package utils

import (
	"io/ioutil"
	"strconv"
	"strings"

	"github.com/pkg/errors"
)

var sizeSuffixes = [...]string{"B", "KiB", "MiB", "GiB", "TiB"}

// ConvertFileSize converts size in bytes down to biggest units it represents.
// Returns converted size, unit and, a concatenation of size and unit
func ConvertFileSize(size int64) (float64, string, string) {
	idx := 0
	fSize := float64(size)

	for ; fSize >= 1024; fSize /= 1024 {
		idx++
	}

	fSizeStr := strconv.FormatFloat(fSize, 'f', 3, 64)
	fSizeStr = strings.TrimRight(fSizeStr, "0")
	fSizeStr = strings.TrimSuffix(fSizeStr, ".")

	return fSize, sizeSuffixes[idx],
		strings.Join([]string{fSizeStr, sizeSuffixes[idx]}, " ")
}

func DirectorySize(path string) (dirSz int64, err error) {
	dir, err := ioutil.ReadDir(path)
	if err != nil {
		return 0, errors.Wrapf(err, "failed to compute %s directory size", path)
	}

	for _, entry := range dir {
		dirSz += entry.Size()
	}

	// Here we subtract a size of a directory's inode to get size of files only.
	return dirSz - 4096, nil
}