#include <iostream>
#include <string>
#include <vector>
using namespace std;
typedef enum {SELECT, RESELECT, INSERT, UPDATE, DELETE, PRINT} CommandType;
typedef enum {author, title, publisher, genre, theme} Field;
class Query{
    private:
        CommandType command_;
        vector<Condition>* condition_:
        vector<Field>* fields_; //for print
    public:
        Query(const string &qu); //if command != print -> fields = NULL
};

class Condition{
    private:
        Field field;
        string relation_;
        string comment_; //value-?
    public:
        Condition(const string &str);
};

class DataBase{
    private:
        Library *library_;
    public:
        DataBase(const string &filename);
        process(Session user)
        bool db_select(Session *user, Query *query);
        bool db_reselect(Session *user, Query *query);
        bool db_insert(Session *user, Query *query);
        bool db_update(Session *user, Query *query);
        bool db_delete(Session *user, Query *query);
        bool db_print(Session *user, Query *query);
};

class Session{
    private:
        string query_;
        Library* result;
    public:
        Session();
}

class Book {
        private:
                char author_[64];
                char title_[124];
                char publisher_[64];
                int class_1;
                int class_2;
                bool presence_;
        public:
                Book(FILE *file);
                bool compare(const Book &book);



class Library {
        private:
                vector<Book*> library_;
        public:
                Library() {}
                Library(FILE* fin);
                void add_book(const Book *book)
                {
                        library_.push_back(book);
                        library_.sort(0, library_.size() - 1);
                }
                void sort(Field field, int first, int last)
                {
                        int i = first, j = last;
                        Book *tmp, *mid = (library_[(i + j) / 2])->field;
                        if(!(library_.emty()))
                        {
                                while(i <= j)
                                {
                                        while((library_[i])->field < mid)
                                                i++;
                                        while((library_[j])->field > mid)
                                                j--;
                                        if(i < j)
                                        {
                                                tmp = library_[i];
                                                library_[i] = library_[j];
                                                library_[j] = tmp;
                                                i++;
                                                j--;
                                        }
                                }
                                if(first < j)
                                        library_.sort(field, first, j);
                                if(last > i)
                                        library_.sort(field, i, last);
                        }
                }
                bool empty_library();
                void del_book();
                void change(Field field, string value);

};





class DB_Exception {
    private:
        int code_;
        std::string messege_;
    public:
        DB_Exception(int c, std::string c)
        {
            code_ = c;
            messege_ = s;
        }
};