From 72f6d5ad52fcb119d68346ed7a712a0490d053ed Mon Sep 17 00:00:00 2001
From: Edouard Marquez <moi@edouard-marquez.me>
Date: Fri, 15 Sep 2023 11:27:06 +0200
Subject: [PATCH 1/8] When we highlight a suggestion, we can't rely on the
 `removeDiacritics`, as it replaces some letters of 1 word into 2 or +

---
 .../smooth_app/lib/widgets/smooth_text.dart   | 21 ++++++++++++++++---
 1 file changed, 18 insertions(+), 3 deletions(-)

diff --git a/packages/smooth_app/lib/widgets/smooth_text.dart b/packages/smooth_app/lib/widgets/smooth_text.dart
index 12820b00cc7..f247466b1d9 100644
--- a/packages/smooth_app/lib/widgets/smooth_text.dart
+++ b/packages/smooth_app/lib/widgets/smooth_text.dart
@@ -1,4 +1,3 @@
-import 'package:diacritic/diacritic.dart';
 import 'package:flutter/material.dart';
 
 /// An extension on [TextStyle] that allows to have "well spaced" variant
@@ -92,8 +91,8 @@ class TextHighlighter extends StatelessWidget {
     required TextStyle? highlightedStyle,
   }) {
     final Iterable<RegExpMatch> highlightedParts =
-        RegExp(removeDiacritics(filter).toLowerCase().trim()).allMatches(
-      removeDiacritics(text).toLowerCase(),
+        RegExp(_removeAccents(filter).toLowerCase().trim()).allMatches(
+      _removeAccents(text).toLowerCase(),
     );
 
     final List<(String, TextStyle?)> parts = <(String, TextStyle?)>[];
@@ -123,4 +122,20 @@ class TextHighlighter extends StatelessWidget {
     }
     return parts;
   }
+
+  /// We can't rely on [removeDiacritics] here, as it replaces some characters
+  /// of 1 letter into 2 or more.
+  /// That's why this simpler algorithm is used instead.
+  String _removeAccents(String str) {
+    const String withAccents =
+        'ÀÁÂÃÄÅàáâãäåÒÓÔÕÕÖØòóôõöøÈÉÊËèéêëðÇçÐÌÍÎÏìíîïÙÚÛÜùúûüÑñŠšŸÿýŽž';
+    const String withoutAccents =
+        'AAAAAAaaaaaaOOOOOOOooooooEEEEeeeeeCcDIIIIiiiiUUUUuuuuNnSsYyyZz';
+
+    for (int i = 0; i < withAccents.length; i++) {
+      str = str.replaceAll(withAccents[i], withoutAccents[i]);
+    }
+
+    return str;
+  }
 }

From 7af2c89f18e1da87b10057fcfec129168d0a3f68 Mon Sep 17 00:00:00 2001
From: Edouard Marquez <moi@edouard-marquez.me>
Date: Sat, 9 Dec 2023 02:47:05 +0100
Subject: [PATCH 2/8] Better algorithm

---
 .../widgets/language_selector.dart            |  16 +--
 .../pages/onboarding/country_selector.dart    |  21 ++--
 .../user_preferences_search_page.dart         |   5 +-
 .../nutrition_add_nutrient_button.dart        |  11 +-
 .../smooth_app/lib/widgets/smooth_text.dart   | 111 ++++++++++++++----
 .../test/utils/smooth_text_test.dart          |  21 ++++
 6 files changed, 140 insertions(+), 45 deletions(-)
 create mode 100644 packages/smooth_app/test/utils/smooth_text_test.dart

diff --git a/packages/smooth_app/lib/generic_lib/widgets/language_selector.dart b/packages/smooth_app/lib/generic_lib/widgets/language_selector.dart
index bf813b3100e..76279771889 100644
--- a/packages/smooth_app/lib/generic_lib/widgets/language_selector.dart
+++ b/packages/smooth_app/lib/generic_lib/widgets/language_selector.dart
@@ -146,19 +146,21 @@ class LanguageSelector extends StatelessWidget {
             prefixIcon: const Icon(Icons.search),
             controller: languageSelectorController,
             onChanged: (String? query) {
-              query = removeDiacritics(query!.trim().toLowerCase());
+              query = query!.trim().toLowerCase().removeDiacritics();
 
