<?php

/**
 * @file
 * Provide Views data for field.module.
 */

use Drupal\Component\Utility\NestedArray;
use Drupal\Core\Entity\Sql\SqlContentEntityStorage;
use Drupal\Core\Entity\EntityStorageInterface;
use Drupal\field\FieldStorageConfigInterface;
use Drupal\field\FieldConfigInterface;

/**
 * Implements hook_views_data().
 *
 * Field modules can implement hook_field_views_data() to override the default
 * behavior for adding fields.
 */
function field_views_data() {
  $data = array();
  $module_handler = \Drupal::moduleHandler();

  foreach (\Drupal::entityManager()->getStorage('field_storage_config')->loadMultiple() as $field) {
    if (_field_views_get_entity_type_storage($field)) {
      $result = (array) $module_handler->invoke($field->module, 'field_views_data', array($field));
      if (empty($result)) {
        $result = field_views_field_default_views_data($field);
      }
      $module_handler->alter('field_views_data', $result, $field);

      if (is_array($result)) {
        $data = NestedArray::mergeDeep($result, $data);
      }
    }
  }

  return $data;
}

/**
 * Implements hook_views_data_alter().
 *
 * Field modules can implement hook_field_views_data_views_data_alter() to
 * alter the views data on a per field basis. This is weirdly named so as
 * not to conflict with the \Drupal::moduleHandler()->alter('field_views_data')
 * in field_views_data.
 */
function field_views_data_alter(&$data) {
  foreach (\Drupal::entityManager()->getStorage('field_storage_config')->loadMultiple() as $field) {
    if (_field_views_get_entity_type_storage($field)) {
      $function = $field->module . '_field_views_data_views_data_alter';
      if (function_exists($function)) {
        $function($data, $field);
      }
    }
  }
}

/**
 * Determines whether the entity type the field appears in is SQL based.
 *
 * @param \Drupal\field\FieldStorageConfigInterface $field_storage
 *   The field storage definition.
 *
 * @return \Drupal\Core\Entity\Sql\SqlContentEntityStorage
 *   Returns the entity type storage if supported.
 */
function _field_views_get_entity_type_storage(FieldStorageConfigInterface $field_storage) {
  $result = FALSE;
  $entity_manager = \Drupal::entityManager();
  if ($entity_manager->hasDefinition($field_storage->getTargetEntityTypeId())) {
    $storage = $entity_manager->getStorage($field_storage->getTargetEntityTypeId());
    $result = $storage instanceof SqlContentEntityStorage ? $storage : FALSE;
  }
  return $result;
}

/**
 * Returns the label of a certain field.
 *
 * Therefore it looks up in all bundles to find the most used field.
 */
function field_views_field_label($entity_type, $field_name) {
  $label_counter = array();
  $all_labels = array();
  // Count the amount of fields per label per field storage.
  foreach (array_keys(\Drupal::entityManager()->getBundleInfo($entity_type)) as $bundle) {
    $bundle_fields = array_filter(\Drupal::entityManager()->getFieldDefinitions($entity_type, $bundle), function ($field_definition) {
      return $field_definition instanceof FieldConfigInterface;
    });
    if (isset($bundle_fields[$field_name])) {
      $field = $bundle_fields[$field_name];
      $label = $field->getLabel();
      $label_counter[$label] = isset($label_counter[$label]) ? ++$label_counter[$label] : 1;
      $all_labels[$label] = TRUE;
    }
  }
  if (empty($label_counter)) {
    return array($field_name, $all_labels);
  }
  // Sort the field labels by it most used label and return the most used one.
  arsort($label_counter);
  $label_counter = array_keys($label_counter);
  return array($label_counter[0], $all_labels);
}

/**
 * Default views data implementation for a field.
 *
 * @param \Drupal\field\FieldStorageConfigInterface $field_storage
 *   The field definition.
 *
 * @return array
 *   The default views data for the field.
 */
function field_views_field_default_views_data(FieldStorageConfigInterface $field_storage) {
  $data = array();

  // Check the field type is available.
  if (!\Drupal::service('plugin.manager.field.field_type')->hasDefinition($field_storage->getType())) {
    return $data;
  }
  // Check the field storage has fields.
  if (!$field_storage->getBundles()) {
    return $data;
  }
  // Check whether the entity type storage is supported.
  $storage = _field_views_get_entity_type_storage($field_storage);
  if (!$storage) {
    return $data;
  }

