package main

import (
	"bytes"
	"fmt"
	"io"
)

type node struct {
	name       string
	children   []node
	attributes map[string]string
}

func (n node) String() string {
	buf := new(bytes.Buffer)
	n.print(buf, " ")
	return buf.String()
}

func (n node) print(out io.Writer, indent string) {
	if len(n.attributes) > 0 {
		fmt.Fprintf(out, "\n%v%v %s", indent, n.name, n.attributes)
	} else {
		fmt.Fprintf(out, "\n%v%v", indent, n.name)
	}
	for _, nn := range n.children {
		nn.print(out, indent+"  ")
	}
}

func Node(name string) node {
	return node{name: name, attributes: make(map[string]string)}
}

func (n node) append(nn ...node) node {
	n.children = append(n.children, nn...)
	return n
}

func (n node) attribute(key string, value string) node {
	n.attributes[key] = value
	return n
}