Base fieldtype validation working with model validation?

Question

How can you ensure that the base fieldtype validation (required etc) and error messages are still applied when validating $value via the validate($value) function??

Validate method in fieldtype class:

public function validate($value)
{
    if(is_array($value) && $value['type'] != '')
    {
        $linkModel = $this->_valuetToModel($value);
        $validated = $linkModel->validate();
        return $validated ? true : $linkModel->getAllErrors();
    }
    return true;
}

Validate method of custom model that the fieldtype populates and returns to the template:

public function validate($attributes = null, $clearErrors = true)
{
    switch($this->type)
    {
        case('email'):
            if( !filter_var($this->value, FILTER_VALIDATE_EMAIL) )
            {
                $this->addError('value', Craft::t('Please enter a valid email address.'));
            }
            break;

        case('tel'):
            $regexp = '/^[0-9+\(\)#\.\s\/ext-]+$/';
            if(!filter_var($this->value, FILTER_VALIDATE_REGEXP, array('options' => array('regexp' => $regexp))))
            {
                $this->addError('value', Craft::t('Please enter a valid telephone.'));
            }
            break;

        case('custom'):
            if(!filter_var($this->value, FILTER_VALIDATE_URL))
            {
                $this->addError('value', Craft::t('Please enter a valid url.'));
            }
            break;

        case('entry'):
            if($this->value == '')
            {
                $this->addError('value', Craft::t('Please select an entry.'));
            }
            break;

        case('asset'):
            if($this->value == '')
            {
                $this->addError('value', Craft::t('Please select an asset.'));
            }
            break;

        case('category'):
            if($this->value == '')
            {
                $this->addError('value', Craft::t('Please select a category.'));
            }
            break;
        // default:
        //     Craft::dd(parent::validate($attributes, null));
        //     $this->addError('value', Craft::t('Please select a sdfasdfsd.'));
        //     break;
    }

    return !$this->hasErrors();
}

Answer 1

Completely untested and this whole pattern feels hacky to me, but something like this should work:

From your field type:

public function validate($value)
{
    if(is_array($value) && $value['type'] != '')
    {
        // Validate the field type.
        $errors = parent::validate($value);

        if (!is_array($errors))
        {
            $errors = array();
        }

        $linkModel = $this->_valuetToModel($value);

        // Validate the model.
        $validated = $linkModel->validate();

        return $validated && empty($errors) ? true : array_merge($linkModel->getAllErrors(), $errors);
    }

    return true;
}

From your model:

public function validate($attributes = null, $clearErrors = true)
{
    switch($this->type)
    {
        case('email'):
            if( !filter_var($this->value, FILTER_VALIDATE_EMAIL) )
            {
                $this->addError('value', Craft::t('Please enter a valid email address.'));
            }
            break;

        ....

    }

    return !$this->hasErrors();
}