// lib/widgets/activity/activity_auto_sync_controller.dart
import 'dart:async';

import 'package:flutter/foundation.dart';
import 'package:flutter/services.dart';

class ActivityAutoSyncController {
  static const EventChannel _activityDirectoryChangeChannel = EventChannel('deckers.thibault/aves/activity_directory_change');

  final Future<void> Function(String reason) onScanRequested;

  StreamSubscription? _subscription;
  Timer? _debounce;
  bool _started = false;
  bool _disposed = false;

  ActivityAutoSyncController({
    required this.onScanRequested,
  });

  void start() {
    if (_disposed) return;
    if (_started) return;

    _started = true;

    _subscription = _activityDirectoryChangeChannel.receiveBroadcastStream().listen(
      _onNativeWatcherEvent,
      onError: _onNativeWatcherError,
      cancelOnError: false,
    );

    debugPrint('[ActivityAutoSync] watcher started');
  }

  void schedule({
    required String reason,
    Duration delay = const Duration(seconds: 2),
  }) {
    if (_disposed) return;

    _debounce?.cancel();

    debugPrint(
      '[ActivityAutoSync] schedule scan reason=$reason delay=${delay.inMilliseconds}ms',
    );

    _debounce = Timer(delay, () {
      _run(reason);
    });
  }

  Future<void> _run(String reason) async {
    if (_disposed) return;

    try {
      debugPrint('[ActivityAutoSync] scan requested reason=$reason');
      await onScanRequested(reason);
    } catch (e, st) {
      debugPrint('[ActivityAutoSync] scan failed reason=$reason error=$e');
      debugPrint('[ActivityAutoSync] stack=$st');
    }
  }

  void _onNativeWatcherEvent(Object? event) {
    if (_disposed) return;

    debugPrint('[ActivityAutoSync] native event=$event');

    schedule(
      reason: 'native_watcher',
      delay: const Duration(seconds: 2),
    );
  }

  void _onNativeWatcherError(Object error, StackTrace stack) {
    if (_disposed) return;

    debugPrint('[ActivityAutoSync] watcher error=$error');
    debugPrint('[ActivityAutoSync] watcher stack=$stack');
  }

  void dispose() {
    if (_disposed) return;

    _disposed = true;

    _debounce?.cancel();
    _debounce = null;

    _subscription?.cancel();
    _subscription = null;

    debugPrint('[ActivityAutoSync] disposed');
  }
}