<?php
// $Id: options.module,v 1.26 2010/04/13 15:23:02 dries Exp $

/**
 * @file
 * Defines selection, check box and radio button widgets for text and numeric fields.
 */

/**
 * Implements hook_help().
 */
function options_help($path, $arg) {
  switch ($path) {
    case 'admin/help#options':
      $output = '';
      $output .= '<h3>' . t('About') . '</h3>';
      $output .= '<p>' . t('The Options module defines checkbox, selection, and other input widgets for the Field module. See the <a href="@field-help">Field module help page</a> for more information about fields.', array('@field-help' => url('admin/help/field'))) . '</p>';
      return $output;
  }
}

/**
 * Implements hook_theme().
 */
function options_theme() {
  return array(
    'options_none' => array(
      'variables' => array('instance' => NULL),
    ),
  );
}

/**
 * Implements hook_field_widget_info().
 *
 * Field type modules willing to use those widgets should:
 * - Use hook_field_widget_info_alter() to append their field own types to the
 *   list of types supported by the widgets,
 * - Implement hook_options_list() to provide the list of options.
 * See list.module.
 */
function options_field_widget_info() {
  return array(
    'options_select' => array(
      'label' => t('Select list'),
      'field types' => array(),
      'behaviors' => array(
        'multiple values' => FIELD_BEHAVIOR_CUSTOM,
      ),
    ),
    'options_buttons' => array(
      'label' => t('Check boxes/radio buttons'),
      'field types' => array(),
      'behaviors' => array(
        'multiple values' => FIELD_BEHAVIOR_CUSTOM,
      ),
    ),
    'options_onoff' => array(
      'label' => t('Single on/off checkbox'),
      'field types' => array(),
      'behaviors' => array(
        'multiple values' => FIELD_BEHAVIOR_CUSTOM,
      ),
    ),
  );
}

/**
 * Implements hook_field_widget_form().
 */
function options_field_widget_form(&$form, &$form_state, $field, $instance, $langcode, $items, $delta, $element) {
  // Abstract over the actual field columns, to allow different field types to
  // reuse those widgets.
  $value_key = key($field['columns']);

  $type = str_replace('options_', '', $instance['widget']['type']);
  $multiple = $field['cardinality'] > 1 || $field['cardinality'] == FIELD_CARDINALITY_UNLIMITED;
  $required = $element['#required'];
  $properties = _options_properties($type, $multiple, $required);

  // Prepare the list of options.
  $options = _options_get_options($field, $instance, $properties);

  // Put current field values in shape.
  $default_value = _options_storage_to_form($items, $options, $value_key, $properties);

  switch ($type) {
    case 'select':
      $element += array(
        '#type' => 'select',
        '#default_value' => $default_value,
        // Do not display a 'multiple' select box if there is only one option.
        '#multiple' => $multiple && count($options) > 1,
        '#options' => $options,
      );
      break;

    case 'buttons':
      // If required and there is one single option, preselect it.
      if ($required && count($options) == 1) {
        reset($options);
        $default_value = array(key($options));
      }
      $element += array(
        '#type' => $multiple ? 'checkboxes' : 'radios',
        // Radio buttons need a scalar value.
        '#default_value' => $multiple ? $default_value : reset($default_value),
        '#options' => $options,
      );
      break;

    case 'onoff':
      $keys = array_keys($options);
      $off_value = array_shift($keys);
      $on_value = array_shift($keys);
      $element += array(
        '#type' => 'checkbox',
        '#default_value' => (isset($default_value[0]) && $default_value[0] == $on_value) ? 1 : 0,
        '#on_value' => $on_value,
        '#off_value' => $off_value,
      );
      // Override the title from the incoming $element.
      $element['#title'] = isset($options[$on_value]) ? $options[$on_value] : '';
      break;
  }

  $element += array(
    '#value_key' => $value_key,
    '#element_validate' => array('options_field_widget_validate'),
    '#properties' => $properties,
  );

  return $element;
}

/**
 * Form element validation handler for options element.
 */
function options_field_widget_validate($element, &$form_state) {
  // Transpose selections from field => delta to delta => field, turning
  // multiple selected options into multiple parent elements.
  $items = _options_form_to_storage($element);
  form_set_value($element, $items, $form_state);
}

/**
 * Describes the preparation steps required by each widget.
 */
function _options_properties($type, $multiple, $required) {
  $base = array(
    'zero_placeholder' => FALSE,
    'filter_xss' => FALSE,
    'strip_tags' => FALSE,
    'empty_value' => FALSE,
    'optgroups' => FALSE,
  );

  $properties = array();

  switch ($type) {
    case 'select':
      $properties = array(
        // Select boxes do not support any HTML tag.
        'strip_tags' => TRUE,
        'empty_value' => !$required,
        'optgroups' => TRUE,
      );
      break;

    case 'buttons':
      $properties = array(
        'filter_xss' => TRUE,
        // Form API 'checkboxes' do not suport 0 as an option, so we replace it with
        // a placeholder within the form workflow.
        'zero_placeholder' => $multiple,
        // Checkboxes do not need a 'none' choice.
        'empty_value' => !$required && !$multiple,
      );
      break;

    case 'onoff':
      $properties = array(
        'filter_xss' => TRUE,
      );
      break;
  }

  return $properties + $base;
}

/**
 * Collects the options for a field.
 */
function _options_get_options($field, $instance, $properties) {
  // Get the list of options.
  $options = (array) module_invoke($field['module'], 'options_list', $field);

