wasm example todo app (#5)

* wasm: todo cubit

- passing JSON serialized filtered todos
- todo cubit remove expiry from menu as wasm doesn't support threads
  easily
- added web support

* chore: optimize wasm release build

- remove threading code

* wasm: adding generated files need to run app

* chore: using published wasmjsgen

* chore: remove support for non-web architectures

* chore: fixing wasm related links in comments

flutter/todo_cubit_wasm/.gitignore

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+.DS_Store
+.idea/
+.metadata
+
+## Flutter ###
+# Flutter/Dart/Pub related
+**/doc/api/
+.dart_tool/
+.flutter-plugins
+.flutter-plugins-dependencies
+.fvm/
+.packages
+.pub-cache/
+.pub/
+build/
+coverage/
+lib/generated_plugin_registrant.dart
+# For library packages, don’t commit the pubspec.lock file.
+# Regenerating the pubspec.lock file lets you test your package against the latest compatible versions of its dependencies.
+# See https://dart.dev/guides/libraries/private-files#pubspeclock
+#pubspec.lock
+
+# Android related
+**/android/**/gradle-wrapper.jar
+**/android/.gradle
+**/android/captures/
+**/android/gradlew
+**/android/gradlew.bat
+**/android/key.properties
+**/android/local.properties
+**/android/**/GeneratedPluginRegistrant.java
+
+# iOS/XCode related
+**/ios/**/*.mode1v3
+**/ios/**/*.mode2v3
+**/ios/**/*.moved-aside
+**/ios/**/*.pbxuser
+**/ios/**/*.perspectivev3
+**/ios/**/*sync/
+**/ios/**/.sconsign.dblite
+**/ios/**/.tags*
+**/ios/**/.vagrant/
+**/ios/**/DerivedData/
+**/ios/**/Icon?
+**/ios/**/Pods/
+**/ios/**/.symlinks/
+**/ios/**/profile
+**/ios/**/xcuserdata
+**/ios/.generated/
+**/ios/Flutter/.last_build_id
+**/ios/Flutter/App.framework
+**/ios/Flutter/Flutter.framework
+**/ios/Flutter/Flutter.podspec
+**/ios/Flutter/Generated.xcconfig
+**/ios/Flutter/app.flx
+**/ios/Flutter/app.zip
+**/ios/Flutter/flutter_assets/
+**/ios/Flutter/flutter_export_environment.sh
+**/ios/ServiceDefinitions.json
+**/ios/Runner/GeneratedPluginRegistrant.*
+
+# Exceptions to above rules.
+!**/ios/**/default.mode1v3
+!**/ios/**/default.mode2v3
+!**/ios/**/default.pbxuser
+!**/ios/**/default.perspectivev3
+!/packages/flutter_tools/test/data/dart_dependencies_test/**/.packages
+
+### Rust ###
+**/target/**
+**/target_wasm/**
+**/Cargo.lock
+
+### Rid ###
+**/generated/**
+**/Classes/bindings.h
+**/macos/*.a
+**/ios/*.a
+**/android/src/main/jniLibs/*
+

flutter/todo_cubit_wasm/Cargo.toml

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+[package]
+name = "todo_cubit"
+version = "0.1.0"
+authors = ["Thorsten Lorenz <thlorenz@gmx.de>"]
+edition = "2018"
+
+[lib]
+crate-type = ["cdylib", "staticlib" ]
+
+[[bin]]
+name = "rid_build"
+path = "rid_build.rs"
+
+[dependencies]
+cbindgen = "0.18.0"
+rid_build = { path = "../../../rid/rid-build" }
+rid = { path = "../../../rid" }
+serde = "1.0.123"
+serde_json = "1.0.64"
+
+# https://rustwasm.github.io/docs/book/reference/code-size.html
+[profile.release]
+opt-level = 'z'

