<?php

/**
 * @file
 * Provides views data for the dynamic_entity_reference module.
 */

use Drupal\Core\Entity\FieldableEntityInterface;
use Drupal\Core\Entity\Sql\SqlEntityStorageInterface;
use Drupal\dynamic_entity_reference\Plugin\Field\FieldType\DynamicEntityReferenceItem;
use Drupal\field\FieldStorageConfigInterface;

/**
 * Implements hook_field_views_data().
 */
function dynamic_entity_reference_field_views_data(FieldStorageConfigInterface $field_storage) {
  $data = views_field_default_views_data($field_storage);
  $entity_manager = \Drupal::entityTypeManager();
  $labels = \Drupal::service('entity_type.repository')->getEntityTypeLabels(TRUE);
  $options = array_keys($labels[(string) t('Content', [], ['context' => 'Entity type group'])]);
  $settings = $field_storage->getSettings();
  // Identify all the target entity type ids that can be referenced.
  if ($settings['exclude_entity_types']) {
    $target_entity_type_ids = array_diff($options, $settings['entity_type_ids'] ?: []);
  }
  else {
    $target_entity_type_ids = array_intersect($options, $settings['entity_type_ids'] ?: []);
  }
  foreach ($data as $table_name => $table_data) {
    // Add a relationship to all the target entity types.
    foreach ($target_entity_type_ids as $target_entity_type_id) {
      if ($entity_manager->hasHandler($target_entity_type_id, 'views_data')) {
        $target_entity_type = $entity_manager->getDefinition($target_entity_type_id);
        $entity_type_id = $field_storage->getTargetEntityTypeId();
        $entity_type = $entity_manager->getDefinition($entity_type_id);
        $target_base_table = $entity_manager->getHandler($target_entity_type_id, 'views_data')
          ->getViewsTableForEntityType($target_entity_type);
        $field_name = $field_storage->getName();

        // Provide a relationship for the entity type with the dynamic entity
        // reference field.
        $args = [
          '@label' => $target_entity_type->getLabel(),
          '@field_name' => $field_name,
        ];
        $data[$table_name][$target_entity_type_id . '__' . $field_name]['relationship'] = [
          'title' => t('@label referenced from @field_name', $args),
          'label' => t('@field_name: @label', $args),
          'group' => $entity_type->getLabel(),
          'help' => t('Appears in: @bundles.', [
            '@bundles' => implode(', ', $field_storage->getBundles()),
          ]),
          'id' => 'standard',
          'base' => $target_base_table,
          'entity type' => $target_entity_type_id,
          'base field' => $target_entity_type->getKey('id'),
          'relationship field' => $field_name . '_target_id',
          // Entity reference field only has one target type whereas dynamic
          // entity reference field can have multiple target types that is why
          // an extra join condition on target types is needed.
          'extra' => [
            [
              'left_field' => $field_name . '_target_type',
              'value' => $target_entity_type_id,
            ],
          ],
        ];

        // Provide a reverse relationship for the entity type that is referenced
        // by the field.
        $pseudo_field_name = 'reverse__' . $entity_type_id . '__' . $field_name;
        /** @var \Drupal\Core\Entity\Sql\DefaultTableMapping $table_mapping */
        $table_mapping = $entity_manager->getStorage($entity_type_id)
          ->getTableMapping();
        $args['@entity'] = $entity_type->getLabel();
        $args['@label'] = $target_entity_type->getSingularLabel();
        $data[$target_base_table][$pseudo_field_name]['relationship'] = [
          'title' => t('@entity using @field_name', $args),
          'label' => t('@field_name', ['@field_name' => $field_name]),
          'group' => $target_entity_type->getLabel(),
          'help' => t('Relate each @entity with a @field_name set to the @label.', $args),
          'id' => 'entity_reverse',
          'base' => $entity_manager->getHandler($entity_type_id, 'views_data')
            ->getViewsTableForEntityType($entity_type),
          'entity_type' => $entity_type_id,
          'base field' => $entity_type->getKey('id'),
          'field_name' => $field_name,
          'field table' => $table_mapping->getDedicatedDataTableName($field_storage),
          'field field' => $field_name . '_target_id',
          // Entity reference field only has one target type whereas dynamic
          // entity reference field can have multiple target types that is why
          // an extra join condition on target types is needed.
          'join_extra' => [
            [
              'field' => $field_name . '_target_type',
              'value' => $target_entity_type_id,
            ],
            [
              'field' => 'deleted',
              'value' => 0,
              'numeric' => TRUE,
            ],
          ],
        ];
      }
    }
  }

  return $data;
}

/**
 * Implements hook_views_data().
 *
 * Adds relationships for dynamic_entity_reference base fields.
 *
 * @todo remove this when https://www.drupal.org/node/2337515 is in.
 */
function dynamic_entity_reference_views_data() {
  $entity_manager = \Drupal::entityTypeManager();

