view_mode_selector.module

<?php

/**
 * @file
 * Main file of View Mode Selector module.
 */

/**
 * Implements hook_field_info().
 */
function view_mode_selector_field_info() {
  return array(
    'view_mode_selector' => array(
      'label' => t('View mode selector'),
      'description' => t('Stores the view mode of the entity.'),
      'instance_settings' => array(
        'number_placeholders' => FALSE,
        'view_modes' => array(),
      ),
      'default_widget' => 'view_mode_selector_select',
      'default_formatter' => 'view_mode_selector',
    ),
  );
}


/**
 * Implements hook_migrate_api().
 */
function view_mode_selector_migrate_api() {
  $api = array(
    'api' => 2,
    'field handlers' => array(
      'MigrateViewModeSelectorValueFieldHandler',
    ),
  );

  return $api;
}

/**
 * Implements hook_field_is_empty().
 */
function view_mode_selector_field_is_empty($item, $field) {
  return !(bool) $item['value'];
}

/**
 * Implements hook_field_instance_settings_form().
 */
function view_mode_selector_field_instance_settings_form($field, $instance) {
  $form = array();
  $settings = $instance['settings'];

  $form['number_placeholders'] = array(
      '#type' => 'checkbox',
      '#title' => t('Number HTML preview placeholders'),
      '#description' => t('Adds the count/delta to the preview placeholders.'),
      '#access' => $instance['widget']['type'] == 'view_mode_selector_radios',
      '#default_value' => isset($settings['number_placeholders']) ? $settings['number_placeholders'] : FALSE,
  );

  // Get all view modes of the entity type.
  $view_modes = view_mode_selector_view_modes($instance['entity_type']);

  foreach ($view_modes as $view_mode_name => $view_mode) {
    if (!isset($form['view_modes'])) {
      $form['view_modes'] = array(
        '#type' => 'fieldset',
        '#title' => t('Available view modes'),
        '#attributes' => array('class' => array('view-mode-selector-view-modes')),
        '#attached' => array(
          'css' => array(
            drupal_get_path('module', 'view_mode_selector') . '/css/view-mode-selector.css',
          ),
        ),
      );
    }

    $form['view_modes'][$view_mode_name]['enable'] = array(
      '#type' => 'checkbox',
      '#title' => $view_mode['label'] . ' (' . $view_mode_name . ')',
      '#default_value' => isset($settings['view_modes'][$view_mode_name]['enable']) ? $settings['view_modes'][$view_mode_name]['enable'] : FALSE,
    );

    // Allow uploading an icon and hide the title for view modes when radio widget is used.
    if ($instance['widget']['type'] == 'view_mode_selector_radios') {
      $form['view_modes'][$view_mode_name]['prefix']['#markup'] = '<div class="settings">';

      $form['view_modes'][$view_mode_name]['hide_title'] = array(
        '#type' => 'checkbox',
        '#title' => t('Hide title'),
        '#default_value' => isset($settings['view_modes'][$view_mode_name]['hide_title']) ? $settings['view_modes'][$view_mode_name]['hide_title'] : FALSE,
        '#states' => array(
          'visible' => array(
            'input[name="instance[settings][view_modes][' . $view_mode_name . '][enable]"]' => array('checked' => TRUE),
          ),
        )
      );

      $form['view_modes'][$view_mode_name]['icon'] = array(
        '#type' => 'managed_file',
        '#title' => t('Icon'),
        '#description' => t('An icon which can be used for a view mode preview.'),
        '#upload_location' => 'public://view-mode-selector/' . $instance['entity_type'],
        '#default_value' => isset($settings['view_modes'][$view_mode_name]['icon']) ? $settings['view_modes'][$view_mode_name]['icon'] : 0,
        '#states' => array(
          'visible' => array(
            'input[name="instance[settings][view_modes][' . $view_mode_name . '][enable]"]' => array('checked' => TRUE),
          ),
        ),
      );
      $form['view_modes'][$view_mode_name]['suffix']['#markup'] = '</div>';
    }
  }

  // Inform the user about the layout preview feature.
  if ($instance['widget']['type'] == 'view_mode_selector_radios' && module_exists('ds')) {
    $form['view_modes']['#description'] = t('It is possible to upload an icon in this widget but when you do not upload an icon a real preview of the view mode is displayed instead.');
  }

  return $form;
}

/**
 * Implements hook_field_widget_info().
 */
function view_mode_selector_field_widget_info() {
  return array(
    'view_mode_selector_select' => array(
      'label' => t('Select list'),
      'field types' => array('view_mode_selector'),
    ),
    'view_mode_selector_radios' => array(
      'label' => t('Radio buttons'),
      'field types' => array('view_mode_selector'),
      'weight' => 1,
    ),
  );
}

