#include <cctype>
#include <ctime>
#include <functional>
#include <iostream>
#include <random>
#include <string>
#include <vector>
#include <windows.h>


void cls()
{
    HANDLE hConsole = GetStdHandle(STD_OUTPUT_HANDLE);
    COORD coordScreen = { 0, 0 };
    DWORD cCharsWritten;
    CONSOLE_SCREEN_BUFFER_INFO csbi;
    DWORD dwConSize;
    if( !GetConsoleScreenBufferInfo( hConsole, &csbi ))
        return;
    dwConSize = csbi.dwSize.X * csbi.dwSize.Y;
    if( !FillConsoleOutputCharacter( hConsole, (TCHAR) ' ', dwConSize, coordScreen, &cCharsWritten ) ||
        !GetConsoleScreenBufferInfo( hConsole, &csbi ) ||
        !FillConsoleOutputAttribute( hConsole, csbi.wAttributes, dwConSize, coordScreen, &cCharsWritten ))
        return;
    SetConsoleCursorPosition( hConsole, coordScreen );
}


template <typename T>
T read(const std::string& request)
{
    std::cout << request;
    T value;
    bool repeat = true;
    while (repeat) {
        repeat = false;
        std::cin >> value;
        if(!std::cin) {
            std::cout << "Invalid input\n";
            std::cin.clear();
            repeat = true;
            while(!isspace(std::cin.get()))
                ;
        }
    }
    return value;
}


bool ask(const std::string& question)
{
    std::cout << question << '\n';
    char c;
    do {
        c = tolower(read<char>(""));
        if(c != 'y' && c != 'n')
            std::cout << "Invalid answer. Only Y, y, N and n are allowed\n";
    } while(c != 'y' && c != 'n');
    return c == 'y';
}


void SuperMarket()
{
    static const std::vector<std::pair<std::string, double>> goods = { {"", -1.0},
        {"Milk",   3.5}, {"Beef",      8.0}, {"Cereal", 3.0}, {"Youghurt", 4.5},
        {"Snacks", 1.5}, {"Chocolate", 4.5}, {"Bacon",  8.5}, {"Oranges",  3.3},
        {"Apples", 3.2}, {"Justin Bieber", 1},
    };
    double cost = 0;
    std::cout << "There's the list of what you can buy\n";
    bool buy = true;
    while (buy) {
        for(unsigned i = 1; i < goods.size(); ++i)
            std::cout << i << " = " << goods[i].first << '\n';
        unsigned item = read<unsigned>("");
        if(item >= 1 && item < goods.size()) {
            cls();
            std::cout << "One pack of " << goods[item].first << " costs " <<
                         goods[item].second << " $\n";
            unsigned amount = read<unsigned>("How many do you want to buy?\n");
            std::cout << "You bought " << amount << " so you have to pay " <<
                         goods[item].second * amount <<" $\n";
            cost += goods[item].second * amount;
        } else
            std::cout << "You haven't entered one valid number\n";
        buy = ask("Do you want to buy another item?");
        cls();
    }
    std::cout <<"The final sum is " << cost << " $\n";
}


void Lottery()
{
    int choice[6];
    std::cout << "Welcome to Lottery!\nEnter six numbers(1 to 6)\n";
    for(int i = 0; i < 6; ++i) {
        int input;
        do {
            input = read<int>("");
            if(input < 1 || 6 < input)
                std::cout << "Input should be in range 1-6\n";
        } while(input < 1 || 6 < input);
        choice[i] = input;
    }
    std::cout << "The winner numbers are:\n";

    static std::mt19937 rg(time(nullptr));
    static std::uniform_int_distribution<> dist(1, 6);
    for(int x =1; x<7 ; x++)
        std::cout << dist(rg) << ' ';
    std::cout << '\n';
    std::cout << " Two numbers   =    50 $\n"
                 " Three numbers =   150 $\n"
                 " Four numbers  =   500 $\n"
                 " Five numbers  =  2000 $\n"
                 " Six numbers   = 10000 $\n";
}