  /** @var \Drupal\Core\Entity\EntityTypeInterface[] $entity_types */
  $entity_types = [];
  $sql_entity_types = [];
  $fields_all = [];
  // Ensure origin and target entity types are SQL.
  foreach ($entity_manager->getDefinitions() as $entity_type) {
    // \Drupal\views\EntityViewsData class only allows entities with
    // \Drupal\Core\Entity\Sql\SqlEntityStorageInterface.
    if ($entity_type->hasHandlerClass('views_data') && $entity_manager->getStorage($entity_type->id()) instanceof SqlEntityStorageInterface) {
      $sql_entity_types[$entity_type->id()] = $entity_type->id();
      // Only fieldable entities have base fields.
      if ($entity_type->entityClassImplements(FieldableEntityInterface::class)) {
        $entity_types[$entity_type->id()] = $entity_type;
        $entity_field_manager = \Drupal::service('entity_field.manager');
        foreach ($entity_field_manager->getBaseFieldDefinitions($entity_type->id()) as $base_field) {
          if ($base_field->getType() == 'dynamic_entity_reference' && !$base_field->isComputed()) {
            $fields_all[$entity_type->id()][] = $base_field;
          }
        }
      }
    }
  }

  $data = [];
  foreach ($fields_all as $entity_type_id => $fields) {
    /** @var \Drupal\Core\Entity\Sql\DefaultTableMapping $table_mapping */
    $table_mapping = $entity_manager->getStorage($entity_type_id)->getTableMapping();

    $entity_type = $entity_types[$entity_type_id];
    $base_table = $entity_manager->getHandler($entity_type_id, 'views_data')->getViewsTableForEntityType($entity_type);

    /** @var \Drupal\Core\Field\BaseFieldDefinition[] $fields */
    foreach ($fields as $field) {
      $field_name = $field->getName();
      $columns = $table_mapping->getColumnNames($field_name);
      $column_id = $columns['target_id'];
      $column_type = $columns['target_type'];

      // Unlimited (-1) or > 1 store field data in a dedicated table.
      $table = $field->getCardinality() == 1 ? $base_table : $entity_type->getBaseTable() . '__' . $field_name;
      // Filter out non SQL entity types because \Drupal\views\EntityViewsData
      // class only allows entities with
      // \Drupal\Core\Entity\Sql\SqlEntityStorageInterface.
      $targets = array_intersect(DynamicEntityReferenceItem::getTargetTypes($field->getSettings()), array_keys($sql_entity_types));
      foreach ($targets as $target_entity_type_id) {
        if ($entity_manager->hasHandler($target_entity_type_id, 'views_data')) {
          $target_entity_type = $entity_types[$target_entity_type_id];
          $target_table = $entity_manager->getHandler($target_entity_type_id, 'views_data')
            ->getViewsTableForEntityType($target_entity_type);

          $t_args = [
            '@origin_label' => $entity_type->getLabel(),
            '@target_label' => $target_entity_type->getLabel(),
            '@field_name' => $field->getLabel() ?: $field_name,
            '@type' => 'base field',
          ];

          // Relationship (Origin -> Target).
          $psuedo_field = $target_entity_type_id . '__' . $field_name;
          $data[$table][$psuedo_field]['relationship'] = [
            'title' => t('@field_name to @target_label entities', $t_args),
            'label' => t('@field_name: @target_label', $t_args),
            'group' => $entity_type->getLabel(),
            'help' => t('References to @target_label entities referenced by @field_name @type on @origin_label entities.', $t_args),
            'id' => 'standard',
            'base' => $target_table,
            'entity type' => $target_entity_type_id,
            'base field' => $target_entity_type->getKey('id'),
            'relationship field' => $column_id,
            'extra' => [
              [
                // Entity reference field only has one target type whereas
                // dynamic entity reference field can have multiple target types
                // that is why extra join condition on target types is needed.
                'left_field' => $column_type,
                'value' => $target_entity_type_id,
              ],
            ],
          ];

          // Reverse Relationship (Target -> Origin).
          $psuedo_field = 'reverse__' . $entity_type_id . '__' . $field_name;
          $data[$target_table][$psuedo_field]['relationship'] = [
            'title' => t('Reverse reference to @field_name @type on @origin_label', $t_args),
            'label' => t('Reverse reference to @field_name @type on @origin_label', $t_args),
            'group' => $target_entity_type->getLabel(),
            'help' => t('Reverse reference from @target_label entities referenced by @field_name @type on @origin_label entities.', $t_args),
          ];
          // When base field cardinality is 1 then the 'base' and 'field table'
          // are same because field column(s) exist in entity base table
          // therefore we can't use entity_reverse relationship plugin.
          if ($field->getCardinality() == 1) {
            $data[$target_table][$psuedo_field]['relationship'] += [
              'id' => 'standard',
              'base' => $table,
              'entity type' => $entity_type_id,
              'base field' => $column_id,
              'field' => $target_entity_type->getKey('id'),
              'extra' => [
                [
                  // Entity reference field only has one target type whereas
                  // dynamic entity reference field can have multiple target
                  // types that is why an extra join condition on target types
                  // is needed.
                  'field' => $column_type,
                  'value' => $target_entity_type_id,
                ],
              ],
            ];
          }
          // When base field cardinality is greater then 1 the 'base' and
          // 'field table' are not same because field column(s) exist in
          // separate table therefore we have to use entity_reverse relationship
          // plugin.
          else {
            $data[$target_table][$psuedo_field]['relationship'] += [
              'id' => 'entity_reverse',
              'base' => $base_table,
              'entity_type' => $entity_type_id,
              'base field' => $entity_type->getKey('id'),
              'field_name' => $field_name,
              'field table' => $table,
              'field field' => $column_id,
              // Entity reference field only has one target type whereas dynamic
              // entity reference field can have multiple target types that is
              // why an extra join condition on target types is needed.
              'join_extra' => [
                [
                  'field' => $column_type,
                  'value' => $target_entity_type_id,
                ],
              ],
            ];
          }
        }
      }
    }
  }

  return $data;
}