package main

import (
	"net/url"
	"os"
	"path"
	"strings"
)

type ID string

func NewID(s string) ID {
	return ID(path.Clean(s)).withClean()
}

func (id ID) Push(child string) ID {
	return NewID(path.Join(id.String(), child)).withClean()
}

func (id ID) Pop() ID {
	pid := path.Clean(NewID(path.Dir(id.String())).withClean().String())
	if strings.HasPrefix(pid, ".") {
		return ""
	}
	return NewID(pid)
}

func (id ID) URLSafeString() string {
	splits := strings.Split(string(id), "/")
	for i := range splits {
		splits[i] = url.PathEscape(splits[i])
	}
	return strings.Join(splits, "/")
}

func (id ID) String() string {
	return string(id)
}

func (id ID) withClean() ID {
	splits := strings.Split(id.String(), string([]rune{os.PathSeparator}))
	for i := range splits {
		splits[i] = strings.Trim(splits[i], string([]rune{os.PathSeparator}))
		splits[i] = strings.Trim(splits[i], "/")
		t, err := url.PathUnescape(splits[i])
		if err == nil {
			splits[i] = t
		}
	}
	clean := path.Join(splits...)
	if clean == "" || clean == "." {
		clean = ""
	}
	return ID(clean)
}