flutter/todo_cubit_wasm/README.md

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+# todo_cubit
+
+Rust integrated Dart Flutter Project
+
+## Getting Started
+
+Use the below scripts to get the app ready to run with Flutter.
+
+### 1. Generate Glue Code
+
+```sh
+./sh/bindgen
+```
+
+### 2. Build For Desired Target/Device
+
+Run any of the below three to build the binary for the specific device and have it placed into
+the devices specific plugin folder.
+
+```sh
+./sh/macos
+```
+
+### 3. Run with Flutter
+
+Run on the device.
+
+```sh
+flutter run -d macos
+```
+
+### 4. Develop
+
+Run step `1` whenever a function exposed to Flutter changes.
+
+Run step `2` whenever any of your Rust code changes.
+
+**Note** that to apply changes from Rust you need to restart the app to reload the compiled binary.
+A hot restart/reload does not achieve this.
+
+## Folder Structure
+
+```
+├── android
+├── ios
+├── macos
+├── lib
+├── plugin
+│   ├── android
+│   ├── ios
+│   ├── macos
+│   └── lib
+└── src
+```
+
+### `./plugin`
+
+Provides connection from Flutter to Rust.
+
+Rust binaries are placed into the respective plugin folders `./ios, ./macos, ./android` when
+they are built.
+
+Generated Dart glue code is placed inside `./plugin/lib/generated` while
+`./plugin/lib/plugin.dart` just exposes the API to the app.
+
+### `./src`
+
+Contains the starter Rust code inside `./src/lib.rs`. Keep developing the Rust part of your app
+here.
+
+### `./lib`
+
+Contains the starter Flutter app inside `./lib/main.dart`.
+
+### `./sh`
+
+Provides scripts to run build and code generation tasks. In the future a tool will provide the
+functionality currently provided by these scripts.
+
+- `bindgen` generates the `binding.h` header file for the extern Rust functions found inside
+  `./src`. These are then placed inside the `./plugin` device folders were needed as well as
+  `./plugin/lib/generated/binding.h` where they are used to generate Dart glue code
+  - as part of this script `ffigen` generates Dart glue code inside
+    `./plugin/lib/generated/ffigen_binding.dart` using `./plugin/lib/generated/binding.h` as input
+- `./android` builds the Rust binary to run on Android devices/emulators and places it inside
+  `./plugin/lib/android`
+- `./ios` builds the Rust binary to run on IOS devices/emulators and places it inside
+  `./plugin/lib/ios`
+- `./macos` builds the Rust binary to run on MacOs directly and places it inside
+  `./plugin/lib/macos`, this is the same format as running `cargo build` on your Mac
+- `clean` cleans both the Flutter plugin and application, run this to reset Flutter when things
+  aren't working

flutter/todo_cubit_wasm/analysis_options.yaml

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+# This file configures the analyzer, which statically analyzes Dart code to
+# check for errors, warnings, and lints.
+#
+# The issues identified by the analyzer are surfaced in the UI of Dart-enabled
+# IDEs (https://dart.dev/tools#ides-and-editors). The analyzer can also be
+# invoked from the command line by running `flutter analyze`.
+
+# The following line activates a set of recommended lints for Flutter apps,
+# packages, and plugins designed to encourage good coding practices.
+include: package:flutter_lints/flutter.yaml
+
+linter:
+  # The lint rules applied to this project can be customized in the
+  # section below to disable rules from the `package:flutter_lints/flutter.yaml`
+  # included above or to enable additional rules. A list of all available lints
+  # and their documentation is published at
+  # https://dart-lang.github.io/linter/lints/index.html.
+  #
+  # Instead of disabling a lint rule for the entire project in the
+  # section below, it can also be suppressed for a single line of code
+  # or a specific dart file by using the `// ignore: name_of_lint` and
+  # `// ignore_for_file: name_of_lint` syntax on the line or in the file
+  # producing the lint.
+  rules:
+    # avoid_print: false  # Uncomment to disable the `avoid_print` rule
+    # prefer_single_quotes: true  # Uncomment to enable the `prefer_single_quotes` rule
+
+# Additional information about this file can be found at
+# https://dart.dev/guides/language/analysis-options

