type pagination struct {
        from int32
        to   int32
}

func (p pagination) prepare() (string, error) {
        if p.to < p.from {
                return "", operations.ErrMalformedPaginationLimits
        } else if p.to == 0 {
                return "", nil
        }

        return fmt.Sprintf(`"from":%d,"size":%d`, p.from, p.to-p.from), nil
}

type stringValueOrQuery struct {
        pagination pagination
        fieldName  string
        termValues []string
}

func (s stringValueOrQuery) prepare() (string, error) {
        var buff bytes.Buffer

        for i, value := range s.termValues {
                buff.WriteString("{")
                buff.WriteString(fmt.Sprintf(`"term":{"%s": "%s"}`, s.fieldName, value))
                buff.WriteString("}")
                if i != len(s.termValues)-1 {
                        buff.WriteString(",")
                }
        }

        paging, err := s.pagination.prepare()
        if err != nil {
                return "", err
        }
        query := fmt.Sprintf(`{"query":{%s,"bool":{"should": [%s]}}}`, paging, buff.String())

        return query, nil
}