From 7cbd3bb1e760dff0f4a3cc080f0e48dc1f7a664a Mon Sep 17 00:00:00 2001
From: Maciej Pienczyn <maciej.pienczyn@inpi.pl>
Date: Mon, 23 Feb 2026 08:54:35 +0100
Subject: [PATCH] fix: forum markdown parser - autolinks, line spacing, Windows
 line endings

- Normalize \r\n to \n before processing
- Strip leading whitespace from lines (textarea indentation)
- Auto-link bare URLs works correctly inside list items
- Smart <br> insertion: skip block elements (ul, li, blockquote, pre)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
---
 utils/markdown.py | 37 +++++++++++++++++++++++++++++++------
 1 file changed, 31 insertions(+), 6 deletions(-)

diff --git a/utils/markdown.py b/utils/markdown.py
index 8cbb62a..a3196f1 100644
--- a/utils/markdown.py
+++ b/utils/markdown.py
@@ -3,7 +3,7 @@ Simple Markdown Parser for Forum
 ================================
 
 Converts basic markdown to safe HTML.
-Supports: bold, italic, code, links, lists, quotes, @mentions
+Supports: bold, italic, code, links, auto-links, lists, quotes, @mentions
 """
 
 import re
@@ -19,6 +19,7 @@ def parse_forum_markdown(text):
     - *italic* or _italic_
     - `inline code`
     - [link text](url)
+    - bare https://... URLs (auto-linked)
     - - list items
     - > quotes
     - @mentions (highlighted)
@@ -32,6 +33,9 @@ def parse_forum_markdown(text):
     if not text:
         return Markup('')
 
+    # Normalize line endings (Windows \r\n -> \n)
+    text = text.replace('\r\n', '\n').replace('\r', '\n')
+
     # Escape HTML first for security
     text = str(escape(text))
 
@@ -44,6 +48,17 @@ def parse_forum_markdown(text):
     for line in lines:
         stripped = line.strip()
 
+        # Skip empty lines but preserve paragraph spacing
+        if not stripped:
+            if in_list:
+                result_lines.append('</ul>')
+                in_list = False
+            if in_quote:
+                result_lines.append('</blockquote>')
+                in_quote = False
+            result_lines.append('')
+            continue
+
         # Quote blocks (> text)
         if stripped.startswith('&gt; '):  # Escaped >
             if not in_quote:
@@ -66,7 +81,7 @@ def parse_forum_markdown(text):
             result_lines.append('</ul>')
             in_list = False
 
-        result_lines.append(line)
+        result_lines.append(stripped)
 
     # Close open blocks
     if in_list:
@@ -121,11 +136,21 @@ def parse_forum_markdown(text):
         text
     )
 
-    # Convert newlines to <br> (but not inside pre/blockquote)
-    # Simple approach: just convert \n to <br>
-    text = text.replace('\n', '<br>\n')
+    # Convert newlines to <br> but skip lines that are HTML block elements
+    lines = text.split('\n')
+    output = []
+    for i, line in enumerate(lines):
+        output.append(line)
+        # Don't add <br> after block elements or before them
+        if i < len(lines) - 1:
+            stripped = line.strip()
+            next_stripped = lines[i + 1].strip() if i + 1 < len(lines) else ''
+            is_block = any(stripped.startswith(t) for t in ['<ul', '</ul>', '<li', '</li>', '<blockquote', '</blockquote>', '<pre', '</pre>'])
+            next_is_block = any(next_stripped.startswith(t) for t in ['<ul', '</ul>', '<li', '</li>', '<blockquote', '</blockquote>', '<pre', '</pre>'])
+            if not is_block and not next_is_block:
+                output.append('<br>')
 
-    return Markup(text)
+    return Markup('\n'.join(output))
 
 
 def register_markdown_filter(app):