  $field_name = $field_storage->getName();
  $field_columns = $field_storage->getColumns();

  // Grab information about the entity type tables.
  // We need to join to both the base table and the data table, if available.
  $entity_manager = \Drupal::entityManager();
  $entity_type_id = $field_storage->getTargetEntityTypeId();
  $entity_type = $entity_manager->getDefinition($entity_type_id);
  if (!$base_table = $entity_type->getBaseTable()) {
    // We cannot do anything if for some reason there is no base table.
    return $data;
  }
  $entity_tables = array($base_table => $entity_type_id);
  // Some entities may not have a data table.
  $data_table = $entity_type->getDataTable();
  if ($data_table) {
    $entity_tables[$data_table] = $entity_type_id;
  }
  $entity_revision_table = $entity_type->getRevisionTable();
  $supports_revisions = $entity_type->hasKey('revision') && $entity_revision_table;
  if ($supports_revisions) {
    $entity_tables[$entity_revision_table] = $entity_type_id;
    $entity_revision_data_table = $entity_type->getRevisionDataTable();
    if ($entity_revision_data_table) {
      $entity_tables[$entity_revision_data_table] = $entity_type_id;
    }
  }

  // Description of the field tables.
  // @todo Generalize this code to make it work with any table layout. See
  //   https://drupal.org/node/2079019.
  $table_mapping = $storage->getTableMapping();
  $field_tables = array(
    EntityStorageInterface::FIELD_LOAD_CURRENT => array(
      'table' => $table_mapping->getDedicatedDataTableName($field_storage),
      'alias' => "{$entity_type_id}__{$field_name}",
    ),
  );
  if ($supports_revisions) {
    $field_tables[EntityStorageInterface::FIELD_LOAD_REVISION] = array(
      'table' => $table_mapping->getDedicatedRevisionTableName($field_storage),
      'alias' => "{$entity_type_id}_revision__{$field_name}",
    );
  }

  // Build the relationships between the field table and the entity tables.
  $table_alias = $field_tables[EntityStorageInterface::FIELD_LOAD_CURRENT]['alias'];
  if ($data_table) {
    // Tell Views how to join to the base table, via the data table.
    $data[$table_alias]['table']['join'][$base_table] = array(
      'left_table' => $data_table,
      'left_field' => $entity_type->getKey('id'),
      'field' => 'entity_id',
      'extra' => array(
        array('field' => 'deleted', 'value' => 0, 'numeric' => TRUE),
        array('left_field' => 'langcode', 'field' => 'langcode'),
      ),
    );
  }
  else {
    // If there is no data table, just join directly.
    $data[$table_alias]['table']['join'][$base_table] = array(
      'left_field' => $entity_type->getKey('id'),
      'field' => 'entity_id',
      'extra' => array(
        array('field' => 'deleted', 'value' => 0, 'numeric' => TRUE),
      ),
    );
  }

  if ($supports_revisions) {
    $table_alias = $field_tables[EntityStorageInterface::FIELD_LOAD_REVISION]['alias'];
    if ($entity_revision_data_table) {
      // Tell Views how to join to the revision table, via the data table.
      $data[$table_alias]['table']['join'][$entity_revision_table] = array(
        'left_table' => $entity_revision_data_table,
        'left_field' => $entity_type->getKey('revision'),
        'field' => 'revision_id',
        'extra' => array(
          array('field' => 'deleted', 'value' => 0, 'numeric' => TRUE),
          array('left_field' => 'langcode', 'field' => 'langcode'),
        ),
      );
    }
    else {
      // If there is no data table, just join directly.
      $data[$table_alias]['table']['join'][$entity_revision_table] = array(
        'left_field' => $entity_type->getKey('revision'),
        'field' => 'revision_id',
        'extra' => array(
          array('field' => 'deleted', 'value' => 0, 'numeric' => TRUE),
        ),
      );
    }
  }

  $group_name = $entity_type->getLabel();
  // Get the list of bundles the field appears in.
  $bundles_names = $field_storage->getBundles();
  // Build the list of additional fields to add to queries.
  $add_fields = array('delta', 'langcode', 'bundle');
  foreach (array_keys($field_columns) as $column) {
    $add_fields[] = $table_mapping->getFieldColumnName($field_storage, $column);
  }
  // Determine the label to use for the field. We don't have a label available
  // at the field level, so we just go through all fields and take the one
  // which is used the most frequently.
  list($label, $all_labels) = field_views_field_label($entity_type_id, $field_name);

