WhiteBeltCapstone

#include <iostream>
#include <set>
#include <map>
#include <exception>
#include <sstream>
#include <string>
#include <iomanip>

using namespace std;

//вспомогательные функции
int CountWords(const string& s) {
    stringstream is(s);
    int number_of_words = 0;
    string word;
    while (is >> word) {number_of_words++;}
    return number_of_words;
}

void WrongDateFormat(const stringstream& flow, const string& date) {
    string error = "Wrong date format: " + date;
    throw runtime_error(error);
}

void EnsureNextSymbolAndSkip(stringstream& stream, const string& input_date) {
    if (stream.peek() != '-') {
        WrongDateFormat(stream, input_date);
    }
    stream.ignore(1);
}

void EnsureCorrectFinal(stringstream& stream, const string& input_date) {
    if (stream.peek() != EOF) {
        WrongDateFormat(stream, input_date);
    }
}

//структура Дейт, функции и операторы для нее
struct Date {
    int year = 0;
    int month = 0;
    int day = 0;
};

void operator<<(ostream& output, const Date& date) {
    output << setfill('0');
    output << setw(4) << date.year << '-'
    << setw(2) << date.month << '-' << setw(2) << date.day;
}

bool operator<(const Date& lhs, const Date& rhs) {
    if (lhs.year == rhs.year) {
        if (lhs.month == lhs.month) {
            return lhs.day < rhs.day;
        }
        return lhs.month < rhs.month;
    }
    return lhs.year < rhs.year;
}

Date ParseDate(const string& s){
    Date date;
    string save_the_date = s;
    stringstream stream(s);
    stream >> date.year;
    EnsureNextSymbolAndSkip(stream, save_the_date);
    stream >> date.month;
    EnsureNextSymbolAndSkip(stream, save_the_date);
    stream >> date.day;
    EnsureCorrectFinal(stream, save_the_date);
    return date;
}

void CheckDate (const Date& new_date) {
    int new_month = new_date.month;
    if (new_month > 12 || new_month < 1) {
        string ss = "Month value is invalid: " + to_string(new_month);
        throw runtime_error(ss);
    }
    int new_day = new_date.day;
    if (new_day > 31 || new_day < 1) {
        string ss = "Day value is invalid: " + to_string(new_day);
        throw runtime_error(ss);
    }
}

//КЛАСС
class Database {
private:
    map<Date, set<string>> db;

public:

    void AddEvent(const Date& date, const string& some_event) {
        db[date].insert(some_event);
    }

    bool DeleteEvent(const Date& date, const string& some_event) {
        if (db.count(date) == 0 || db[date].count(some_event) == 0) {
            return false;
            //cout << "Event not found" << endl;
        }
        else {
            set<string> day = db[date];
            day.erase(some_event);
            db[date] = day;
            return true;
            //cout << "Deleted successfully" << endl;
        }
    }

    int DeleteDate(Date& date) {
        int res = db.at(date).size();
        db.erase(date);
        return res;
    }

    void FindDate(const Date& date) const{
      if (db.count(date) > 0) {
        for (auto s: db.at(date)) {
            cout << s << endl;
        }
      }
    }

    void PrintAll() const{
        for (auto x:db) {
            set<string> events = x.second;
            for (string s: events) {
                cout << x.first;
                cout << " " << s << endl;
            }
        }
    }
};

//Проверка команды из потока ввода
void CheckCommand(const string& some_command, Database& database) {
    set<string> commands = {"Del", "Find", "Add"};
    string action;
    string input_date;
    string new_event;

    int words = CountWords(some_command);
    stringstream stream(some_command);
      if (words == 1) {
          if (some_command == "Print") {
            database.PrintAll();
          }
          else {
            string error = "Unknown command: " + some_command;
            throw runtime_error(error);
          }
        }
      else if (words > 1) {
            getline(stream, action, ' ');
            if (commands.count(action) == 0 ) {
            string error = "Unknown command: " + action;
            throw runtime_error(error);
            }
            else if (words == 2) {
                getline(stream, input_date);
                Date new_date = ParseDate(input_date);
                CheckDate(new_date);
                if (action == "Del") {
                  cout << "Deleted " << database.DeleteDate(new_date) << " events" << endl;
                }
                else if (action == "Find") {
                    database.FindDate(new_date);
                }
            }
            else if (words == 3){
                getline(stream, input_date, ' ');
                Date new_date = ParseDate(input_date);
                CheckDate(new_date);
                getline(stream, new_event);
                if (action == "Del") {
                    if (database.DeleteEvent(new_date, new_event)) {
                        cout << "Deleted successfully" << endl;
                    }
                    else {
                        cout << "Event not found" << endl;
                    }
                }
                else if (action == "Add") {
                    database.AddEvent(new_date, new_event);
                }
        }
    }
}

//мэйн
int main() {
    Database yandex;
    string command;

    while (getline(cin, command)) {
        try {
            if (command > "") {
                CheckCommand(command, yandex);
            }
        } catch (exception& ex) {
            cout << ex.what() << endl;
        }
    }

    return 0;
}