#include <stdio.h>
#include <stdlib.h>
#include "fdtd-macro.h"

static int temporalStride = -2, frameX = 0, frameY = 0, startTime;
static char basename[80];

void snapshot3dInit(Grid *g) {
  
  int choice;
  
  printf("Do you want 2D snapshots of the 3D grid? (1=yes, 0=no) ");
  scanf("%d", &choice);
  if (choice == 0) {
    temporalStride = -1;
    return;
  }

  printf("Duration of simulation is %d steps.\n", MaxTime);
  printf("Enter start time and temporal stride: ");
  scanf(" %d %d", &startTime, &temporalStride);
  printf("Enter the base name: ");
  scanf(" %s", basename);

  return;
}  /* end snapshot3dInit() */


void snapshot3d(Grid *g) {
  int mm, nn, pp;
  float dim1, dim2, temp;
  char filename[100];
  FILE *out;

  /* ensure temporal stride set to a reasonable value */
  if (temporalStride == -1) {
    return;
  } if (temporalStride < -1) {
    fprintf(stderr,
      "snapshot2d: snapshotInit2d must be called before snapshot.\n"
      "            Temporal stride must be set to positive value.\n");
    exit(-1);
  }

  /* get snapshot if temporal conditions met */
  if (Time >= startTime && 
      (Time - startTime) % temporalStride == 0) {

    /************ write the constant-x slice ************/
    sprintf(filename, "%s-x.%d", basename, frameX++);
    out = fopen(filename, "wb");

    /* write dimensions to output file */
    dim1 = SizeY; // express dimensions as floats
    dim2 = SizeZ; // express dimensions as floats
    fwrite(&dim1, sizeof(float), 1, out);
    fwrite(&dim2, sizeof(float), 1, out);

    /* write remaining data */
    mm = (SizeX - 1) / 2;
    for (pp = SizeZ - 1; pp >= 0; pp--)
      for (nn = 0; nn < SizeY; nn++) {
	temp = (float)Ex(mm, nn, pp); // store data as a float
	fwrite(&temp, sizeof(float), 1, out); // write the float
      }

    fclose(out);  // close file

    /************ write the constant-y slice ************/
    sprintf(filename, "%s-y.%d", basename, frameY++);
    out = fopen(filename, "wb");

    /* write dimensions to output file */
    dim1 = SizeX - 1; // express dimensions as floats
    dim2 = SizeZ; // express dimensions as floats
    fwrite(&dim1, sizeof(float), 1, out);
    fwrite(&dim2, sizeof(float), 1, out);

    /* write remaining data */
    nn = SizeY / 2;
    for (pp = SizeZ - 1; pp >= 0; pp--)
      for (mm = 0; mm < SizeX - 1; mm++) {
	temp = (float)Ex(mm, nn, pp); // store data as a float
	fwrite(&temp, sizeof(float), 1, out); // write the float
      }

    fclose(out);  // close file
  }

  return;
}  /* end snapshot3d() */