  // Sanitize the options.
  _options_prepare_options($options, $properties);

  if (!$properties['optgroups']) {
    $options = options_array_flatten($options);
  }

  if ($properties['empty_value']) {
    $options = array('_none' => theme('options_none', array('instance' => $instance))) + $options;
  }

  return $options;
}

/**
 * Sanitizes the options.
 *
 * The function is recursive to support optgroups.
 */
function _options_prepare_options(&$options, $properties) {
  // Substitute the '_0' placeholder.
  if ($properties['zero_placeholder']) {
    $values = array_keys($options);
    $labels = array_values($options);
    // Use a strict comparison, because 0 == 'any string'.
    $index = array_search(0, $values, TRUE);
    if ($index !== FALSE && !is_array($options[$index])) {
      $values[$index] = '_0';
      $options = array_combine($values, $labels);
    }
  }

  foreach ($options as $value => $label) {
    // Recurse for optgroups.
    if (is_array($label)) {
      _options_prepare_options($options[$value], $properties);
    }
    else {
      if ($properties['strip_tags']) {
        $options[$value] = strip_tags($label);
      }
      if ($properties['filter_xss']) {
        $options[$value] = field_filter_xss($label);
      }
    }
  }
}

/**
 * Transforms stored field values into the format the widgets need.
 */
function _options_storage_to_form($items, $options, $column, $properties) {
  $items_transposed = options_array_transpose($items);
  $values = (isset($items_transposed[$column]) && is_array($items_transposed[$column])) ? $items_transposed[$column] : array();

  // Substitute the '_0' placeholder.
  if ($properties['zero_placeholder']) {
    $index = array_search('0', $values);
    if ($index !== FALSE) {
      $values[$index] = '_0';
    }
  }

  // Discard values that are not in the current list of options. Flatten the
  // array if needed.
  if ($properties['optgroups']) {
    $options = options_array_flatten($options);
  }
  $values = array_values(array_intersect($values, array_keys($options)));
  return $values;
}

/**
 * Transforms submitted form values into field storage format.
 */
function _options_form_to_storage($element) {
  $values = array_values((array) $element['#value']);
  $properties = $element['#properties'];

  // On/off checkbox: transform '0 / 1' into the 'on / off' values.
  if ($element['#type'] == 'checkbox') {
    $values = array($values[0] ? $element['#on_value'] : $element['#off_value']);
  }

  // Substitute the '_0' placeholder.
  if ($properties['zero_placeholder']) {
    $index = array_search('_0', $values);
    if ($index !== FALSE) {
      $values[$index] = 0;
    }
  }

  // Filter out the 'none' option. Use a strict comparison, because
  // 0 == 'any string'.
  if ($properties['empty_value']) {
    $index = array_search('_none', $values, TRUE);
    if ($index !== FALSE) {
      unset($values[$index]);
    }
  }

  // Make sure we populate at least an empty value.
  if (empty($values)) {
    $values = array(NULL);
  }

  $result = options_array_transpose(array($element['#value_key'] => $values));
  return $result;
}

/**
 * Manipulates a 2D array to reverse rows and columns.
 *
 * The default data storage for fields is delta first, column names second.
 * This is sometimes inconvenient for field modules, so this function can be
 * used to present the data in an alternate format.
 *
 * @param $array
 *   The array to be transposed. It must be at least two-dimensional, and
 *   the subarrays must all have the same keys or behavior is undefined.
 * @return
 *   The transposed array.
 */
function options_array_transpose($array) {
  $result = array();
  if (is_array($array)) {
    foreach ($array as $key1 => $value1) {
      if (is_array($value1)) {
        foreach ($value1 as $key2 => $value2) {
          if (!isset($result[$key2])) {
            $result[$key2] = array();
          }
          $result[$key2][$key1] = $value2;
        }
      }
    }
  }
  return $result;
}

/**
 * Flattens an array of allowed values.
 *
 * @param $array
 *   A single or multidimensional array.
 * @return
 *   A flattened array.
 */
function options_array_flatten($array) {
  $result = array();
  if (is_array($array)) {
    foreach ($array as $key => $value) {
      if (is_array($value)) {
        $result += options_array_flatten($value);
      }
      else {
        $result[$key] = $value;
      }
    }
  }
  return $result;
}

/**
 * Implements hook_field_widget_error().
 */
function options_field_widget_error($element, $error, $form, &$form_state) {
  form_error($element, $error['message']);
}

/**
 * Returns HTML for the label for the empty value for options that are not required.
 *
 * The default theme will display N/A for a radio list and blank for a select.
 *
 * @param $variables
 *   An associative array containing:
 *   - instance: An array representing the widget requesting the options.
 *
 * @ingroup themeable
 */
function theme_options_none($variables) {
  $instance = $variables['instance'];
  switch ($instance['widget']['type']) {
    case 'options_buttons':
      return t('N/A');
    case 'options_select':
      return t('- None -');
    default :
      return '';
  }
}
