From f008564c328f70da90d210c31e201ec2420f1122 Mon Sep 17 00:00:00 2001
From: Gabriel Kaszewski <gabrielkaszewski@gmail.com>
Date: Fri, 15 May 2026 05:26:56 +0200
Subject: [PATCH] feat(ap): add hashtag tag array to outbound Notes

---
 .../adapters/activitypub-base/src/service.rs  | 24 +++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/crates/adapters/activitypub-base/src/service.rs b/crates/adapters/activitypub-base/src/service.rs
index 0b11eff..93c30ff 100644
--- a/crates/adapters/activitypub-base/src/service.rs
+++ b/crates/adapters/activitypub-base/src/service.rs
@@ -46,6 +46,26 @@ fn content_to_html(text: &str) -> String {
     }
 }
 
+fn extract_hashtag_tags(content: &str, base_url: &str) -> Vec<serde_json::Value> {
+    let mut seen = std::collections::HashSet::new();
+    let mut tags = Vec::new();
+    for word in content.split_whitespace() {
+        let tag = word.trim_matches(|c: char| !c.is_alphanumeric() && c != '#');
+        if let Some(name) = tag.strip_prefix('#')
+            && !name.is_empty()
+            && seen.insert(name.to_lowercase())
+        {
+            let lower = name.to_lowercase();
+            tags.push(serde_json::json!({
+                "type": "Hashtag",
+                "name": format!("#{}", lower),
+                "href": format!("{}/tags/{}", base_url, lower),
+            }));
+        }
+    }
+    tags
+}
+
 fn thought_note_json(
     thought: &domain::models::thought::Thought,
     local_actor: &crate::actors::DbActor,
@@ -89,6 +109,10 @@ fn thought_note_json(
     if let Some(updated_at) = thought.updated_at {
         note["updated"] = serde_json::json!(updated_at.to_rfc3339());
     }
+    let hashtag_tags = extract_hashtag_tags(thought.content.as_str(), base_url);
+    if !hashtag_tags.is_empty() {
+        note["tag"] = serde_json::json!(hashtag_tags);
+    }
     Ok((ap_id, note))
 }