afm.module

<?php
//$Id$

/**
 * Implements hook_field_info().
 */
function afm_field_info() {
  return array(
    'afm' => array(
      'label' => t('ΑΦΜ'),
      'description' => t('Εισάγετε Αριθμό Φορολογικού Μητρώου.'),
      'default_widget' => 'afm_afm_form',
      'default_formatter' => 'afm_default',
    ),
  );
}

/**
 * Implements hook_field_is_empty().
 */
function afm_field_is_empty($item, $field) {
  if($field['type'] == 'afm'){
    if(empty($item['value'])){
      return TRUE;
    }
  }
  return FALSE;
}

/**
 * Implements hook_field_widget_info().
 */
function afm_field_widget_info(){
  return array(
    'afm_afm_form' => array(
      'label' => t('ΑΦΜ form'),
      'field types' => array('afm'),
      'behaviors' => array(
        'multiple values' => FIELD_BEHAVIOR_DEFAULT,
        'default value' => FIELD_BEHAVIOR_NONE,
      ),
    ),
  );
}

/**
 * Implementation of hook_field_widget_form().
  */
function afm_field_widget_form(&$form, &$form_state, $field, $instance, $langcode, $items, $delta, $element) {
 $base = $element;
 if ($instance['widget']['type'] == 'afm_afm_form') {
  $widget = $instance['widget'];
  $settings = $widget['settings'];
  $element['value'] = array(
   '#type' => 'textfield',
   '#title' => t('ΑΦΜ'),
   '#default_value' => isset($items[$delta]['value']) ? $items[$delta]['value'] : NULL,
   '#element_validate' => array('_afm_value_validate'),
  );
 }
 return $element;
}

/**
 * Validation callback for an afm value element.
 */
function _afm_value_validate($element, &$form_state, $form){
  $value = $element['#value'];
  if(!empty($value)){
    if(!ctype_digit($value)){
      form_error($element, t('Ο ΑΦΜ αποτελείται μόνο από αριθμητικά ψηφία'));
    }
    if(((strlen($value) > 1) && (strlen($value) < 9)) || (strlen($value) > 9)){
      form_error($element, t('Ο ΑΦΜ αποτελείται από 9 ψηφία'));
    }
    if(strlen($value) == 9){
      if(!_afm_check($value)){
        form_error($element, t('Ο ΑΦΜ δεν είναι έγκυρος'));
      }
    }
  }
}

/**
 * Check tax number validity
 */
function _afm_check($afm){
  $remainder = 0;
  $sum = 0;
  for ($nn = 2, $k = 7, $sum = 0; $k >= 0; $k--, $nn += $nn){
    $sum += $nn * ($afm[$k]);
  }
  $remainder = $sum % 11;
  return ($remainder == 10)?($afm[8] == '0'):($afm[8] == $remainder);
}

/**
 * Implements hook_field_formatter_info().
 */
function afm_field_formatter_info(){
  return array(
    'afm_default' => array(
      'label' => t('Default'),
      'field types' => array('afm'),
    ),
  );
}

/**
 * Implements hook_field_formatter_view().
 */
function afm_field_formatter_view($entity_type, $entity, $field, $instance, $langcode, $items, $display){
  $element = array();
  switch($display['type']){
    case 'afm_default':
      foreach($items as $delta => $item){
        $element[$delta]['#markup'] = t('ΑΦΜ: ').$item['value'];
      }
      break;
  }
  return $element;
}