#pragma once
#include <string>
#include <vector>

class Date {
 public:
    Date(int year, int month, int day) {
        y = year;
        m = month;
        d = day;
    }
    bool IsLeap() const {
        bool a = true;
        if (y % 400 != 0 && y % 100 == 0) a = false;
        if (y % 4 != 0) a = false;
        return a;
    }
    std::string ToString() const {
        std::string a = d < 10 ? "0" + std::to_string(d) : std::to_string(d);
        a += "." + (m < 10 ? "0" + std::to_string(m) : std::to_string(m));
        a += ".";
        a += (y < 1000 ? y < 100 ? y < 10 ? "000" : "00" : "0" : "");
        a += std::to_string(y);
        return a;
    }
    Date DaysLater(int days) const {
        int64_t yy = y, mm = m, dd = d + days;
        while (true) {
            if (mm > 12) {
                mm = 1;
                yy++;
            }
            if (mm == 2 && ((dd > 28 && yy % 4 != 0) || (dd > 29 && yy % 4 == 0))) {
                dd -= y % 4 == 0 ? 29 : 28;
                mm++;
                continue;
            }
            if (dd > 30 && (mm == 4 || mm == 6 || mm == 9 || mm == 11)) {
                dd -= 30;
                mm++;
                continue;
            }
            if (dd > 31 && std::find(m31.begin(), m31.end(), m) != m31.end()) {
                dd -= 31;
                mm++;
                continue;
            }
            break;
        }
        Date a(yy, mm, dd);
        return a;
    }
    int DaysLeft(const Date& date) const {
        int64_t v = 0, dif_d = - d + date.d;
        for (int64_t i = y; i < date.y; i++) {
            if (i % 4 == 0) v++;
        }
        for (int64_t i = 1; i < m; i++) {
            if (std::find(m31.begin(), m31.end(), i) != m31.end())
                dif_d -= 31;
            else if (i == 4 || i == 6 || i == 9 || i == 11)
                dif_d -= 30;
            else 
                dif_d -= y % 4 == 0 ? 29 : 28;
        }
        for (int64_t i = 1; i < date.m; i++) {
            if (std::find(m31.begin(), m31.end(), i) != m31.end())
               dif_d += 31;
            else if (i == 4 || i == 6 || i == 9 || i == 11)
                dif_d += 30;
            else
                dif_d += date.y % 4 == 0 ? 29 : 28;
        }
        return 365 * (date.y - y) + v + dif_d;
    }
    
    int64_t y, m, d;
    std::vector<int64_t> m31 = { 1, 3, 5, 7, 8, 10, 12};
};