#include <iostream>
#include "mpi.h"
#include <random>
using namespace std;

#define VECTOR_SIZE 21

inline int generateRandomInRange(int a, int b) {
    random_device rd;
    uniform_int_distribution gen(a, b);
    return gen(rd);
}

void fill_vector_values(int *vec){
    for(size_t i = 0; i < VECTOR_SIZE; i++){
        vec[i] = generateRandomInRange(1, 100);
    }
}


void print_vec(int *vec){
    for(size_t i = 0; i < VECTOR_SIZE; i++){
        std::cout << vec[i] << endl;
    }
    std::cout << "---------" << std::endl;
}


int main(int argc, char **argv){
    int rank, size;
    int VEC_SIZE = VECTOR_SIZE;
    auto *vec1 = new int[VECTOR_SIZE];
    auto *vec2 = new int[VECTOR_SIZE];
    auto *res = new int[VECTOR_SIZE];
    fill_vector_values(vec1);
    fill_vector_values(vec2);


    MPI_Init(&argc, &argv);
    MPI_Comm_size(MPI_COMM_WORLD, &size);
    MPI_Comm_rank(MPI_COMM_WORLD, &rank);
    if(rank == 0){
        for(size_t i = 0; i < VEC_SIZE; i++){
            size_t num_process = (i % (size - 1)) + 1;
            MPI_Send(&i, 1, MPI_INT, static_cast<int>(num_process), 0, MPI_COMM_WORLD);
            int dot_result;
            MPI_Status status;
            MPI_Recv(&dot_result, 1, MPI_INT, MPI_ANY_SOURCE, 0, MPI_COMM_WORLD, &status);
            std::cout << " <- " << dot_result << endl;
            res[i] = dot_result;
        }
        print_vec(vec1);
        print_vec(vec2);
        print_vec(res);
    }else{
        int index;
        MPI_Status status;
        MPI_Recv(&index, 1, MPI_INT, 0, 0, MPI_COMM_WORLD, &status);
        int dot = vec1[index]*vec2[index];
        MPI_Send(&dot, 1, MPI_INT, 0, 0, MPI_COMM_WORLD);
        std::cout << rank << " -> " << index << endl;
    };



    MPI_Finalize();
    delete []vec1;
    delete []vec2;
    delete []res;
    return 0;
}