#include "mat_mul.h"
#include "util.h"
#include <cstdio>
#include <cstdlib>
#include <mpi.h>
#include <immintrin.h>
#define MASTER 0
#define FROM_MASTER 1
#define FROM_WORKER 2
#define ITILESIZE (32)
#define JTILESIZE (1024)
#define KTILESIZE (1024)

static float *A, *B, *C;
static int M, N, K;
static int num_threads;
static int mpi_rank, mpi_world_size;
MPI_Status status;
MPI_Request request;

  int numworkers, // number of worker tasks  
      source, // task id of message source
      dest, // task id of message destination
      mtype, // message type
      rows, // rows of matrix A sent to each worker
      averow, extra, offset, // used to determine rows sent to each worker
      i, j, k;
static int min(int x, int y) {
  return x < y ? x : y;
}
static void mat_mul_omp() {
  // TODO: parallelize & optimize matrix multiplication
  // Use num_threads per node
 int is = 0;
 int ie = rows;

#pragma omp parallel for num_threads(num_threads) schedule(dynamic) 
 
  for (int ii = is; ii < ie; ii += ITILESIZE) {
    for (int jj = 0; jj < N; jj += JTILESIZE) {
      for (int kk = 0; kk < K; kk += KTILESIZE) {
        for ( k = kk; k < min(K, kk + KTILESIZE); k++) {
          for ( i = ii; i < min(ie, ii + ITILESIZE); i++) {
            float ar = A[i * K + k];
            for ( 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;
  // TODO: parallelize & optimize matrix multiplication on multi-node
  // You must allocate & initialize A, B, C for non-root processes
	numworkers = mpi_world_size;
if (numworkers == 0) {
	rows = M;
    mat_mul_omp();
} else {

 // MASTER initialization & send matrix data to the worker tasks
	if (mpi_rank == MASTER) {
		averow = M / numworkers;
		int os, de;
		extra = M % numworkers;
		offset = 0;
		mtype = FROM_MASTER;
		for (dest = 1; dest < numworkers; dest++) {
			os = offset = dest * averow;
			de = dest == numworkers - 1 ? M : (dest + 1) * averow;
			rows = de - os;
			printf("sending %d rows to task %d offset =%d\n", rows, dest, offset);
			MPI_Isend(&offset, 1, MPI_INT, dest, mtype, MPI_COMM_WORLD, &request);
			MPI_Isend(&rows, 1, MPI_INT, dest, mtype, MPI_COMM_WORLD, &request);
			MPI_Isend(&A[offset * K], rows * K, MPI_FLOAT, dest, mtype, MPI_COMM_WORLD, &request);
			MPI_Isend(B, K * N, MPI_FLOAT, dest, mtype, MPI_COMM_WORLD, &request);
		}
			rows = averow;

    mat_mul_omp();

 // Receive results from worker tasks
		mtype = FROM_WORKER;
		for (i = 1; i < numworkers; i++){
			source = i;
			MPI_Recv(&offset, 1, MPI_INT, source, mtype, MPI_COMM_WORLD, &status);
			MPI_Recv(&rows, 1, MPI_INT, source, mtype, MPI_COMM_WORLD, &status);
			MPI_Recv(&C[offset * N], rows * N, MPI_FLOAT, source, mtype, MPI_COMM_WORLD, &status);
			printf("Received result from task %d\n", source);
		}
	} 
	
	if (mpi_rank > MASTER) {
		alloc_mat(&A, M, K);
		alloc_mat(&B, K, N);
		alloc_mat(&C, M, N);
		zero_mat(C, M, N);
		mtype = FROM_MASTER;
		MPI_Recv(&offset, 1, MPI_INT, MASTER, mtype, MPI_COMM_WORLD, &status);
		MPI_Recv(&rows, 1, MPI_INT, MASTER, mtype, MPI_COMM_WORLD, &status);
		MPI_Recv(A, rows * K, MPI_FLOAT, MASTER, mtype, MPI_COMM_WORLD, &status);
		MPI_Recv(B, K * N, MPI_FLOAT, MASTER, mtype, MPI_COMM_WORLD, &status);

    mat_mul_omp();

		mtype = FROM_WORKER;
		MPI_Isend(&offset, 1, MPI_INT, MASTER, mtype, MPI_COMM_WORLD, &request);
		MPI_Isend(&rows, 1, MPI_INT, MASTER, mtype, MPI_COMM_WORLD, &request);
		MPI_Isend(C, rows * N, MPI_FLOAT, MASTER, mtype, MPI_COMM_WORLD, &request);
	}
    }
}