#include <iostream>
#include <iomanip>
#include <cstdlib>
#include <string>
#include <chrono>
#include <random>
#include <functional>
#include <algorithm>  //for the algorthms sort and for_each
#include <vector>
using namespace std;

const string nameBank[] {
	"pa63",
	"kab33",
	"fdb4",
	"mb341",
	"jc208",
	"scortes9",
	"mrd22",
	"lee2",
	"rfrancolini1",
	"eh141",
	"mh182",
	"ljl8",
	"jmanu4",
	"jmm56",
	"aco8",
	"is49",
	"els13",
	"jt88",
	"mjt6",
	"ju13",
	"lov",
	"kwesner1",
	"rz54",
	"mmeretzky"
};

const size_t n {size(nameBank)};

struct stats {
	string name;
	int lvl;
	int hp;
	int xp;
};

stats a[n];

unsigned seed = chrono::system_clock::now().time_since_epoch().count();
default_random_engine engine {seed};
	uniform_int_distribution<size_t> distribution {0, 999};
auto r {bind(distribution, engine)};

//Declarations for the functions that perfrom the tasks.
//Each function has no arguments and no return value.
void tourney();
void train();
void battle();
void list();

void defeated(size_t victor, size_t vanquished, size_t e);
void xpCheck(size_t i);

int main()
{
	for (int i {0}; i < n; ++i){
		a[i].name = nameBank[i];
		a[i].lvl = 1;
		a[i].hp = r() % 50 + 100 + a[i].lvl * 25;
		a[i].xp = 0;
	};

	list();

	struct task {
		string name;
		void (*f)(); //a pointer to a function with no arguments
			     //or return value
	};

	//Write the name of each function in the second column.
	//The name of a function, all by itself,
	//means the address of the function.
	const task tasks[] {
		{"Start a tournament", tourney},
		{"Train a player",     train},
		{"Random battle",      battle},
		{"Leaderboard",        list}
	};

	for (;;) {
		cout << "Would you like to\n";

		//List the four tasks.
		int i {0};
		for_each(begin(tasks), end(tasks),
			[&i](const task& t) {
				cout << ++i << ". " << t.name << "\n";
			}
		);
		
		int t {0};
		cin >> t;

		if (!cin) {
			cerr << "Sorry, something went wrong.\n";
			return EXIT_FAILURE;
		}

		if (t <= 0 || t > size(tasks)) {
			cerr << "Sorry, Please select a number in the range 1 "
				<< "to " << size(tasks) << "inclusive and "
				<< "press enter.\n";

				cin.clear();
				const streamsize n
					{numeric_limits<streamsize>::max()};
				cin.ignore(n, '\n');
				cout << "Try again: ";
				continue;
		}

		tasks[t-1].f();  //Call one of the four possible task functions.
	}

	return EXIT_SUCCESS;
}

void list()
{
	//In order of decreasing lvl.
	sort(begin(a), end(a),
		[](const stats& a, const stats& b) {return a.lvl > b.lvl;});

	for_each(begin(a), end(a),
		[](const stats& s) {
			cout << "Player: " << setw(12) << left << s.name
				<< right << ".  "
				<< "Level:  " << setw(6) << s.lvl << ".  "  
				<< "HP:  "    << setw(6) << s.hp  << ".  "
				<< "XP:  "    << setw(6) << s.xp  << ".\n";
		});
}

void tourney() 
{
	cout << "Under Construction\n";
	cout << "\n==== BEGIN TOURNAMENT ====\n";
	cout << "There are " << n << " participants who will compete through rounds.\n";
	for_each(begin(a), end(a), [](const stats& s) {});
}

void train()
{
	cout << "Which player would you like to train?\n";
	string trainer;
	cin >> trainer;
	cout << "Pending\n";
	for_each(begin(a), end(a), [](const stats& s) {});
}

void battle()
{
	//Select two different random numbers in the range 0 to n-1 inclusive.
	const size_t y {r() % n};
	size_t z {r() % n};
	while (y == z) {
		z = r() % n;
	}

	int tempHPy {a[y].hp};
	int tempHPz {a[z].hp};
	int rounds {1};   //Should this be 0?
	const size_t e {500 + (r() % 250)};

	for (; tempHPy > 0 && tempHPz > 0; ++rounds) {
	       tempHPz -= a[y].lvl * 15 + (r() % (a[y].lvl * 15));
	       tempHPy -= a[z].lvl * 15 + (r() % (a[z].lvl * 15));
	}

	cout << "After " << rounds << " rounds of combat, ";

	if (tempHPy <= 0 && tempHPz <= 0){
		cout << "it's a tie. "
			<< e << " XP points will be divided evenly between "
			<< a[y].name << " and " << a[z].name << ".\n";
		a[y].xp += e/2;
		a[z].xp += e/2;
	} else if (tempHPy <= 0) {
		defeated(z, y, e);   //z defeated y.
	} else {
		defeated(y, z, e);   //y defeated z.
	}

	xpCheck(y);
	xpCheck(z);
}

void defeated(size_t victor, size_t vanquished, size_t e)
{
	cout << a[victor].name << " has won!\n"
		<< a[victor].name << " has defeated "
		<< a[vanquished].name << " and gained " << e << " xp.\n";

	a[victor].xp += e;
}

void xpCheck(size_t i)
{
	if (a[i].xp > (a[i].lvl * 1.25 * 1000)) {
		a[i].lvl += 1;
		a[i].hp += (r() % 50 + 25);
		cout << a[i].name << " has leveled up!\n";
	}
}