keep track of focused widget

1 files changed, 33 insertions, 0 deletions

diff --git a/focus.go b/focus.go
new file mode 100644
index 0000000..e6de390
--- /dev/null
+++ b/focus.go
@@ -0,0 +1,33 @@
+package main
+
+type Focus struct {
+	widgets []chan bool
+	i       int // index of focused widget
+}
+
+func NewFocus(nWidgets int) Focus {
+	f := Focus{make([]chan bool, nWidgets), 0}
+	for i := range f.widgets {
+		f.widgets[i] = make(chan bool)
+	}
+	return f
+}
+
+func (f *Focus) Next() {
+	f.widgets[f.i] <- false
+	f.i = (f.i + 1) % len(f.widgets)
+	f.widgets[f.i] <- true
+}
+
+func (f *Focus) Prev() {
+	f.widgets[f.i] <- false
+	f.i = abs(f.i-1) % len(f.widgets)
+	f.widgets[f.i] <- true
+}
+
+func abs(n int) int {
+	if n < 0 {
+		return -n
+	}
+	return n
+}