               setState(
                 () {
                   filteredList = leftovers
                       .where((OpenFoodFactsLanguage item) =>
-                          removeDiacritics(_languages
-                                  .getNameInEnglish(item)
-                                  .toLowerCase())
+                          _languages
+                              .getNameInEnglish(item)
+                              .toLowerCase()
+                              .removeDiacritics()
                               .contains(query!.toLowerCase()) ||
-                          removeDiacritics(_languages
-                                  .getNameInLanguage(item)
-                                  .toLowerCase())
+                          _languages
+                              .getNameInLanguage(item)
+                              .toLowerCase()
+                              .removeDiacritics()
                               .contains(query.toLowerCase()) ||
                           item.code.contains(query))
                       .toList();
diff --git a/packages/smooth_app/lib/pages/onboarding/country_selector.dart b/packages/smooth_app/lib/pages/onboarding/country_selector.dart
index bb5ff8dbb97..1511233a5d3 100644
--- a/packages/smooth_app/lib/pages/onboarding/country_selector.dart
+++ b/packages/smooth_app/lib/pages/onboarding/country_selector.dart
@@ -104,23 +104,26 @@ class _CountrySelectorState extends State<CountrySelector> {
                         prefixIcon: const Icon(Icons.search),
                         controller: _countryController,
                         onChanged: (String? query) {
-                          query = removeDiacritics(query!.trim().toLowerCase());
+                          query =
+                              query!.trim().toLowerCase().removeDiacritics();
 
                           setState(
                             () {
                               filteredList = _countryList
                                   .where(
                                     (Country item) =>
-                                        removeDiacritics(
-                                                item.name.toLowerCase())
+                                        item.name
+                                            .toLowerCase()
+                                            .removeDiacritics()
                                             .contains(
-                                          query!,
-                                        ) ||
-                                        removeDiacritics(
-                                                item.countryCode.toLowerCase())
+                                              query!,
+                                            ) ||
+                                        item.countryCode
+                                            .toLowerCase()
+                                            .removeDiacritics()
                                             .contains(
-                                          query,
-                                        ),
+                                              query,
+                                            ),
                                   )
                                   .toList(growable: false);
                             },
diff --git a/packages/smooth_app/lib/pages/preferences/user_preferences_search_page.dart b/packages/smooth_app/lib/pages/preferences/user_preferences_search_page.dart
index ded2608cd82..3ba5ed641b9 100644
--- a/packages/smooth_app/lib/pages/preferences/user_preferences_search_page.dart
+++ b/packages/smooth_app/lib/pages/preferences/user_preferences_search_page.dart
@@ -6,6 +6,7 @@ import 'package:smooth_app/generic_lib/design_constants.dart';
 import 'package:smooth_app/pages/preferences/abstract_user_preferences.dart';
 import 'package:smooth_app/pages/preferences/user_preferences_item.dart';
 import 'package:smooth_app/pages/preferences/user_preferences_page.dart';
+import 'package:smooth_app/widgets/smooth_text.dart';
 
 /// Search page for preferences, with TextField filter.
 class UserPreferencesSearchPage extends StatefulWidget {
@@ -70,7 +71,7 @@ class _UserPreferencesSearchPageState extends State<UserPreferencesSearchPage> {
     final String searchString,
     final UserPreferences userPreferences,
   ) {
-    final String needle = removeDiacritics(searchString.toLowerCase());
+    final String needle = searchString.toLowerCase().removeDiacritics();
     final List<Widget> result = <Widget>[];
     final List<PreferencePageType> types =
         PreferencePageType.getPreferencePageTypes(userPreferences);
@@ -101,7 +102,7 @@ class _UserPreferencesSearchPageState extends State<UserPreferencesSearchPage> {
 
