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

void main() {
  // riverpod 세팅
  runApp(ProviderScope(child: MyApp()));
}

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

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: HomePage(),
    );
  }
}

class HomePage extends ConsumerWidget {
  const HomePage({super.key});

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    int num = ref.watch(numProvider); // read or watch는 state에 접근가능!!

    return Scaffold(
      body: Center(child: Text("$num", style: TextStyle(fontSize: 30))),
      floatingActionButton: FloatingActionButton(
        onPressed: () {
          NumVM vm = ref.read(numProvider.notifier); // 창고에 접근가능
          vm.increase();
        },
        child: Icon(Icons.add),
      ),
    );
  }
}

// 프로바이더 (창고 관리자)
final numProvider = StateNotifierProvider<NumVM, int>((ref) {
  return NumVM(1);
});

// 뷰모델 (창고)
class NumVM extends StateNotifier<int> {
  NumVM(super.state);

  void increase() {
    state++;
  }
}