From 9a356cf5a1d027e6ca97b30d799b0052da202c54 Mon Sep 17 00:00:00 2001
From: Giao Ho <joutvhu@gmail.com>
Date: Fri, 28 Apr 2023 19:34:41 +0700
Subject: [PATCH] Fix group of negative number.

---
 CHANGELOG.md                               |  4 ++
 lib/src/filter.dart                        |  9 +++-
 pubspec.yaml                               |  2 +-
 test/number_text_input_formatter_test.dart | 50 ++++++++++++++++++++++
 4 files changed, 63 insertions(+), 2 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index b9e7b06..dfe71ac 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 1.0.0+5
+
+- Fix group of negative numbers.
+
 ## 1.0.0+4
 
 - Allow disable fix number.
diff --git a/lib/src/filter.dart b/lib/src/filter.dart
index 6c99a45..9ef9d38 100644
--- a/lib/src/filter.dart
+++ b/lib/src/filter.dart
@@ -34,6 +34,7 @@ class TextNumberFilter {
   bool limitedNumber = false;
   bool limitedInteger = false;
   bool? limitedDecimal;
+  bool isNegative = false;
   bool numberStarted = false;
   bool hasNumber = false;
   bool foundNumbers = false;
@@ -81,6 +82,7 @@ class TextNumberFilter {
   bool filterNext(int value, int index, LookupTextValueEditor state) {
     bool allow = false;
     if (!numberStarted && options.allowNegative && value == _negative) {
+      isNegative = true;
       allow = true;
     } else if (decimalPoint == null) {
       if (_number_0 <= value && value <= _number_9) {
@@ -315,9 +317,14 @@ class TextNumberFilter {
   void groupDigits() {
     if (options.groupDigits != null) {
       var index = integerDigits;
+      var startPoint = 0;
+      if (isNegative) {
+        index += 1;
+        startPoint = 1;
+      }
       while (true) {
         index -= options.groupDigits!;
-        if (index < 1) {
+        if (index <= startPoint) {
           break;
         }
         editor.insert(index, groupSeparator);
diff --git a/pubspec.yaml b/pubspec.yaml
index 9084402..81b4a2c 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,6 +1,6 @@
 name: number_text_input_formatter
 description: Number Text Input Formatter for Flutter
-version: 1.0.0+4
+version: 1.0.0+5
 
 homepage: https://github.com/joutvhu/number_text_input_formatter
 repository: https://github.com/joutvhu/number_text_input_formatter.git
diff --git a/test/number_text_input_formatter_test.dart b/test/number_text_input_formatter_test.dart
index 0202116..dd7a22e 100644
--- a/test/number_text_input_formatter_test.dart
+++ b/test/number_text_input_formatter_test.dart
@@ -410,6 +410,56 @@ void main() {
     expect(result.text, '-2454.41');
   });
 
+  test('allow_negative_4', () {
+    var result = NumberTextInputFormatter(
+      integerDigits: 13,
+      decimalDigits: 2,
+      groupDigits: 3,
+      allowNegative: true,
+    ).formatEditUpdate(
+      const TextEditingValue(
+        text: '',
+      ),
+      const TextEditingValue(
+        text: '-245.41',
+      ),
+    );
+    expect(result.text, '-245.41');
+  });
+
+  test('allow_negative_5', () {
+    var result = NumberTextInputFormatter(
+      integerDigits: 13,
+      decimalDigits: 2,
+      groupDigits: 3,
+      allowNegative: true,
+    ).formatEditUpdate(
+      const TextEditingValue(
+        text: '',
+      ),
+      const TextEditingValue(
+        text: '-2405.41',
+      ),
+    );
+    expect(result.text, '-2,405.41');
+  });
+
+  test('allow_negative_6', () {
+    var result = NumberTextInputFormatter(
+      integerDigits: 13,
+      decimalDigits: 2,
+      allowNegative: true,
+    ).formatEditUpdate(
+      const TextEditingValue(
+        text: '',
+      ),
+      const TextEditingValue(
+        text: '--245.41',
+      ),
+    );
+    expect(result.text, '-245.41');
+  });
+
   test('insert_decimal_point_1', () {
     var result = NumberTextInputFormatter(
       integerDigits: 13,