import pg from "pg";
import { Collection, Option } from "scats";
import { FindTasksParameters, QueueStat, TaskDto, TasksCount, TasksResult, UpdatePendingPeriodicScheduleDetails, UpdatePendingTaskDetails } from "./manage.model.js";
/**
 * Operational management service for inspecting and mutating queued tasks.
 *
 * This service is intended for admin panels, support tooling, and maintenance
 * workflows. It does not execute tasks itself; execution belongs to
 * {@link TasksQueueService} and {@link TasksPoolsService}.
 *
 * See also {@link TaskDto}, {@link TasksResult}, {@link QueueStat}, and
 * {@link TasksCount}.
 */
export declare class ManageTasksQueueService {
    private readonly pool;
    constructor(pool: pg.Pool);
    private mapTaskRow;
    /**
     * Finds a task by its identifier.
     *
     * Returns the full management view of the task if it exists, otherwise `none`.
     *
     * @param taskId task identifier
     * @returns task details wrapped in Option
     */
    findById(taskId: number): Promise<Option<TaskDto>>;
    /**
     * Finds all descendant tasks for the provided root task.
     *
     * The root task itself is not included in the result; only direct and nested
     * children are returned.
     *
     * @param rootTaskId root task identifier
     * @returns descendant tasks ordered by id ascending
     */
    findChildrenTree(rootTaskId: number): Promise<Collection<TaskDto>>;
    /**
     * Finds tasks using optional management filters.
     *
     * Supported filters include task status, queue name, and periodic flag.
     * Result ordering supports whitelisted task date fields.
     *
     * @param params search and pagination parameters
     * @returns paginated tasks result
     */
    findByParameters(params: FindTasksParameters): Promise<TasksResult>;
    /**
     * Count tasks currently in terminal `error` state.
     *
     * @returns number of failed tasks as returned by PostgreSQL
     */
    failedCount(): Promise<any>;
    /**
     * Delete all tasks currently in terminal `error` state.
     *
     * This is a bulk cleanup operation and does not filter by queue.
     *
     * @returns PostgreSQL query promise for the delete operation
     */
    clearFailed(): Promise<pg.QueryResult<any>>;
    /**
     * Deletes a task by id only when it is safe to remove from the queue.
     *
     * Deletion is allowed only for tasks in one of the terminal or inactive states:
     * - `pending`
     * - `error`
     * - `finished`
     *
     * Tasks in `in_progress` state are never deleted because removing an actively
     * processed task can break worker execution semantics. Tasks that still have
     * an unfinished ancestor in the parent chain are also preserved, because
     * removing them can break parent-child workflow recovery.
     *
     * @param taskId task identifier
     * @returns true if the task was deleted, false if it was not found or is in a non-deletable status
     */
    deleteTask(taskId: number): Promise<boolean>;
    /**
     * Updates the editable runtime configuration of a pending task.
     *
     * Only tasks currently in `pending` state can be updated. This method changes
     * task execution and retry settings, but does not modify periodic scheduling fields.
     *
     * @param taskId task identifier
     * @param details full replacement of editable task fields
     * @returns true if the pending task was updated, false if it was not found or is no longer pending
     */
    updatePendingTask(taskId: number, details: UpdatePendingTaskDetails): Promise<boolean>;
    /**
     * Updates the periodic schedule of a pending periodic task.
     *
     * Only tasks currently in `pending` state and already configured as periodic can be updated.
     * This method changes scheduling fields only and does not modify payload, priority, timeout,
     * or retry settings.
     *
     * @param taskId task identifier
     * @param details full replacement of editable periodic scheduling fields
     * @returns true if the pending periodic task was updated, false if it was not found, is not periodic, or is no longer pending
     */
    updatePendingPeriodicSchedule(taskId: number, details: UpdatePendingPeriodicScheduleDetails): Promise<boolean>;
    /**
     * Compute queue-level wait-time percentiles.
     *
     * Wait time is measured as `started - created` for first-attempt executions
     * only. Results are grouped by queue and returned in seconds.
     *
     * @returns queue wait-time percentile stats
     */
    waitTimeByQueue(): Promise<Collection<QueueStat>>;
    /**
     * Restart a single failed task by resetting it back to `pending`.
     *
     * This operation affects only tasks currently in terminal `error` state and
     * resets their attempt counter to `0`.
     *
     * @param taskId task identifier
     * @returns resolved promise when the update completes
     */
    restartFailedTask(taskId: number): Promise<void>;
    /**
     * Restart all failed tasks in the selected queue.
     *
     * Only tasks currently in terminal `error` state are affected.
     *
     * @param queue queue name
     * @returns resolved promise when the update completes
     */
    restartAllFailedInQueue(queue: string): Promise<void>;
    /**
     * Count tasks grouped by queue and status.
     *
     * This method is used both by management UIs and by the auxiliary worker's
     * metrics synchronization.
     *
     * @returns queue/status aggregate counts
     */
    tasksCount(): Promise<Collection<TasksCount>>;
    /**
     * Compute queue-level work-time percentiles.
     *
     * Work time is measured as `finished - started` for tasks that have both
     * timestamps. Results are grouped by queue and returned in seconds.
     *
     * @returns queue work-time percentile stats
     */
    workTimeByQueue(): Promise<Collection<QueueStat>>;
}