adding i18n for dynamic page

2026-10-02 22:03:21 +05:30
parent 63ecc3e7e6
commit 2527b957aa
23 changed files with 3053 additions and 2 deletions
@@ -0,0 +1,92 @@
+import 'package:flutter/material.dart';
+import 'package:shared_preferences/shared_preferences.dart';
+
+/// Single source of truth for app language (Group-2).
+/// Drives BOTH systems together:
+/// - ARB static words via MaterialApp.locale (AppLocalizations)
+/// - wireframe field words via DynamicStrings.tr(key) backed by
+///   assets/translations_dynamic/{lang}.json (free, offline, KBs).
+/// Revert: remove provider wiring in main.dart; generated screens fall back
+/// to English keys (DynamicStrings.tr returns readable fallback, never crash).
+class LocaleProvider with ChangeNotifier {
+  static const _prefKey = 'app_locale_code';
+  static const supportedCodes = ['en', 'hi'];
+
+  Locale _locale = const Locale('en');
+  Locale get locale => _locale;
+  String get code => _locale.languageCode;
+
+  /// lang -> (key -> translated value). Embedded assets loaded once at startup.
+  final Map<String, Map<String, String>> _tables = {};
+
+  /// Server-supplied diff cache (future: portal-backend translations API).
+  /// Key format: "lang::key" -> value, persisted to SharedPreferences.
+  final Map<String, String> _serverDiff = {};
+
+  bool _ready = false;
+  bool get ready => _ready;
+
+  Future<void> init() async {
+    final prefs = await SharedPreferences.getInstance();
+    final saved = prefs.getString(_prefKey);
+    if (saved != null && supportedCodes.contains(saved)) {
+      _locale = Locale(saved);
+    }
+    _ready = true;
+    notifyListeners();
+  }
+
+  /// Called once from bootstrap with preloaded asset tables.
+  void seedTables(Map<String, Map<String, String>> tables) {
+    _tables.addAll(tables);
+  }
+
+  /// Merge server diff (new wireframe fields added after release).
+  /// Works offline afterwards because diff is persisted.
+  Future<void> updateFromServer(Map<String, String> words, String lang) async {
+    if (words.isEmpty) return;
+    final table = _tables.putIfAbsent(lang, () => {});
+    table.addAll(words);
+    for (final e in words.entries) {
+      _serverDiff['$lang::${e.key}'] = e.value;
+    }
+    final prefs = await SharedPreferences.getInstance();
+    // Persist each entry individually to survive restarts (small volume).
+    for (final e in words.entries) {
+      await prefs.setString('dyn_${lang}_${e.key}', e.value);
+    }
+    notifyListeners();
+  }
+
+  Future<void> loadServerCache() async {
+    final prefs = await SharedPreferences.getInstance();
+    for (final lang in supportedCodes) {
+      final table = _tables.putIfAbsent(lang, () => {});
+      for (final key in prefs.getKeys().where((k) => k.startsWith('dyn_${lang}_'))) {
+        final field = key.substring('dyn_${lang}_'.length);
+        final v = prefs.getString(key);
+        if (v != null) table[field] = v;
+      }
+    }
+    notifyListeners();
+  }
+
+  Future<void> setLocale(String code) async {
+    if (!supportedCodes.contains(code)) return;
+    _locale = Locale(code);
+    final prefs = await SharedPreferences.getInstance();
+    await prefs.setString(_prefKey, code);
+    notifyListeners();
+  }
+
+  /// Runtime lookup for wireframe-driven strings.
+  /// Never throws: missing key -> English table -> pretty fallback.
+  String trDynamic(String key) {
+    final norm = key.trim().toLowerCase().replaceAll(RegExp(r'\s+'), '_');
+    final cur = _tables[code]?[norm];
+    if (cur != null && cur.isNotEmpty) return cur;
+    final en = _tables['en']?[norm];
+    if (en != null && en.isNotEmpty) return en;
+    return key.replaceAll('_', ' ');
+  }
+}