   bool _findLabels(final String needle, final Iterable<String> labels) {
     for (final String label in labels) {
-      if (removeDiacritics(label.toLowerCase()).contains(needle)) {
+      if (label.toLowerCase().removeDiacritics().contains(needle)) {
         return true;
       }
     }
diff --git a/packages/smooth_app/lib/pages/product/nutrition_add_nutrient_button.dart b/packages/smooth_app/lib/pages/product/nutrition_add_nutrient_button.dart
index b513ed827bf..9ffb61a8edb 100644
--- a/packages/smooth_app/lib/pages/product/nutrition_add_nutrient_button.dart
+++ b/packages/smooth_app/lib/pages/product/nutrition_add_nutrient_button.dart
@@ -55,9 +55,14 @@ class NutritionAddNutrientButton extends StatelessWidget {
                 controller: nutritionTextController,
                 onChanged: (String? query) => setState(
                   () => filteredList = leftovers
-                      .where((OrderedNutrient item) =>
-                          removeDiacritics(item.name!).toLowerCase().contains(
-                              removeDiacritics(query!).toLowerCase().trim()))
+                      .where(
+                        (OrderedNutrient item) => item.name!
+                            .removeDiacritics()
+                            .toLowerCase()
+                            .contains(
+                              query!.removeDiacritics().toLowerCase().trim(),
+                            ),
+                      )
                       .toList(),
                 ),
               ),
diff --git a/packages/smooth_app/lib/widgets/smooth_text.dart b/packages/smooth_app/lib/widgets/smooth_text.dart
index f247466b1d9..8caa8c21fd8 100644
--- a/packages/smooth_app/lib/widgets/smooth_text.dart
+++ b/packages/smooth_app/lib/widgets/smooth_text.dart
@@ -1,4 +1,30 @@
+import 'package:diacritic/diacritic.dart' as lib show removeDiacritics;
 import 'package:flutter/material.dart';
+import 'package:smooth_app/services/smooth_services.dart';
+
+/// An extension on [String]
+extension StringExtension on String {
+  /// Simple algorithm to only remove accents AND not diacritics.
+  String removeAccents() {
+    const String withAccents =
+        'ÀÁÂÃÄÅàáâãäåÒÓÔÕÕÖØòóôõöøÈÉÊËèéêëðÇçÐÌÍÎÏìíîïÙÚÛÜùúûüÑñŠšŸÿýŽž';
+    const String withoutAccents =
+        'AAAAAAaaaaaaOOOOOOOooooooEEEEeeeeeCcDIIIIiiiiUUUUuuuuNnSsYyyZz';
+
+    String str = this;
+    for (int i = 0; i < withAccents.length; i++) {
+      str = str.replaceAll(withAccents[i], withoutAccents[i]);
+    }
+
+    return str;
+  }
+
+  /// Please use this method instead of directly calling the library.
+  /// It will use the migration if we decide to remove/change it.
+  String removeDiacritics() {
+    return lib.removeDiacritics(this);
+  }
+}
 
 /// An extension on [TextStyle] that allows to have "well spaced" variant
 extension TextStyleExtension on TextStyle {
@@ -59,13 +85,23 @@ class TextHighlighter extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    final List<(String, TextStyle?)> parts = _getParts(
-      defaultStyle: TextStyle(fontWeight: selected ? FontWeight.bold : null),
-      highlightedStyle: TextStyle(
-        fontWeight: selected ? FontWeight.bold : null,
-        backgroundColor: Theme.of(context).primaryColor.withOpacity(0.2),
-      ),
-    );
+    List<(String, TextStyle?)> parts;
+    try {
+      parts = _getParts(
+        defaultStyle: TextStyle(fontWeight: selected ? FontWeight.bold : null),
+        highlightedStyle: TextStyle(
+          fontWeight: selected ? FontWeight.bold : null,
+          backgroundColor: Theme.of(context).primaryColor.withOpacity(0.2),
+        ),
+      );
+    } catch (e, trace) {
+      parts = <(String, TextStyle?)>[(text, null)];
+      Logs.e(
+        'Unable to parse text "$text" with filter "$filter".',
+        ex: e,
+        stacktrace: trace,
+      );
+    }
 
     final TextStyle defaultTextStyle = DefaultTextStyle.of(context).style;
 
@@ -90,9 +126,15 @@ class TextHighlighter extends StatelessWidget {
     required TextStyle? defaultStyle,
     required TextStyle? highlightedStyle,
   }) {
+    final String filterWithoutDiacritics = filter.removeDiacritics();
+    final int filterDiacriticsLength =
+        filterWithoutDiacritics.length - filter.length;
+    final String textWithoutDiacritics = text.removeDiacritics();
+    final int textDiacriticsLength = textWithoutDiacritics.length - text.length;
+
     final Iterable<RegExpMatch> highlightedParts =
-        RegExp(_removeAccents(filter).toLowerCase().trim()).allMatches(
-      _removeAccents(text).toLowerCase(),
+        RegExp(filterWithoutDiacritics.toLowerCase().trim()).allMatches(
+      textWithoutDiacritics.toLowerCase(),
     );
 
