#include <stdlib.h>
#include <time.h>
#include <stdio.h>
#include <string.h>
#include <cstring>

#include "file.cuh"
#include "game.cuh"
#include "create_grid.cuh"


/*
  Rules for life:
  Any live cell with fewer than two live neighbors dies (underpopulation).
  Any live cell with two or three live neighbors continues to live.
  Any live cell with more than three live neighbors dies (overpopulation).
  Any dead cell with exactly three live neighbors becomes a live cell (reproduction).
 */
#define BLOCK 32
#define PADDING 10
//#define VERBOSE 1
#define SEED 100

// gpuErrchk source: https://stackoverflow.com/questions/14038589/what-is-the-canonical-way-to-check-for-errors-using-the-cuda-runtime-api
#define gpuErrchk(ans) { gpuAssert((ans), __FILE__, __LINE__); }
inline void gpuAssert(cudaError_t code, const char *file, int line, bool abort =
true) {
  if (code != cudaSuccess) {
    fprintf(stderr, "GPUassert: %s %s %d\n", cudaGetErrorString(code), file,
            line);
    if (abort)
      exit(code);
  }
}

void simulate(int argc, char** argv) {
  srand(SEED);
  clock_t totalStart = clock();
  char* filename;
  struct GAME game;
  game.padding = PADDING;
  int iterations, log_each_step, block_size;
  if (argc == 7) {
    filename = argv[2];
    game.width = atoi(argv[3]);
    game.height = atoi(argv[4]);
    iterations = atoi(argv[5]);
    log_each_step = atoi(argv[6]);
  } else {
    printf("Usage: ./gol simulate <filename | random> <width> <height> <iterations> <log-each-step?1:0> <block-size>\n");
    filename = "random";
    game.height = 10;
    game.width = 10;
    iterations = 5;
    log_each_step = 0;
  }

  // Allocate space for current grid (1 byte per tile)
  int size = (game.height+(2*game.padding)) * (game.width+(2*game.padding)) * sizeof(unsigned char);
  game.grid = (unsigned char*)malloc(size);
  memset(game.grid, 0, size);

  if (strcmp(filename, "random") == 0) {
    randomize(&game);
  } else {
    read_in(filename, &game);
  }  

  char iteration_file[1024];

  unsigned char* grid_d;
  unsigned char* newGrid_d;
  gpuErrchk(cudaMalloc(&grid_d, size));
  gpuErrchk(cudaMemcpy(grid_d, game.grid, size, cudaMemcpyHostToDevice));
  gpuErrchk(cudaMalloc(&newGrid_d, size));

  unsigned char* grid_h = (unsigned char*)malloc(size);
  unsigned char* temp;

  game.grid = grid_d;

  int grid_num = (int)ceil((game.width+(2*game.padding))/(float)BLOCK);
  dim3 dim_grid(grid_num, grid_num, 1);
  dim3 dim_block(BLOCK, BLOCK, 1);

  cudaEvent_t startLife, stopLife;
  cudaEventCreate(&startLife);
  cudaEventCreate(&stopLife);
  double timeComputingLife = 0;
  float localTime = 0;

  for (int i = 0; i <= iterations; i++) {
    if (i > 0) {
      cudaEventRecord(startLife);
      next<<<dim_grid, dim_block>>>(game, newGrid_d);
      cudaEventRecord(stopLife);
      cudaEventSynchronize(stopLife);
      cudaEventElapsedTime(&localTime, startLife, stopLife);
      timeComputingLife += localTime/1000;

      temp = game.grid;
      game.grid = newGrid_d;
      newGrid_d = temp;
    }
    if (log_each_step) {
      gpuErrchk(cudaMemcpy(grid_h, game.grid, size, cudaMemcpyDeviceToHost));
      #ifdef VERBOSE
        printf("\n===Iteration %i===\n", i);
        for (int y = game.padding; y < game.height+game.padding; y++) {
          for (int x = game.padding; x < game.width+game.padding; x++) {
            printf("%s ", grid_h[y*(game.width+2*game.padding) + x] ? "X" : " ");
          }
          printf("\n");
        }
        printf("===End iteration %i===\n", i);
      #endif
      sprintf(iteration_file, "output/iteration-%07d.bin", i);
      temp = game.grid;
      game.grid = grid_h;
      write_out(iteration_file, &game);
      game.grid = temp;
    }
  }

  clock_t totalEnd = clock();
  printf("\n===Timing===\nTime computing life: %f\nClock time: %f\n", timeComputingLife, ((double)totalEnd - (double)totalStart)/CLOCKS_PER_SEC);

  cudaFree(&newGrid_d);
  cudaFree(&grid_d);
  cudaFree(&game.grid);
  free(grid_h);
}

int main(int argc, char** argv) {
  if (argc >= 2) {
    if (strcmp(argv[1], "simulate") == 0) {
      simulate(argc, argv);
    } else if (strcmp(argv[1], "create-grid") == 0) {
      create_grid(argc, argv);
    } else {
      printf("Unknown input: %s\n", argv[1]);
      exit(1);
    }
  } else {
    printf("Usage: ./gol <simulate | create-grid>\n");
    exit(1);
  }
  return 0;
}