Currency-Validator.php

<?php

require_once 'Zend/Validate/Abstract.php';

/**
 * Mo' money, mo' money, mo' money.
 *
 * @package System_Form_Validate
 */
class System_Form_Validate_Currency extends Zend_Validate_Abstract {
	/**
	 * Validation failure message key for effed up money format.
	 */
	const FORMAT = 'format';
	/**
	 * Validation failure message key for an amount not meeting the minimum required.
	 */
	const NOT_ENOUGH = 'notEnough';
	/**
	 * Validation failure message key for an amount being too high.
	 */
	const TOO_MUCH = 'tooMuch'; // No such thing! HA!
	
	/**
	 * @var float
	 */
	protected $min = null;
	/**
	 * @var float
	 */
	protected $max = null;
	/**
	 * @var string
	 */
	protected $strMin = '';
	/**
	 * @var string
	 */
	protected $strMax = '';
	
	/**
	 * Validation failure messages.
	 *
	 * @var array
	 */
	protected $_messageTemplates = array(
		self::FORMAT => '%field% must be in the format: <strong><em>123.45</em></strong>',
		self::NOT_ENOUGH => '%field% must be at least <strong>%min%</strong>',
		self::TOO_MUCH => '%field% may not be more than <strong>%max%</strong>'
	);
	
	/**
	 * Message variable mappings.
	 *
	 * @var array
	 */
	protected $_messageVariables = array(
		'min' => 'strMin', 'max' => 'strMax'
	);
	
	/**
	 * Constructor.
	 *
	 * @param float $min
	 * @param float $max
	 */
	public function __construct($min = null, $max = null) {
		$this->min = $min;
		$this->max = $max;
	}
	
	/**
	 * Tests the value given as valid expiration date as returned by a MonthYear form element.
	 * Assume that if $this->max is the same as $value, validation should pass.
	 *
	 * @param mixed $value
	 */
	public function isValid($value) {

		$value = (integer)(floatval($value) * 100);

		$this->min = (null !== $this->min) ? intval(ceil($this->min * 100)) : null;
		$this->max = (null !== $this->max) ? intval(ceil($this->max * 100)) : null;

		$value = floatval($value);

		if (! preg_match('/^\d+(?:\.\d{0,2})?$/', $value)) {
			$this->_error(self::FORMAT);
			return false;
		}
		if (null !== $this->min && $value < $this->min) {
			$this->strMin = sprintf('$%.2f', $this->min);
			$this->_error(self::NOT_ENOUGH);
			return false;
		}
		elseif (null !== $this->max && $value > $this->max) {
			$this->strMax = sprintf('$%.2f', $this->max);
			$this->_error(self::TOO_MUCH);
			return false;
		}
		return true;
	}
}