     final List<(String, TextStyle?)> parts = <(String, TextStyle?)>[];
@@ -102,40 +144,61 @@ class TextHighlighter extends StatelessWidget {
     } else {
       parts
           .add((text.substring(0, highlightedParts.first.start), defaultStyle));
+      int diff = 0;
+
       for (int i = 0; i != highlightedParts.length; i++) {
         final RegExpMatch subPart = highlightedParts.elementAt(i);
+        final int startPosition = subPart.start - diff;
+        final int endPosition = _computeEndPosition(
+          startPosition,
+          subPart.end - diff,
+          subPart,
+          textWithoutDiacritics,
+          filterWithoutDiacritics,
+        );
+        diff = subPart.end - endPosition;
 
         parts.add(
-          (text.substring(subPart.start, subPart.end), highlightedStyle),
+          (text.substring(startPosition, endPosition), highlightedStyle),
         );
 
         if (i < highlightedParts.length - 1) {
           parts.add((
             text.substring(
-                subPart.end, highlightedParts.elementAt(i + 1).start),
+                endPosition, highlightedParts.elementAt(i + 1).start - diff),
             defaultStyle
           ));
-        } else if (subPart.end < text.length) {
-          parts.add((text.substring(subPart.end, text.length), defaultStyle));
+        } else if (endPosition < text.length) {
+          parts.add((text.substring(endPosition, text.length), defaultStyle));
         }
       }
     }
     return parts;
   }
 
-  /// We can't rely on [removeDiacritics] here, as it replaces some characters
-  /// of 1 letter into 2 or more.
-  /// That's why this simpler algorithm is used instead.
-  String _removeAccents(String str) {
-    const String withAccents =
-        'ÀÁÂÃÄÅàáâãäåÒÓÔÕÕÖØòóôõöøÈÉÊËèéêëðÇçÐÌÍÎÏìíîïÙÚÛÜùúûüÑñŠšŸÿýŽž';
-    const String withoutAccents =
-        'AAAAAAaaaaaaOOOOOOOooooooEEEEeeeeeCcDIIIIiiiiUUUUuuuuNnSsYyyZz';
+  int _computeEndPosition(
+    int startPosition,
+    int endPosition,
+    RegExpMatch subPart,
+    String textWithoutDiacritics,
+    String filterWithoutDiacritics,
+  ) {
+    final String subText = text.substring(startPosition);
+    if (subText.startsWith(filterWithoutDiacritics)) {
+      return endPosition;
+    }
 
-    for (int i = 0; i < withAccents.length; i++) {
-      str = str.replaceAll(withAccents[i], withoutAccents[i]);
+    int diff = 0;
+    for (int pos = 0; pos < endPosition; pos++) {
+      if (pos == subText.length - 1) {
+        diff = pos - (subText.length);
+        break;
+      }
+
+      final int charLength = subText[pos].removeDiacritics().length;
+      diff -= charLength > 1 ? charLength - 1 : 0;
     }
 
-    return str;
+    return endPosition + diff;
   }
 }
diff --git a/packages/smooth_app/test/utils/smooth_text_test.dart b/packages/smooth_app/test/utils/smooth_text_test.dart
new file mode 100644
index 00000000000..9a4004af6d1
--- /dev/null
+++ b/packages/smooth_app/test/utils/smooth_text_test.dart
@@ -0,0 +1,21 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:smooth_app/widgets/smooth_text.dart' show StringExtension;
+
+void main() {
+  group('Smooth text', () {
+    group('String extension', () {
+      test('Remove accents', () {
+        expect(
+          'àáâãäåéèêëòóôõöìíîïùúûüñšÿýž'.removeAccents(),
+          equals('aaaaaaeeeeoooooiiiiuuuunsyyz'),
+        );
+      });
+      test('Remove diacritics', () {
+        expect(
+          'àáâãäåéèêëòóôõöìíîïùúûüñšÿýž'.removeDiacritics(),
+          equals('aaaaaaeeeeoooooiiiiuuuunsyyz'),
+        );
+      });
+    });
+  });
+}

From 6a775a6b64ad2fd0526fa559522e4bce1edeb5e0 Mon Sep 17 00:00:00 2001
From: Edouard Marquez <moi@edouard-marquez.me>
Date: Sat, 9 Dec 2023 02:50:03 +0100
Subject: [PATCH 3/8] Remove unused things

