<?php
class CTag {

	private $_tag;
	private $_id = 0;
	private $_ob = 0;
		
	private static $void=array(
		'area','base','br','col',
		'command','embed','hr','img',
		'input','keygen','link','meta',
		'param','source','track','wbr');

	public function __construct($tag, $value = null) {
		$this->_tag = array();
		$this->att($tag, $value);
	}

	// new tag in collection @link->add
	// return $this
	public function add($name, $value = null) {
		$this->_id++;
		return $this->att($name, $value);
	}

	// attribute: @link->att(name, value)
	public function att($name, $value = null) {
		return $this->__call($name, array($value));
	}

	// attribute: @link->name(value)
	public function __call($name, $args = null) {
		$value = @$args[0];
		if(isset($this->_tag[$this->_id][$name]) && $value !== null)
			$this->_tag[$this->_id][$name] .= (' ' . $value);
		else
			$this->_tag[$this->_id][$name] = $value;
		return $this;
	}
	
	// attach new tag to tag @link->ins(tag, node)
	public function ins($name, $value = null) {
		return $this->__invoke($name, $value);
	}

	// attach new tag to tag @link(tag, node)
	public function __invoke($name, $value = null) {
        $class_name = get_class();
		return $this->_tag[$this->_id][$this->_ob++] = new $class_name($name, $value);
	}

	public function __toString() {

		$echo = array();

		foreach($this->_tag as $tag) {

			$index = 0;

			foreach($tag as $name => $value) {

				if($index++ == 0) {

					$s = '<' . $name;
					$v = array();

					if(in_array(strtolower($name), self::$void)) {
						$c = ' />';
						$g = null;
					}
					else {
						$c = '</' . $name . '>'; 
						$g = '>';
						$v[] = $value;
					}
				}	
				elseif(is_numeric($name))
					$v[] = $value;
				elseif($value !== null)
					$s .= ' ' . $name . '="' . $value . '"';

			}

			$echo[] = $s . $g . join(null, $v) . $c . PHP_EOL;

		}

		return join(null, $echo);

	}
	
}