#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>

#define BUFFSIZE 135

/*******************************************************************************
 * The following two functions are not part of the assignment. They are needed *
 * to generate simulated observatory data.                                     *
 ******************************************************************************/

char bin2hex ( char *s )
{
   int h, i;

   h = (*s) - '0';
   for (i=1; i<4; ++i) {
      ++s;
      h *= 2;
      if (*s == '1') ++h;
   }
   if (h < 10) return '0'+h; else return 'a' + h - 10;
}

void geninput ( int n )
{
   FILE *ifp, *ofp;
   char I[64][128], J[64][128], ofname[16];
   int i, j, k, p, nline, ncorrupt, opflag[128];

   ifp = (FILE *)fopen("../img/sample01.txt", "r");
   for (i=0; i<64; ++i) {
      for (j=0; j<128; ++j) {
         fscanf(ifp, "%c", &I[i][j]);
      }
      getc(ifp);
   }
   fclose(ifp);

   for (p=1; p<=n; ++p) {
      nline = 0;
      for (i=0; i<64; ++i) {
         for (j=0; j<128; ++j) J[i][j] = I[i][j];
         if ((opflag[i] = rand() % 2)) {
            ++nline;
            ncorrupt = rand() % 8;
            for (k=0; k<ncorrupt; ++k) {
               j = rand() % 128;
               if (J[i][j] == '0') J[i][j] = '1'; else J[i][j] = '0';
            }
         }
      }
      sprintf(ofname, "C2/A%02d.txt", p);
      ofp = (FILE *)fopen(ofname,"w");
      for (k=0; k<nline; ++k) {
         i = rand() % 64;
         while (!opflag[i]) { ++i; if (i >= 64) i -= 64; }
         opflag[i] = 0;
         fprintf(ofp, "%2d ", i);
         for (j=0; j<128; j+=4) fprintf(ofp, "%c", bin2hex(J[i]+j));
         fprintf(ofp, "\n");
      }
      fclose(ofp);
   }
}

/*********** The solution of the assignment starts below this line ************/

void hex2bin ( char d, char *s )
{
   int digit, i;

   if ((d >= '0') && (d <= '9')) digit = d - '0';
   else digit = 10 + d - 'a';
   for (i=3; i>=0; --i,++s) *s = (digit & (1 << i)) ? '1' : '0';
}

void senddata ( int i, int wfd )
{
   FILE *ifp;
   char ifname[20], line[128], buffer[BUFFSIZE];;
   int lineno, j, k;

   sprintf(ifname, "C2/A%02d.txt", i);
   ifp = (FILE *)fopen(ifname, "r");
   while (1) {
      fscanf(ifp, "%d%s", &lineno, line);
      if (feof(ifp)) break;
      sprintf(buffer, "%2d %2d ", i, lineno);
      for (j=0,k=6; j<32; ++j,k+=4) hex2bin(line[j],buffer+k);
      buffer[BUFFSIZE-1] = '\0';
      write(wfd,buffer,BUFFSIZE);
   }
   fclose(ifp);
   sprintf(buffer, "%d -1", i);
   write(wfd,buffer,BUFFSIZE);
}

char **receivedata ( int n, int rfd, int nline[] )
{
   char **T, buffer[BUFFSIZE];
   int i, r, ndone;

   T = (char **)malloc(64 * n * sizeof(char *));
   for (i=0; i<64*n; ++i) T[i] = NULL;
   for (i=0; i<64; ++i) nline[i] = 0;
   ndone = 0;
   while (ndone < n) {
      read(rfd, buffer, BUFFSIZE);
      sscanf(buffer, "%d%d", &r, &i);
      if (i == -1) ++ndone;
      else {
         T[n*i+nline[i]] = (char *)malloc(129*sizeof(char));
         sscanf(buffer+6, "%s", T[n*i+nline[i]]);
         ++(nline[i]);
      }
   }
   return T;
}

void stitchdata ( int n, char I[][129], char **T, int nline[] )
{
   int i, j, k, n0, n1;

   for (i=0; i<64; ++i) {
      for (j=0; j<128; ++j) {
         n0 = n1 = 0;
         for (k=0; k<nline[i]; ++k) {
            if (T[n*i+k][j] == '0') ++n0; else ++n1;
         }
         if (n0 > n1) I[i][j] = '0';
         else if (n1 > n0) I[i][j] = '1';
         else I[i][j] = '?';
      }
      I[i][128] = '\0';
   }
}

void sendimage ( char I[][129] )
{
   int i;

   for (i=0; i<64; ++i) printf("%s\n", I[i]);
}

void receiveimage ( )
{
   int i, j, nqm;
   char I[64][129], pixel;

   for (i=0; i<64; ++i) {
      for (j=0; j<128; ++j) scanf("%c",I[i]+j);
      I[i][128] = '\0';
      getchar();
   }

   printf("\n+++ The unprocessed image\n\n");
   for (i=0; i<64; ++i) printf("    %s\n", I[i]);

   nqm = 0;
   for (i=1; i<63; ++i) {
      for (j=1; j<127; ++j) {
         if (I[i][j] == '?') {
            pixel = I[i-1][j-1];
            if (pixel != '?') {
               if (I[i-1][j] != pixel) continue;
               if (I[i-1][j+1] != pixel) continue;
               if (I[i][j-1] != pixel) continue;
               if (I[i][j+1] != pixel) continue;
               if (I[i+1][j-1] != pixel) continue;
               if (I[i+1][j] != pixel) continue;
               if (I[i+1][j+1] != pixel) continue;
               I[i][j] = pixel; ++nqm;
            }
         }
      }
   }

   printf("\n%d question marks replaced\n", nqm);

   printf("\n+++ Printing for light terminals\n\n");
   for (i=0; i<64; ++i) {
      printf("    ");
      for (j=0; j<128; ++j) printf("%c", (I[i][j]=='0')?' ':I[i][j]);
      printf("\n");
   }
   printf("\n");

   printf("\n+++ Printing for dark terminals\n\n");
   for (i=0; i<64; ++i) {
      printf("    ");
      for (j=0; j<128; ++j) printf("%c", (I[i][j]=='1')?' ':I[i][j]);
      printf("\n");
   }
   printf("\n");
}

int main ( int argc, char *argv[] )
{
   int n, i;
   pid_t *sndpid, stcpid, cpid;
   int fd[2], sfd[2];

   n = (argc > 1) ? atoi(argv[1]) : 10;
   if ((n <= 0) || (n > 16)) n = 10;
   srand((unsigned int)time(NULL));

   #ifdef _CREATE_INPUT
   geninput(n);
   #endif


   if (pipe(fd) == -1) {
      fprintf(stderr, "*** Unable to set up pipe\n");
      exit(1);
   }

   if (pipe(sfd) == -1) {
      fprintf(stderr, "*** Unable to set up pipe\n");
      exit(1);
   }

   sndpid = (pid_t *)malloc(n * sizeof(pid_t));

   for (i=0; i<n; ++i) {
      cpid = fork();
      if (cpid == 0) {
         senddata(i+1,fd[1]);
         exit(0);
      }
      sndpid[i] = cpid;
   }

   stcpid = fork();
   if (stcpid == 0) {
      char **T, I[64][129];
      int nline[64];

      T = receivedata(n,fd[0],nline);
      stitchdata(n,I,T,nline);

      close(1);
      dup(sfd[1]);

      sendimage(I);

      exit(0);
   }

   for (i=0; i<n; ++i) waitpid(sndpid[i],NULL,0);

   close(0);
   dup(sfd[0]);

   receiveimage();

   waitpid(stcpid,NULL,0);

   exit(0);
}