// Assignment 8 Solution - Fall 2020
#define _CRT_SECURE_NO_WARNINGS

#include <ctime>
#include <iomanip>
#include <iostream>
#include <cstdlib>
#include <string>
using namespace std;

class Date
{
    unsigned month, day, year;
public:
    Date();
    Date(unsigned, unsigned, unsigned);
    void increment();
    bool isGreaterThan(const Date&) const;
    bool isEqualTo(const Date&) const;
    void print() const;
    void letTimePass();
    static const double DaysPerYear;
    static unsigned DaysPerMonth[13];
    static Date getBirthday();
};

const double Date::DaysPerYear = 365.25;
unsigned Date::DaysPerMonth[13] = {0,31,28,31,30,31,30,31,31,30,31,30,31};

Date getBirthday();

class Human
{
    string  name;
    Date	birthday;
    bool	isAlive;
public:
    Human(const string& n, const Date& b);
    string get_name() const
    {
        return name;
    }

    const Date& get_birthday() const
    {
        return birthday;
    }

    bool is_alive() const
    {
        return isAlive;
    }

    unsigned short age() const;
    void die()
    {
        isAlive = false;
    }
    void print() const;
};

class Population
{
    Human**	people;
    void determine_oldest() const;
    static const int OriginalPopulationSize;
public:
    Population();
    ~Population();
    void print() const;
    void examinePopulation();
    int getNumberLiving() const;
    static int getOriginalPopulationSize()
    {
        return OriginalPopulationSize;
    }
};

const int Population::OriginalPopulationSize = 54;

float rollTheDice(unsigned short age);

Date TODAY;
const string NAMES[] =
{
    "Fadak","Adis","Kia","Adam","Ran","Jason","Brian","Hin Hang",
    "Swati","Alaxendar","Robert","Samar","Thi Thu Vy","Salomon","Marian","Nicolas",
    "Brian Ha","Wanjia","Dolly","Trien Bang","Suraj","Bereket","Ben",
    "Victor","Xinru","Zheng","Ken","Jason Kai","Ryan","Seyedamirhossei","Arrzu",
    "Nimra","Brian Ndiaye","Le Ngoc","Pham Bao Bao","Xuan Yen Tram","Kuangzhong","Joseph",
    "Het","Isha","Ahmad","Mehui","Tarandeep","Minrou","Lauren","Trang","Victoria",
    "An","Vinh","William","Benjamin","Hsin-Chieh","Jiasheng","Siyun"
};

int main()
{
    Population World;
    World.print();

    // let time pass until half of the world's Population dies
    do
    {
        TODAY.letTimePass();
        World.examinePopulation();
    }
    while (World.getNumberLiving() > Population::getOriginalPopulationSize() / 2);

    World.print();
}

// Creates today's date
Date::Date() : month(0), day(0), year(0)
{
    time_t now = time(NULL);
    tm* ptr = localtime(&now);
    month = ptr->tm_mon + 1;	// note  ptr->tm mon is current month% -1
    day = ptr->tm_mday;
    year = ptr->tm_year + 1900;
}

Date::Date(unsigned m, unsigned d, unsigned y)
    : month(m), day(d),year(y)
{
    if (y < 100) year += (year < 21) ? 2000 : 1900;
}

void Date::increment(void)
{
    day++;

    // Leap year correction
    if (year%4 == 0) DaysPerMonth[2] = 29;
    else if (year%400 == 0) DaysPerMonth[2] = 29;
    else if (year%100 == 0) DaysPerMonth[2] = 28;
    else DaysPerMonth[2] = 28;

    if (day > DaysPerMonth[month])
    {
        day = 1;
        month++;
    }
    if (month > 12)
    {
        month = 1;
        year++;
    }
}

bool Date::isGreaterThan(const Date& d) const
{
    return 10000*year+100*month+day>10000*d.year+100*d.month+d.day;
}

bool Date::isEqualTo(const Date& d) const
{
    return 10000*year+100*month+day==10000*d.year+100*d.month+d.day;
}

void Date::print() const
{
    cout << setfill('0');
    cout << setw(2) << month << '/' << setw(2) << day << '/' << setw(2) << year;
    cout << setfill(' ');
}

void Date::letTimePass()
{
    int random = rand() % 365+1;
    int i;
    for (i = 0; i < random; i++) increment();
}

// returns the number of days between d1 and d2 (same as d1 - d2)
int difference_between_2_Dates(Date d1,Date d2)
{
    int days = 0;
    if (d1.isGreaterThan(d2))
    {
        do
        {
            days++;
            d2.increment();
        }
        while (!d1.isEqualTo(d2));
        return days;
    }
    else
    {
        do
        {
            days++;
            d1.increment();
        }
        while (!d2.isEqualTo(d1));
        return -days;
    }
}

Human::Human(const string& n,const Date& b) : name(n), birthday(b), isAlive(true)
{
}

unsigned short Human::age() const
{
    return static_cast<unsigned short> (difference_between_2_Dates(TODAY,birthday)/Date::DaysPerYear);
}

void Human::print() const
{
    cout << name << " was born on ";
    birthday.print();
    cout << " is " << age() << endl;
}

Population::Population() : people(new Human*[OriginalPopulationSize])
{
    for (int i = 0; i < OriginalPopulationSize; ++i)
    {
        people[i] = new Human(NAMES[i],Date::getBirthday());
    }
}

Population::~Population()
{
    for (int i = 0; i < OriginalPopulationSize; ++i) delete people[i];
    delete [] people;
    people = nullptr;
}


void Population::print() const
{
    cout << "================================================\n";
    cout << "Today is ";
    TODAY.print();
    cout << endl;
    for (short i = 0; i< OriginalPopulationSize; ++i)
    {
        if (people[i] -> is_alive()) people[i] -> print();
    }
    cout << "================================================\n";
}


void Population::examinePopulation()
{
    short i;

    for (i = 0; i < OriginalPopulationSize; i++)
    {
        // who lives and who dies?
        if (people[i]->is_alive())
        {
            if (rollTheDice(people[i]->age())>.67)
            {
                people[i] ->die();
                TODAY.print();
                cout << " " << people[i]->get_name() <<
                     " died at the age of " << people[i] -> age() << endl;
            }
        }
    }
}

int Population::getNumberLiving() const
{
    int count = 0;
    for (short i = 0; i < OriginalPopulationSize; i++)
    {
        if (people[i]->is_alive()) count++;
    }
    return count;
}

float rollTheDice(unsigned short age)
{
    return static_cast<float>(age)* (rand() % 100) / 10000.f;
}

Date Date::getBirthday()
{
    const int number_of_days_in_100_years = 35625;
    int number_of_days_after_birthdate;
    Date temp_birthday(1,1,1920);

    // generate a random number between 0 and 36524
    number_of_days_after_birthdate = rand() % number_of_days_in_100_years;

    // increment the temp_birthday a random number of days
    for (int j = 0; j < number_of_days_after_birthdate; ++j)
    {
        temp_birthday.increment();
    }
    return temp_birthday;
}