---
 .../smooth_app/lib/generic_lib/widgets/language_selector.dart  | 1 -
 packages/smooth_app/lib/pages/onboarding/country_selector.dart | 1 -
 .../lib/pages/preferences/user_preferences_search_page.dart    | 1 -
 .../lib/pages/product/nutrition_add_nutrient_button.dart       | 1 -
 packages/smooth_app/lib/widgets/smooth_text.dart               | 3 ---
 5 files changed, 7 deletions(-)

diff --git a/packages/smooth_app/lib/generic_lib/widgets/language_selector.dart b/packages/smooth_app/lib/generic_lib/widgets/language_selector.dart
index 76279771889..bf9f2d97ed9 100644
--- a/packages/smooth_app/lib/generic_lib/widgets/language_selector.dart
+++ b/packages/smooth_app/lib/generic_lib/widgets/language_selector.dart
@@ -1,4 +1,3 @@
-import 'package:diacritic/diacritic.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter_gen/gen_l10n/app_localizations.dart';
 import 'package:openfoodfacts/openfoodfacts.dart';
diff --git a/packages/smooth_app/lib/pages/onboarding/country_selector.dart b/packages/smooth_app/lib/pages/onboarding/country_selector.dart
index 1511233a5d3..da5c4699860 100644
--- a/packages/smooth_app/lib/pages/onboarding/country_selector.dart
+++ b/packages/smooth_app/lib/pages/onboarding/country_selector.dart
@@ -1,4 +1,3 @@
-import 'package:diacritic/diacritic.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
 import 'package:flutter_gen/gen_l10n/app_localizations.dart';
diff --git a/packages/smooth_app/lib/pages/preferences/user_preferences_search_page.dart b/packages/smooth_app/lib/pages/preferences/user_preferences_search_page.dart
index 3ba5ed641b9..4bd879f7ad4 100644
--- a/packages/smooth_app/lib/pages/preferences/user_preferences_search_page.dart
+++ b/packages/smooth_app/lib/pages/preferences/user_preferences_search_page.dart
@@ -1,4 +1,3 @@
-import 'package:diacritic/diacritic.dart';
 import 'package:flutter/material.dart';
 import 'package:provider/provider.dart';
 import 'package:smooth_app/data_models/preferences/user_preferences.dart';
diff --git a/packages/smooth_app/lib/pages/product/nutrition_add_nutrient_button.dart b/packages/smooth_app/lib/pages/product/nutrition_add_nutrient_button.dart
index 9ffb61a8edb..21fd7e56e77 100644
--- a/packages/smooth_app/lib/pages/product/nutrition_add_nutrient_button.dart
+++ b/packages/smooth_app/lib/pages/product/nutrition_add_nutrient_button.dart
@@ -1,4 +1,3 @@
-import 'package:diacritic/diacritic.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter_gen/gen_l10n/app_localizations.dart';
 import 'package:openfoodfacts/openfoodfacts.dart';
diff --git a/packages/smooth_app/lib/widgets/smooth_text.dart b/packages/smooth_app/lib/widgets/smooth_text.dart
index 8caa8c21fd8..78b3ee63bbb 100644
--- a/packages/smooth_app/lib/widgets/smooth_text.dart
+++ b/packages/smooth_app/lib/widgets/smooth_text.dart
@@ -127,10 +127,7 @@ class TextHighlighter extends StatelessWidget {
     required TextStyle? highlightedStyle,
   }) {
     final String filterWithoutDiacritics = filter.removeDiacritics();
-    final int filterDiacriticsLength =
-        filterWithoutDiacritics.length - filter.length;
     final String textWithoutDiacritics = text.removeDiacritics();
-    final int textDiacriticsLength = textWithoutDiacritics.length - text.length;
 
     final Iterable<RegExpMatch> highlightedParts =
         RegExp(filterWithoutDiacritics.toLowerCase().trim()).allMatches(

From a8fdddaae9b752486c069d458a346652dfc4e894 Mon Sep 17 00:00:00 2001
From: Edouard Marquez <moi@edouard-marquez.me>
Date: Sat, 9 Dec 2023 02:52:18 +0100
Subject: [PATCH 4/8] Fix typo

---
 packages/smooth_app/lib/widgets/smooth_text.dart | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/smooth_app/lib/widgets/smooth_text.dart b/packages/smooth_app/lib/widgets/smooth_text.dart
index 78b3ee63bbb..1a95eb8b59d 100644
--- a/packages/smooth_app/lib/widgets/smooth_text.dart
+++ b/packages/smooth_app/lib/widgets/smooth_text.dart
@@ -20,7 +20,7 @@ extension StringExtension on String {
   }
 
