Add reverse traversal

main.go

@@ -58,7 +58,9 @@ func main() {
 			return
 		case "<Space>":
 			tree.SelectNext()
-			termui.Render(tree)
+		case "<C-<Space>>":
+			tree.SelectPrev()
 		}
+		termui.Render(tree)
 	}
 }

tree.go

@@ -60,6 +60,24 @@ func (tree *TreeWidget) AddRootNode(node *Node) {
 	node.setTree(tree)
 }
 
+// SelectPrev marks the previous node as the currently selected node
+func (tree *TreeWidget) SelectPrev() {
+	if tree.selectedNode.prev != nil && len(tree.selectedNode.prev.children) == 0 {
+		// If there's a previous node with no children, we can go straight to it.
+		tree.selectedNode = tree.selectedNode.prev
+	} else if tree.selectedNode.prev == nil && tree.selectedNode.parent != nil {
+		// If we can go right up to the next parent node, we're good - we go there.
+		tree.selectedNode = tree.selectedNode.parent
+	} else if tree.selectedNode.prev != nil {
+		// If we have a node before us, we're going to want to go to the absolute bottom of it.
+		cursorNode := tree.selectedNode.prev
+		for len(cursorNode.children) > 0 {
+			cursorNode = cursorNode.children[len(cursorNode.children)-1]
+		}
+		tree.selectedNode = cursorNode
+	}
+}
+
 // SelectNext marks the next node as the currently selected node
 func (tree *TreeWidget) SelectNext() {
 	if len(tree.selectedNode.children) > 0 {
@@ -117,8 +135,6 @@ func (node *Node) render(buffer *termui.Buffer, row, col, width int) int {
 	}
 	if node.tree.selectedNode == node {
 		style.Fg, style.Bg = style.Bg, style.Fg
-	} else if node.tree.selectedNode.next == node {
-		style.Bg = termui.ColorBlue
 	}
 
 	listItem := termui.ParseStyles(node.Text, style)