class MoneyParser
{
	/**
	 * Returns a converted float value or null if $value is not a correct money value.
	 *
	 * @static
	 * @param string $value
	 * @return float|null
	 */
	public static function tryParse($value)
	{
		$correctValuePattern = '/^\d+([.,]\d{1,2})?$/';
		$value = trim($value);
		$valueIsCorrect = preg_match($correctValuePattern, $value);
		return $valueIsCorrect ? (float)str_replace(',', '.', $value) : null;
	}

	/**
	 * Returns a converted float value or throws an exception if $value is not a correct money value.
	 *
	 * @static
	 * @param string $value
	 * @return float
	 * @throws Exception
	 */
	public static function parse($value)
	{
		$parsed = self::tryParse($value);
		if($parsed === null)
			throw new Exception('Wrong money value.');

		return $parsed;
	}
}

class MoneyParserTests extends PHPUnit_Framework_TestCase
{
	private $testDataCorrect = array(
		'1234.56' 	=> 1234.56,
		'1234.5'		=> 1234.5,
		'1234'			=> 1234,
		'1234,56'		=> 1234.56,
		'1234,5'		=> 1234.5,
		'0,5'				=> 0.5,
		'0.5'				=> 0.5,
		'0'					=> 0,
		'0,0'				=> 0,
		'0.00'			=> 0,
		' 123   '		=> 123,
		' 123.01	'	=> 123.01
	);

	private $testDataToFail = array(
		'123.01.01',
		'987,123,13',
		'987,123,134',
		',1',
		'1,',
		'1.',
		'123.123,12',
		'123,456.12',
		'',
		' ',
		'true',
		null,
		'123 usd',
		'$123'
		);

	public function testTryParse()
	{
		foreach($this->testDataCorrect as $str => $expectedFloatValue)
			$this->assertEquals($expectedFloatValue, MoneyParser::tryParse($str));

		foreach($this->testDataToFail as $str)
			$this->assertNull(MoneyParser::tryParse($str));
	}

	public function testParse()
	{
		foreach($this->testDataCorrect as $str => $expectedFloatValue)
			$this->assertEquals($expectedFloatValue, MoneyParser::parse($str));

		foreach($this->testDataToFail as $str)
		{
			try
			{
				MoneyParser::parse($str);
				$this->fail('Exception has to be thrown.');
			}
			catch(Exception $ex) { }
		}
	}
}