   /// Please use this method instead of directly calling the library.
-  /// It will use the migration if we decide to remove/change it.
+  /// It will ease the migration if we decide to remove/change it.
   String removeDiacritics() {
     return lib.removeDiacritics(this);
   }

From daecba15c3c356733ea814e934780a03f4924de5 Mon Sep 17 00:00:00 2001
From: Edouard Marquez <moi@edouard-marquez.me>
Date: Sat, 9 Dec 2023 02:54:21 +0100
Subject: [PATCH 5/8] Unnecessary brackets

---
 packages/smooth_app/lib/widgets/smooth_text.dart | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/smooth_app/lib/widgets/smooth_text.dart b/packages/smooth_app/lib/widgets/smooth_text.dart
index 1a95eb8b59d..262cbb27cef 100644
--- a/packages/smooth_app/lib/widgets/smooth_text.dart
+++ b/packages/smooth_app/lib/widgets/smooth_text.dart
@@ -188,7 +188,7 @@ class TextHighlighter extends StatelessWidget {
     int diff = 0;
     for (int pos = 0; pos < endPosition; pos++) {
       if (pos == subText.length - 1) {
-        diff = pos - (subText.length);
+        diff = pos - subText.length;
         break;
       }
 

From 23caf4fb142ea4dc0223700939730531db1af9b7 Mon Sep 17 00:00:00 2001
From: Edouard Marquez <moi@edouard-marquez.me>
Date: Mon, 11 Dec 2023 14:17:29 +0100
Subject: [PATCH 6/8] Replace all `toLowerCase` + `removeDiacritics` by a
 single `getComparisonSafeString`

---
 .../lib/generic_lib/widgets/language_selector.dart |  8 +++-----
 .../lib/pages/onboarding/country_selector.dart     |  8 +++-----
 .../preferences/user_preferences_search_page.dart  |  4 ++--
 .../product/nutrition_add_nutrient_button.dart     |  6 +++---
 packages/smooth_app/lib/widgets/smooth_text.dart   | 14 ++++++++++----
 5 files changed, 21 insertions(+), 19 deletions(-)

diff --git a/packages/smooth_app/lib/generic_lib/widgets/language_selector.dart b/packages/smooth_app/lib/generic_lib/widgets/language_selector.dart
index bf9f2d97ed9..3239402d9f8 100644
--- a/packages/smooth_app/lib/generic_lib/widgets/language_selector.dart
+++ b/packages/smooth_app/lib/generic_lib/widgets/language_selector.dart
@@ -145,7 +145,7 @@ class LanguageSelector extends StatelessWidget {
             prefixIcon: const Icon(Icons.search),
             controller: languageSelectorController,
             onChanged: (String? query) {
-              query = query!.trim().toLowerCase().removeDiacritics();
+              query = query!.trim().getComparisonSafeString();
 
               setState(
                 () {
@@ -153,13 +153,11 @@ class LanguageSelector extends StatelessWidget {
                       .where((OpenFoodFactsLanguage item) =>
                           _languages
                               .getNameInEnglish(item)
-                              .toLowerCase()
-                              .removeDiacritics()
+                              .getComparisonSafeString()
                               .contains(query!.toLowerCase()) ||
                           _languages
                               .getNameInLanguage(item)
-                              .toLowerCase()
-                              .removeDiacritics()
+                              .getComparisonSafeString()
                               .contains(query.toLowerCase()) ||
                           item.code.contains(query))
                       .toList();
diff --git a/packages/smooth_app/lib/pages/onboarding/country_selector.dart b/packages/smooth_app/lib/pages/onboarding/country_selector.dart
index da5c4699860..a64ca7c52c9 100644
--- a/packages/smooth_app/lib/pages/onboarding/country_selector.dart
+++ b/packages/smooth_app/lib/pages/onboarding/country_selector.dart
@@ -104,7 +104,7 @@ class _CountrySelectorState extends State<CountrySelector> {
                         controller: _countryController,
                         onChanged: (String? query) {
                           query =
-                              query!.trim().toLowerCase().removeDiacritics();
+                              query!.trim()..getComparisonSafeString();
 
