#include "mat_mul.h"
#include "util.h"
#include <cstdio>
#include <cstdlib>
#include <mpi.h>
#include "omp.h"

static float *A, *B, *C;
static int M, N, K;
static int num_threads;
static int mpi_rank, mpi_world_size;

static int min(int x, int y) {
	return x < y ? x : y;
}

static void mat_mul_omp() {
#define ITILESIZE (32)
#define JTILESIZE (1024)
#define KTILESIZE (1024)

	omp_set_num_threads(num_threads);

#pragma omp parallel for
  for (int ii = 0; ii < M; ii += ITILESIZE) {
    for (int jj = 0; jj < N; jj += JTILESIZE) {
      for (int kk = 0; kk < K; kk += KTILESIZE) {

        for (int k = kk; k < min(K, kk + KTILESIZE); k++) {
          for (int i = ii; i < min(M, ii + ITILESIZE); i++) {
            float ar = A[i * K + k];
            for (int j = jj; j < min(N, jj + JTILESIZE); j+=1) {
              C[i * N + j] += ar * B[k * N + j];
            }
          }
        }

      }
    }
  }
}

void mat_mul(float *_A, float *_B, float *_C, int _M, int _N, int _K,
             int _num_threads, int _mpi_rank, int _mpi_world_size) {
  A = _A, B = _B, C = _C;
  M = _M, N = _N, K = _K;
  num_threads = _num_threads, mpi_rank = _mpi_rank,
  mpi_world_size = _mpi_world_size;

	MPI_Status status;
	MPI_Request req;
	int averow = M / mpi_world_size;
	int extra = M % mpi_world_size;

  if (mpi_rank == 0) {
		//timer_start(0);

		for (int node = 1, offset = averow + extra; node < mpi_world_size; node++) {
			//printf("Master sending partial matrix A to node(%d)\n", mpi_rank);
			MPI_Isend(B, K * N, MPI_FLOAT, node, node, MPI_COMM_WORLD, &req);
			MPI_Isend(&A[offset * K], averow * K, MPI_FLOAT, node, node, MPI_COMM_WORLD, &req);
			offset += averow;
		}

		//printf("Sending time %f\n", timer_stop(0));
		M = averow + extra;
		mat_mul_omp();
	}
	else {
		alloc_mat(&B, K, N);
		MPI_Recv(B, K * N, MPI_FLOAT, 0, mpi_rank, MPI_COMM_WORLD, &status);
		alloc_mat(&A, averow, K);
		alloc_mat(&C, averow, N);
		zero_mat(C, averow, N);

		MPI_Recv(A, averow * K, MPI_FLOAT, 0, mpi_rank, MPI_COMM_WORLD, &status);
		//printf("Worker node(%d) received partial matrix A\n", mpi_rank);

		M = averow;
		mat_mul_omp();

		MPI_Isend(C, averow * N, MPI_FLOAT, 0, mpi_rank, MPI_COMM_WORLD, &req);
		//printf("Worker node(%d) sent calculation result to Master\n", mpi_rank);
	}

  if (mpi_rank == 0) {
		//timer_start(1);
		for (int node = 1, offset = averow + extra; node < mpi_world_size; node++) {
			MPI_Recv(&C[offset * N], averow * N, MPI_FLOAT, node, node, MPI_COMM_WORLD, &status);
			offset += averow;
		}
		//printf("Receiving time %f\n", timer_stop(1));
	}
}