package main

import (
	"fmt"
	"io"
)

type TreeNode interface {
	Left() TreeNode
	Right() TreeNode
	Print(io.Writer)
}

type BTreeNode struct {
	left  TreeNode
	right TreeNode
}

type StringyBTreeNode struct {
	k string
	v interface{}
	BTreeNode
}

func NewStringyBTree(k string, v interface{}) *StringyBTreeNode {
	return &StringyBTreeNode{
		k: k,
		v: v,
	}
}

func (sbt *StringyBTreeNode) Left() TreeNode {
	return sbt.left
}

func (sbt *StringyBTreeNode) Right() TreeNode {
	return sbt.right
}

func (sbt *StringyBTreeNode) Print(w io.Writer) {
	fmt.Printf("%+v\n", sbt)
	if sbt.left != nil {
		sbt.left.Print(w)
	}
	if sbt.right != nil {
		sbt.right.Print(w)
	}
}

func (sbt *StringyBTreeNode) Insert(k string, v interface{}) *StringyBTreeNode {
	if sbt.k == k {
		sbt.v = v // set new value
		return sbt
	}
	newNode := &StringyBTreeNode{k: k, v: v}
	if sbt.k > k {
		if sbt.left == nil {
			sbt.left = newNode
		} else {
			sbt.left.(*StringyBTreeNode).Insert(k, v)
		}
	}
	if sbt.k < k {
		if sbt.right == nil {
			sbt.right = newNode
		} else {
			sbt.right.(*StringyBTreeNode).Insert(k, v)
		}
	}
	return sbt
}

func (sbt *StringyBTreeNode) Get(k string) interface{} {
	if sbt.k == k {
		return sbt.v
	}
	if sbt.k > k {
		if sbt.left != nil {
			return sbt.left.(*StringyBTreeNode).Get(k)
		}
	}
	if sbt.k < k {
		if sbt.right != nil {
			return sbt.right.(*StringyBTreeNode).Get(k)
		}
	}
	return nil // not found
}