context menus

2 files changed, 89 insertions, 1 deletions

diff --git a/tui/context_menu.go b/tui/context_menu.go
new file mode 100644
index 0000000..e6d5bb9
--- /dev/null
+++ b/tui/context_menu.go
@@ -0,0 +1,75 @@
+package tui
+
+import (
+	"github.com/rivo/uniseg"
+	"strings"
+)
+
+var menuStyle = Style {Fg: Black, Bg: Yellow}
+
+var menuState struct {
+	open bool
+	x, y int
+	width, height int
+	boxId string
+	menu []string
+	selected string
+}
+
+func MenuOption(name string) bool {
+	b := top()
+	b.contextMenu = append(b.contextMenu, name)
+	if menuState.boxId == top().id && menuState.selected == name {
+		menuState.selected = ""
+		return true
+	}
+	return false
+}
+
+func openContextMenu(x int, y int, b *Box) {
+	menuState.open = true
+	menuState.boxId = b.id
+	menuState.menu = b.contextMenu
+
+	menuState.height = len(menuState.menu)
+	for _, option := range menuState.menu {
+		menuState.width = max(menuState.width, uniseg.StringWidth(option))
+	}
+	size := Size()
+	if x + menuState.width < size.Width {
+		menuState.x = x + 1
+	} else {
+		menuState.x = x - menuState.width - 1
+	}
+	if y + menuState.height < size.Height {
+		menuState.y = y
+	} else {
+		menuState.y = y - menuState.height
+	}
+}
+
+
+func processContextMenu(ev MouseEvent) {
+	for i, option := range menuState.menu {
+		x, y := menuState.x, menuState.y + i
+		if ev.Button <= 2 && (ev.Pressed || ev.Released) &&
+				ev.X >= x && ev.X < x + menuState.width && ev.Y == y {
+			menuState.selected = option
+			menuState.open = false
+		}
+	}
+	if ev.Button <= 2 && ev.Pressed {
+		menuState.open = false
+	}
+}
+
+func drawContextMenu() {
+	if !menuState.open {
+		return
+	}
+	for i, option := range menuState.menu {
+		x, y := menuState.x, menuState.y + i
+		WriteAt(x, y, strings.Repeat(" ", menuState.width), menuStyle)
+		WriteAt(x, y, option, menuStyle)
+	}
+}
diff --git a/tui/layout.go b/tui/layout.go
index ede0fa6..039ce52 100644
--- a/tui/layout.go
+++ b/tui/layout.go
@@ -24,6 +24,7 @@ type Box struct {
 	computedRect rect
 	isOverflow bool
 	mouseEvent MouseEvent
+	contextMenu []string
 }
 
 type BoxSize int
@@ -439,6 +440,9 @@ func (b *Box) mouseEvents(ev MouseEvent) {
 		bev.Pressed = ev.Pressed
 		bev.Released = ev.Released
 		bev.Scroll = ev.Scroll
+		if ev.Pressed && ev.Button == 2 && len(b.contextMenu) > 0 {
+			openContextMenu(ev.X, ev.Y, b)
+		}
 	}
 	b.mouseEvent = bev
 	for _, c := range b.children {
@@ -470,5 +474,14 @@ func DrawLayout() {
 	b.drawComputed(parentRect, DefaultStyle)
 
 	ev := getLastEvent()
-	b.mouseEvents(ev.Mouse)
+	if menuState.open {
+		processContextMenu(ev.Mouse)
+		var releaseEvent MouseEvent
+		releaseEvent.Button = ev.Mouse.Button
+		releaseEvent.ReleasedAnywhere = ev.Mouse.ReleasedAnywhere
+		b.mouseEvents(releaseEvent)
+	} else {
+		b.mouseEvents(ev.Mouse)
+	}
+	drawContextMenu()
 }