<?php

/**
 * Implements hook_permission().
 */
function entity_view_mode_permission() {
  return array(
    'administer entity view modes' => array(
      'title' => t('Add, edit and delete custom entity view modes.'),
    ),
  );
}

/**
 * Implements hook_entity_info_alter().
 */
function entity_view_mode_entity_info_alter(&$info) {
  foreach (variable_get('entity_view_modes', array()) as $entity_type => $view_modes) {
    if (isset($info[$entity_type]['view modes'])) {
      $info[$entity_type]['view modes'] += $view_modes;
    }
  }
}

/**
 * Implements hook_menu().
 */
function entity_view_mode_menu() {
  $items['admin/config/system/entity-view-modes'] = array(
    'title' => 'Entity view modes',
    'page callback' => 'entity_view_mode_list',
    'access arguments' => array('administer entity view modes'),
    'file' => 'entity_view_mode.admin.inc',
  );
  $items['admin/config/system/entity-view-modes/add/%'] = array(
    'title' => 'Add view mode',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('entity_view_mode_edit_form', 5),
    'access arguments' => array('administer entity view modes'),
    'file' => 'entity_view_mode.admin.inc',
  );
  $items['admin/config/system/entity-view-modes/edit/%/%'] = array(
    'title' => 'Edit view mode',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('entity_view_mode_edit_form', 5, 6),
    'access arguments' => array('administer entity view modes'),
    'file' => 'entity_view_mode.admin.inc',
  );
  $items['admin/config/system/entity-view-modes/delete/%/%'] = array(
    'title' => 'Edit view mode',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('entity_view_mode_delete_form', 5, 6),
    'access arguments' => array('administer entity view modes'),
    'file' => 'entity_view_mode.admin.inc',
  );

  return $items;
}

/**
 * Implements hook_menu_local_tasks_alter() {
 */
//function entity_view_mode_local_tasks_alter(&$data, $router_item, $root_path) {
//}

/**
 * Implements hook_form_FORM_ID_alter().
 */
//function entity_view_mode_field_ui_display_overview_form_alter(&$form, &$form_state) {
//}

/**
 * Load a custom entity view mode by entity type and machine name.
 */
function entity_view_mode_load($entity_type, $machine_name) {
  $view_modes = variable_get('entity_view_modes', array());
  return !empty($view_modes[$entity_type][$machine_name]) ? $view_modes[$entity_type][$machine_name] : FALSE;
}

/**
 * Save a custom entity view mode.
 */
function entity_view_mode_save($entity_type, $view_mode) {
  $existing_view_mode = !empty($view_mode['old_machine_name']) ? $view_mode['old_machine_name'] : $view_mode['machine_name'];

  // Load the stored view mode, if any.
  if (!isset($view_mode['original'])) {
    $view_mode['original'] = entity_view_mode_load($entity_type, $existing_view_mode);
  }

  // Determine if we will be inserting a new view mode.
  if (!isset($view_mode['is_new'])) {
    $view_mode['is_new'] = !empty($view_mode['original']);
  }

  // Let modules modify the view mode before it is saved.
  module_invoke_all('entity_view_mode_presave', $view_mode, $entity_type);

  // Save the view mode.
  $view_modes = variable_get('entity_view_modes', array());
  unset($view_modes[$entity_type][$existing_view_mode]);
  $view_modes[$entity_type][$view_mode['machine_name']] = array_intersect_key($view_mode, drupal_map_assoc(array('label'))) + array('custom settings' => FALSE);
  variable_set('entity_view_modes', $view_modes);

  // Allow modules to respond after the view mode is saved.
  if ($view_mode['is_new']) {
    module_invoke_all('entity_view_mode_insert', $view_mode, $entity_type);
  }
  else {
    module_invoke_all('entity_view_mode_update', $view_mode, $entity_type);
  }

  // Clear internal properties.
  unset($view_mode['original']);
  unset($view_mode['is_new']);

  // Clear the static entity info cache.
  entity_info_cache_clear();
}

function entity_view_mode_delete($entity_type, $machine_name) {
  if ($view_mode = entity_view_mode_load($entity_type, $machine_name)) {
    module_invoke_all('entity_view_mode_delete', $view_mode, $entity_type);

    $view_modes = variable_get('entity_view_modes', array());
    unset($view_modes[$entity_type][$machine_name]);
    variable_set('entity_view_modes', $view_modes);

    // Clear the static entity info cache.
    entity_info_cache_clear();
  }
}