added timestamp to bloc cache, showing age in offline mode

lib/state/app/infrastructure/utilityWidgets/loadableHydratedBloc/loadable_hydrated_bloc.dart

@@ -6,6 +6,7 @@ import '../../loadableState/loading_error.dart';
 import '../../repository/repository.dart';
 import 'loadable_hydrated_bloc_event.dart';
 import '../../loadableState/loadable_state.dart';
+import 'loadable_save_context.dart';
 
 abstract class LoadableHydratedBloc<
   TEvent extends LoadableHydratedBlocEvent<TState>,
@@ -17,10 +18,29 @@ abstract class LoadableHydratedBloc<
 > {
   late TRepository _repository;
   LoadableHydratedBloc() : super(const LoadableState()) {
-    on<Emit<TState>>((event, emit) => emit(LoadableState(isLoading: event.loading, data: event.state(innerState ?? fromNothing()), reFetch: retry)));
-    on<RefetchStarted<TState>>((event, emit) => emit(LoadableState(isLoading: true, data: innerState)));
+
+    on<Emit<TState>>((event, emit) => emit(LoadableState(
+        isLoading: event.loading,
+        data: event.state(innerState ?? fromNothing()),
+        lastFetch: DateTime.now().millisecondsSinceEpoch,
+        reFetch: retry
+    )));
+
+    on<RefetchStarted<TState>>((event, emit) => emit(LoadableState(
+        isLoading: true,
+        data: innerState,
+        lastFetch: state.lastFetch
+    )));
+
     on<ClearState<TState>>((event, emit) => emit(const LoadableState()));
-    on<Error<TState>>((event, emit) => emit(LoadableState(isLoading: false, data: innerState, reFetch: retry, error: event.error)));
+
+    on<Error<TState>>((event, emit) => emit(LoadableState(
+        isLoading: false,
+        data: innerState,
+        lastFetch: state.lastFetch,
+        reFetch: retry,
+        error: event.error
+    )));
 
     _repository = repository();
     fetch();
@@ -41,19 +61,26 @@ abstract class LoadableHydratedBloc<
       (e) {
         log('Error while fetching ${TState.toString()}: ${e.toString()}');
         add(Error(LoadingError(
-          message: e.toString(),
+          message: e.message,
           allowRetry: true,
         )));
-      }
+      },
     ).then((value) {
       log('Fetch for ${TState.toString()} completed!');
     });
   }
 
   @override
-  fromJson(Map<String, dynamic> json) => LoadableState(isLoading: true, data: fromStorage(json));
+  fromJson(Map<String, dynamic> json) {
+    var rawData = LoadableSaveContext.unwrap(json);
+    return LoadableState(isLoading: true, lastFetch: rawData.meta.timestamp, data: fromStorage(rawData.data));
+  }
+
   @override
-  Map<String, dynamic>? toJson(LoadableState<TState> state) => state.data == null ? {} : state.data.toJson();
+  Map<String, dynamic>? toJson(LoadableState<TState> state) => LoadableSaveContext.wrap(
+      toStorage(state.data),
+      state.lastFetch ?? DateTime.now().millisecondsSinceEpoch
+  );
 
   Future<void> gatherData();
   TRepository repository();

lib/state/app/infrastructure/utilityWidgets/loadableHydratedBloc/loadable_save_context.dart

@@ -0,0 +1,24 @@
+import 'package:freezed_annotation/freezed_annotation.dart';
+
+part 'loadable_save_context.freezed.dart';
+part 'loadable_save_context.g.dart';
+
+@freezed
+class LoadableSaveContext with _$LoadableSaveContext {
+  const LoadableSaveContext._();
+  const factory LoadableSaveContext({
+    required int timestamp,
+  }) = _LoadableSaveContext;
+
+  factory LoadableSaveContext.fromJson(Map<String, dynamic> json) => _$LoadableSaveContextFromJson(json);
+
+  static String dataKey = 'data';
+  static String metaKey = 'meta';
+
+  static Map<String, dynamic> wrap(Map<String, dynamic>? data, int lastFetch) =>
+      {dataKey: data, metaKey: LoadableSaveContext(timestamp: lastFetch).toJson()};
+
+  static ({Map<String, dynamic> data, LoadableSaveContext meta}) unwrap(Map<String, dynamic> data) =>
+      (data: data[dataKey] as Map<String, dynamic>, meta: LoadableSaveContext.fromJson(data[metaKey]));
+}
+

lib/state/app/infrastructure/utilityWidgets/loadableHydratedBloc/loadable_save_context.freezed.dart

