package main

import (
	"fmt"
	"io/ioutil"
	"os"
	"os/user"
	"strconv"
)

func main() {
	if len(os.Args) < 2 {
		return
	}

	u, err := user.Current()
	if err != nil {
		fmt.Print("none")
		return
	}
	dir := fmt.Sprintf("%s/.version", u.HomeDir)
	if err := os.MkdirAll(dir, os.ModePerm); err != nil {
		fmt.Print("none")
		return
	}
	fname := fmt.Sprintf(`%s/%s`, dir, os.Args[1])
	v, err := versionGet(&fname)
	if err != nil {
		fmt.Print("none")
	}
	versionSet(&fname, v)
	fmt.Print(v)
}

func versionGet(fname *string) (v uint64, err error) {
	f, err := os.OpenFile(*fname, os.O_RDONLY|os.O_CREATE, 0600)
	if err != nil {
		return
	}
	defer f.Close()

	b, err := ioutil.ReadAll(f)
	if err != nil {
		return
	}

	v, _ = strconv.ParseUint(string(b), 10, 64)
	v++
	return
}

func versionSet(fname *string, v uint64) error {
	f, err := os.OpenFile(*fname, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0600)
	if err != nil {
		return err
	}
	defer f.Close()

	buf := strconv.FormatUint(v, 10)
	if _, err := f.WriteString(buf); err != nil {
		return err
	}

	return nil
}