<?php

/**
 * Page callback for viewing a variable entity.
 */
function variable_entity_view($variable_entity) {
  $elements = array();

  $elements['variable'] = array(
    '#type' => 'fieldset',
    '#title' => t('Variable entity @id', array('@id' => $variable_entity->id)),
  );
  $elements['variable']['content'] = array(
    '#prefix' => '<strong>' . t('Variable contents:') . '</strong><div>',
    '#markup' => is_array($variable_entity->variable) ? '<pre>' . print_r($variable_entity->variable, TRUE) . '</pre>' : $variable_entity->variable,
    '#suffix' => '</div>',
  );
  $elements['variable']['fields'] = field_attach_view('variable_entity', $variable_entity, 'full');
  $elements['form'] = drupal_get_form('variable_entity_form', $variable_entity);
  return $elements;
}

/**
 * Page callback for variable entity administration.
 *
 * Actually, just list some links, and a place for the field admin UI to attach a tab.
 */
function variable_entity_admin_page() {
  $elements = array();

  $variables = entity_get_controller('variable_entity')->variables;

  $variable_entity_links = array();
  foreach(array_keys($variables) as $id) {
    $uri = entity_uri('variable_entity', variable_entity_load($id));
    $variable_entity_links[] = l(t('View entity @id', array('@id' => $id)), $uri['path']);
  }

  $elements['variable_list'] = array(
    '#theme' => 'item_list',
    '#title' => t('All variable entities'),
    '#items' => $variable_entity_links,
  );

  return $elements;
}

/**
 * Form callback for a variable entity.
 */
function variable_entity_form($form, &$form_state, $variable_entity) {
  global $conf;
  // save the entity in a fake form property
  $form['#variable_entity'] = $variable_entity;

  $form['variable'] = array(
    '#type' => 'fieldset',
    '#title' => t('Variable entity @id form', array('@id' => $variable_entity->id)),
  );

  $form['variable']['variable_name'] = array(
    '#type' => 'select',
    '#title' => t('Variable name'),
    '#options' => drupal_map_assoc(array_keys($conf)),
    '#default_value' => $variable_entity->variable_name,
  );

  field_attach_form('variable_entity', $variable_entity, $form['variable'], $form_state);

  $form['variable']['actions'] = array('#type' => 'actions');
  $form['variable']['actions']['submit'] = array(
    '#type' => 'submit',
    '#value' => t('Save'),
  );
  return $form;
}

/**
 * Validate the variable entity form.
 */
function variable_entity_form_validate($form, &$form_state) {
  $variable_entity = $form['#variable_entity'];
  field_attach_form_validate('variable_entity', $variable_entity, $form, $form_state);
}

/**
 * Variable form submit callback.
 */
function variable_entity_form_submit($form, &$form_state) {
  $variable_entity = $form['#variable_entity'];

  // update the variable where the entities live
  $variables = entity_get_controller('variable_entity')->variables;
  $variables[$variable_entity->id] = $form_state['values']['variable_name'];
  variable_set('variable_entity', $variables);

  field_attach_submit('variable_entity', $variable_entity, $form, $form_state);
  field_attach_presave('variable_entity', $variable_entity);
  field_attach_update('variable_entity', $variable_entity); 
}