main.dart

import 'package:flutter/material.dart';
import 'package:flutter_solidart/flutter_solidart.dart';

class SignalInputController extends Signal<TextEditingValue>
    implements TextEditingController {
  late final TextEditingController _controller;
  late final Effect _effect;

  SignalInputController({String? text})
    : super(TextEditingValue(text: text ?? "")) {
    _controller = TextEditingController(text: text);
    // Bind the internal controller to the signal and vice versa
    _controller.addListener(() {
      super.value = _controller.value;
    });
    _effect = Effect(() {
      _controller.value = super.value;
    });
  }

  // Ensure both listeners are disposed when the controller is disposed
  @override
  void dispose() {
    _effect.dispose();
    super.dispose();
  }

  // Read methods should register listeners by reading the value from the signal
  @override
  TextSelection get selection => super.value.selection;

  @override
  // Register listeners by reading the value from the signal
  String get text => super.value.text;

  @override
  // This will always return true because the signal is always listening
  // The ValueNotifier does not expose how many listeners it has
  // It's a shame, becuase we could have done: _controller.listenerCount > 1 || super.listenerCount > 0;
  bool get hasListeners => _controller.hasListeners;

  @override
  TextSpan buildTextSpan({
    required BuildContext context,
    TextStyle? style,
    required bool withComposing,
  }) {
    return _controller.buildTextSpan(
      context: context,
      style: style,
      withComposing: withComposing,
    );
  }

  @override
  void addListener(VoidCallback listener) => _controller.addListener(listener);

  @override
  void clear() => _controller.clear();

  @override
  void clearComposing() => _controller.clearComposing();

  @override
  void notifyListeners() => _controller.notifyListeners();

  @override
  void removeListener(VoidCallback listener) =>
      _controller.removeListener(listener);

  @override
  set selection(TextSelection newSelection) {
    _controller.selection = newSelection;
  }

  @override
  set text(String newText) {
    _controller.text = newText;
  }
}

void main() {
  runApp(const MyApp());
}

class MyApp extends StatefulWidget {
  const MyApp({super.key});

  @override
  State<MyApp> createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  late final SignalInputController _controller;
  late final Computed<String> _computed;
  @override
  void initState() {
    _controller = SignalInputController(text: 'Hello, World!');
    _computed = Computed(() => '${_controller.text} => I am computed!');
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        body: Center(
          child: Column(
            mainAxisSize: MainAxisSize.min,
            children: [
              TextField(controller: _controller),
              SignalBuilder(
                builder: (context, child) {
                  return Text(_controller.text);
                },
              ),
              SignalBuilder(
                builder: (context, child) {
                  return Text(_computed.value);
                },
              ),
              ElevatedButton(
                onPressed: () {
                  _controller.text = 'Hello, World!';
                },
                child: const Text('Reset'),
              ),
            ],
          ),
        ),
      ),
    );
  }
}