/// base node
public protocol BaseNode {
    associatedtype T: BaseNode
    var parent: T? { get }
    var childs: [T] { get }
}

/// base treeNode structure and position
public protocol IndexPathNode: BaseNode {
    var indexPath: IndexPath { get }
}

/// Node protocol
public protocol VerticalTreeNode: IndexPathNode where Self.T == Self {
    /// indexViewLegnth
    var length: TreeNodeLength { get }
    /// info description
    var info: Infomation { get }
    var isFold: Bool { set get }
}

// in ViewController
let treeVC = VerticalTreeListController(source: NodeWrapper(obj: view))
// then show the treeVC

/// config current node’s property value and recurrence apply the same rule in childNodes if you want
///
/// - Parameters:
///   - inChild: recurrence config in child or just config current
///   - config: rules
/// - Returns: self
@discardableResult
public func changeProperties(inChild: Bool = true, config: (NodeWrapper<Obj>) -> Void) -> Self {}

// default to change all subnode in the same rules unless inChild set false
let wrapper = NodeWrapper(obj: keyWindow.rootController).changeProperties {
    $0.isFold = false	// all node set unfold in default 
    $0.nodeDescription = "more infomation that you see now"
}

extension UIView: BaseNode {
    public var parent: UIView? {
        return superview
    }
    public var childs: [UIView] {
        return subviews
    }
}

// in ViewController
let rootNode = NodeWrapper(obj: view)
// print node structure in text
print(rootNode.subTreePrettyText())

extension BaseNode where Self: NSObject, Self == Self.T {
    /// print
    public func treePrettyPrint(inDebug: Bool = false) {...}
    /// baseTree‘s structure
    public func treePrettyText(inDebug: Bool = false) -> String {...}
    /// get ofTop‘s structure & highlight position of self
    public func treePrettyText(ofTop: Self, inDebug: Bool = false) { ... }
    // get the baseTree of rootNode
    public var getTreeRoot: Self { ... }
}