Frontend first draft

frontend/pshared/lib/models/settings/localizations.dart

@@ -0,0 +1,77 @@
+import 'package:flutter/material.dart';
+
+
+typedef LangLocalization = Map<String, String>;
+
+String _translation(LangLocalization loc, String key) {
+  return loc[key] ?? '';
+}
+
+typedef Localizations = Map<String, LangLocalization>;
+
+typedef Localizer = String Function(BuildContext);
+
+class Localization {
+
+  static const String keyHint = 'hint';
+  static const String keyLink = 'link';
+  static const String keyName = 'name';
+  static const String keyError = 'error';
+  static const String keyAddress = 'address';
+  static const String keyDetails = 'details';
+  static const String keyRoute = 'route';
+  static const String keyLocationName = 'location_name';
+
+  static String _localizeImp(Localizations localizations, String locale, String Function(LangLocalization) functor) {
+    final localization = localizations[locale];
+    if (localization != null) {
+      return functor(localization);
+    }
+    return '';
+  }
+
+  static String _localize(Localizations localizations, String locale, String Function(LangLocalization) functor, {String? fallback}) {
+    final res = _localizeImp(localizations, locale, functor);
+    return res.isNotEmpty ? res : (fallback ?? '');
+  }
+
+  static bool localizationExists(Localizations loc, String locale) {
+    return loc.containsKey(locale);
+  }
+
+  static String hint(Localizations loc, String locale, {String? fallback}) {
+    return _localize(loc, locale, (localization) => _translation(localization, keyHint), fallback: fallback);
+  }
+
+  static String link(Localizations loc, String locale, {String? fallback}) {
+    return _localize(loc, locale, (localization) => _translation(localization, keyLink), fallback: fallback);
+  }
+
+  static String name(Localizations loc, String locale, {String? fallback}) {
+    return _localize(loc, locale, (localization) => _translation(localization, keyName), fallback: fallback);
+  }
+
+  static String error(Localizations loc, String locale, {String? fallback}) {
+    return _localize(loc, locale, (localization) => _translation(localization, keyError), fallback: fallback);
+  }
+
+  static String address(Localizations loc, String locale, {String? fallback}) {
+    return _localize(loc, locale, (localization) => _translation(localization, keyAddress), fallback: fallback);
+  }
+
+  static String details(Localizations loc, String locale, {String? fallback}) {
+    return _localize(loc, locale, (localization) => _translation(localization, keyDetails), fallback: fallback);
+  }
+
+  static String route(Localizations loc, String locale, {String? fallback}) {
+    return _localize(loc, locale, (localization) => _translation(localization, keyRoute), fallback: fallback);
+  }
+
+  static String locationName(Localizations loc, String locale, {String? fallback}) {
+    return _localize(loc, locale, (localization) => _translation(localization, keyLocationName), fallback: fallback);
+  }
+
+  static String translate(Localizations loc, String locale, String key, {String? fallback}) {
+    return _localize(loc, locale, (localization) => _translation(localization, key), fallback: fallback);
+  }
+}

frontend/pshared/lib/models/settings/time_validity.dart

@@ -0,0 +1,27 @@
+import 'package:json_annotation/json_annotation.dart';
+
+part 'time_validity.g.dart';
+
+
+@JsonSerializable()
+class TimeValidity {
+  final DateTime? start;
+  final DateTime? expiry;
+
+  const TimeValidity({this.start, this.expiry});
+
+  bool get isExpired => expiry?.isBefore(DateTime.now()) ?? false;
+  bool get isNotStarted => start?.isAfter(DateTime.now()) ?? false;
+  bool get isActive => (!isNotStarted) && (!isExpired);
+
+  TimeValidity copyWith({
+    DateTime? Function()? start, 
+    DateTime? Function()? expiry, 
+  }) => TimeValidity(
+    start: start == null ? this.start : start(),
+    expiry: expiry == null ? this.expiry : expiry(),
+  );
+
+  factory TimeValidity.fromJson(Map<String, dynamic> json) => _$TimeValidityFromJson(json);
+  Map<String, dynamic> toJson() => _$TimeValidityToJson(this);
+}