                           setState(
                             () {
@@ -112,14 +112,12 @@ class _CountrySelectorState extends State<CountrySelector> {
                                   .where(
                                     (Country item) =>
                                         item.name
-                                            .toLowerCase()
-                                            .removeDiacritics()
+                                            .getComparisonSafeString()
                                             .contains(
                                               query!,
                                             ) ||
                                         item.countryCode
-                                            .toLowerCase()
-                                            .removeDiacritics()
+                                            .getComparisonSafeString()
                                             .contains(
                                               query,
                                             ),
diff --git a/packages/smooth_app/lib/pages/preferences/user_preferences_search_page.dart b/packages/smooth_app/lib/pages/preferences/user_preferences_search_page.dart
index 4bd879f7ad4..82e908eb516 100644
--- a/packages/smooth_app/lib/pages/preferences/user_preferences_search_page.dart
+++ b/packages/smooth_app/lib/pages/preferences/user_preferences_search_page.dart
@@ -70,7 +70,7 @@ class _UserPreferencesSearchPageState extends State<UserPreferencesSearchPage> {
     final String searchString,
     final UserPreferences userPreferences,
   ) {
-    final String needle = searchString.toLowerCase().removeDiacritics();
+    final String needle = searchString.getComparisonSafeString();
     final List<Widget> result = <Widget>[];
     final List<PreferencePageType> types =
         PreferencePageType.getPreferencePageTypes(userPreferences);
@@ -101,7 +101,7 @@ class _UserPreferencesSearchPageState extends State<UserPreferencesSearchPage> {
 
   bool _findLabels(final String needle, final Iterable<String> labels) {
     for (final String label in labels) {
-      if (label.toLowerCase().removeDiacritics().contains(needle)) {
+      if (label.getComparisonSafeString().contains(needle)) {
         return true;
       }
     }
diff --git a/packages/smooth_app/lib/pages/product/nutrition_add_nutrient_button.dart b/packages/smooth_app/lib/pages/product/nutrition_add_nutrient_button.dart
index 21fd7e56e77..1234051f5cf 100644
--- a/packages/smooth_app/lib/pages/product/nutrition_add_nutrient_button.dart
+++ b/packages/smooth_app/lib/pages/product/nutrition_add_nutrient_button.dart
@@ -56,10 +56,10 @@ class NutritionAddNutrientButton extends StatelessWidget {
                   () => filteredList = leftovers
                       .where(
                         (OrderedNutrient item) => item.name!
-                            .removeDiacritics()
-                            .toLowerCase()
+                            .trim()
+                            .getComparisonSafeString()
                             .contains(
-                              query!.removeDiacritics().toLowerCase().trim(),
+                              query!.trim().getComparisonSafeString(),
                             ),
                       )
                       .toList(),
diff --git a/packages/smooth_app/lib/widgets/smooth_text.dart b/packages/smooth_app/lib/widgets/smooth_text.dart
index 262cbb27cef..199d47cf083 100644
--- a/packages/smooth_app/lib/widgets/smooth_text.dart
+++ b/packages/smooth_app/lib/widgets/smooth_text.dart
@@ -24,6 +24,12 @@ extension StringExtension on String {
   String removeDiacritics() {
     return lib.removeDiacritics(this);
   }
+
+  /// Same as [removeDiacritics] but also lowercases the string.
+  /// Prefer this method when you want to compare two strings.
+  String getComparisonSafeString() {
+    return toLowerCase().removeDiacritics();
+  }
 }
 
 /// An extension on [TextStyle] that allows to have "well spaced" variant
@@ -126,12 +132,12 @@ class TextHighlighter extends StatelessWidget {
     required TextStyle? defaultStyle,
     required TextStyle? highlightedStyle,
   }) {
-    final String filterWithoutDiacritics = filter.removeDiacritics();
-    final String textWithoutDiacritics = text.removeDiacritics();
+    final String filterWithoutDiacritics = filter.getComparisonSafeString();
+    final String textWithoutDiacritics = text.getComparisonSafeString();
 
     final Iterable<RegExpMatch> highlightedParts =
-        RegExp(filterWithoutDiacritics.toLowerCase().trim()).allMatches(
-      textWithoutDiacritics.toLowerCase(),
+        RegExp(filterWithoutDiacritics.trim()).allMatches(
+      textWithoutDiacritics,
     );
 
     final List<(String, TextStyle?)> parts = <(String, TextStyle?)>[];