/**
 * Implements hook_field_widget_form().
 */
function view_mode_selector_field_widget_form(&$form, &$form_state, $field, $instance, $langcode, $items, $delta, $element) {
  $entity_type = $instance['entity_type'];
  $entity_bundle = $instance['bundle'];

  $element['value'] = $element + array(
    '#type' => 'select',
    '#options' => array(),
    '#default_value' => isset($items[$delta]['value']) ? $items[$delta]['value'] : NULL,
    '#attached' => array(
      'css' => array(
        drupal_get_path('module', 'view_mode_selector') . '/css/view-mode-selector.css',
      ),
    ),
  );

  // Get all view modes of the entity type.
  $view_modes = view_mode_selector_view_modes($entity_type);

  // Gather enabled view modes.
  foreach ($view_modes as $view_mode => $view_mode_settings) {
    if (isset($instance['settings']['view_modes'][$view_mode]) && $instance['settings']['view_modes'][$view_mode]['enable']) {
      $label = $view_modes[$view_mode]['label'];
      $element['value']['#options'][$view_mode] = $label;
    }
  }

  // Show all view modes in widget when no view modes are enabled.
  if (!count($element['value']['#options'])) {
    foreach ($view_modes as $view_mode => $view_mode_settings) {
      $label = $view_modes[$view_mode]['label'];
      $element['value']['#options'][$view_mode] = $label;
    }
  }

  // Cut out all view modes with Display Suite layouts with regions.
  if (module_exists('ds')) {
    $ds_view_modes = array();

    foreach ($element['value']['#options'] as $view_mode => $view_mode_label) {
      $layout = ds_get_layout($entity_type, $entity_bundle, $view_mode);

      if (!$layout || !isset($layout['settings']['regions'])) {
        continue;
      }

      $ds_view_modes[$view_mode] = array(
        'label' => $element['value']['#options'][$view_mode],
        'layout' => $layout
      );
      unset($element['value']['#options'][$view_mode]);
    }

    // Sort Display Suite view modes by number of regions.
    uasort($ds_view_modes, '_view_mode_selector_sort_by_region_count');

    // Append the sorted view modes to the field options.
    foreach ($ds_view_modes as $view_mode => $ds_view_mode) {
      $element['value']['#options'][$view_mode] = $ds_view_mode['label'];
    }
  }

  // Icon support for radio widget.
  if ($instance['widget']['type'] == 'view_mode_selector_radios') {
    $element['value']['#type'] = 'radios';

    // Override label with preview or icon if available.
    foreach ($element['value']['#options'] as $view_mode => $view_mode_label) {
      $output = array();

      if (!empty($instance['settings']['view_modes'][$view_mode]['icon'])) {
        $icon = file_load($instance['settings']['view_modes'][$view_mode]['icon']);

        if (!$icon) {
          continue;
        }

        $output[] = theme('image', array(
          'path' => file_create_url($icon->uri),
          'attributes' => array(
            'title' => $view_modes[$view_mode]['label'],
          ),
        ));
      }
      // When Display Suite is installed we can show a nice preview.
      elseif (module_exists('ds') && isset($ds_view_modes[$view_mode])) {
        $layout = $ds_view_modes[$view_mode]['layout'];

        // Create a new empty entity for the preview.
        $entity_properties = array('type' => $entity_bundle, 'id' => FALSE);
        $entity = entity_create($entity_type, $entity_properties);
        $entity_view = entity_view($entity_type, array($entity), $view_mode);

        // Render one field containing a placeholder <div> in every region.
        $count = 0;
        foreach ($layout['settings']['regions'] as $region_settings) {
          foreach ($region_settings as $field) {
            $count++;
            $entity_view[$entity_type][0][$field] = array(
              '#type' => 'html_tag',
              '#tag' => 'div',
              '#value' => $instance['settings']['number_placeholders'] ? $count : '',
              '#attributes' => array('class' => 'placeholder'),
              '#field_name' => $field,
            );

            continue;
          }
        }

        // Disable contextual links.
        $entity_view[$entity_type][0]['#contextual_links'] = FALSE;

        // Render the preview.
        $output[] = drupal_render($entity_view);
      }
      else {
        $element['value'][$view_mode]['#attributes']['class'][] = 'no-preview';
      }

