/*
 * Realiza a filtragem da media a partir da convolucao entre uma imagem ruidosa
 * com uma mascara de tamanho nxn (n, impar, eh um parametro de entrada)
 *
 * n = 3 (default)
 */
 
#define MAX
#include "lib.h"
#include <math.h>
#include <time.h>

IMAGE avg(IMAGE x, int n);

IMAGE avg(IMAGE x, int n)
{
	int i,j,mi,mj;
    IMAGE y;
    unsigned int av;
    
    y = newimage(x->info->nr, x->info->nc);
	for (i = n/2; i < x->info->nr-n/2; i++) {
        for (j = n/2; j < x->info->nc-n/2; j++) {
            av = 0;
            //Average calculation
            for (mi = i - n/2; mi <= i + n/2; mi++) {
                for (mj = j - n/2; mj <= j + n/2; mj++) {
                    av += x->data[mi][mj];
                }
            }
            y->data[i][j] = (unsigned char)(av / (n*n));
        }
    }
    
    return(y);
}   
 
IMAGE avg_test() {
    IMAGE x;
    
    //small case test
    x = newimage(3,3);
    x->data[0][0] = 200;
    x->data[0][1] = 150;
    x->data[0][2] = 200;
    x->data[1][0] = 150;
    x->data[1][1] = 200;
    x->data[1][2] = 150;
    x->data[2][0] = 200;
    x->data[2][1] = 150;
    x->data[2][2] = 100;
   
    return(avg(x, 3));
}

main(int argc, char *argv[])
{
    int n = 3;
	IMAGE x=0;
    time_t t0, t1;

	if (argc < 2)
	{
	  printf("Usage: avg <image> [<mask_size>]\n");
	  exit(1);
	}

	x = Input_PBM(argv[1]);
	if (x == 0)
	{
	  printf("No input image ('%s')\n", argv[1]);
	  exit(2);
	}

    if (argc > 2) {
        sscanf(argv[2], "%d", &n);
        if (n % 2 <= 0) {
            printf("Mask size must be an odd natural number\n");
            exit(2);
        }
    }

    printf("Average filter with mask of size %d\n", n);

    t0 = time(NULL);
	x = avg(x, n);
    t1 = time(NULL);

	Output_PBM(x, "avg.pgm");
	printf("Output is in file 'avg.pgm'\n");
	printf("Processing time: %lf seconds\n", difftime(t1,t0));
}