From d29e34e7fe17ea3ad7ef2f47c36efdd80c16b0f9 Mon Sep 17 00:00:00 2001
From: Edouard Marquez <moi@edouard-marquez.me>
Date: Mon, 11 Dec 2023 14:23:21 +0100
Subject: [PATCH 7/8] Reformat CountrySelector

---
 packages/smooth_app/lib/pages/onboarding/country_selector.dart | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/packages/smooth_app/lib/pages/onboarding/country_selector.dart b/packages/smooth_app/lib/pages/onboarding/country_selector.dart
index a64ca7c52c9..c49845a1be5 100644
--- a/packages/smooth_app/lib/pages/onboarding/country_selector.dart
+++ b/packages/smooth_app/lib/pages/onboarding/country_selector.dart
@@ -103,8 +103,7 @@ class _CountrySelectorState extends State<CountrySelector> {
                         prefixIcon: const Icon(Icons.search),
                         controller: _countryController,
                         onChanged: (String? query) {
-                          query =
-                              query!.trim()..getComparisonSafeString();
+                          query = query!.trim()..getComparisonSafeString();
 
                           setState(
                             () {

From b963ca240d030ffd9f698b9b9eb4ab1468cfd720 Mon Sep 17 00:00:00 2001
From: Edouard Marquez <moi@edouard-marquez.me>
Date: Tue, 12 Dec 2023 11:23:03 +0100
Subject: [PATCH 8/8] `removeAccents` removed + 1 new test

---
 packages/smooth_app/lib/widgets/smooth_text.dart  | 15 ---------------
 .../smooth_app/test/utils/smooth_text_test.dart   | 12 ++++++------
 2 files changed, 6 insertions(+), 21 deletions(-)

diff --git a/packages/smooth_app/lib/widgets/smooth_text.dart b/packages/smooth_app/lib/widgets/smooth_text.dart
index 199d47cf083..6447bf15e7b 100644
--- a/packages/smooth_app/lib/widgets/smooth_text.dart
+++ b/packages/smooth_app/lib/widgets/smooth_text.dart
@@ -4,21 +4,6 @@ import 'package:smooth_app/services/smooth_services.dart';
 
 /// An extension on [String]
 extension StringExtension on String {
-  /// Simple algorithm to only remove accents AND not diacritics.
-  String removeAccents() {
-    const String withAccents =
-        'ÀÁÂÃÄÅàáâãäåÒÓÔÕÕÖØòóôõöøÈÉÊËèéêëðÇçÐÌÍÎÏìíîïÙÚÛÜùúûüÑñŠšŸÿýŽž';
-    const String withoutAccents =
-        'AAAAAAaaaaaaOOOOOOOooooooEEEEeeeeeCcDIIIIiiiiUUUUuuuuNnSsYyyZz';
-
-    String str = this;
-    for (int i = 0; i < withAccents.length; i++) {
-      str = str.replaceAll(withAccents[i], withoutAccents[i]);
-    }
-
-    return str;
-  }
-
   /// Please use this method instead of directly calling the library.
   /// It will ease the migration if we decide to remove/change it.
   String removeDiacritics() {
diff --git a/packages/smooth_app/test/utils/smooth_text_test.dart b/packages/smooth_app/test/utils/smooth_text_test.dart
index 9a4004af6d1..1f7ed724b63 100644
--- a/packages/smooth_app/test/utils/smooth_text_test.dart
+++ b/packages/smooth_app/test/utils/smooth_text_test.dart
@@ -4,16 +4,16 @@ import 'package:smooth_app/widgets/smooth_text.dart' show StringExtension;
 void main() {
   group('Smooth text', () {
     group('String extension', () {
-      test('Remove accents', () {
+      test('Remove diacritics (oeuf)', () {
         expect(
-          'àáâãäåéèêëòóôõöìíîïùúûüñšÿýž'.removeAccents(),
-          equals('aaaaaaeeeeoooooiiiiuuuunsyyz'),
+          'œuf'.removeDiacritics(),
+          equals('oeuf'),
         );
       });
-      test('Remove diacritics', () {
+      test('Comparison Safe String', () {
         expect(
-          'àáâãäåéèêëòóôõöìíîïùúûüñšÿýž'.removeDiacritics(),
-          equals('aaaaaaeeeeoooooiiiiuuuunsyyz'),
+          'œuF'.getComparisonSafeString(),
+          equals('oeuf'),
         );
       });
     });