From effbc42f2295e8eb1bdb2b4d228b4684dc7bcefd Mon Sep 17 00:00:00 2001
From: Aman <aman2@me.iitr.ac.in>
Date: Mon, 21 Mar 2022 16:25:46 +0530
Subject: [PATCH] feat: implement custom builder for backticks content

---
 lib/services/ib_engine_service.dart           | 21 +---------
 lib/ui/views/ib/ib_page_view.dart             |  2 +
 .../ib/syntaxes/ib_backticks_syntax.dart      | 38 +++++++++++++++++++
 .../ib/syntaxes/ib_inline_html_syntax.dart    |  4 +-
 4 files changed, 43 insertions(+), 22 deletions(-)
 create mode 100644 lib/ui/views/ib/syntaxes/ib_backticks_syntax.dart

diff --git a/lib/services/ib_engine_service.dart b/lib/services/ib_engine_service.dart
index 1f570c09..135a3502 100644
--- a/lib/services/ib_engine_service.dart
+++ b/lib/services/ib_engine_service.dart
@@ -249,31 +249,12 @@ class IbEngineServiceImpl implements IbEngineService {
 
     if (_ibRawPageData == null) return null;
 
-    /// Inline HTML Tags bounded by Backticks(`) are not parsed
-    /// For example,
-    ///   2<sup>6</sup> -> 2^6
-    ///   whereas, `2<sup>6</sup>` -> `2<sup>6</sup>`
-    final content = HtmlUnescape()
-        .convert(_ibRawPageData.rawContent)
-        .splitMapJoin(
-          RegExp(r'\`(.*?)\`'),
-          onMatch: (m) {
-            if (m[1] != null &&
-                RegExp(r'<(\S*?)[^>]*>(.*?)<\/\1>|<.*?\/>').hasMatch(m[1]!)) {
-              return '${m[1]}';
-            }
-
-            return '${m[0]}';
-          },
-          onNonMatch: (n) => n,
-        );
-
     return IbPageData(
       id: _ibRawPageData.id,
       pageUrl: _ibRawPageData.httpUrl,
       title: _ibRawPageData.title,
       content: [
-        IbMd(content: '$content\n'),
+        IbMd(content: '${HtmlUnescape().convert(_ibRawPageData.rawContent)}\n'),
       ],
       tableOfContents: _ibRawPageData.hasToc
           ? _getTableOfContents(_ibRawPageData.content!)
diff --git a/lib/ui/views/ib/ib_page_view.dart b/lib/ui/views/ib/ib_page_view.dart
index 83cea9e6..93ac5c31 100644
--- a/lib/ui/views/ib/ib_page_view.dart
+++ b/lib/ui/views/ib/ib_page_view.dart
@@ -19,6 +19,7 @@ import 'package:mobile_app/ui/views/ib/builders/ib_pop_quiz_builder.dart';
 import 'package:mobile_app/ui/views/ib/builders/ib_subscript_builder.dart';
 import 'package:mobile_app/ui/views/ib/builders/ib_superscript_builder.dart';
 import 'package:mobile_app/ui/views/ib/builders/ib_webview_builder.dart';
+import 'package:mobile_app/ui/views/ib/syntaxes/ib_backticks_syntax.dart';
 import 'package:mobile_app/ui/views/ib/syntaxes/ib_embed_syntax.dart';
 import 'package:mobile_app/ui/views/ib/syntaxes/ib_filter_syntax.dart';
 import 'package:mobile_app/ui/views/ib/syntaxes/ib_inline_html_syntax.dart';
@@ -214,6 +215,7 @@ class _IbPageViewState extends State<IbPageView> {
         [
           IbInlineHtmlSyntax(builders: _inlineBuilders),
           IbMathjaxSyntax(),
+          IbBackTicksSyntax(),
           md.EmojiSyntax(),
           ...md.ExtensionSet.gitHubFlavored.inlineSyntaxes,
         ],
diff --git a/lib/ui/views/ib/syntaxes/ib_backticks_syntax.dart b/lib/ui/views/ib/syntaxes/ib_backticks_syntax.dart
new file mode 100644
index 00000000..6976d644
--- /dev/null
+++ b/lib/ui/views/ib/syntaxes/ib_backticks_syntax.dart
@@ -0,0 +1,38 @@
+import 'package:markdown/markdown.dart' as md;
+import 'package:mobile_app/ui/views/ib/syntaxes/ib_inline_html_syntax.dart';
+
+class IbBackTicksSyntax extends md.InlineSyntax {
+  IbBackTicksSyntax() : super(_pattern);
+
+  static const String _pattern = r'\`(.*?)\`';
+
+  @override
+  bool onMatch(md.InlineParser parser, Match match) {
+    final String matched = match[1] ?? '';
+
+    final inlineRegex = RegExp(IbInlineHtmlSyntax.Pattern);
+
+    /// Inline HTML Tags bounded by Backticks(`) are not parsed
+    if (inlineRegex.hasMatch(matched)) {
+      for (var word in matched.split(' ')) {
+        if (inlineRegex.hasMatch(word)) {
+          parser.addNode(md.Text(word.substring(0, word.indexOf('<'))));
+
+          final match = inlineRegex.firstMatch(word);
+          if (match != null) {
+            parser.addNode(md.Element.text(match[1]!, match[2]!));
+          }
+
+          parser.addNode(
+              md.Text("${word.substring(word.lastIndexOf('>') + 1)} "));
+          continue;
+        }
+        parser.addNode(md.Text('$word '));
+      }
+    } else {
+      parser.addNode(md.Element.text('code', matched));
+    }
+
+    return true;
+  }
+}
diff --git a/lib/ui/views/ib/syntaxes/ib_inline_html_syntax.dart b/lib/ui/views/ib/syntaxes/ib_inline_html_syntax.dart
index 8e8e255f..8fed2a3c 100644
--- a/lib/ui/views/ib/syntaxes/ib_inline_html_syntax.dart
+++ b/lib/ui/views/ib/syntaxes/ib_inline_html_syntax.dart
@@ -2,11 +2,11 @@ import 'package:flutter_markdown/flutter_markdown.dart';
 import 'package:markdown/markdown.dart' as md;
 
 class IbInlineHtmlSyntax extends md.InlineSyntax {
-  IbInlineHtmlSyntax({required this.builders}) : super(_pattern);
+  IbInlineHtmlSyntax({required this.builders}) : super(Pattern);
 
   Map<String, MarkdownElementBuilder> builders;
 
-  static const String _pattern = r'<(\S*?)[^>]*>(.*?)<\/\1>|<.*?\/>';
+  static const String Pattern = r'<(\S*?)[^>]*>(.*?)<\/\1>|<.*?\/>';
 
   @override
   bool onMatch(md.InlineParser parser, Match match) {