use runtimeType to determine state type

cyberwow/lib/main.dart

@@ -32,12 +32,7 @@ import 'config.dart' as config;
 import 'logging.dart';
 import 'controller/process/deploy.dart' as process;
 import 'controller/process/run.dart' as process;
-import 'widget/loading.dart' as widget;
-import 'widget/blank.dart' as widget;
-import 'widget/syncing.dart' as widget;
-import 'widget/synced.dart' as widget;
-import 'widget/resyncing.dart' as widget;
-import 'widget/exiting.dart' as widget;
+import 'widget.dart' as widget;
 
 void main() {
   Logger.root.level = kReleaseMode ? Level.INFO : Level.FINE;
@@ -128,7 +123,7 @@ class _CyberWOW_PageState extends State<CyberWOW_Page> with WidgetsBindingObserv
     .runBinary(binName, input: inputStreamController.stream, shouldExit: _isExiting)
     .asBroadcastStream();
 
-    HookedState _syncedNextState = await _syncingState.next(inputStreamController.sink, syncing);
+    AppState _syncedNextState = await _syncingState.next(inputStreamController.sink, syncing);
 
     var exited = false;
 
@@ -143,19 +138,25 @@ class _CyberWOW_PageState extends State<CyberWOW_Page> with WidgetsBindingObserv
 
     var validState = true;
     while (validState && !exited) {
-      await _getState().use
-      (
-        (s) => validState = false,
-        (s) => validState = false,
-        (s) => validState = false,
-        (s) => s.next(),
-        (s) => s.next(),
-        (s) async {
-          await s.wait();
+      AppState _state = _getState();
+      switch (_state.runtimeType) {
+        case ExitingState: {
+          await (_state as ExitingState).wait();
           log.finer('exit state wait done');
           exited = true;
         }
-      );
+        break;
+
+        case SyncedState:
+          (_state as SyncedState).next();
+          break;
+
+        case ReSyncingState:
+          (_state as ReSyncingState).next();
+          break;
+
+        default: validState = false;
+      }
     }
 
     log.finer('state machine finished');
@@ -203,15 +204,7 @@ class _CyberWOW_PageState extends State<CyberWOW_Page> with WidgetsBindingObserv
     return WillPopScope
     (
       onWillPop: () => _exitApp(context),
-      child: _state.use
-      (
-        (s) => widget.buildBlank(context, s),
-        (s) => widget.buildLoading(context, s),
-        (s) => widget.buildSyncing(context, s),
-        (s) => widget.buildSynced(context, s),
-        (s) => widget.buildReSyncing(context, s),
-        (s) => widget.buildExiting(context, s),
-      ),
+      child: widget.build(context, _state),
     );
   }
 }

cyberwow/lib/state.dart

@@ -40,39 +40,6 @@ import 'helper.dart';
 import 'controller/rpc/rpcView.dart' as rpcView;
 import 'controller/rpc/rpc2View.dart' as rpc2View;
 
-abstract class AppState {
-  T use<T>
-  (
-    T Function(BlankState) useBlankState,
-    T Function(LoadingState) useLoadingState,
-    T Function(SyncingState) useSyncingState,
-    T Function(SyncedState) useSyncedState,
-    T Function(ReSyncingState) useReSyncingState,
-    T Function(ExitingState) useExitingState,
-  )
-  {
-    if (this is BlankState) {
-      return useBlankState(this);
-    }
-    if (this is LoadingState) {
-      return useLoadingState(this);
-    }
-    if (this is SyncingState) {
-      return useSyncingState(this);
-    }
-    if (this is SyncedState) {
-      return useSyncedState(this);
-    }
-    if (this is ReSyncingState) {
-      return useReSyncingState(this);
-    }
-    if (this is ExitingState) {
-      return useExitingState(this);
-    }
-    throw Exception('Invalid state');
-  }
-}
-
 typedef SetStateFunc = void Function(AppState);
 typedef GetNotificationFunc = AppLifecycleState Function();
 typedef IsExitingFunc = bool Function();
@@ -84,21 +51,21 @@ class AppHook {
   AppHook(this.setState, this.getNotification, this.isExiting);
 }
 
-class HookedState extends AppState {
+class AppState {
   final AppHook appHook;
-  HookedState(this.appHook);
+  AppState(this.appHook);
 
   syncState() {
     appHook.setState(this);
   }
 
-  HookedState moveState(HookedState _next) {
+  AppState moveState(AppState _next) {
     appHook.setState(_next);
     return _next;
   }
 }
 
-class BlankState extends HookedState {
+class BlankState extends AppState {
   BlankState(appHook) : super (appHook);
 
   Future<LoadingState> next(String status) async {
@@ -107,7 +74,7 @@ class BlankState extends HookedState {
   }
 }
 
-class LoadingState extends HookedState {
+class LoadingState extends AppState {
   final String banner;
   String status = '';
 
