class SearchExtraTypeSearch

class SearchExtraTypeSearch extends ConfigurableSearchPluginBase {
    
    /**
     * {@inheritdoc}
     */
    public function setSearch($keywords, array $parameters, array $attributes) {
        if (empty($parameters['search_conditions'])) {
            $parameters['search_conditions'] = '';
        }
        parent::setSearch($keywords, $parameters, $attributes);
        return $this;
    }
    
    /**
     * Verifies if the given parameters are valid enough to execute a search for.
     *
     * @return bool
     *   TRUE if there are keywords or search conditions in the query.
     */
    public function isSearchExecutable() {
        return (bool) ($this->keywords || !empty($this->searchParameters['search_conditions']));
    }
    
    /**
     * Execute the search.
     *
     * This is a dummy search, so when search "executes", we just return a dummy
     * result containing the keywords and a list of conditions.
     *
     * @return array
     *   A structured list of search results
     */
    public function execute() {
        $results = [];
        if (!$this->isSearchExecutable()) {
            return $results;
        }
        return [
            [
                'link' => Url::fromRoute('test_page_test.test_page')->toString(),
                'type' => 'Dummy result type',
                'title' => 'Dummy title',
                'snippet' => new FormattableMarkup("Dummy search snippet to display. Keywords: @keywords\n\nConditions: @search_parameters", [
                    '@keywords' => $this->keywords,
                    '@search_parameters' => print_r($this->searchParameters, TRUE),
                ]),
            ],
        ];
    }
    
    /**
     * {@inheritdoc}
     */
    public function buildResults() {
        $results = $this->execute();
        $output['prefix']['#markup'] = '<h2>Test page text is here</h2> <ol class="search-results">';
        foreach ($results as $entry) {
            $output[] = [
                '#theme' => 'search_result',
                '#result' => $entry,
                '#plugin_id' => 'search_extra_type_search',
            ];
        }
        $pager = [
            '#type' => 'pager',
        ];
        $output['suffix']['#markup'] = '</ol>' . \Drupal::service('renderer')->render($pager);
        return $output;
    }
    
    /**
     * {@inheritdoc}
     */
    public function buildConfigurationForm(array $form, FormStateInterface $form_state) {
        // Output form for defining rank factor weights.
        $form['extra_type_settings'] = [
            '#type' => 'fieldset',
            '#title' => $this->t('Extra type settings'),
            '#tree' => TRUE,
        ];
        $form['extra_type_settings']['boost'] = [
            '#type' => 'select',
            '#title' => $this->t('Boost method'),
            '#options' => [
                'bi' => $this->t('Bistro mathematics'),
                'ii' => $this->t('Infinite Improbability'),
            ],
            '#default_value' => $this->configuration['boost'],
        ];
        return $form;
    }
    
    /**
     * {@inheritdoc}
     */
    public function submitConfigurationForm(array &$form, FormStateInterface $form_state) {
        $this->configuration['boost'] = $form_state->getValue([
            'extra_type_settings',
            'boost',
        ]);
    }
    
    /**
     * {@inheritdoc}
     */
    public function defaultConfiguration() {
        return [
            'boost' => 'bi',
        ];
    }

}