Improve nested lists

Co-authored-by: Copilot <copilot@github.com>

lib/Md/MdParser.cpp

@@ -19,6 +19,15 @@ static std::string trimLeft(const std::string& s) {
   return s.substr(i);
 }
 
+static uint8_t parseListIndentLevel(size_t leadingSpaces) {
+  // Top-level list markers may be preceded by up to 3 spaces.
+  // Nested list items require at least 4 spaces before the marker.
+  if (leadingSpaces < TAB_WIDTH) {
+    return 0;
+  }
+  return static_cast<uint8_t>((leadingSpaces - TAB_WIDTH) / TAB_WIDTH + 1);
+}
+
 static bool isWordChar(char c) { return std::isalnum(static_cast<unsigned char>(c)) || c == '_'; }
 
 static bool isUnderscoreEmphasis(const std::string& text, size_t pos, size_t count) {
@@ -249,7 +258,8 @@ ParsedLine parseLine(const std::string& rawLine, bool inCodeBlock) {
     return result;
   }
 
-  // Count leading whitespace for nesting level before trimming
+  // Count leading whitespace for nesting level before trimming.
+  // Up to 3 spaces before a list marker are still top-level in CommonMark.
   size_t leadingSpaces = 0;
   for (size_t i = 0; i < rawLine.size(); i++) {
     if (rawLine[i] == ' ')
@@ -259,7 +269,7 @@ ParsedLine parseLine(const std::string& rawLine, bool inCodeBlock) {
     else
       break;
   }
-  result.indentLevel = static_cast<uint8_t>(leadingSpaces / TAB_WIDTH);
+  result.indentLevel = parseListIndentLevel(leadingSpaces);
 
   std::string trimmed = trimLeft(rawLine);
 

src/activities/reader/MdReaderActivity.cpp

@@ -335,13 +335,18 @@ bool MdReaderActivity::wordWrapParsedLine(const MdParser::ParsedLine& parsed, in
   const int availableWidth = viewportWidth - indent;
   if (availableWidth <= 0) return true;
 
-  // Build a flat list of all spans, prepending the list prefix if present
+  // Build a flat list of all spans, prepending the list prefix if present.
   std::vector<MdParser::Span> allSpans;
   if (!parsed.listPrefix.empty()) {
     allSpans.push_back({parsed.listPrefix, EpdFontFamily::REGULAR});
   }
   allSpans.insert(allSpans.end(), parsed.spans.begin(), parsed.spans.end());
 
+  const int listPrefixIndent =
+      !parsed.listPrefix.empty()
+          ? renderer.getTextAdvanceX(cachedFontId, parsed.listPrefix.c_str(), EpdFontFamily::REGULAR)
+          : 0;
+
   // Check if everything fits on one line
   int totalWidth = measureSpans(allSpans);
   if (totalWidth <= availableWidth) {
@@ -359,6 +364,7 @@ bool MdReaderActivity::wordWrapParsedLine(const MdParser::ParsedLine& parsed, in
   currentLine.isCodeBlock = isCodeBlock;
   int currentWidth = 0;
   bool fullyConsumed = true;
+  bool firstLine = true;
 
   for (size_t si = 0; si < allSpans.size(); si++) {
     const auto& span = allSpans[si];
@@ -415,8 +421,10 @@ bool MdReaderActivity::wordWrapParsedLine(const MdParser::ParsedLine& parsed, in
           }
         } else {
           outLines.push_back(std::move(currentLine));
+          firstLine = false;
           currentLine = RenderedLine();
-          currentLine.indent = indent;
+          currentLine.indent = indent + (firstLine ? 0 : listPrefixIndent);
+          currentLine.isCodeBlock = isCodeBlock;
           currentWidth = 0;
           continue;
         }
@@ -424,8 +432,9 @@ bool MdReaderActivity::wordWrapParsedLine(const MdParser::ParsedLine& parsed, in
 
       currentLine.spans.push_back({remaining.substr(0, breakPos), style});
       outLines.push_back(std::move(currentLine));
+      firstLine = false;
       currentLine = RenderedLine();
-      currentLine.indent = indent;
+      currentLine.indent = indent + (firstLine ? 0 : listPrefixIndent);
       currentLine.isCodeBlock = isCodeBlock;
       currentWidth = 0;
 

test/md_parser/MdParserTest.cpp

@@ -78,6 +78,26 @@ void testUnderscoreBoldWorks() {
   PASS();
 }
 
+void testNestedUnorderedListIndentLevel() {
+  printf("testNestedUnorderedListIndentLevel...\n");
+  auto parsed = MdParser::parseLine("    - nested item", false);
+  ASSERT_EQ(parsed.blockType, MdParser::BlockType::UnorderedList);
+  ASSERT_EQ(parsed.listPrefix, "\xe2\x80\xa2 ");
+  ASSERT_EQ(parsed.indentLevel, 1);
+  ASSERT_EQ(flattenText(parsed.spans), "nested item");
+  PASS();
+}
+
+void testNestedOrderedListIndentLevel() {
+  printf("testNestedOrderedListIndentLevel...\n");
+  auto parsed = MdParser::parseLine("        1. nested ordered", false);
+  ASSERT_EQ(parsed.blockType, MdParser::BlockType::OrderedList);
+  ASSERT_EQ(parsed.listPrefix, "1. ");
+  ASSERT_EQ(parsed.indentLevel, 2);
+  ASSERT_EQ(flattenText(parsed.spans), "nested ordered");
+  PASS();
+}
+
 int main() {
   printf("=== Markdown Parser Tests ===\n\n");
 
@@ -86,6 +106,8 @@ int main() {
   testUnderscoreEmphasisStillWorks();
   testAsteriskEmphasisStillWorks();
   testUnderscoreBoldWorks();
+  testNestedUnorderedListIndentLevel();
+  testNestedOrderedListIndentLevel();
 
   printf("\n=== Results: %d passed, %d failed ===\n", testsPassed, testsFailed);
   return testsFailed > 0 ? 1 : 0;