From c7329644944e6a10e71ea7581bf0a5923ed9546b Mon Sep 17 00:00:00 2001
From: yggverse <yggverse@project>
Date: Mon, 9 Mar 2026 02:40:42 +0200
Subject: [PATCH] add header tags renderer

---
 .../tab/item/page/content/text/markdown.rs    | 30 ++--------
 .../item/page/content/text/markdown/tag.rs    | 56 ++++++++++++++++++-
 2 files changed, 59 insertions(+), 27 deletions(-)

diff --git a/src/app/browser/window/tab/item/page/content/text/markdown.rs b/src/app/browser/window/tab/item/page/content/text/markdown.rs
index 3ffef743..5dd62197 100644
--- a/src/app/browser/window/tab/item/page/content/text/markdown.rs
+++ b/src/app/browser/window/tab/item/page/content/text/markdown.rs
@@ -108,8 +108,10 @@ impl Markdown {
             t == 0 || t.is_multiple_of(2)
         };
 
-        // Parse in-line markdown tags
-        // * keep order!
+        // Render markdown tags
+        // * keep in order!
+
+        tag::header(&buffer, &tag);
 
         reference::image_link(&buffer, &tag, base, &link_color.0, &mut links);
         reference::image(&buffer, &tag, base, &link_color.0, &mut links);
@@ -201,30 +203,6 @@ impl Markdown {
                 }
             }
 
-            // Is 1-6 level header
-            for level in 1..=6 {
-                if let Some(t) = header(
-                    &buffer,
-                    match level {
-                        1 => &tag.h1,
-                        2 => &tag.h2,
-                        3 => &tag.h3,
-                        4 => &tag.h4,
-                        5 => &tag.h5,
-                        6 => &tag.h6,
-                        _ => unreachable!(),
-                    },
-                    line,
-                    &H.repeat(level),
-                ) {
-                    // Update document title by tag, if not set before
-                    if title.is_none() {
-                        title = Some(t);
-                    }
-                    continue 'l;
-                }
-            }
-
             // Is list
 
             if let Some(value) = ggemtext::line::list::Gemtext::as_value(line) {
diff --git a/src/app/browser/window/tab/item/page/content/text/markdown/tag.rs b/src/app/browser/window/tab/item/page/content/text/markdown/tag.rs
index 1ff62227..3a814541 100644
--- a/src/app/browser/window/tab/item/page/content/text/markdown/tag.rs
+++ b/src/app/browser/window/tab/item/page/content/text/markdown/tag.rs
@@ -4,11 +4,15 @@ mod plain;
 mod quote;
 mod title;
 
-use gtk::{TextTag, TextTagTable};
+use gtk::{
+    TextBuffer, TextTag, TextTagTable,
+    prelude::{TextBufferExt, TextBufferExtManual},
+};
 use header::Header;
 use list::List;
 use plain::Plain;
 use quote::Quote;
+use regex::Regex;
 use title::Title;
 
 pub struct Tag {
@@ -77,3 +81,53 @@ impl Tag {
         }
     }
 }
+
+// Headers `#`, `##`, etc.
+
+const REGEX_HEADER: &str = r"(?m)^(?P<level>#{1,6})\s+(?P<title>.*)$";
+
+/// Apply header `Tag` to given `TextBuffer`
+pub fn header(buffer: &TextBuffer, tag: &Tag) {
+    let (start, end) = buffer.bounds();
+    let full_content = buffer.text(&start, &end, true).to_string();
+
+    let matches: Vec<_> = Regex::new(REGEX_HEADER)
+        .unwrap()
+        .captures_iter(&full_content)
+        .collect();
+
+    for cap in matches.into_iter().rev() {
+        let full_match = cap.get(0).unwrap();
+
+        let start_char_offset = full_content[..full_match.start()].chars().count() as i32;
+        let end_char_offset = full_content[..full_match.end()].chars().count() as i32;
+
+        let mut start_iter = buffer.iter_at_offset(start_char_offset);
+        let mut end_iter = buffer.iter_at_offset(end_char_offset);
+
+        buffer.delete(&mut start_iter, &mut end_iter);
+
+        match cap["level"].chars().count() {
+            1 => buffer.insert_with_tags(&mut start_iter, &cap["title"], &[&tag.h1]),
+            2 => buffer.insert_with_tags(&mut start_iter, &cap["title"], &[&tag.h2]),
+            3 => buffer.insert_with_tags(&mut start_iter, &cap["title"], &[&tag.h3]),
+            4 => buffer.insert_with_tags(&mut start_iter, &cap["title"], &[&tag.h4]),
+            5 => buffer.insert_with_tags(&mut start_iter, &cap["title"], &[&tag.h5]),
+            6 => buffer.insert_with_tags(&mut start_iter, &cap["title"], &[&tag.h6]),
+            _ => buffer.insert_with_tags(&mut start_iter, &cap["title"], &[]),
+        }
+    }
+}
+
+#[test]
+fn test_regex_header() {
+    let cap: Vec<_> = Regex::new(REGEX_HEADER)
+        .unwrap()
+        .captures_iter(r"## Title ![alt](https://link.com)")
+        .collect();
+
+    let first = cap.get(0).unwrap();
+    assert_eq!(&first[0], "## Title ![alt](https://link.com)");
+    assert_eq!(&first["level"], "##");
+    assert_eq!(&first["title"], "Title ![alt](https://link.com)");
+}