Show focus on active agent in agents panel like spaces panel does (#84)

* feat: show focus on active agent in agents panel like spaces panel does

* refactor: improve to calculation and binding style

2 files changed, 44 insertions, 4 deletions

diff --git a/src/app/state.rs b/src/app/state.rs
index 315872f4..f7c4daa1 100644
--- a/src/app/state.rs
+++ b/src/app/state.rs
@@ -735,6 +735,29 @@ impl AppState {
             (24, 80)
         }
     }
+
+    /// Returns true when the given (workspace, tab, pane) refers to the
+    /// currently focused pane in the active workspace's active tab.
+    pub fn is_active_pane(
+        &self,
+        ws_idx: usize,
+        tab_idx: usize,
+        pane_id: crate::layout::PaneId,
+    ) -> bool {
+        let Some(active_ws_idx) = self.active else {
+            return false;
+        };
+        if ws_idx != active_ws_idx {
+            return false;
+        }
+        let Some(ws) = self.workspaces.get(ws_idx) else {
+            return false;
+        };
+        if tab_idx != ws.active_tab_index() {
+            return false;
+        }
+        ws.active_tab().map(|tab| tab.layout.focused()) == Some(pane_id)
+    }
 }
 
 pub fn key_matches(
diff --git a/src/ui/sidebar.rs b/src/ui/sidebar.rs
index 36d1385a..04a3acd9 100644
--- a/src/ui/sidebar.rs
+++ b/src/ui/sidebar.rs
@@ -788,12 +788,29 @@ fn render_agent_detail(app: &AppState, frame: &mut Frame, area: Rect) {
             break;
         }
 
+        // Check if this agent entry corresponds to the active session
+        let is_active = app.is_active_pane(detail.ws_idx, detail.tab_idx, detail.pane_id);
+
         let (icon, icon_style) = agent_icon(detail.state, detail.seen, app.spinner_tick, p);
         let label_color = state_label_color(detail.state, detail.seen, p);
         let label = state_label(detail.state, detail.seen);
 
-        let name_style = Style::default().fg(p.subtext0).add_modifier(Modifier::BOLD);
-        let status_style = Style::default().fg(label_color).add_modifier(Modifier::DIM);
+        let row_style = if is_active {
+            Style::default().bg(p.surface_dim)
+        } else {
+            Style::default()
+        };
+
+        let name_style = if is_active {
+            Style::default().fg(p.text).add_modifier(Modifier::BOLD)
+        } else {
+            Style::default().fg(p.subtext0).add_modifier(Modifier::BOLD)
+        };
+        let status_style = if is_active {
+            Style::default().fg(label_color)
+        } else {
+            Style::default().fg(label_color).add_modifier(Modifier::DIM)
+        };
         let agent_style = Style::default().fg(p.overlay0).add_modifier(Modifier::DIM);
 
         let primary_label =
@@ -805,7 +822,7 @@ fn render_agent_detail(app: &AppState, frame: &mut Frame, area: Rect) {
             Span::styled(primary_label, name_style),
         ]);
         frame.render_widget(
-            Paragraph::new(name_line),
+            Paragraph::new(name_line).style(row_style),
             Rect::new(body.x, row_y, body.width, 1),
         );
         row_y += 1;
@@ -819,7 +836,7 @@ fn render_agent_detail(app: &AppState, frame: &mut Frame, area: Rect) {
             status_spans.push(Span::styled(agent_label, agent_style));
         }
         frame.render_widget(
-            Paragraph::new(Line::from(status_spans)),
+            Paragraph::new(Line::from(status_spans)).style(row_style),
             Rect::new(body.x, row_y, body.width, 1),
         );
         row_y += 1;