Cevaplarınız için teşekkür ederim, iki sistemde işime yaradı :)

usttekı kutuphane guzel cozum ayrıca soyle bır sey var

function bbcode($bbtext){
  $bbtags = array(
    '[heading1]' => '<h1>','[/heading1]' => '</h1>',
    '[heading2]' => '<h2>','[/heading2]' => '</h2>',
    '[heading3]' => '<h3>','[/heading3]' => '</h3>',
    '[h1]' => '<h1>','[/h1]' => '</h1>',
    '[h2]' => '<h2>','[/h2]' => '</h2>',
    '[h3]' => '<h3>','[/h3]' => '</h3>',
	  
    '[youtube]' => '<h3>','[/youtube]' => '</h3>',

    '[paragraph]' => '<p>','[/paragraph]' => '</p>',
    '[para]' => '<p>','[/para]' => '</p>',
    '[p]' => '<p>','[/p]' => '</p>',
    '[left]' => '<p style="text-align:left;">','[/left]' => '</p>',
    '[right]' => '<p style="text-align:right;">','[/right]' => '</p>',
    '[center]' => '<p style="text-align:center;">','[/center]' => '</p>',
    '[justify]' => '<p style="text-align:justify;">','[/justify]' => '</p>',

    '[bold]' => '<span style="font-weight:bold;">','[/bold]' => '</span>',
    '[italic]' => '<span style="font-weight:bold;">','[/italic]' => '</span>',
    '[underline]' => '<span style="text-decoration:underline;">','[/underline]' => '</span>',
    '[b]' => '<span style="font-weight:bold;">','[/b]' => '</span>',
    '[i]' => '<span style="font-weight:bold;">','[/i]' => '</span>',
    '[u]' => '<span style="text-decoration:underline;">','[/u]' => '</span>',
    '[break]' => '<br>',
    '[br]' => '<br>',
    '[newline]' => '<br>',
    '[nl]' => '<br>',
    
    '[unordered_list]' => '<ul>','[/unordered_list]' => '</ul>',
    '[list]' => '<ul>','[/list]' => '</ul>',
    '[ul]' => '<ul>','[/ul]' => '</ul>',
	
    '[ordered_list]' => '<ol>','[/ordered_list]' => '</ol>',
    '[ol]' => '<ol>','[/ol]' => '</ol>',
    '[list_item]' => '<li>','[/list_item]' => '</li>',
    '[li]' => '<li>','[/li]' => '</li>',
	    
    '[*]' => '<li>','[/*]' => '</li>',
    '[code]' => '<code>','[/code]' => '</code>',
    '[preformatted]' => '<pre>','[/preformatted]' => '</pre>',
    '[pre]' => '<pre>','[/pre]' => '</pre>',		    
  );
	
  $bbtext = str_ireplace(array_keys($bbtags), array_values($bbtags), $bbtext);

  $bbextended = array(
    "/[url](.*?)[/url]/i" => "<a href="http://$1" title="$1">$1</a>",
    "/[url=(.*?)](.*?)[/url]/i" => "<a href="$1" title="$1">$2</a>",
    "/[email=(.*?)](.*?)[/email]/i" => "<a href="mailto:$1">$2</a>",
    "/[mail=(.*?)](.*?)[/mail]/i" => "<a href="mailto:$1">$2</a>",
    "/[img]([^[]*)[/img]/i" => "<img src="$1" alt=" " />",
    "/[image]([^[]*)[/image]/i" => "<img src="$1" alt=" " />",
    "/[image_left]([^[]*)[/image_left]/i" => "<img src="$1" alt=" " class="img_left" />",
    "/[image_right]([^[]*)[/image_right]/i" => "<img src="$1" alt=" " class="img_right" />",
  );

  foreach($bbextended as $match=>$replacement){
    $bbtext = preg_replace($match, $replacement, $bbtext);
  }
  return $bbtext;
}

echo bbcode($yazi); // KULLANIMI

PHP için şöyle bir kütüphane buldum işine yarayabilir.
https://github.com/chriskonnertz/bbcode