<?php

final class PhabricatorSearchDocumentQuery
  extends PhabricatorPolicyAwareQuery {

  private $savedQuery;
  private $objectCapabilities;
  private $unfilteredOffset;
  private $fulltextResultSet;

  public function withSavedQuery(PhabricatorSavedQuery $query) {
    $this->savedQuery = $query;
    return $this;
  }

  public function requireObjectCapabilities(array $capabilities) {
    $this->objectCapabilities = $capabilities;
    return $this;
  }

  protected function getRequiredObjectCapabilities() {
    if ($this->objectCapabilities) {
      return $this->objectCapabilities;
    }

    return $this->getRequiredCapabilities();
  }

  /**
   * @return PhabricatorFulltextResultSet
   */
  public function getFulltextResultSet() {
    if (!$this->fulltextResultSet) {
      throw new PhutilInvalidStateException('execute');
    }

    return $this->fulltextResultSet;
  }

  protected function willExecute() {
    $this->unfilteredOffset = 0;
    $this->fulltextResultSet = null;
  }

  /**
   * Load a raw page of results.
   *
   * @return list PHIDs of the search result objects as array keys.
   */
  protected function loadPage() {
    // NOTE: The offset and limit information in the inherited properties of
    // this object represent a policy-filtered offset and limit, but the
    // underlying query engine needs an unfiltered offset and limit. We keep
    // track of an unfiltered result offset internally.

    $query = id(clone($this->savedQuery))
      ->setParameter('offset', $this->unfilteredOffset)
      ->setParameter('limit', $this->getRawResultLimit());

    $result_set = PhabricatorSearchService::newResultSet($query);
    $phids = $result_set->getPHIDs();

    $this->fulltextResultSet = $result_set;
    $this->unfilteredOffset += count($phids);

    $handles = id(new PhabricatorHandleQuery())
      ->setViewer($this->getViewer())
      ->requireObjectCapabilities($this->getRequiredObjectCapabilities())
      ->withPHIDs($phids)
      ->execute();

    // Retain engine order.
    $handles = array_select_keys($handles, $phids);

    return $handles;
  }

  protected function willFilterPage(array $handles) {
    // NOTE: This is used by the object selector dialog to exclude the object
    // you're looking at, so that, e.g., a task can't be set as a dependency
    // of itself in the UI.

    // TODO: Remove this after object selection moves to ApplicationSearch.

    $exclude = array();
    if ($this->savedQuery) {
      $exclude_phids = $this->savedQuery->getParameter('excludePHIDs', array());
      $exclude = array_fuse($exclude_phids);
    }

    foreach ($handles as $key => $handle) {
      if (!$handle->isComplete()) {
        unset($handles[$key]);
        continue;
      }
      if ($handle->getPolicyFiltered()) {
        unset($handles[$key]);
        continue;
      }
      if (isset($exclude[$handle->getPHID()])) {
        unset($handles[$key]);
        continue;
      }
    }

    return $handles;
  }

  public function getQueryApplicationClass() {
    return PhabricatorSearchApplication::class;
  }

  protected function nextPage(array $page) {
    // We already updated the internal offset in `loadPage()` after loading
    // results, so we do not need to make any additional state updates here.
  }

}