@@ -0,0 +1,155 @@
+// coverage:ignore-file
+// GENERATED CODE - DO NOT MODIFY BY HAND
+// ignore_for_file: type=lint
+// ignore_for_file: unused_element, deprecated_member_use, deprecated_member_use_from_same_package, use_function_type_syntax_for_parameters, unnecessary_const, avoid_init_to_null, invalid_override_different_default_values_named, prefer_expression_function_bodies, annotate_overrides, invalid_annotation_target, unnecessary_question_mark
+
+part of 'loadable_save_context.dart';
+
+// **************************************************************************
+// FreezedGenerator
+// **************************************************************************
+
+T _$identity<T>(T value) => value;
+
+final _privateConstructorUsedError = UnsupportedError(
+    'It seems like you constructed your class using `MyClass._()`. This constructor is only meant to be used by freezed and you are not supposed to need it nor use it.\nPlease check the documentation here for more information: https://github.com/rrousselGit/freezed#adding-getters-and-methods-to-our-models');
+
+LoadableSaveContext _$LoadableSaveContextFromJson(Map<String, dynamic> json) {
+  return _LoadableSaveContext.fromJson(json);
+}
+
+/// @nodoc
+mixin _$LoadableSaveContext {
+  int get timestamp => throw _privateConstructorUsedError;
+
+  Map<String, dynamic> toJson() => throw _privateConstructorUsedError;
+  @JsonKey(ignore: true)
+  $LoadableSaveContextCopyWith<LoadableSaveContext> get copyWith =>
+      throw _privateConstructorUsedError;
+}
+
+/// @nodoc
+abstract class $LoadableSaveContextCopyWith<$Res> {
+  factory $LoadableSaveContextCopyWith(
+          LoadableSaveContext value, $Res Function(LoadableSaveContext) then) =
+      _$LoadableSaveContextCopyWithImpl<$Res, LoadableSaveContext>;
+  @useResult
+  $Res call({int timestamp});
+}
+
+/// @nodoc
+class _$LoadableSaveContextCopyWithImpl<$Res, $Val extends LoadableSaveContext>
+    implements $LoadableSaveContextCopyWith<$Res> {
+  _$LoadableSaveContextCopyWithImpl(this._value, this._then);
+
+  // ignore: unused_field
+  final $Val _value;
+  // ignore: unused_field
+  final $Res Function($Val) _then;
+
+  @pragma('vm:prefer-inline')
+  @override
+  $Res call({
+    Object? timestamp = null,
+  }) {
+    return _then(_value.copyWith(
+      timestamp: null == timestamp
+          ? _value.timestamp
+          : timestamp // ignore: cast_nullable_to_non_nullable
+              as int,
+    ) as $Val);
+  }
+}
+
+/// @nodoc
+abstract class _$$LoadableSaveContextImplCopyWith<$Res>
+    implements $LoadableSaveContextCopyWith<$Res> {
+  factory _$$LoadableSaveContextImplCopyWith(_$LoadableSaveContextImpl value,
+          $Res Function(_$LoadableSaveContextImpl) then) =
+      __$$LoadableSaveContextImplCopyWithImpl<$Res>;
+  @override
+  @useResult
+  $Res call({int timestamp});
+}
+
+/// @nodoc
+class __$$LoadableSaveContextImplCopyWithImpl<$Res>
+    extends _$LoadableSaveContextCopyWithImpl<$Res, _$LoadableSaveContextImpl>
+    implements _$$LoadableSaveContextImplCopyWith<$Res> {
+  __$$LoadableSaveContextImplCopyWithImpl(_$LoadableSaveContextImpl _value,
+      $Res Function(_$LoadableSaveContextImpl) _then)
+      : super(_value, _then);
+
+  @pragma('vm:prefer-inline')
+  @override
+  $Res call({
+    Object? timestamp = null,
+  }) {
+    return _then(_$LoadableSaveContextImpl(
+      timestamp: null == timestamp
+          ? _value.timestamp
+          : timestamp // ignore: cast_nullable_to_non_nullable
+              as int,
+    ));
+  }
+}
+
+/// @nodoc
+@JsonSerializable()
+class _$LoadableSaveContextImpl extends _LoadableSaveContext {
+  const _$LoadableSaveContextImpl({required this.timestamp}) : super._();
+
+  factory _$LoadableSaveContextImpl.fromJson(Map<String, dynamic> json) =>
+      _$$LoadableSaveContextImplFromJson(json);
+
+  @override
+  final int timestamp;
+
+  @override
+  String toString() {
+    return 'LoadableSaveContext(timestamp: $timestamp)';
+  }
+
+  @override
+  bool operator ==(Object other) {
+    return identical(this, other) ||
+        (other.runtimeType == runtimeType &&
+            other is _$LoadableSaveContextImpl &&
+            (identical(other.timestamp, timestamp) ||
+                other.timestamp == timestamp));
+  }
+
+  @JsonKey(ignore: true)
+  @override
+  int get hashCode => Object.hash(runtimeType, timestamp);
+
+  @JsonKey(ignore: true)
+  @override
+  @pragma('vm:prefer-inline')
+  _$$LoadableSaveContextImplCopyWith<_$LoadableSaveContextImpl> get copyWith =>
+      __$$LoadableSaveContextImplCopyWithImpl<_$LoadableSaveContextImpl>(
+          this, _$identity);
+
+  @override
+  Map<String, dynamic> toJson() {
+    return _$$LoadableSaveContextImplToJson(
+      this,
+    );
+  }
+}
+
+abstract class _LoadableSaveContext extends LoadableSaveContext {
+  const factory _LoadableSaveContext({required final int timestamp}) =
+      _$LoadableSaveContextImpl;
+  const _LoadableSaveContext._() : super._();
+
+  factory _LoadableSaveContext.fromJson(Map<String, dynamic> json) =
+      _$LoadableSaveContextImpl.fromJson;
+
+  @override
+  int get timestamp;
+  @override
+  @JsonKey(ignore: true)
+  _$$LoadableSaveContextImplCopyWith<_$LoadableSaveContextImpl> get copyWith =>
+      throw _privateConstructorUsedError;
+}

lib/state/app/infrastructure/utilityWidgets/loadableHydratedBloc/loadable_save_context.g.dart

@@ -0,0 +1,19 @@
+// GENERATED CODE - DO NOT MODIFY BY HAND
+
+part of 'loadable_save_context.dart';
+
+// **************************************************************************
+// JsonSerializableGenerator
+// **************************************************************************
+
+_$LoadableSaveContextImpl _$$LoadableSaveContextImplFromJson(
+        Map<String, dynamic> json) =>
+    _$LoadableSaveContextImpl(
+      timestamp: json['timestamp'] as int,
+    );
+
+Map<String, dynamic> _$$LoadableSaveContextImplToJson(
+        _$LoadableSaveContextImpl instance) =>
+    <String, dynamic>{
+      'timestamp': instance.timestamp,
+    };