/**
	 * Moves a term within the vocabulary. Returns a Term object. null parameters append the term to the end of any hierarchies.
	 * @return Term The Term object added
	 **/
	public function move_term($term, $parent_term = null, $before_term = null)
	{
		// We assume that the arguments passed are valid terms. Check them before calling this.

		// If there are terms in the vocabulary, work out the reference point
		if ( !$this->is_empty() ) {

			$moving_left = $term->mptt_left;
			$moving_right = $term->mptt_right;

			$nodes_moved = count( $term->descendants() ) + 1;

			DB::begin_transaction();

			if ( $this->hierarchical ) {
				// Check first if this is to be inserted to the left of a term
				if ( null != $before_term ) {
					$before_left = $before_term->mptt_left;
					// there should be no need to check for parent term if before_term is being used.
				}
				else {
					// If no parent is specified, put the new term after the last term
					if ( null != $parent_term ) {
						$parent_term_left = $parent_term->mptt_left;
						$parent_term_right = $parent_term->mptt_right;
					}
				}
			}
			else {
				// check before term only. parent should be null. Or do we throw an exception?
				if ( null != $before_term ) {
					$before_left = $before_term->mptt_left;
				}
				else {
					// send it all the way to the right.
					$rightmost_right = DB::get_value( 'SELECT mptt_right FROM {terms} WHERE vocabulary_id=? ORDER BY mptt_right DESC LIMIT 1', array($this->id) );
// /* would this be faster? */ 		$rightmost_right = DB::get_value( 'SELECT MAX(mptt_right) FROM {terms} WHERE vocabulary_id=?', array($this->id) );
// once we have this, we can subtract number of nodes * 2 from everything between source_mptt_left and this, then start renumbering and end up at this.
				}
			}

			// Move the existing nodes out of the way by making mptt_left and mptt_right negative


// $target_right = something....
			// Figure out where to make the space ... does this need to be separate updates?
			$res = DB::query('UPDATE {terms} SET mptt_left=mptt_left+2 WHERE vocabulary_id=? AND mptt_left>?', $params);
			if( ! $res ) {
				DB::rollback();
				return FALSE;
			}

			$params = array( $nodes_moved, $nodes_moved, $this->id, $moving_right, $target_right ); // not sure about that last one.
			$res = DB::query('UPDATE {terms} SET mptt_right=mptt_right-? WHERE vocabulary_id=? AND mptt_left>? AND mptt_right<?', $params);
			if( ! $res ) {
				DB::rollback();
				return FALSE;
			}
/* 
			// Set the right and left appropriately
			$new_term->mptt_left = $ref + 1;
			$new_term->mptt_right = $ref + 2;
*/ 
			// Update the node
			$result = $moving_term->update(); // update() not insert(), right?
			if ( $result ) {
				DB::commit();
				return $moving_term;
			}
			else {
				DB::rollback();
				return FALSE;
			}
		
		}
		return FALSE; // probably should put this in an else.
	}