<?php
$_POST['uname'] = 'abc';

$Registration =& new ValidationMaster;

$User = $Registration->add_field('uname', 'Username');
$User->add_rule('Required');
$User->add_rule('MinLength', 4);
$User->add_rule('MaxLength', 20);

$e =& $Registration->validate();
/* just shows the errors */
if(count($e))
{
	echo '<ul>';
	foreach($e as $err)
	{
		echo '<li>' . $err . '</li>';
	}
	echo '</ul>';
}

/* classes */

class ValidationMaster
{
	var $fields;

	function ValidationMaster() {}

	function &add_field($form_name, $label)
	{
		$Field =& new Field($label, $_POST[$form_name]);
		$this->fields[] =& $Field;
		return $Field;
	}

	function validate()
	{
		$errors = array();
		foreach($this->fields as $Field)
		{
			$errors = array_merge($errors, $Field->validate());
		}
	}
}

class Field
{
	var $label;
	var $data;
	var $rules;

	function Field($label, $data)
	{
		$this->label = $label;
		$this->data = $data;
	}

	function add_rule($name, $param = 0)
	{

		$name = $name . 'Rule';
		$this->rules[] =new $name($param, $this->data, $this->label);

	}

	function &validate()
	{
		echo count($this->rules);
		$errors = array();
		foreach($this->rules as $Rule)
		{
			$errors[] = $Rule->execute();
		}

		return $errors;
	}
}

class Rule
{
	var $param;
	var $data;
	var $label;

	function Rule($param, $data, $label)
	{
		$this->param = $param;
		$this->data = $data;
		$this->label = $label;
	}

	function execute()
	{
		die('Abstract function must be implemented');
	}
}

class RequiredRule extends Rule
{
	function RequiredRule($param, $data, $label)
	{
		parent::Rule($param, $data, $label);
	}

	function execute()
	{
		if(empty($this->data))
		{
			return $this->label . ' is required & must have a value';
		}
	}
}

class MinLengthRule extends Rule
{
	function RequiredRule($param, $data, $label)
	{
		parent::Rule($param, $data, $label);
	}

	function execute()
	{
		if(strlen($this->data) < $this->param)
		{
			return $this->label . ' must be longer than' . $this->param;
		}
	}
}

class MaxLengthRule extends Rule
{
	function RequiredRule($param, $data, $label)
	{
		parent::Rule($param, $data, $label);
	}

	function execute()
	{
		if(strlen($this->data) > $this->param)
		{
			return $this->label . ' must be shorter than' . $this->param;
		}
	}
}
?>