#include "pch.h"
#include "mpi.h"
#include <stdio.h>
#include <iostream>
#include <math.h>
#include <ctime>
#include <cmath>
#include <vector>
#include <string>
using namespace std;

bool IsRingTopology(MPI_Comm comm) {
	int status;
	MPI_Topo_test(comm, &status);
	if (status != MPI_CART)
		return false;

	int ndims;
	MPI_Cartdim_get(comm, &ndims);
	if (ndims != 1)
		return false;

	std::vector<int> dims(ndims), periods(ndims), coords(ndims);
	MPI_Cart_get(comm, ndims, dims.data(), periods.data(), coords.data());
	if (periods[0] != 1)
		return false;

	return true;
}

std::vector<int> Send(MPI_Comm ringcomm, int source, int dest,
	std::vector <int> message, int mess_size) {
	int size, rank;
	MPI_Comm_size(ringcomm, &size);
	MPI_Comm_rank(ringcomm, &rank);
	std::vector<int> result;

	if (source > (size - 1) || source < 0 || dest >(size - 1) || dest < 0)
		throw - 1;

	if (((rank >= source) && (rank <= dest)) ||
		((dest - source < 0) && ((rank >= source) || (rank <= dest)))) {
		if (dest == source)
			return message;

		int curr_dest, curr_source;
		MPI_Status status;

		MPI_Cart_shift(ringcomm, 0, 1, &curr_source, &curr_dest);

		if (rank == source) {
			MPI_Send(&message[0], mess_size, MPI_INT, curr_dest, 1, ringcomm);
		}
		else if (rank == dest) {
			result.resize(mess_size);
			MPI_Recv(&result[0], mess_size, MPI_INT, curr_source, 1, ringcomm, &status);
		}
		else {
			std::vector<int> *tmp = new std::vector<int>;
			tmp->resize(mess_size);

			MPI_Recv(&((*tmp)[0]), mess_size, MPI_INT, curr_source, 1, ringcomm, &status);
			MPI_Send(&((*tmp)[0]), mess_size, MPI_INT, curr_dest, 1, ringcomm);

			delete tmp;
		}
	}
	return result;
}

int main(int argc, char* argv[]) {
	MPI_Comm oldcomm = MPI_COMM_WORLD;
	MPI_Comm ringcomm;
	MPI_Init(&argc, &argv); //СЮДА ЕБАТЬ?
	std::vector<int> dims(1), periods(1);

	MPI_Comm_size(oldcomm, &dims[0]);
	periods[0] = 1;

	MPI_Cart_create(oldcomm, 1, dims.data(), periods.data(), 0, &ringcomm);

	bool IsW = IsRingTopology(ringcomm);
	cout << IsW;
	int res = (ringcomm, -1, 0, 1024, 3);
	cout<< res;
	MPI_Finalize(); //СЮДА ЕБАТЬ?
	return 0;
}