improve uri handling

app/lib/data/database/converters/uri.dart

@@ -25,7 +25,8 @@ class UriConverter extends TypeConverter<Uri, String> {
 
   @override
   Uri fromSql(String fromDb) {
-    return uri_parser.tryParseUrl(fromDb, eagerParsing: true)!;
+    return uri_parser.tryParseUrl(fromDb, eagerParsing: true) ??
+        Uri.parse(fromDb);
   }
 
   @override

app/lib/features/geckoview/features/search/presentation/dialogs/edit_top_site_dialog.dart

@@ -18,6 +18,7 @@
  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  */
 import 'package:flutter/material.dart';
+import 'package:weblibre/utils/uri_parser.dart' as uri_parser;
 
 Future<({String title, Uri url})?> showEditTopSiteDialog(
   BuildContext context, {
@@ -94,8 +95,11 @@ class _EditTopSiteDialogState extends State<_EditTopSiteDialog> {
                 if (value == null || value.trim().isEmpty) {
                   return 'URL cannot be empty';
                 }
-                final uri = Uri.tryParse(value.trim());
+                final parsed = uri_parser.tryParseUrl(
-                if (uri == null || !uri.hasScheme || uri.host.isEmpty) {
+                  value.trim(),
+                  eagerParsing: true,
+                );
+                if (parsed == null) {
                   return 'Enter a valid URL';
                 }
                 return null;
@@ -112,7 +116,11 @@ class _EditTopSiteDialogState extends State<_EditTopSiteDialog> {
         TextButton(
           onPressed: () {
             if (_formKey.currentState?.validate() == true) {
-              final url = Uri.parse(_urlController.text.trim());
+              final url = uri_parser.tryParseUrl(
+                _urlController.text.trim(),
+                eagerParsing: true,
+              );
+              if (url == null) return;
               Navigator.pop(
                 context,
                 (title: _titleController.text.trim(), url: url),

app/lib/features/geckoview/features/top_sites/domain/repositories/top_site_repository.dart

@@ -30,6 +30,7 @@ import 'package:weblibre/features/geckoview/features/top_sites/data/providers.da
 import 'package:weblibre/features/geckoview/features/top_sites/domain/entities/top_site_item.dart';
 import 'package:weblibre/features/geckoview/features/top_sites/domain/entities/top_site_source.dart';
 import 'package:weblibre/features/geckoview/features/top_sites/domain/providers.dart';
+import 'package:weblibre/utils/uri_parser.dart' as uri_parser;
 
 part 'top_site_repository.g.dart';
 
@@ -81,9 +82,7 @@ class TopSiteRepository extends _$TopSiteRepository {
     final remaining = targetCount - persisted.length;
     final historyItems = await _getHistoryItems(
       limit: remaining,
-      excludeUrls: persisted
+      excludeUrls: persisted.map((s) => s.url.normalized.toString()).toSet(),
-          .map((s) => s.url.normalized.toString())
-          .toSet(),
     );
 
     return [...persisted, ...historyItems];
@@ -126,10 +125,23 @@ class TopSiteRepository extends _$TopSiteRepository {
     );
   }
 
+  static Uri _validateUrl(Uri url) {
+    final normalized = url.normalized;
+    final parsed = uri_parser.tryParseUrl(
+      normalized.toString(),
+      eagerParsing: true,
+    );
+    if (parsed == null) {
+      throw ArgumentError.value(url.toString(), 'url', 'Invalid URL');
+    }
+    return normalized;
+  }
+
   Future<String> addPinnedSite({
     required String title,
     required Uri url,
   }) async {
+    _validateUrl(url);
     final db = ref.read(topSiteDatabaseProvider);
 
     // Check if URL already exists as a persisted site
@@ -163,6 +175,7 @@ class TopSiteRepository extends _$TopSiteRepository {
     required String title,
     required Uri url,
   }) {
+    _validateUrl(url);
     return ref
         .read(topSiteDatabaseProvider)
         .topSiteDao