struct DocumentData {
        std::set<std::string> content;
        std::map<std::string_view, double> freqs;
        int rating;
        DocumentStatus status;
    };

    std::set<std::string_view> stop_words_;
    std::map<std::string_view, std::map<int, double>> word_to_document_freqs_;
    std::map<int, DocumentData> documents_;
    std::set<int> document_ids_;

    struct QueryWord {
        std::string data;
        bool is_minus;
        bool is_stop;
    };

    struct Query {
        std::set<std::string> plus_words;
        std::set<std::string> minus_words;
    };

    struct QueryVector {
        std::vector<std::string> plus_words;
        std::vector<std::string> minus_words;
    };