1 files changed, 60 insertions, 0 deletions
diff --git a/internal/tui/screenrouter.go b/internal/tui/screenrouter.go
new file mode 100644
index 0000000..9a110c8
--- /dev/null
+++ b/internal/tui/screenrouter.go
@@ -0,0 +1,60 @@
+package tui
+
+import (
+	"ior/internal/tui/pidpicker"
+
+	tea "charm.land/bubbletea/v2"
+)
+
+// screenRouter owns screen-transition state for the TUI. It tracks the picker
+// return bookmark used when the user navigates from the dashboard to the PID or
+// TID picker and may want to cancel back to the original dashboard view.
+type screenRouter struct {
+	// pickerReturn is non-nil while the user has navigated from the dashboard
+	// back to the PID/TID picker. The stored values are used to restart the
+	// trace if the user presses Esc to cancel the picker navigation.
+	pickerReturn *pickerReturnState
+}
+
+// newScreenRouter creates an empty screenRouter with no pending return state.
+func newScreenRouter() screenRouter {
+	return screenRouter{}
+}
+
+// savePendingReturn records the current pid/tid so Esc can restore the
+// dashboard if the user decides not to select a new process.
+func (r *screenRouter) savePendingReturn(pid, tid int) {
+	r.pickerReturn = &pickerReturnState{
+		pidFilter: pid,
+		tidFilter: tid,
+	}
+}
+
+// takePendingReturn consumes and returns the stored picker return state,
+// clearing it in the process. Returns (zero, false) when no pending state exists.
+func (r *screenRouter) takePendingReturn() (pickerReturnState, bool) {
+	if r.pickerReturn == nil {
+		return pickerReturnState{}, false
+	}
+	state := *r.pickerReturn
+	r.pickerReturn = nil
+	return state, true
+}
+
+// hasPendingReturn reports whether the user navigated from the dashboard to
+// the picker (meaning Esc should return to the dashboard instead of quitting).
+func (r *screenRouter) hasPendingReturn() bool {
+	return r.pickerReturn != nil
+}
+
+// applyWindowSizeToPicker sends the current window size to the pid picker when
+// valid dimensions are available. Returns the updated picker and an optional
+// size command.
+func applyWindowSizeToPicker(picker pidpicker.Model, width, height int) (pidpicker.Model, tea.Cmd) {
+	if width <= 0 || height <= 0 {
+		return picker, nil
+	}
+	msg := tea.WindowSizeMsg{Width: width, Height: height}
+	next, cmd := picker.Update(msg)
+	return next.(pidpicker.Model), cmd
+}