void AgeCaluclator()
{
    int year = read<int>("Enter the year you were born\n");
    int age = 2014 - year;
    std::cout << "You were born in " << year << " so ... You now are " << age << " years old\n" <<
                 (age < 30?"You are still young...\n":"You are getting old...\n");
}


void advanced_calculator_impl(std::function<int(int, int)> op)
{
    int current = read<int>("Enter first number\n");
    for(int i = 1; i < 6; ++i) {
        int next = read<int>("Enter next number\n");
        std::cout << "Your sum is " << (current = op(current, next)) << '\n';
    }
}

void AdvencedCalculator()
{
    static const std::vector<std::function<int(int, int)>> op = { nullptr,
        std::plus<int>(), std::minus<int>(), std::multiplies<int>(),
    };
    unsigned operation = read<unsigned>("Choose the type of operation\n"
                              "1 for plus | 2 for minus | 3 for multi\n");
    if(0 < operation && operation < op.size()) {
        do {
            cls();
            advanced_calculator_impl(op[operation]);
        } while(ask("Do you want to continue?"));
    }
}

void moneycalculator_impl()
{
    static const std::vector<std::pair<std::string, double>> conv = { {"", 0.0/0.0}, //Another dummy
        {"Leu-Euro", 1./4.42}, {"Euro-Leu", 4.42}, {"Lire-Leu", 5.5671}, {"Leu-Lire", 1./5.5671},
    };
    int cur_money = read<int>("Write the money you have\n");
    std::cout << "Choose what you want to convert\n";
    for(unsigned i = 1; i < conv.size(); ++i)
        std::cout << (i != 1?" | ":"") << i << " for " << conv[i].first;
    std::cout << '\n';
    unsigned choice = read<unsigned>("");
    if(choice > 0 && choice < conv.size())
        std::cout << "Your money (" << cur_money << ") converted (" <<
                     conv[choice].first << ") is " << cur_money * conv[choice].second << '\n';
    else
        std::cout << "You haven't entered 1,2,3 or 4\n";
}

void moneycalculator()
{
    do {
        cls();
        moneycalculator_impl();
    } while(ask("Do you want to continue?"));
}


void basicCalculator_impl()
{
    static const std::vector<std::function<int(int, int)>> op = {
        std::plus<int>(), std::minus<int>(), std::multiplies<int>(), std::divides<int>(),
    };
    int first = read<int>("Enter first number\n");
    int second = read<int>("Enter second number\n");
    int type = read<int>("Choose the type (0 = + | 1 = - | 2 = * | 3 = / |)\n");
    if(type >= 0 && type <= 3)
        std::cout << "Your number is: " << op[type](first, second) << '\n';
    else
        std::cout << "Please write 0 ,1, 2 or 3\n";
}

void basicCalculator()
{
    do {
        cls();
        basicCalculator_impl();
    } while(ask("Do you want to continue?"));
}


int main()
{
    const std::vector<std::pair<std::string, std::function<void(void)>>> menu = { {"", nullptr}, //Dummy to avoid index convertion
        {"Lottery",         Lottery},          {"Money Converting",         moneycalculator},
        {"Age Calculator",  AgeCaluclator},    {"Super Market",             SuperMarket},
        {"Basic Calculator", basicCalculator}, {"Multi-Numbers Calculator", AdvencedCalculator},
    };
    std::cout << "Choose what do you want to do...\n\n";
    for(unsigned i = 1; i < menu.size(); ++i) {
        const int margin = 23;
        const int item_margin = margin - menu[i].first.size() / 2;
        std::cout << std::string(margin - 3/*<-{ length*/, ' ') << "<-{" << i << "}->\n" <<
                     std::string(item_margin, ' ') << menu[i].first << "\n\n";
    }
    unsigned choice = read<int>("");
    if(choice > 0 && choice < menu.size()) {
        cls();
        menu[choice].second(); //Call function stored in vector by index "choice"
    }
}