<?php


class HTMLElement
{
    var $element_name;
    var $attributes;
    var $child_elements;
    var $value;
    var $is_empty;

    function HTMLElement($element_name = "", $is_empty = false)
    {
        $this->element_name   = $element_name;
        $this->attributes     = array();
        $this->child_elements = array();
        $this->is_empty       = $is_empty;
    }

    function set_attribute($name, $value)
    {
        $this->attributes[$name] = $value; 
    }

    function get_attribute($name)
    {
        return $this->attributes[$name];
    }

    function add_element($element)
    {
        if ($this->is_empty)
        {
            die("Error: the HTMLElement " . get_class($this) . " is empty and thus does not allow adding of elements.");
        }
        else
        {
            $this->child_elements[] = $element;
        }
    }

    function to_html()
    {
        $result = "";

        // create attribute name="value" pairs
        $attributes = " ";
        foreach ($this->attributes as $attribute => $value)
        {
            if ($value == "")
            {
                 $attributes .= $attribute . " " ;
            }
            else
            {
                 $attributes .= $attribute . "=\"" . htmlentities($value, ENT_COMPAT) . "\" ";
            }
        }
        
        // create start tag
        $result = "<" . $this->element_name . rtrim($attributes);

        // end start tag the xhtml way
        if ($is_empty)
        {
            $result .= "/>";
        }
        else // include children elements followed by an end tag
        {
            $result .= ">";
            
            // create html between start and end tags
            $inner_html = "";
            foreach($this->child_elements as $element)
            {
                if (is_subclass_of($element, "HTMLElement") || get_class($element) == "htmlelement")
                {
                    $inner_html .= $element->to_html();
                }
                else
                {
                    $inner_html .= $element;
                }
            }
            
            $result .= $inner_html . "</" . $this->element_name . ">\n";
        }

        return $result;
    }
}
?>