flutter/todo_cubit_wasm/assets

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+../todo/assets/

flutter/todo_cubit_wasm/lib/blocs/cubit/filter_cubit.dart

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+import 'package:bloc/bloc.dart';
+import 'package:plugin/generated/rid_api.dart';
+
+class FilterCubit extends Cubit<Filter> {
+  final Store _store = Store.instance;
+  FilterCubit() : super(Store.instance.filter);
+
+  Future<void> setFilter(Filter filter) async {
+    await _store.msgSetFilter(filter);
+    emit(_store.filter);
+  }
+}

flutter/todo_cubit_wasm/lib/blocs/cubit/settings_cubit.dart

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+import 'package:bloc/bloc.dart';
+import 'package:plugin/generated/rid_api.dart';
+
+class SettingsCubit extends Cubit<Settings> {
+  final Store _store = Store.instance;
+  SettingsCubit() : super(Store.instance.settings);
+
+  Future<void> setAutoExpireCompleted(bool val) async {
+    await _store.msgSetAutoExpireCompletedTodos(val);
+    emit(_store.settings);
+  }
+}

flutter/todo_cubit_wasm/lib/blocs/cubit/todo_cubit.dart

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+import 'dart:async';
+
+import 'package:bloc/bloc.dart';
+import 'package:flutter/foundation.dart';
+import 'package:meta/meta.dart';
+import 'package:plugin/generated/rid_api.dart';
+
+part 'todo_state.dart';
+
+class TodoCubit extends Cubit<TodoState> {
+  final Store _store = Store.instance;
+  late final StreamSubscription<PostedReply> tickSub;
+  TodoCubit(Todo todo) : super(ExistingTodo(todo)) {
+    _subscribe();
+  }
+
+  // Reply.Tick is a reply that includes data, in this case the id
+  // of the completed todo whose life is ticking away
+  bool _tickIsForThisTodo(PostedReply reply) {
+    // We make sure that the data is a parseable int id
+    assert(
+      reply.data != null,
+      'Reply.Tick should include data containing the id of the ticked todo',
+    );
+    final id = int.tryParse(reply.data!);
+    assert(id != null, 'Reply.Tick included invalid id ${reply.data}');
+    return id == state.id;
+  }
+
+  void _subscribe() {
+    tickSub = replyChannel.stream
+        .where((x) => x.type == Reply.Tick && _tickIsForThisTodo(x))
+        .listen(_refreshState);
+  }
+
+  @override
+  Future<void> close() {
+    tickSub.cancel();
+    return super.close();
+  }
+
+  void _refreshState(PostedReply _reply) async {
+    final todo = _store.todoById(state.id);
+    if (todo == null) {
+      emit(MissingTodo(state.id));
+    } else {
+      emit(ExistingTodo(todo));
+    }
+  }
+
+  Future<void> toggleCompleted() =>
+      _store.msgToggleTodo(state.id).then(_refreshState);
+
+  Future<void> removeTodo(int id) =>
+      _store.msgRemoveTodo(id).then(_refreshState);
+}

flutter/todo_cubit_wasm/lib/blocs/cubit/todo_state.dart

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+part of 'todo_cubit.dart';
+
+@immutable
+abstract class TodoState {
+  final int id;
+
+  TodoState(this.id);
+
+  @override
+  bool operator ==(Object other) =>
+      identical(this, other) || other is TodoState && other.id == id;
+
+  @override
+  int get hashCode => id;
+}
+
+class ExistingTodo extends TodoState {
+  final Todo todo;
+
+  ExistingTodo(this.todo) : super(todo.id);
+
+  @override
+  bool operator ==(Object other) =>
+      identical(this, other) || other is ExistingTodo && other.todo == todo;
+
+  @override
+  int get hashCode => todo.hashCode;
+}
+
+class MissingTodo extends TodoState {
+  MissingTodo(int id) : super(id);
+
+  @override
+  bool operator ==(Object other) =>
+      identical(this, other) || other is MissingTodo && other.id == id;
+
+  @override
+  int get hashCode => super.hashCode;
+}