package defrag

import (
	"bytes"
	"strconv"
	"strings"
)

func Blocks(diskMap []byte) ([]byte, error) {
	current := 0
	onFile := false
	buff := bytes.Buffer{}
	for _, by := range diskMap {
		count, err := strconv.Atoi(string(by))
		if err != nil {
			return nil, err
		}
		onFile = !onFile
		if count == 0 {
			continue
		}
		append := "."
		if onFile {
			append = strconv.Itoa(current)
			current++
		}
		buff.WriteString(strings.Repeat(append, count))
	}
	return buff.Bytes(), nil
}