Add basic dropdown functionality

src/utils.go

@@ -17,3 +17,39 @@ func drawText(s tcell.Screen, x1, y1, x2, y2 int, style tcell.Style, text string
 		}
 	}
 }
+
+func drawBox(s tcell.Screen, x1, y1, x2, y2 int, style tcell.Style) {
+	if y2 < y1 {
+		y1, y2 = y2, y1
+	}
+	if x2 < x1 {
+		x1, x2 = x2, x1
+	}
+
+	// Fill background
+	for row := y1; row <= y2; row++ {
+		for col := x1; col <= x2; col++ {
+			s.SetContent(col, row, ' ', nil, style)
+		}
+	}
+
+	// Draw borders
+	for col := x1; col <= x2; col++ {
+		s.SetContent(col, y1, tcell.RuneHLine, nil, style)
+		s.SetContent(col, y2, tcell.RuneHLine, nil, style)
+	}
+	for row := y1 + 1; row < y2; row++ {
+		s.SetContent(x1, row, tcell.RuneVLine, nil, style)
+		s.SetContent(x2, row, tcell.RuneVLine, nil, style)
+	}
+
+	// Only draw corners if necessary
+	if y1 != y2 && x1 != x2 {
+		s.SetContent(x1, y1, tcell.RuneULCorner, nil, style)
+		s.SetContent(x2, y1, tcell.RuneURCorner, nil, style)
+		s.SetContent(x1, y2, tcell.RuneLLCorner, nil, style)
+		s.SetContent(x2, y2, tcell.RuneLRCorner, nil, style)
+	}
+
+	drawText(s, x1+1, y1+1, x2-1, y2-1, style, " ")
+}