package namespace

type FileSizeQuota struct {
	AllowanceKB  int64
	CurrentUsage int64
}

func (f FileSizeQuota) Allows(size int64) bool {
	return f.Remaining() >= size
}

func (f FileSizeQuota) Remaining() int64 {
	return f.AllowanceKB - f.CurrentUsage
}

func (f FileSizeQuota) Add(size int64) (*FileSizeQuota, error) {
	if !f.Allows(size) {
		return nil, ErrExceedQuota
	}

	n := FileSizeQuota {
		f.AllowanceKB,
		f.CurrentUsage + size,
	}
	return &n, nil
}

func (f FileSizeQuota) Remove(size int64) (*FileSizeQuota, error) {
	if size > f.CurrentUsage {
		return nil, ErrQuotaInvalid
	}

	n := FileSizeQuota {
		f.AllowanceKB,
		f.CurrentUsage - size,
	}
	return &n, nil
}

type FileStat struct {
	Num   int64
	SizeB int64
}

func (s FileStat) Add(size int64) FileStat {
	return FileStat{
		s.Num + 1,
		s.SizeB + size,
	}
}