  // Expose data for the field as a whole.
  foreach ($field_tables as $type => $table_info) {
    $table = $table_info['table'];
    $table_alias = $table_info['alias'];

    if ($type == EntityStorageInterface::FIELD_LOAD_CURRENT) {
      $group = $group_name;
      $field_alias = $field_name;
    }
    else {
      $group = t('@group (historical data)', array('@group' => $group_name));
      $field_alias = $field_name . '-revision_id';
    }

    $data[$table_alias][$field_alias] = array(
      'group' => $group,
      'title' => $label,
      'title short' => $label,
      'help' =>  t('Appears in: @bundles.', array('@bundles' => implode(', ', $bundles_names))),
    );

    // Go through and create a list of aliases for all possible combinations of
    // entity type + name.
    $aliases = array();
    $also_known = array();
    foreach ($all_labels as $label_name => $true) {
      if ($type == EntityStorageInterface::FIELD_LOAD_CURRENT) {
        if ($label != $label_name) {
          $aliases[] = array(
            'base' => $base_table,
            'group' => $group_name,
            'title' => $label_name,
            'help' => t('This is an alias of @group: @field.', array('@group' => $group_name, '@field' => $label)),
          );
          $also_known[] = t('@group: @field', array('@group' => $group_name, '@field' => $label_name));
        }
      }
      elseif ($supports_revisions && $label != $label_name) {
        $aliases[] = array(
          'base' => $table,
          'group' => t('@group (historical data)', array('@group' => $group_name)),
          'title' => $label_name,
          'help' => t('This is an alias of @group: @field.', array('@group' => $group_name, '@field' => $label)),
        );
        $also_known[] = t('@group (historical data): @field', array('@group' => $group_name, '@field' => $label_name));
      }
    }
    if ($aliases) {
      $data[$table_alias][$field_alias]['aliases'] = $aliases;
      $data[$table_alias][$field_alias]['help'] .= ' ' . t('Also known as: !also.', array('!also' => implode(', ', $also_known)));
    }

    $keys = array_keys($field_columns);
    $real_field = reset($keys);
    $data[$table_alias][$field_alias]['field'] = array(
      'table' => $table,
      'id' => 'field',
      'field_name' => $field_name,
      'entity_type' => $entity_type_id,
      // Provide a real field for group by.
      'real field' => $field_alias . '_' . $real_field,
      'additional fields' => $add_fields,
      'entity_tables' => $entity_tables,
      // Default the element type to div, let the UI change it if necessary.
      'element type' => 'div',
      'is revision' => $type == EntityStorageInterface::FIELD_LOAD_REVISION,
    );
  }

  // Expose data for each field property individually.
  foreach ($field_columns as $column => $attributes) {
    $allow_sort = TRUE;

    // Identify likely filters and arguments for each column based on field type.
    switch ($attributes['type']) {
      case 'int':
      case 'mediumint':
      case 'tinyint':
      case 'bigint':
      case 'serial':
      case 'numeric':
      case 'float':
        $filter = 'numeric';
        $argument = 'numeric';
        $sort = 'standard';
        break;
      case 'text':
      case 'blob':
        // It does not make sense to sort by blob or text.
        $allow_sort = FALSE;
      default:
        $filter = 'string';
        $argument = 'string';
        $sort = 'standard';
        break;
    }

    if (count($field_columns) == 1 || $column == 'value') {
      $title = t('@label (!name)', array('@label' => $label, '!name' => $field_name));
      $title_short = $label;
    }
    else {
      $title = t('@label (!name:!column)', array('@label' => $label, '!name' => $field_name, '!column' => $column));
      $title_short = t('@label:!column', array('@label' => $label, '!column' => $column));
    }

    // Expose data for the property.
    foreach ($field_tables as $type => $table_info) {
      $table = $table_info['table'];
      $table_alias = $table_info['alias'];

      if ($type == EntityStorageInterface::FIELD_LOAD_CURRENT) {
        $group = $group_name;
      }
      else {
        $group = t('@group (historical data)', array('@group' => $group_name));
      }
      $column_real_name = $table_mapping->getFieldColumnName($field_storage, $column);

      // Load all the fields from the table by default.
      $additional_fields = $table_mapping->getAllColumns($table);

      $data[$table_alias][$column_real_name] = array(
        'group' => $group,
        'title' => $title,
        'title short' => $title_short,
        'help' =>  t('Appears in: @bundles.', array('@bundles' => implode(', ', $bundles_names))),
      );