@@ -156,7 +123,7 @@ class LoadingState extends HookedState {
   }
 }
 
-class SyncingState extends HookedState {
+class SyncingState extends AppState {
   final Queue<String> stdout = Queue.from(['']);
 
   bool synced = false;
@@ -171,7 +138,7 @@ class SyncingState extends HookedState {
     syncState();
   }
 
-  Future<HookedState> next
+  Future<AppState> next
   (
     StreamSink<String> processInput, Stream<String> processOutput
   ) async {
@@ -233,7 +200,7 @@ class SyncingState extends HookedState {
   }
 }
 
-class SyncedState extends HookedState {
+class SyncedState extends AppState {
   final Queue<String> stdout;
   final StreamSink<String> processInput;
   final Stream<String> processOutput;
@@ -281,7 +248,7 @@ class SyncedState extends HookedState {
     this.pageIndex = value;
   }
 
-  Future<HookedState> next() async {
+  Future<AppState> next() async {
     log.fine("Synced next");
 
     Future<void> logStdout() async {
@@ -353,7 +320,7 @@ class SyncedState extends HookedState {
 }
 
 
-class ReSyncingState extends HookedState {
+class ReSyncingState extends AppState {
   final Queue<String> stdout;
   final StreamSink<String> processInput;
   final Stream<String> processOutput;
@@ -372,7 +339,7 @@ class ReSyncingState extends HookedState {
     syncState();
   }
 
-  Future<HookedState> next() async {
+  Future<AppState> next() async {
     log.fine("ReSyncing next");
 
     Future<void> printStdout() async {
@@ -420,7 +387,7 @@ class ReSyncingState extends HookedState {
   }
 }
 
-class ExitingState extends HookedState {
+class ExitingState extends AppState {
   final Queue<String> stdout;
   final Stream<String> processOutput;
 

cyberwow/lib/widget.dart

@@ -0,0 +1,42 @@
+/*
+
+Copyright 2019 fuwa
+
+This file is part of CyberWOW.
+
+CyberWOW is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+CyberWOW is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with CyberWOW.  If not, see <https://www.gnu.org/licenses/>.
+
+*/
+
+import 'package:flutter/material.dart';
+
+import 'state.dart';
+import 'widget/blank.dart' as blank;
+import 'widget/loading.dart' as loading;
+import 'widget/syncing.dart' as syncing;
+import 'widget/synced.dart' as synced;
+import 'widget/resyncing.dart' as resyncing;
+import 'widget/exiting.dart' as exiting;
+
+Widget build(final BuildContext context, final AppState state) {
+  switch (state.runtimeType) {
+    case BlankState: return blank.build(context, state);
+    case LoadingState: return loading.build(context, state);
+    case SyncingState: return syncing.build(context, state);
+    case SyncedState: return synced.build(context, state);
+    case ReSyncingState: return resyncing.build(context, state);
+    case ExitingState: return exiting.build(context, state);
+    default: Placeholder();
+  }
+}

cyberwow/lib/widget/blank.dart

@@ -24,7 +24,7 @@ import 'package:flutter/material.dart';
 import '../state.dart';
 import '../config.dart' as config;
 
-Widget buildBlank(BuildContext context, BlankState state) {
+Widget build(BuildContext context, BlankState state) {
   return Scaffold(
     body: Container
     (

cyberwow/lib/widget/exiting.dart

@@ -24,7 +24,7 @@ import 'package:flutter/material.dart';
 import '../state.dart';
 import '../config.dart' as config;
 
-Widget buildExiting(BuildContext context, ExitingState state) {
+Widget build(BuildContext context, ExitingState state) {
   return Scaffold
   (
     // appBar: AppBar

cyberwow/lib/widget/loading.dart

@@ -24,7 +24,7 @@ import 'package:flutter/material.dart';
 import '../state.dart';
 import '../config.dart' as config;
 
-Widget buildLoading(BuildContext context, LoadingState state) {
+Widget build(BuildContext context, LoadingState state) {
   return Scaffold(
     // appBar: AppBar(
     //   // title: Text(widget.title),

cyberwow/lib/widget/resyncing.dart

@@ -24,7 +24,7 @@ import 'package:flutter/material.dart';
 import '../state.dart';
 import '../config.dart' as config;
 
-Widget buildReSyncing(BuildContext context, ReSyncingState state) {
+Widget build(BuildContext context, ReSyncingState state) {
   return Scaffold
   (
     // appBar: AppBar

cyberwow/lib/widget/synced.dart

@@ -320,7 +320,7 @@ Widget pageView (BuildContext context, SyncedState state) {
   );
 }
 
-Widget buildSynced(BuildContext context, SyncedState state) {
+Widget build(BuildContext context, SyncedState state) {
   return Scaffold
   (
     body: pageView(context, state)

cyberwow/lib/widget/syncing.dart

@@ -24,7 +24,7 @@ import 'package:flutter/material.dart';
 import '../state.dart';
 import '../config.dart' as config;
 
-Widget buildSyncing(BuildContext context, SyncingState state) {
+Widget build(BuildContext context, SyncingState state) {
   return Scaffold
   (
     // appBar: AppBar