<?php

/**
 * @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';
}

/**
 * Implements hook_form_FORM_ID_alter().
 */
function checkall_form_field_ui_field_edit_form_alter(&$form, $form_state) {
  $instance = $form['#instance'];
  if ($instance['widget']['type'] == 'options_buttons') {
    $field = $form['#field'];
    if (empty($form['instance']['settings'])) {
      $form['instance']['settings'] = array();
    }
    $form['instance']['settings'] += checkall_widget_settings_form($field, $instance);
  }
}

/**
 * Implements hook_element_info().
 */
function checkall_element_info() {
  $elements['options_buttons '] = array('#after_build' => array('checkall_element_process'));
  return $elements;
}

/**
 * Implements hook_field_widget_info_alter().
 */
function checkall_field_widget_info_alter(&$info) {
  if (isset($info['options_buttons']['settings'])) {
    $info['options_buttons']['settings'] += array('checkall' => FALSE);
  }
}

/**
 * Configuration form for checkall settings for a field instance.
 */
function checkall_widget_settings_form($field, $instance) {
  $widget = $instance['widget'];
  $settings = $instance['settings'];

  $form['checkall'] = array(
    '#title' => t('Checkall settings'),
    '#type' => 'fieldset',
    '#collapsible' => TRUE,
    '#collapsed' => FALSE,
    '#weight' => 2,
  );
  $form['checkall']['checkall'] = array(
    '#title' => t('Include checkall options'),
    '#type' => 'radios',
    '#options' => array(
      0 => t('Disabled'),
      1 => t('Enabled')
    ),
    '#default_value' => isset($settings['checkall']['checkall']) ? $settings['checkall']['checkall'] : 0,
    '#description' => t('Enable this to display checkall options near checkbox groups when this field is configured to accept multiple values.'),
  );
  $form['checkall']['checkall-check-all'] = array(
    '#type' => 'checkbox',
    '#title' => 'Show Check All Link',
    '#default_value' => isset($settings['checkall']['checkall-check-all']) ? $settings['checkall']['checkall-check-all'] : 1,
    '#states' => array(
      'visible' => array(
        ':input[name="instance[settings][checkall][checkall]"]' => array(
          'value' => 1,
        ),
      ),
    ),
  );
  $form['checkall']['checkall-toggle'] = array(
    '#type' => 'checkbox',
    '#title' => 'Show Toggle Link',
    '#default_value' => isset($settings['checkall']['checkall-toggle']) ? $settings['checkall']['checkall-toggle'] : 1,
    '#states' => array(
      'visible' => array(
        ':input[name="instance[settings][checkall][checkall]"]' => array(
          'value' => 1,
        ),
      ),
    ),
  );
  $form['checkall']['checkall-uncheck-all'] = array(
    '#type' => 'checkbox',
    '#title' => 'Show Uncheck All Link',
    '#default_value' => isset($settings['checkall']['checkall-uncheck-all']) ? $settings['checkall']['checkall-uncheck-all'] : 1,
    '#states' => array(
      'visible' => array(
        ':input[name="instance[settings][checkall][checkall]"]' => array(
          'value' => 1,
        ),
      ),
    ),
  );
  return $form;
}

/**
 * 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, $settings = array()) {
  foreach (element_children($elements) as $key) {
    if (isset($elements[$key]) && $elements[$key]) {

      if (isset($checkall)) {
        // Inherit checkall attribute if specified by the caller.
        $children_checkall = $checkall;
        $children_settings = $settings;
      }
      elseif (!empty($elements[$key]['#checkall'])) {
        // Inherit checkall attribute if specified in the form element.
        $children_checkall = $elements[$key]['#checkall'];

        // Enable, but allow overrides
        $elements[$key] += array(
          '#checkall-check-all' => TRUE,
          '#checkall-toggle' => TRUE,
          '#checkall-uncheck-all' => TRUE,
        );

        $children_settings = array(
          'checkall_check_all' => $elements[$key]['#checkall-check-all'],
          'checkall_toggle' => $elements[$key]['#checkall-toggle'],
          'checkall_uncheck_all' => $elements[$key]['#checkall-uncheck-all'],
        );
      }
      else {
        // Assume no checkall attribute has been specified.
        $children_checkall = NULL;
        $children_settings = array();

        // Inherit checkall attribute if specified in CCK field settings.
        if (isset($elements[$key]['#type']) && ($elements[$key]['#type'] == 'container') && isset($elements['#entity']->type)) {
          $field = field_info_instance('node', $key, $elements['#entity']->type);
          if (!empty($field) && isset($field['settings']) && !empty($field['settings']['checkall'])) {
            $children_checkall = TRUE;
            $children_settings = array(
              'checkall_check_all' => $field['settings']['checkall']['checkall-check-all'],
              'checkall_toggle' => $field['settings']['checkall']['checkall-toggle'],
              'checkall_uncheck_all' => $field['settings']['checkall']['checkall-uncheck-all'],
            );
          }
        }
      }

      checkall_form_after_build_recursive($elements[$key], $form_state, $children_checkall, $children_settings);
    }
  }
  if (isset($checkall) && isset($elements['#type']) && $elements['#type'] == 'checkboxes') {
    $elements['#checkall'] = $checkall;
    $elements['#checkall-check-all'] = $children_settings['checkall_check_all'];
    $elements['#checkall-toggle'] = $children_settings['checkall_toggle'];
    $elements['#checkall-uncheck-all'] = $children_settings['checkall_uncheck_all'];
    $elements = checkall_element_process($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'])) {
      $element['#attributes'] = array();
    }
    if (!isset($element['#attributes']['class'])) {
      $element['#attributes']['class'] = array();
    }

    $element['#attributes']['class'][] = 'form-checkall';
    $element['#attributes']['class'][] = $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 (!isset($element[$key]['#attributes']['class'])) {
          $element[$key]['#attributes']['class'] = array();
        }

        $element[$key]['#attributes']['class'][] = $class;
      }
    }

    if (!isset($element['#attached'])) {
      $element['#attached'] = array();
    }
    if (!isset($element['#attached']['css'])) {
      $element['#attached']['css'] = array();
    }
    if (!isset($element['#attached']['js'])) {
      $element['#attached']['js']  = array();
    }

    // Append the unique checkboxes class to Drupal.settings.checkall.
    $element['#attached']['js'][] = array(
      'data' => array('checkall' => array(
        'groups' => $class,
        'show_check_all' => $element['#checkall-check-all'],
        'show_toggle' => $element['#checkall-toggle'],
        'show_uncheck_all' => $element['#checkall-uncheck-all']
      )),
      'type' => 'setting',
    );

    // Add our stylesheet and javascript files to the page.
    $element['#attached']['css'][] = drupal_get_path('module', 'checkall') . '/checkall.css';

    //drupal_add_js(drupal_get_path('module', 'checkall') .'/checkall.js',array('type'=>'file','cache'=>FALSE));
    $element['#attached']['js'][] = drupal_get_path('module', 'checkall') . '/checkall.js';
  }

  return $element;
}