<?php

/**
 * @file
 * Provides an option to hide CER fields on inline entity forms. Spun off
 * from Issue #2240371.
 */

/**
 * Implements hook_form_FORM_ID_alter().
 */
function cer_ief_form_field_ui_field_edit_form_alter(array &$form, array &$form_state) {
  // Add option to hide corresponding entity reference fields on inline entity
  // forms, even if the field instance isn't part of any CER preset.
  $instance = $form['#instance'];

  if (in_array($instance['widget']['type'], array('inline_entity_form', 'inline_entity_form_single'))) {
    $settings = &$form['instance']['widget']['settings']['type_settings'];

    $settings['hide_cer_fields'] = array(
      '#type' => 'checkbox',
      '#title' => t('Hide corresponding entity reference field(s) on form.'),
      '#default_value' => !empty($instance['widget']['settings']['type_settings']['hide_cer_fields']),
    );
  }
}

/**
 * Implements hook_field_widget_form_alter().
 *
 * @todo This could be cached into an array and only rebuilt when a contextual
 * field instance is updated or CER pattern added/removed.
 */
function cer_ief_field_widget_form_alter(array &$element, array &$form_state, array $context) {
  // If this widget form isn't in an IEF, bail out.
  if (! isset($context['form']['#ief_id'])) {
    return;
  }

  // Get the form ID.
  $ief_id = $context['form']['#ief_id'];

  // Get instance information for the IEF field.
  $ief_field_instance = $form_state['inline_entity_form'][$ief_id]['instance'];

  // The left chain is the field that *has* the IEF, and the right chain is the
  // field *in* the IEF.
  $left_chain = $ief_field_instance['entity_type'] . ':' . $ief_field_instance['bundle'] . ':' . $ief_field_instance['field_name'];
  $right_chain = $context['instance']['entity_type'] . ':' . $context['instance']['bundle'] . ':' . $context['instance']['field_name'];

  // Check if "hide" is enabled on the IEF that is holding this field.
  $hide_cer_fields = !empty($ief_field_instance['widget']['settings']['type_settings']['hide_cer_fields']);
  if ($hide_cer_fields) {
    $finder = new CerPresetFinder();
    $element['#access'] = !($finder->find($left_chain, $right_chain)->count()->execute() || $finder->find($right_chain, $left_chain, TRUE)->count()->execute());
  }
}