Trying to solve a Sokoban level with brute force

<?php
 
function echo_map($map,$width){
	$rows = strlen($map)/$width;
	for($x=0;$x<$rows;$x++){
		for($y=0;$y<$width;$y++){
			$pos = $y+$x*$width;
			if($map{$pos}==" "){
				$return .= "&nbsp;";
			}
			else{
				$return .= $map{$pos};
			}
		}
		$return .= "<br>";
	}
	return("<div style = \"font:normal 18px lucida console\">".$return."</div>");
}
 
function is_solved($map){
	return(!strpos($map,"$"));
}
 
function is_empty($map,$pos){
	return(($map{$pos}==" ")or($map{$pos}=="."));
}
 
function is_crate($map,$pos){
	return(($map{$pos}=="$")or($map{$pos}=="*"));
}
 
function get_player_pos($map){
	return(strpos($map,"@")+strpos($map,"+"));
}
 
function echo_possible_directions($map,$width){
	$player_pos = get_player_pos($map);
	if (is_empty($map,$player_pos-1) or (is_crate($map,$player_pos-1) and is_empty($map,$player_pos-2))){
		$return .= "L";
	}
	if (is_empty($map,$player_pos+1) or (is_crate($map,$player_pos+1) and is_empty($map,$player_pos+2))){
		$return .= "R";
	}
	if (is_empty($map,$player_pos-$width) or (is_crate($map,$player_pos-$width) and is_empty($map,$player_pos-2*$width))){
		$return .= "U";
	}
	if (is_empty($map,$player_pos+$width) or (is_crate($map,$player_pos+$width) and is_empty($map,$player_pos+2*$width))){
		$return .= "D";
	}
	return($return);
}
 
function move($map,$width,$dir){
	$player_pos = get_player_pos($map);
	if($dir=="L"){
		if($map{$player_pos}=="@"){
			$map{$player_pos} = " ";
		}
		else{
			$map{$player_pos} = ".";
		}
		if (!is_empty($map,$player_pos-1)){
			if($map{$player_pos-1}=="$"){
				if($map{$player_pos-2}==" "){
					$map{$player_pos-2}="$";
					$map{$player_pos-1}=" ";
				}
				else{
					$map{$player_pos-2}="*";
					$map{$player_pos-1}=" ";
				}
			}
			else{	
				if($map{$player_pos-2}==" "){
					$map{$player_pos-2}="$";
					$map{$player_pos-1}=".";
				}
				else{
					$map{$player_pos-2}="*";
					$map{$player_pos-1}=".";
				}
			}			
		}
		if($map{$player_pos-1}==" "){
			$map{$player_pos-1}="@";
		}
		else{
			$map{$player_pos-1}="+";
		}	
	}
	if($dir=="R"){
		if($map{$player_pos}=="@"){
			$map{$player_pos} = " ";
		}
		else{
			$map{$player_pos} = ".";
		}
		if (!is_empty($map,$player_pos+1)){
			if($map{$player_pos+1}=="$"){
				if($map{$player_pos+2}==" "){
					$map{$player_pos+2}="$";
					$map{$player_pos+1}=" ";
				}
				else{
					$map{$player_pos+2}="*";
					$map{$player_pos+1}=" ";
				}
			}
			else{	
				if($map{$player_pos+2}==" "){
					$map{$player_pos+2}="$";
					$map{$player_pos+1}=".";
				}
				else{
					$map{$player_pos+2}="*";
					$map{$player_pos+1}=".";
				}
			}			
		}
		if($map{$player_pos+1}==" "){
			$map{$player_pos+1}="@";
		}
		else{
			$map{$player_pos+1}="+";
		}	
	}
	if($dir=="U"){
		if($map{$player_pos}=="@"){
			$map{$player_pos} = " ";
		}
		else{
			$map{$player_pos} = ".";
		}
		if (!is_empty($map,$player_pos-$width)){
			if($map{$player_pos-$width}=="$"){
				if($map{$player_pos-2*$width}==" "){
					$map{$player_pos-2*$width}="$";
					$map{$player_pos-$width}=" ";
				}
				else{
					$map{$player_pos-2*$width}="*";
					$map{$player_pos-$width}=" ";
				}
			}
			else{	
				if($map{$player_pos-2*$width}==" "){
					$map{$player_pos-2*$width}="$";
					$map{$player_pos-$width}=".";
				}
				else{
					$map{$player_pos-2*$width}="*";
					$map{$player_pos-$width}=".";
				}
			}			
		}
		if($map{$player_pos-$width}==" "){
			$map{$player_pos-$width}="@";
		}
		else{
			$map{$player_pos-$width}="+";
		}	
	}
	if($dir=="D"){
		if($map{$player_pos}=="@"){
			$map{$player_pos} = " ";
		}
		else{
			$map{$player_pos} = ".";
		}
		if (!is_empty($map,$player_pos+$width)){
			if($map{$player_pos+$width}=="$"){
				if($map{$player_pos+2*$width}==" "){
					$map{$player_pos+2*$width}="$";
					$map{$player_pos+$width}=" ";
				}
				else{
					$map{$player_pos+2*$width}="*";
					$map{$player_pos+$width}=" ";
				}
			}
			else{	
				if($map{$player_pos+2*$width}==" "){
					$map{$player_pos+2*$width}="$";
					$map{$player_pos+$width}=".";
				}
				else{
					$map{$player_pos+2*$width}="*";
					$map{$player_pos-$width}=".";
				}
			}			
		}
		if($map{$player_pos+$width}==" "){
			$map{$player_pos+$width}="@";
		}
		else{
			$map{$player_pos+$width}="+";
		}	
	}
	return($map);
}
 
 
 
/*  
 
# = wall
$ = crate
. = place
* = crate in place
@ = man
+ = man in place
 
*/
 
$width = 8;
$map = "  ###     #.#     # #######$ $.##. $@#######$#     #.#     ###  ";
for($x=1;$x<=100;$x++){
     echo echo_map($map,$width);
     $possible = echo_possible_directions($map,$width);
     echo "Possible directions: $possible";
     $new_dir = $possible{rand(0,strlen($possible)-1)};
     echo " - going ".$new_dir;
     $map = move($map,$width,$new_dir);
     if(is_solved($map)){
          echo "<h1>S</h1>";
     }
}
 
?>