import 'dart:async';
import 'package:fluttery/fluttery.dart';

abstract class Worker extends Service {
  Future<T> spawn<T>(
    String debugName,
    FutureOr<T> Function() task, {
    void Function()? preTask,
    Duration? timeout, // per-job override
  });

  /// Currently running jobs.
  List<WorkerInfo> getActiveWorkers();

  /// All known jobs (active + completed + failed), up to a capped history.
  List<WorkerInfo> getAllWorkers();

  /// Optional: get a single worker by id.
  WorkerInfo? getWorker(String id);

  /// Remove completed/failed jobs older than [maxAge] from history.
  void purge({Duration maxAge = const Duration(minutes: 30)});
}

enum WorkerStatus { running, completed, failed, timedOut }

class WorkerInfo {
  WorkerInfo({
    required this.id,
    required this.name,
    required this.startedAt,
    required this.status,
    this.endedAt,
    this.error,
    this.stackTrace,
  });

  final String id;
  final String name;
  final DateTime startedAt;
  final WorkerStatus status;
  final DateTime? endedAt;
  final Object? error;
  final StackTrace? stackTrace;

  Duration get duration => ((endedAt ?? DateTime.now()).difference(startedAt));
}