From 9ea5bafecfba2a6cf80de9326a3291ebd53c803c Mon Sep 17 00:00:00 2001
From: Tien Do Nam <dev.tien.donam@gmail.com>
Date: Fri, 16 Sep 2022 16:52:10 +0200
Subject: [PATCH] fix: interpolation bugs

---
 slang/lib/builder/model/node.dart             |  5 +++-
 .../string_interpolation_extensions.dart      |  5 ++--
 .../string_interpolation_extensions_test.dart | 25 +++++++++++++++++++
 3 files changed, 32 insertions(+), 3 deletions(-)

diff --git a/slang/lib/builder/model/node.dart b/slang/lib/builder/model/node.dart
index 5b2f27da..4153071c 100644
--- a/slang/lib/builder/model/node.dart
+++ b/slang/lib/builder/model/node.dart
@@ -485,7 +485,10 @@ _ParamWithArg _parseParamWithArg({
   required String input,
   required CaseStyle? paramCase,
 }) {
-  final match = RegexUtils.paramWithArg.firstMatch(input)!;
+  final match = RegexUtils.paramWithArg.firstMatch(input);
+  if (match == null) {
+    throw 'Rich text parameters must follow the syntax: "param(default text)"\nGot instead: "$input"\n';
+  }
   return _ParamWithArg(match.group(1)!.toCase(paramCase), match.group(3));
 }
 
diff --git a/slang/lib/builder/utils/string_interpolation_extensions.dart b/slang/lib/builder/utils/string_interpolation_extensions.dart
index f48ce9b1..fd85c2da 100644
--- a/slang/lib/builder/utils/string_interpolation_extensions.dart
+++ b/slang/lib/builder/utils/string_interpolation_extensions.dart
@@ -56,9 +56,10 @@ String _replaceBetween({
       buffer.write(curr.substring(0, startIndex));
     }
 
-    int endIndex = curr.indexOf(endCharacter);
+    int endIndex =
+        curr.indexOf(endCharacter, startIndex + startCharacterLength);
     if (endIndex == -1) {
-      buffer.write(curr);
+      buffer.write(curr.substring(startIndex));
       break;
     }
 
diff --git a/slang/test/unit/utils/string_interpolation_extensions_test.dart b/slang/test/unit/utils/string_interpolation_extensions_test.dart
index cd1459b3..75889087 100644
--- a/slang/test/unit/utils/string_interpolation_extensions_test.dart
+++ b/slang/test/unit/utils/string_interpolation_extensions_test.dart
@@ -37,6 +37,21 @@ void main() {
       expect(input.braces(), 'Hello X');
     });
 
+    test('start with closing bracket', () {
+      final input = '} {a}';
+      expect(input.braces(), '} X');
+    });
+
+    test('ends with opening bracket', () {
+      final input = '{a} {';
+      expect(input.braces(), 'X {');
+    });
+
+    test('has double braces instead single braces', () {
+      final input = 'Hello {{a}} {{b}}';
+      expect(input.braces(), 'Hello X} X}');
+    });
+
     test('ignore \\{ only', () {
       final input = 'Hello \\{ World!';
       expect(input.braces(), 'Hello { World!');
@@ -69,6 +84,16 @@ void main() {
       expect(input.doubleBraces(), 'Hello X');
     });
 
+    test('start with closing bracket', () {
+      final input = '}} {{a}}';
+      expect(input.doubleBraces(), '}} X');
+    });
+
+    test('ends with opening bracket', () {
+      final input = '{{a}} {{';
+      expect(input.doubleBraces(), 'X {{');
+    });
+
     test('ignore \\{{ only', () {
       final input = 'Hello \\{{ World!';
       expect(input.doubleBraces(), 'Hello {{ World!');