CakePHP custom check with variable in error message

Good afternoon.

I have a model that has a field called "percentage". All similar models cannot have a percentage of more than 100%. A check for this is performed during the check.

I need a validation error message to indicate how many percent of the “room” the user has left. For example, if all MyModels already have 80%, and the user tries to create a new MyModel with a percentage of 40%, the error message will say: "Your percentage is too high. Only 20% left."

The problem is that I do not know how to put a variable in a validation error message.

In MyModel.php:

public $validate = array(
    'percentage' => array(
        'rule' => array('confirmValidPercentage', 'percentage'),
        'message' => 'foo',
        'required' => true,
    ),
);

public function confirmValidPercentage($data) {
    $percentage = floatval($data['percentage']);

    $total = 0.00;
    $weights = $this->find('all', array('recursive'=>-1));
    foreach ($weights as $weight) {
        $total += floatval($weight[$this->name]['percentage']);
    }

    if ($total + $percentage > 100) {
        // handle the error variable here
        return false;
    }
    else {
        return true;
    }
}

I tried:

$this->validate['percentage']['message'] = 'You have '.(100-$total).'% remaining';

- "foo". $validation , , "". :

unset($this->validate['percentage']['message']);

, .

- , ? .