( ($phpmeow_animal_height / 5) * -1, $phpmeow_animal_height / 5 );
		
		$right_mod = 0 - $left_mod;
		$bottom_mod = 0 - $top_mod;
		
		/* Load the image resources without rendering.  --Kris */
		$ims = array();
		
		foreach ( $images as $ikey => $ival )
		{
			if ( $ikey % 2 == 0 )
			{
				$xmod = $left_mod;
			}
			else
			{
				$xmod = $right_mod;
			}
			
			if ( $ikey <= 1 )
			{
				$ymod = $top_mod;
			}
			else
			{
				$ymod = $bottom_mod;
			}
			
			$ims[$ikey] = $animal->create( $ival, $xmod, $ymod, TRUE );
		}
		
		return $ims;
	}
	
	/*
	 * Array keys must correspond to the following layout:
	 * 
	 * 01
	 * 23
	 * 
	 * --Kris
	 */
	function merge_animals( $ims = array() )
	{
		require_once( "animal.phpmeow.class.php" );
		
		if ( count( $ims ) != 4 )
		{
			return FALSE;
		}
		
		$img_width = imagesx( $ims[0] ) + imagesx( $ims[1] );
		$img_height = imagesy( $ims[0] ) + imagesy( $ims[2] );
		
		if ( $img_width == 0 || $img_height == 0 )
		{
			return FALSE;
		}
		
		$blockim = imagecreatetruecolor( $img_width, $img_height );
		
		/* This approach allows us to completely hide the animal image paths from the client.  --Kris */
		imagecopy( $blockim, $ims[0], 0, 0, 0, 0, imagesx( $ims[0] ), imagesy( $ims[0] ) );
		imagecopy( $blockim, $ims[1], imagesx( $ims[0] ), 0, 0, 0, imagesx( $ims[1] ), imagesy( $ims[1] ) );
		imagecopy( $blockim, $ims[2], 0, imagesy( $ims[0] ), 0, 0, imagesx( $ims[2] ), imagesy( $ims[2] ) );
		imagecopy( $blockim, $ims[3], imagesx( $ims[0] ), imagesy( $ims[0] ), 0, 0, imagesx( $ims[3] ), imagesy( $ims[3] ) );
		
		return $blockim;
	}
	
	/* This generates the actual HTML img tag.  The image resource is destroyed immediately after the image script is called.  --Kris */
	function render( $ims, $whichblock, $xpos = 0, $ypos = 0 )
	{
		require( "config.phpmeow.php" );
		
		$session = new phpmeow_session();
		$session->start();
		
		$blockim = self::merge_animals( $ims );
		
		$block_key = "phpmeow_blockfile_" . $session->generate_sid( 20 );
		$_SESSION[$block_key] = "phpMeow_temp/" . $_SERVER["REMOTE_ADDR"] . "-" . $session->generate_sid() . ".jpg";
		
		self::save( $blockim, $_SESSION[$block_key] );
		
		print "<div style=\"position: absolute; left: " . $xpos . "px; top: " . $ypos . "px; border: 10px solid navy\" name=\"phpmeow_block" . $whichblock . "\"";
		print " id=\"phpmeow_block" . $whichblock . "\" onClick=\"phpmeow_selblock( this );\">\r\n";
		print "<img src=\"animal.image.phpmeow.php?getkey=" . urlencode( $block_key ) . "\" />\r\n";
		print "</div>\r\n";
		print "<input type=\"hidden\" name=\"fphpmeow_block" . $whichblock . "\" id=\"fphpmeow_block" . $whichblock . "\" value=\"0\" />\r\n";
	}
	
	/* Saves to disk for swapping purposes.  --Kris */
	function save( $blockim, $filename )
	{
		return imagejpeg( $blockim, $filename );
	}
	
	/* Clean-up the temporary image file.  --Kris */
	function destroy( $filekey )
	{
		$filename = $_SESSION[$filekey];
		
		$ok = unlink( $filename );
		
		unset( $_SESSION[$filekey] );
		
		return $ok;
	}
}