system/classes/terms.php

<?php 
namespace Habari;

class Terms extends \ArrayObject implements FormStorage
{

  public function has( $tags )
  {
    if ( is_string( $tags ) || ( is_array( $tags ) && is_string( $tags[0] ) ) ) {
      $tags = (array)Terms::parse( $tags );
    }

    $diff = array_diff( $tags, (array)$this );
    foreach ( $tags as $tag ) {
      if ( in_array( $tag, $diff ) ) {
        return false;
      }
    }

    return true;
  }


  public static function parse( $terms, $term_class = '\Habari\Term', $vocabulary = null )
  {
    if ( is_string( $terms ) ) {
      if ( '' === $terms ) {
        return new Terms();
      }
      $terms = trim( MultiByte::str_replace( '&quot;', '"', $terms ) );
      // dirrty ;)
      $rez = array( '\\"'=>':__unlikely_quote__:', '\\\''=>':__unlikely_apos__:' );
      $zer = array( ':__unlikely_quote__:'=>'"', ':__unlikely_apos__:'=>"'" );
      // escape
      $tagstr = str_replace( array_keys( $rez ), $rez, $terms );
      // match-o-matic
      preg_match_all( '/((("|((?<= )|^)\')\\S([^\\3]*?)\\3((?=[\\W])|$))|[^,])+/u', $tagstr, $matches );
      // cleanup
      $terms = array_map( 'trim', $matches[0] );
      $terms = preg_replace( array_fill( 0, count( $terms ), '/^(["\'])(((?!").)+)(\\1)$/' ), '$2', $terms );
      // unescape
      $terms = str_replace( array_keys( $zer ), $zer, $terms );
      // hooray
    }
    if ( is_array( $terms ) ) {
      if ( $vocabulary instanceof Vocabulary ) {
        foreach ( $terms as $k => $term ) {
          if ( $saved_term = $vocabulary->get_term( $term, $term_class ) ) {
            $terms[$k] = $saved_term;
          }
          else {
            $terms[$k] = new $term_class( $term );
          }
        }
      }
      else {
        array_walk( $terms, function( &$tag ) use ($term_class) {$tag = new $term_class($tag);} );
      }
      return new Terms( $terms );
    }
    return new Terms();
  }

  function field_load($key)
  {
    return $this;
  }

  function field_save($key, $value)
  {
    Vocabulary::prep_update($value);
    foreach($value as $term) {
      if($term instanceof Term) {
        $term->update();
      }
    }
  }

  function tree_sort($sort_fn = null)
  {
    if(empty($sort_fn)) {
      $sort_fn = function($a, $b) {
        return $a->mptt_left > $b->mptt_left;
      };
    }
    $terms = $this->getArrayCopy();
    usort($terms, $sort_fn);
    return new Terms($terms);
  }
}

?>