acp: Hide history unless in native agent (#36644)

Release Notes:

- N/A

crates/agent2/src/history_store.rs

@@ -10,6 +10,7 @@ use itertools::Itertools;
 use paths::contexts_dir;
 use serde::{Deserialize, Serialize};
 use std::{collections::VecDeque, path::Path, sync::Arc, time::Duration};
+use ui::ElementId;
 use util::ResultExt as _;
 
 const MAX_RECENTLY_OPENED_ENTRIES: usize = 6;
@@ -68,6 +69,15 @@ pub enum HistoryEntryId {
     TextThread(Arc<Path>),
 }
 
+impl Into<ElementId> for HistoryEntryId {
+    fn into(self) -> ElementId {
+        match self {
+            HistoryEntryId::AcpThread(session_id) => ElementId::Name(session_id.0.into()),
+            HistoryEntryId::TextThread(path) => ElementId::Path(path),
+        }
+    }
+}
+
 #[derive(Serialize, Deserialize, Debug)]
 enum SerializedRecentOpen {
     AcpThread(String),

crates/agent_ui/src/acp/thread_history.rs

@@ -673,18 +673,9 @@ impl AcpHistoryEntryElement {
 
 impl RenderOnce for AcpHistoryEntryElement {
     fn render(self, _window: &mut Window, _cx: &mut App) -> impl IntoElement {
-        let (id, title, timestamp) = match &self.entry {
+        let id = self.entry.id();
-            HistoryEntry::AcpThread(thread) => (
+        let title = self.entry.title();
-                thread.id.to_string(),
+        let timestamp = self.entry.updated_at();
-                thread.title.clone(),
-                thread.updated_at,
-            ),
-            HistoryEntry::TextThread(context) => (
-                context.path.to_string_lossy().to_string(),
-                context.title.clone(),
-                context.mtime.to_utc(),
-            ),
-        };
 
         let formatted_time = {
             let now = chrono::Utc::now();
@@ -701,7 +692,7 @@ impl RenderOnce for AcpHistoryEntryElement {
             }
         };
 
-        ListItem::new(SharedString::from(id))
+        ListItem::new(id)
             .rounded()
             .toggle_state(self.selected)
             .spacing(ListItemSpacing::Sparse)

crates/agent_ui/src/acp/thread_view.rs

@@ -2404,16 +2404,18 @@ impl AcpThreadView {
 
     fn render_empty_state(&self, window: &mut Window, cx: &mut Context<Self>) -> AnyElement {
         let loading = matches!(&self.thread_state, ThreadState::Loading { .. });
-        let recent_history = self
+        let render_history = self
-            .history_store
+            .agent
-            .update(cx, |history_store, cx| history_store.recent_entries(3, cx));
+            .clone()
-        let no_history = self
+            .downcast::<agent2::NativeAgentServer>()
-            .history_store
+            .is_some()
-            .update(cx, |history_store, cx| history_store.is_empty(cx));
+            && self
+                .history_store
+                .update(cx, |history_store, cx| !history_store.is_empty(cx));
 
         v_flex()
             .size_full()
-            .when(no_history, |this| {
+            .when(!render_history, |this| {
                 this.child(
                     v_flex()
                         .size_full()
@@ -2445,7 +2447,10 @@ impl AcpThreadView {
                         })),
                 )
             })
-            .when(!no_history, |this| {
+            .when(render_history, |this| {
+                let recent_history = self
+                    .history_store
+                    .update(cx, |history_store, cx| history_store.recent_entries(3, cx));
                 this.justify_end().child(
                     v_flex()
                         .child(