From 61a63fec579f88766c6be0d392bb4eaed3b8564a Mon Sep 17 00:00:00 2001
From: Sam Anthony <sam@samanthony.xyz>
Date: Sun, 12 May 2024 17:14:30 -0400
Subject: button widget

---
 gui/widget/button.go | 62 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 gui/widget/tree.go   |  1 -
 2 files changed, 62 insertions(+), 1 deletion(-)
 create mode 100644 gui/widget/button.go

diff --git a/gui/widget/button.go b/gui/widget/button.go
new file mode 100644
index 0000000..fe2f30b
--- /dev/null
+++ b/gui/widget/button.go
@@ -0,0 +1,62 @@
+package widget
+
+import (
+	"image"
+	"image/draw"
+	"sync"
+
+	"volute/gui"
+	"volute/gui/text"
+	"volute/gui/win"
+)
+
+func Button[T any](
+	signal chan<- T,
+	val T,
+	label string,
+	r image.Rectangle,
+	focus FocusSlave,
+	env gui.Env,
+	wg *sync.WaitGroup,
+) {
+	defer wg.Done()
+	defer close(signal)
+
+	focused := false
+	env.Draw() <- buttonDraw(label, focused, r)
+	for {
+		select {
+		case _, ok := <-focus.gain:
+			if !ok {
+				return
+			}
+			focused = true
+			env.Draw() <- buttonDraw(label, focused, r)
+		case dir, ok := <-focus.lose:
+			if !ok {
+				return
+			}
+			focus.yield <- dir
+			focused = false
+			env.Draw() <- buttonDraw(label, focused, r)
+		case event, ok := <-env.Events():
+			if !ok {
+				return
+			}
+			if event, ok := event.(win.KbDown); ok && focused && event.Key == win.KeyEnter {
+				signal <- val
+			}
+		}
+	}
+}
+
+func buttonDraw(label string, focused bool, r image.Rectangle) func(drw draw.Image) image.Rectangle {
+	return func(drw draw.Image) image.Rectangle {
+		if focused {
+			text.Draw(label, drw, r, BLACK, FOCUS_COLOR, text.ALIGN_LEFT)
+		} else {
+			text.Draw(label, drw, r, BLACK, WHITE, text.ALIGN_LEFT)
+		}
+		return r
+	}
+}
diff --git a/gui/widget/tree.go b/gui/widget/tree.go
index 9e4af13..ff4d139 100644
--- a/gui/widget/tree.go
+++ b/gui/widget/tree.go
@@ -54,7 +54,6 @@ func flatten[T any](root Node[T], depth int) []string {
 		make([]rune, depth),
 		'─'))
 	nodes := []string{indent + root.Label}
-	root.expanded = true // TODO: remove me
 	if root.expanded {
 		for _, c := range root.Children {
 			nodes = append(nodes, flatten(c, depth+1)...)
-- 
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