improved tab & topic handling

app/lib/features/search_browser/domain/providers.dart

@@ -2,12 +2,18 @@
 
 import 'dart:async';
 
+import 'package:collection/collection.dart';
 import 'package:flutter/widgets.dart';
+import 'package:flutter_inappwebview/flutter_inappwebview.dart';
 import 'package:lensai/features/bangs/data/models/bang_data.dart';
 import 'package:lensai/features/bangs/domain/repositories/data.dart';
 import 'package:lensai/features/search_browser/domain/entities/modes.dart';
 import 'package:lensai/features/search_browser/domain/entities/sheet.dart';
 import 'package:lensai/features/search_browser/domain/services/create_tab.dart';
+import 'package:lensai/features/topics/data/database/database.dart';
+import 'package:lensai/features/topics/domain/repositories/tab.dart';
+import 'package:lensai/features/web_view/domain/repositories/web_view.dart';
+import 'package:lensai/features/web_view/presentation/widgets/web_view.dart';
 import 'package:riverpod_annotation/riverpod_annotation.dart';
 import 'package:rxdart/rxdart.dart';
 
@@ -137,3 +143,65 @@ class ShowFindInPage extends _$ShowFindInPage {
     return false;
   }
 }
+
+@Riverpod()
+class WebViewWidgetCache extends _$WebViewWidgetCache {
+  final _requestedWidgets = <String>{};
+
+  List<TabData> _availableTabs = [];
+
+  @override
+  List<WebView> build() {
+    ref.listen(
+      tabRepositoryProvider,
+      (previous, next) {
+        if (next.hasValue && next.valueOrNull != null) {
+          _availableTabs = next.valueOrNull!;
+
+          _removeClosedWidgets();
+          _requestedWidgets.removeWhere(_ensureWidgetCached);
+        }
+      },
+    );
+
+    ref.listen(
+      webViewTabControllerProvider,
+      (_, tabId) {
+        if (tabId != null && !_ensureWidgetCached(tabId)) {
+          _requestedWidgets.add(tabId);
+        }
+      },
+    );
+
+    return stateOrNull ?? [];
+  }
+
+  void _removeClosedWidgets() {
+    state = [...state]..removeWhere(
+        (element) => !_availableTabs.any((tab) => tab.id == element.tabId),
+      );
+  }
+
+  bool _ensureWidgetCached(String tabId) {
+    final index = state.indexWhere((tab) => tab.tabId == tabId);
+    if (index < 0) {
+      final tab = _availableTabs.firstWhereOrNull((tab) => tab.id == tabId);
+      if (tab != null) {
+        state = [
+          ...state,
+          WebView(
+            key: GlobalKey(),
+            tabId: tabId,
+            initialUrlRequest: URLRequest(url: WebUri.uri(tab.url)),
+          ),
+        ];
+
+        return true;
+      }
+
+      return false;
+    }
+
+    return true;
+  }
+}