#include <iostream>
#include "windows.h"
#include <vector>
#include <string>
#include <conio.h>
#include <functional>
#include <cmath>

using namespace std;

#define WIDTH 80
#define HEIGHT 30
const double PI = 3.141592653589793238463;

void print(const char text[], int x, int y)
{
    HANDLE hCon = GetStdHandle(STD_OUTPUT_HANDLE);
    COORD pos;
    pos.X = x;
    pos.Y = y;
    SetConsoleCursorPosition(hCon, pos);
    cout << text;
}

class menu
{
    vector <string> points;
    vector <function<void()>> actions;
    int point = 0;
    void show()
    {
        system("cls");
        int xMiddle = WIDTH / 2;
        int yPart = HEIGHT / (points.size() + 1);
        for (int i = 0; i < points.size(); i++)
        {
            if (i == point)
            {
                string temp = "<<" + points[i] + ">>";
                print(temp.c_str(), xMiddle - temp.length() / 2, yPart*(i+1));
            }
            else
                print(points[i].c_str(), xMiddle - points[i].length() / 2, yPart*(i+1));
        }
    }
    void up()
    {
        point = point == 0 ? points.size() - 1 : point - 1;
    }
    void down()
    {
        point = point == points.size() - 1 ? 0 : point + 1;
    }
    void enter()
    {
        actions[point]();
    }
    public:
        void add(string newP, function<void()> newA)
        {
            points.push_back(newP);
            actions.push_back(newA);
        }
        void get()
        {
            show();
            int button;
            while (true)
            {
                button = _getch();
                switch (button)
                {
                case 72:
                    up();
                    break;
                case 80:
                    down();
                    break;
                case 13:
                    enter();
                    break;
                case 27:
                    return;
                    break;
                }
                show();
            }
        }
};

void calck_sin()
{
    system("cls");
    string output;
    output = "sin(x)";
    print(output.c_str(), WIDTH / 2 - output.length() / 2, HEIGHT / 2 - 1);
    output = "x(grad)=";
    print(output.c_str(), WIDTH / 2 - output.length() / 2, HEIGHT / 2);
    double x;
    cin >> x;
    output = "sin("+ to_string(x)+")="+ to_string(sin((x * PI) / 180));
    print(output.c_str(), WIDTH / 2 - output.length() / 2, HEIGHT / 2 + 1);
    int input = 0;
    while (input!=27 && input!=13)
    {
        input = _getch();
    }
}

void calck_cos()
{
    system("cls");
    string output;
    output = "cos(x)";
    print(output.c_str(), WIDTH / 2 - output.length() / 2, HEIGHT / 2 - 1);
    output = "x(grad)=";
    print(output.c_str(), WIDTH / 2 - output.length() / 2, HEIGHT / 2);
    double x;
    cin >> x;
    output = "cos(" + to_string(x) + ")=" + to_string(cos((x * PI) / 180));
    print(output.c_str(), WIDTH / 2 - output.length() / 2, HEIGHT / 2 + 1);
    int input = 0;
    while (input != 27 && input != 13)
    {
        input = _getch();
    }
}

void calck_tg()
{
    system("cls");
    string output;
    output = "tg(x)";
    print(output.c_str(), WIDTH / 2 - output.length() / 2, HEIGHT / 2 - 1);
    output = "x(grad)=";
    print(output.c_str(), WIDTH / 2 - output.length() / 2, HEIGHT / 2);
    double x;
    cin >> x;
    output = "tg(" + to_string(x) + ")=" + to_string(tan((x * PI) / 180));
    print(output.c_str(), WIDTH / 2 - output.length() / 2, HEIGHT / 2 + 1);
    int input = 0;
    while (input != 27 && input != 13)
    {
        input = _getch();
    }
}

void calck_simple()
{
    system("cls");
    string output;
    output = "Enter action:";
    print(output.c_str(), WIDTH / 2 - output.length() / 2, HEIGHT / 2 - 2);
    int action = 0;
    while (action != '+' && action != '-' && action != '*' && action != '/')
    {
        action = _getch();
        if (action == '+' || action == '-' || action == '*' || action == '/')
            cout << (char)action;
    }
    output = "x";
    output += (char)action;
    output += "y";
    print(output.c_str(), WIDTH / 2 - output.length() / 2, HEIGHT / 2 - 1);
    double x, y, result;
    output = "x=";
    print(output.c_str(), WIDTH / 2 - output.length() / 2, HEIGHT / 2);
    cin >> x;
    output = "y=";
    print(output.c_str(), WIDTH / 2 - output.length() / 2, HEIGHT / 2 + 1);
    cin >> y;
    switch (action)
    {
    case '+':
        result = x + y;
        break;
    case '-':
        result = x - y;
        break;
    case '*':
        result = x * y;
        break;
    case '/':
        result = x / y;
        break;
    }
    output = to_string(x);
    output += (char)action;
    output += to_string(y) + "=" + to_string(result);
    print(output.c_str(), WIDTH / 2 - output.length() / 2, HEIGHT / 2 + 2);
    int input = 0;
    while (input != 27 && input != 13)
    {
        input = _getch();
    }
}

int main()
{
    string resize = "mode "+ to_string(WIDTH)+ ", "+ to_string(HEIGHT);
    system(resize.c_str());
    setlocale(LC_ALL, "Russian");
    menu first;
    first.add("sin", calck_sin);
    first.add("cos", calck_cos);
    first.add("tg", calck_tg);
    first.add("simple function", calck_simple);
    first.get();
}