<?php
/**
 * a baisc constraint for string.  This class can be used in setter methods
 * to validate input data and constrain it to a valid string regex.
 * 
 * @see Constraint
 * @author Cory
 * @package constraints
 */

require_once ROGUE_DIR . '/constraints/Constraint.php';

class RegExConstraint extends Constraint
{
    private $_regex;
    
    /**
     * build a new Contraint for strings with regexes
     * 
     * @param string $name the name of the constraint
     * @param string $regex the pcre (perl) regular expression to validate data against default alpha numeric
     * @param boolean $nullAble true if the paramater may be null
     */
    public function __construct($name = false, $regex = '/[a-zA-Z0-9/', $nullAble = false)
    {
        // setup the base constraint
        parent::__construct($name, 'string', $nullAble);
        
        // assign the min and max values
        $this->_regex = $regex;
    }
    
    /**
     * validate that the passed paramater matches the constraint.  Tests Constraint tests
     * Constraint base class validation, as well as the regular expression.
     *
     * @param string $param the paramater to test
     * @return boolean true if validation succeeds
     */
    public function validate($param, $message = false)
    {
        // validate the type and nullability
        parent::validate($param);
        
        // if it's an allowed null value, then return success
        if ($this->_isNull)
            return true;
        
        $res = '';
        if (!preg_match($this->_regex, $param))
            $res = ($message) ? $message : 'constraint: ' . $this->_name . ' may does not match ' . $this->_regex . ' / ' . $param;
        if ($res)
            throw new ConstraintException ($res);
        // life is good
        return true;
    }
}