autoclose.dart

import 'dart:async';

import 'package:bloc/bloc.dart';
import 'package:flutter/widgets.dart';

// interface to close something
abstract class AppClosable {
  void close();
}

// List of things that can be closed

class ClosableSubscription implements AppClosable {
  final StreamSubscription subscription;
  ClosableSubscription(this.subscription);
  @override
  void close() {
    subscription.cancel();
  }
}

class ClosableChangeNotifier implements AppClosable {
  final ChangeNotifier notifier;
  ClosableChangeNotifier(this.notifier);
  @override
  void close() {
    notifier.dispose();
  }
}

// abstract thing which contain closable things and close them when closes itself
abstract class Closer {
  void addClosable(AppClosable closable);
}

extension SubscriptionClose on StreamSubscription {
  void closeWith(Closer closer) {
    closer.addClosable(ClosableSubscription(this));
  }
}

extension ChangeNotifierClose on ChangeNotifier {
  void closeWith(Closer closer) {
    closer.addClosable(ClosableChangeNotifier(this));
  }
}

mixin AutoCloseBloc<T> on BlocBase<T> implements Closer {
  final List<AppClosable> closables = [];

  @override 
  void addClosable(AppClosable closable) {
    closables.add(closable);
  }
  
  @override
  Future<void> close() {
    for (final closable in closables) {
      closable.close();
    }
    return super.close();
  }
}


mixin AutoCloseWidgetState<T extends StatefulWidget> on State<T> implements Closer {
  final List<AppClosable> closables = [];

  @override 
  void addClosable(AppClosable closable) {
    closables.add(closable);
  }

  @override
  void dispose() {
    for (final closable in closables) {
      closable.close();
    }
    super.dispose();
  }
}