<?php

/**
 * @file
 * Relation endpoints field.
 */

/**
 * Implements hook_field_info().
 */
function relation_endpoint_field_info() {
  return array(
    'relation_endpoint' => array(
      'label' => t('Relation endpoint'),
      'description' => t('This field contains the endpoints of the relation'),
      'default_widget' => 'relation_endpoint',
      'default_formatter' => 'relation_endpoint',
      'entity types' => array('relation'),
      'no_ui' => TRUE,
    ),
  );
}

/**
 * Implements hook_field_validate().
 */
function relation_endpoint_field_validate($entity_type, $entity, $field, $instance, $langcode, $items, &$errors) {
  $relation_type = relation_type_load($entity->relation_type);
  // Check that relation_type exists.
  if (!$relation_type) {
    $errors[] = array(
      'error' => 'relation_nonexistent_type',
      'message' => t("The !relation_type relation type does not exist.", array('!relation_type' => $entity->relation_type)),
    );
  }
  // Check for unique flag.
  if ($relation_type->r_unique) {
    if (relation_relation_exists($items, $relation_type->relation_type)) {
      $errors[] = array(
        'error' => 'relation_already_exists',
        'message' => t("The !relation_type is unique but the relation already exists.", array('!relation_type' => $entity->relation_type)),
      );
    }
  }

  // Check that arity is within acceptable bounds.
  if (count($items) < $relation_type->min_arity && empty($entity->in_progress)) {
    $errors[] = array(
      'error' => 'relation_too_few_endpoints',
      'message' => t("Relation has too few end points (:relation_type min arity :min_arity)", array(':relation_type' => $entity->relation_type, ':min_arity' => $relation_type->min_arity)),
    );
  }
  if ($relation_type->max_arity && count($items) > $relation_type->max_arity) {
    $errors[] = array(
      'error' => 'relation_too_many_endpoints',
      'message' => t("Relation has too many end points (:relation_type max arity :max_arity)", array(':relation_type' => $entity->relation_type, ':max_arity' => $relation_type->max_arity)),
    );
  }
  //Check that each entity is has acceptable bundle type and index.
  foreach ($items as $delta => $item) {
    $acceptable = FALSE;
    $directional = $relation_type->directional;
    $endpoint = ($directional && ($delta > 0)) ? 'target' : 'source';
    $end_bundles = $endpoint . '_bundles';
    foreach ($relation_type->$end_bundles as $relation_bundle) {
      if (!isset($item['entity_bundle'])) {
        $endpoint_entities = entity_load($item['entity_type'], array($item['entity_id']));
        $endpoint_entity = reset($endpoint_entities);
        list(, , $item['entity_bundle']) = entity_extract_ids($item['entity_type'], $endpoint_entity);
      }
      $relation_bundle_array = explode(':', $relation_bundle, 2);
      if (($relation_bundle == $item['entity_type'] . ':' . $item['entity_bundle']) || (($item['entity_type'] == $relation_bundle_array[0]) && ($relation_bundle_array[1] == '*'))) {
        $acceptable = TRUE;
        break;
      }
    }
    if (!$acceptable) {
      $t_arguments = array('%relation_type' => $entity->relation_type, '@bundle' => $item['entity_bundle']);
      if ($relation_type->directional) {
        if ($endpoint == 'target') {
          $errors[] = array(
            'error' => 'relation_unsupported_target',
            'message' => t("The %relation_type relation type does not allow @bundle entities as target.", $t_arguments),
          );
        }
        else {
          $errors[] = array(
            'error' => 'relation_unsupported_source',
            'message' => t("The %relation_type relation type does not allow @bundle entities as source.", $t_arguments),
          );
        }
      }
      else {
        $errors[] = array(
          'error' => 'relation_unsupported_endpoint',
          'message' => t("The %relation_type relation type does not allow @bundle entities as an endpoint.", $t_arguments),
        );
      }
    }
  }
}

/**
 * Implements hook_field_presave().
 */
function relation_endpoint_field_presave($entity_type, $entity, $field, $instance, $langcode, &$items) {
  // We need r_index here because EntityFieldQuery can't query on deltas.
  foreach ($items as $delta => &$item) {
    $item['r_index'] = $delta;
  }
}

/**
 * Implements hook_field_update().
 */
function relation_endpoint_field_update($entity_type, $entity, $field, $instance, $langcode, &$items) {
  // We do not update.
}

/**
 * Implements hook_field_is_empty().
 */
function relation_endpoint_field_is_empty($item, $field) {
  // We are never empty.
  return FALSE;
}

/**
 * Helper to create an HTML table representing a relation.
 */
function _relation_endpoint_field_create_html_table($endpoints) {
  $list_items = array();
  foreach ($endpoints as $delta => $endpoint) {
    $entities = entity_load($endpoint['entity_type'], array($endpoint['entity_id']));
    $entity = reset($entities);
    $label = entity_label($endpoint['entity_type'], $entity);
    $uri = entity_uri($endpoint['entity_type'], $entity);
    $list_items[$delta] = array(l($label, $uri['path'], $uri['options']), $endpoint['entity_type']);
  }
  $headers = array(
    'Entity',
    array('width' => '22%', 'data' => 'Entity_type'),
  );
  return array(
    '#theme' => 'table',
    '#header' => $headers,
    '#rows' => $list_items,
  );
}

/**
 * Implements hook_field_formatter_info().
 */
function relation_endpoint_field_formatter_info() {
  return array(
    'relation_endpoint' => array(
      'label' => t('Endpoints table'),
      'field types' => array('relation_endpoint'),
    ),
  );
}

/**
 * Implements hook_field_widget_info().
 */
function relation_endpoint_field_widget_info() {
  return array(
    'relation_endpoint' => array(
      'label' => t('Endpoints table'),
      'field types' => array('relation_endpoint'),
      'behaviors' => array(
        'multiple values' => FIELD_BEHAVIOR_CUSTOM,
      ),
    ),
  );
}

/**
 * Implements hook_field_formatter_view().
 */
function relation_endpoint_field_formatter_view($entity_type, $entity, $field, $instance, $langcode, $items, $display) {
  return array(_relation_endpoint_field_create_html_table($items));
}

/**
 * Implements hook_field_widget_form().
 */
function relation_endpoint_field_widget_form(&$form, &$form_state, $field, $instance, $langcode, $items, $delta, $element) {
  foreach ($items as $delta => $item) {
    foreach (array('entity_type', 'entity_id') as $column) {
      $element[$delta][$column] = array(
        '#type' => 'value',
        '#value' => $item[$column],
      );
    }
  }
  $element['link_list'] = _relation_endpoint_field_create_html_table($items);
  return $element;
}

/**
 * Implements hook_form_field_ui_field_overview_form_alter().
 */
function relation_endpoint_form_field_ui_field_overview_form_alter(&$form, $form_state) {
  // Deleting endpoints would make the module useless.
  if ($form['#entity_type'] == 'relation') {
    $form['fields']['endpoints']['delete'] = array(
      '#type' => 'markup',
      '#markup' => '&nbsp;',
    );
  }
}