From e015ebefabc82967e77be0028e978c58e19a9039 Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Fri, 16 May 2025 12:48:21 +0530
Subject: [PATCH] Implement focus tracking in kitten infrastructure

---
 tools/tui/loop/api.go            | 3 +++
 tools/tui/loop/run.go            | 6 ++++++
 tools/tui/loop/terminal-state.go | 4 ++--
 3 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/tools/tui/loop/api.go b/tools/tui/loop/api.go
index 4c702546f..5baad0dff 100644
--- a/tools/tui/loop/api.go
+++ b/tools/tui/loop/api.go
@@ -121,6 +121,9 @@ type Loop struct {
 
 	// Called when the terminal's color scheme changes
 	OnColorSchemeChange func(ColorPreference) error
+
+	// Called on focus in/out events
+	OnFocusChange func(bool) error
 }
 
 func New(options ...func(self *Loop)) (*Loop, error) {
diff --git a/tools/tui/loop/run.go b/tools/tui/loop/run.go
index 7a5a87976..f97cabceb 100644
--- a/tools/tui/loop/run.go
+++ b/tools/tui/loop/run.go
@@ -113,6 +113,12 @@ func (self *Loop) handle_csi(raw []byte) (err error) {
 				return nil
 			}
 		}
+	} else if csi == "I" || csi == "O" {
+		if self.OnFocusChange != nil {
+			return self.OnFocusChange(csi == "I")
+		}
+		return nil
+
 	}
 	ke := KeyEventFromCSI(csi)
 	if ke != nil {
diff --git a/tools/tui/loop/terminal-state.go b/tools/tui/loop/terminal-state.go
index 286f6b643..7d6468b10 100644
--- a/tools/tui/loop/terminal-state.go
+++ b/tools/tui/loop/terminal-state.go
@@ -129,9 +129,9 @@ func (self *TerminalStateOptions) SetStateEscapeCodes() string {
 	}
 	sb.WriteString(DECSACE_DEFAULT_REGION_SELECT)
 	reset_modes(&sb,
-		IRM, DECKM, DECSCNM, BRACKETED_PASTE, FOCUS_TRACKING,
+		IRM, DECKM, DECSCNM, BRACKETED_PASTE,
 		MOUSE_BUTTON_TRACKING, MOUSE_MOTION_TRACKING, MOUSE_MOVE_TRACKING, MOUSE_UTF8_MODE, MOUSE_SGR_MODE)
-	set_modes(&sb, DECARM, DECAWM, DECTCEM)
+	set_modes(&sb, DECARM, DECAWM, DECTCEM, FOCUS_TRACKING)
 	if self.in_band_resize_notification {
 		set_modes(&sb, INBAND_RESIZE_NOTIFICATION)
 	}