class Search

class Search extends ArgumentPluginBase {
    
    /**
     * A search query to use for parsing search keywords.
     *
     * @var \Drupal\search\ViewsSearchQuery
     */
    protected $searchQuery = NULL;
    
    /**
     * The search type name (value of {search_index}.type in the database).
     *
     * @var string
     */
    protected $searchType;
    
    /**
     * {@inheritdoc}
     */
    public function init(ViewExecutable $view, DisplayPluginBase $display, array &$options = NULL) {
        parent::init($view, $display, $options);
        $this->searchType = $this->definition['search_type'];
    }
    
    /**
     * Sets up and parses the search query.
     *
     * @param string $input
     *   The search keywords entered by the user.
     */
    protected function queryParseSearchExpression($input) {
        if (!isset($this->searchQuery)) {
            $this->searchQuery = \Drupal::service('database.replica')->select('search_index', 'i')
                ->extend(ViewsSearchQuery::class);
            $this->searchQuery
                ->searchExpression($input, $this->searchType);
            $this->searchQuery
                ->publicParseSearchExpression();
        }
    }
    
    /**
     * {@inheritdoc}
     */
    public function query($group_by = FALSE) {
        $required = FALSE;
        $this->queryParseSearchExpression($this->argument);
        if (!isset($this->searchQuery)) {
            $required = TRUE;
        }
        else {
            $words = $this->searchQuery
                ->words();
            if (empty($words)) {
                $required = TRUE;
            }
        }
        if ($required) {
            if ($this->operator == 'required') {
                $this->query
                    ->addWhere(0, 'FALSE');
            }
        }
        else {
            $search_index = $this->ensureMyTable();
            $search_condition = $this->view->query
                ->getConnection()
                ->condition('AND');
            // Create a new join to relate the 'search_total' table to our current 'search_index' table.
            $definition = [
                'table' => 'search_total',
                'field' => 'word',
                'left_table' => $search_index,
                'left_field' => 'word',
            ];
            $join = Views::pluginManager('join')->createInstance('standard', $definition);
            $search_total = $this->query
                ->addRelationship('search_total', $join, $search_index);
            // Add the search score field to the query.
            $this->search_score = $this->query
                ->addField('', "{$search_index}.score * {$search_total}.count", 'score', [
                'function' => 'sum',
            ]);
            // Add the conditions set up by the search query to the views query.
            $search_condition->condition("{$search_index}.type", $this->searchType);
            $search_dataset = $this->query
                ->addTable('node_search_dataset');
            $conditions = $this->searchQuery
                ->conditions();
            $condition_conditions =& $conditions->conditions();
            foreach ($condition_conditions as $key => &$condition) {
                // Make sure we just look at real conditions.
                if (is_numeric($key)) {
                    // Replace the conditions with the table alias of views.
                    $this->searchQuery
                        ->conditionReplaceString('d.', "{$search_dataset}.", $condition);
                }
            }
            $search_conditions =& $search_condition->conditions();
            $search_conditions = array_merge($search_conditions, $condition_conditions);
            // Add the keyword conditions, as is done in
            // SearchQuery::prepareAndNormalize(), but simplified because we are
            // only concerned with relevance ranking so we do not need to normalize.
            $or = $this->view->query
                ->getConnection()
                ->condition('OR');
            foreach ($words as $word) {
                $or->condition("{$search_index}.word", $word);
            }
            $search_condition->condition($or);
            // Add the GROUP BY and HAVING expressions to the query.
            $this->query
                ->addWhere(0, $search_condition);
            $this->query
                ->addGroupBy("{$search_index}.sid");
            $matches = $this->searchQuery
                ->matches();
            $placeholder = $this->placeholder();
            $this->query
                ->addHavingExpression(0, "COUNT(*) >= {$placeholder}", [
                $placeholder => $matches,
            ]);
        }
        // Set to NULL to prevent PDO exception when views object is cached
        // and to clear out memory.
        $this->searchQuery = NULL;
    }

}