      // Render the title.
      if (isset($instance['settings']['view_modes'][$view_mode]['hide_title']) && !$instance['settings']['view_modes'][$view_mode]['hide_title']) {
        $output[] = '<small>' . $view_modes[$view_mode]['label'] . '</small>';
      };

      // Use the generated markup as our label value.
      $element['value']['#options'][$view_mode] = implode($output, '');
    }
  }

  return $element;
}

/**
 * Implements hook_field_formatter_info().
 */
function view_mode_selector_field_formatter_info() {
  return array(
    'view_mode_selector' => array(
      'label' => t('Default'),
      'field types' => array('view_mode_selector'),
    ),
  );
}

/**
 * Implements hook_field_formatter_view().
 */
function view_mode_selector_field_formatter_view($entity_type, $entity, $field, $instance, $langcode, $items, $display) {
  $element = array();

  switch ($display['type']) {
    case 'view_mode_selector':
      foreach ($items as $delta => $item) {
        $element[$delta] = array(
          '#markup' => $item['value'],
        );

        return $element;
      }
      break;
  }

  return $element;
}

/**
 * Implements hook_form_FORM_ID_alter().
 */
function view_mode_selector_form_field_ui_field_edit_form_alter(&$form, &$form_state, $form_id) {
  if ($form['#field']['type'] == 'view_mode_selector') {
    // Don't allow more than one value for a view mode selector field.
    $form['field']['cardinality']['#access'] = FALSE;
    $form['field']['cardinality']['#value'] = 1;
  }
}

/**
 * Implements hook_entity_view_mode_alter().
 */
function view_mode_selector_entity_view_mode_alter(&$view_mode, $context) {
  if ($view_mode !== 'view_mode_selector') {
    return;
  }
  
  list(, , $bundle) = entity_extract_ids($context['entity_type'], $context['entity']);
  $fields_info = field_info_instances($context['entity_type'], $bundle);

  // Set view mode to 'Default', this is for entites without
  // a view mode selector field.
  $view_mode = 'default';

  // Find a view mode selector field and change the view mode.
  foreach ($fields_info as $field_name => $value) {
    $field_info = field_info_field($field_name);

    if ($field_info['type'] == 'view_mode_selector') {
      $items = field_get_items($context['entity_type'], $context['entity'], $field_info['field_name']);

      if ($items) {
        $value = $items[0]['value'];

        if ($value) {
          $view_mode = $value;

          // It would not make sense to have multiple view mode selector
          // fields so stop after the first was found.
          return;
        }
      }
    }
  }
}

/**
 * Implements hook_entity_info_alter().
 */
function view_mode_selector_entity_info_alter(&$entity_info) {
  $field_infos = field_info_field_map();

  // Create a 'View mode selector' view mode in every bundle.
  foreach ($field_infos as $field_info) {
    if ($field_info['type'] == 'view_mode_selector') {
      foreach (array_keys($field_info['bundles']) as $bundle) {
        $entity_info[$bundle]['view modes']['view_mode_selector'] = array(
          'label' => t('View mode selector'),
          'custom settings' => FALSE,
        );
      }
    }
  }
}

/**
 * Implements hook_form_field_ui_display_overview_form_alter().
 */
function view_mode_selector_form_field_ui_display_overview_form_alter(&$form, &$form_state) {
  if ($form['#view_mode'] == 'view_mode_selector') {
    drupal_set_message(t('This is a placeholder view mode from the <a href="@view-mode-selector">View Mode Selector</a> module. It will be replaced with a selected view mode.', array(
      '@view-mode-selector' => url('https://www.drupal.org/project/view_mode_selector'),
    )), 'status');
    drupal_set_message(t('Make sure that all fields are visible in order to get access to them.'), 'warning');

    // @TODO Make all fields visible programmatically.
  }
}

/**
 * Helper function which returns all view modes of an entity type.
 *
 * @param string $entity_type
 *   The specific entity type.
 *
 * @return array
 *   An array containing all view modes of the entity type.
 */
function view_mode_selector_view_modes($entity_type) {
  $entity_info = entity_get_info($entity_type);

  // Add 'Default' view mode to all view modes in order
  // to allow switching to it.
  $view_modes = array(
    'default' => array(
      'label' => t('Default'),
      'custom settings' => TRUE,
    ),
  ) + $entity_info['view modes'];

  // The 'View mode selector' view mode is only for allow switching.
  unset($view_modes['view_mode_selector']);

  return $view_modes;
}

/**
 * Sort function to order Display Suite view modes by number of regions.
 */
function _view_mode_selector_sort_by_region_count($a, $b) {
  return count($a['layout']['settings']['regions']) - count($b['layout']['settings']['regions']);
}