<?php
// $Id: checkall.module,v 1.2.2.11 2009-12-27 20:45:36 markuspetrux Exp $

/**
 * @file
 * Extends FormAPI checkboxes with the 'checkall' behavior.
 */

/**
 * Implementation of hook_form_alter().
 */
function checkall_form_alter(&$form, $form_state, $form_id) {
  $form['#after_build'][] = 'checkall_form_after_build';
}

/**
 * Implementation of hook_widget_settings_alter().
 *
 * Note: This hook is available since CCK 2.5.
 *
 * Control '#checkall' attribute in CCK form field definition.
 */
function checkall_widget_settings_alter(&$settings, $op, $widget) {
  $widget_types = array(
    'optionwidgets_buttons',
    'nodereference_buttons',
    'userreference_buttons',
    'content_taxonomy_options',
  );
  if ((isset($widget['type']) && in_array($widget['type'], $widget_types)) || (isset($widget['widget_type']) && in_array($widget['widget_type'], $widget_types))) {
    switch ($op) {
      case 'form':
        $settings['checkall'] = array(
          '#title' => t('Checkall settings'),
          '#type' => 'fieldset',
          '#collapsible' => TRUE,
          '#collapsed' => FALSE,
          '#weight' => 2,
        );
        $settings['checkall']['checkall'] = array(
          '#title' => t('Include checkall options'),
          '#type' => 'radios',
          '#options' => array(0 => t('Disabled'), 1 => t('Enabled')),
          '#default_value' => isset($widget['checkall']) ? $widget['checkall'] : 0,
          '#description' => t('Enable this to display checkall options near checkbox groups when this field is configured to accept multiple values.'),
        );
        break;
      case 'save':
        $settings[] = 'checkall';
        break;
    }
  }
}

/**
 * After build callback.
 */
function checkall_form_after_build($elements, &$form_state) {
  checkall_form_after_build_recursive($elements, $form_state);
  return $elements;
}

/**
 * Helper function to find elements with '#checkall' attribute recursively.
 */
function checkall_form_after_build_recursive(&$elements, &$form_state, $checkall = NULL) {
  foreach (element_children($elements) as $key) {
    if (isset($elements[$key]) && $elements[$key]) {

      if (isset($checkall)) {
        // Inherit checkall attribute if specified by the caller.
        $children_checkall = $checkall;
      }
      elseif (!empty($elements[$key]['#checkall'])) {
        // Inherit checkall attribute if specified in the form element.
        $children_checkall = $elements[$key]['#checkall'];
      }
      else {
        // Assume no checkall attribute has been specified.
        $children_checkall = NULL;

        // Inherit checkall attribute if specified in CCK field settings.
        if (isset($elements[$key]['#field_name']) && isset($elements[$key]['#type_name'])) {
          $field = content_fields($elements[$key]['#field_name'], $elements[$key]['#type_name']);
          if (!empty($field) && isset($field['widget']) && !empty($field['widget']['checkall'])) {
            $children_checkall = TRUE;
          }
        }
      }

      checkall_form_after_build_recursive($elements[$key], $form_state, $children_checkall);
    }
  }
  if (isset($checkall) && isset($elements['#type']) && $elements['#type'] == 'checkboxes') {
    $elements['#checkall'] = $checkall;
    $elements = checkall_element_process($elements);
  }
}

/**
 * Process the checkall extension for the checkboxes element.
 */
function checkall_element_process($element) {
  // See if the #checkall flag is present.
  if (!empty($element['#checkall'])) {
    $class = is_string($element['#checkall']) ? trim($element['#checkall']) : '';
    if (empty($class)) {
      $class = 'checkall-'. $element['#id'];
    }

    // Append classes to the checkboxes element.
    if (!isset($element['#attributes'])) {
      $element['#attributes'] = array();
    }
    if (empty($element['#attributes']['class'])) {
      $element['#attributes']['class'] = 'form-checkall '. $class;
    }
    else {
      $element['#attributes']['class'] .= ' form-checkall '. $class;
    }

    // Append class to the checkboxes items.
    foreach (element_children($element) as $key) {
      if ($element[$key]['#type'] == 'checkbox') {
        if (!isset($element[$key]['#attributes'])) {
          $element[$key]['#attributes'] = array();
        }
        if (empty($element[$key]['#attributes']['class'])) {
          $element[$key]['#attributes']['class'] = $class;
        }
        else {
          $element[$key]['#attributes']['class'] .= ' '. $class;
        }
      }
    }

    // Append the unique checkboxes class to Drupal.settings.checkall.
    drupal_add_js(array('checkall' => array('groups' => $class)), 'setting');

    // Add our stylesheet and javascript files to the page.
    drupal_add_css(drupal_get_path('module', 'checkall') .'/checkall.css');
    drupal_add_js(drupal_get_path('module', 'checkall') .'/checkall.js');
  }

  return $element;
}