tasks.types.ts

import { SortOrder, TaskSortField } from './entities/task-sort.enum';
import { TaskStatus } from './entities/task-status.enum';
import { Task, TaskPriority } from './entities/task.entity';
import { CursorPayload } from './pagination/cursor.codec';

/**
 * Domain query model — the storage-agnostic description of "which tasks, in
 * what order, which page". The service builds this from the HTTP DTO; each
 * repository implementation decides HOW to satisfy it (JS array ops in memory,
 * `WHERE/ORDER BY/LIMIT` in SQL, an aggregation pipeline in Mongo …).
 *
 * Keeping this separate from the HTTP DTO means the data layer has zero
 * knowledge of the web layer.
 */
export interface TaskFilter {
  status?: TaskStatus;
  priority?: TaskPriority;
  tag?: string;
}

export interface TaskSort {
  field: TaskSortField;
  order: SortOrder;
}

export interface TaskPageRequest {
  /** Decoded keyset anchor (the service decodes the opaque token before this). */
  cursor?: CursorPayload;
  limit?: number;
}

export interface TaskQuery {
  filter: TaskFilter;
  sort: TaskSort;
  page: TaskPageRequest;
}

/** A page of tasks plus the cursor needed to fetch the next page. */
export interface TaskPage {
  items: Task[];
  nextCursor: string | null;
  total: number;
}

/** Aggregate task counts grouped by status and by priority. */
export interface TaskStats {
  total: number;
  byStatus: Record<TaskStatus, number>;
  byPriority: Record<TaskPriority, number>;
}