      // Go through and create a list of aliases for all possible combinations of
      // entity type + name.
      $aliases = array();
      $also_known = array();
      foreach ($all_labels as $label_name => $true) {
        if ($label != $label_name) {
          if (count($field_columns) == 1 || $column == 'value') {
            $alias_title = t('@label (!name)', array('@label' => $label_name, '!name' => $field_name));
          }
          else {
            $alias_title = t('@label (!name:!column)', array('@label' => $label_name, '!name' => $field_name, '!column' => $column));
          }
          $aliases[] = array(
            'group' => $group_name,
            'title' => $alias_title,
            'help' => t('This is an alias of @group: @field.', array('@group' => $group_name, '@field' => $title)),
          );
          $also_known[] = t('@group: @field', array('@group' => $group_name, '@field' => $title));
        }
      }
      if ($aliases) {
        $data[$table_alias][$column_real_name]['aliases'] = $aliases;
        $data[$table_alias][$column_real_name]['help'] .= ' ' . t('Also known as: !also.', array('!also' => implode(', ', $also_known)));
      }

      $data[$table_alias][$column_real_name]['argument'] = array(
        'field' => $column_real_name,
        'table' => $table,
        'id' => $argument,
        'additional fields' => $additional_fields,
        'field_name' => $field_name,
        'entity_type' => $entity_type_id,
        'empty field name' => t('- No value -'),
      );
      $data[$table_alias][$column_real_name]['filter'] = array(
        'field' => $column_real_name,
        'table' => $table,
        'id' => $filter,
        'additional fields' => $additional_fields,
        'field_name' => $field_name,
        'entity_type' => $entity_type_id,
        'allow empty' => TRUE,
      );
      if (!empty($allow_sort)) {
        $data[$table_alias][$column_real_name]['sort'] = array(
          'field' => $column_real_name,
          'table' => $table,
          'id' => $sort,
          'additional fields' => $additional_fields,
          'field_name' => $field_name,
          'entity_type' => $entity_type_id,
        );
      }

      // Expose additional delta column for multiple value fields.
      if ($field_storage->isMultiple()) {
        $title_delta = t('@label (!name:delta)', array('@label' => $label, '!name' => $field_name));
        $title_short_delta = t('@label:delta', array('@label' => $label));

        $data[$table_alias]['delta'] = array(
          'group' => $group,
          'title' => $title_delta,
          'title short' => $title_short_delta,
          'help' => t('Delta - Appears in: @bundles.', array('@bundles' => implode(', ', $bundles_names))),
        );
        $data[$table_alias]['delta']['field'] = array(
          'id' => 'numeric',
        );
        $data[$table_alias]['delta']['argument'] = array(
          'field' => 'delta',
          'table' => $table,
          'id' => 'numeric',
          'additional fields' => $additional_fields,
          'empty field name' => t('- No value -'),
          'field_name' => $field_name,
          'entity_type' => $entity_type_id,
        );
        $data[$table_alias]['delta']['filter'] = array(
          'field' => 'delta',
          'table' => $table,
          'id' => 'numeric',
          'additional fields' => $additional_fields,
          'field_name' => $field_name,
          'entity_type' => $entity_type_id,
          'allow empty' => TRUE,
        );
        $data[$table_alias]['delta']['sort'] = array(
          'field' => 'delta',
          'table' => $table,
          'id' => 'standard',
          'additional fields' => $additional_fields,
          'field_name' => $field_name,
          'entity_type' => $entity_type_id,
        );
      }
    }
  }

  return $data;
}

/**
 * Have a different filter handler for lists. This should allow to select values of the list.
 */
function list_field_views_data(FieldStorageConfigInterface $field_storage) {
  $data = field_views_field_default_views_data($field_storage);
  foreach ($data as $table_name => $table_data) {
    foreach ($table_data as $field_name => $field_data) {
      if (isset($field_data['filter']) && $field_name != 'delta') {
        $data[$table_name][$field_name]['filter']['id'] = 'field_list';
      }
      if (isset($field_data['argument']) && $field_name != 'delta') {
        if ($field_storage->getType() == 'list_string') {
          $data[$table_name][$field_name]['argument']['id'] = 'field_list_string';
        }
        else {
          $data[$table_name][$field_name]['argument']['id'] = 'field_list';
        }
      }
    }
  }
  return $data;
}