<?php
declare(strict_types=1);

namespace Civi\Mailinglistsync;

use Civi\Mailinglistsync\Exceptions\MailinglistException;
use CRM_Queue_Queue;

class QueueHelper {
  use Singleton;

  private CRM_Queue_Queue $groupQueue;
  private CRM_Queue_Queue $eventQueue;
  private CRM_Queue_Queue $emailQueue;

  private array $groups;

  private array $events;

  private array $emails;

  /**
   * Protect singleton from being instantiated.
   */
  protected function __construct() {
    // Get queues
    $this->groupQueue = \Civi::queue(
      'propeace-mailinglist-group-queue', [
      'type' => 'SqlParallel',
      'is_autorun' => FALSE,
      'reset' => FALSE,
      'error' => 'drop',
    ]);
    $this->eventQueue = \Civi::queue(
      'propeace-mailinglist-event-queue', [
      'type' => 'SqlParallel',
      'is_autorun' => FALSE,
      'reset' => FALSE,
      'error' => 'drop',
    ]);
    $this->emailQueue = \Civi::queue(
      'propeace-mailinglist-email-queue', [
      'type' => 'SqlParallel',
      'is_autorun' => FALSE,
      'reset' => FALSE,
      'error' => 'drop',
    ]);

    $this->groups = [];
    $this->events = [];
    $this->emails = [];
  }

  /**
   * Getter for the group queue.
   *
   * @return \CRM_Queue_Queue
   */
  public function getGroupQueue(): CRM_Queue_Queue {
    return $this->groupQueue;
  }

  /**
   * Getter for the event queue.
   *
   * @return \CRM_Queue_Queue
   */
  public function getEventQueue(): CRM_Queue_Queue {
    return $this->eventQueue;
  }

  /**
   * Getter for the email queue.
   *
   * @return \CRM_Queue_Queue
   */
  public function getEmailQueue(): CRM_Queue_Queue {
    return $this->emailQueue;
  }

  public function getGroups(): array {
    return $this->groups;
  }

  public function addToGroups(GroupMailingList $group): void {
    $this->groups[] = $group;
  }

  public function getEvents(): array {
    return $this->events;
  }

  public function addToEvents(EventMailingList $event): void {
    $this->events[] = $event;
  }

  public function getEmails(): array {
    return $this->emails;
  }

  public function addToEmails(string $email): void {
    $this->emails[] = $email;
  }

  /**
   * Stores an email address in the queue helper singleton.
   *
   * @param \CRM_Queue_TaskContext $context
   * @param string $email
   *
   * @return bool
   */
  public static function storeEmail(\CRM_Queue_TaskContext $context, string $email): bool {
    self::getInstance()->addToEmails($email);
    return TRUE;
  }

  /**
   * Stores an instance of the given class in the queue helper singleton.
   * Meant to be passed as callback to the queue.
   *
   * @param \CRM_Queue_TaskContext $context
   * @param int $entityId
   * @param string $class
   *
   * @return bool TRUE if the instance was stored successfully.
   * @throws \Civi\Mailinglistsync\Exceptions\MailinglistException
   */
  public static function storeInstance(\CRM_Queue_TaskContext $context, int $entityId, string $class): bool {

    // Throw exception if class is invalid
    if ($class != GroupMailingList::class &&
      $class != ADGroupMailingList::class &&
      $class != EventMailingList::class) {
      throw new MailinglistException(
        "Invalid class '$class'",
        MailinglistException::ERROR_CODE_INVALID_CLASS
      );
    }

    // Instantiate the mailing list object
    /* @var $instance GroupMailingList|ADGroupMailingList|EventMailingList */
    $instance = new $class($entityId);

    // Ignore disabled mailing lists
    if (!$instance->isEnabled()) {
      return TRUE;
    }

    // Store instance in the queue helper singleton
    if (
      $instance::class === GroupMailingList::class
      || $instance::class === ADGroupMailingList::class
    ) {
      self::getInstance()->addToGroups($instance);
    } else {
      self::getInstance()->addToEvents($instance);
    }
    return TRUE;
  }
}