#include <stdio.h>
#include <string.h>

typedef int *RowType;

void printPicture(RowType picture[], int numRows, int numCols );
void printToFile(FILE *fp, RowType picture[], 
                 int numRows, int numCols, int maxPixel );

int main()
{
    FILE *fp, *fp2;
    char str[81];
    char ch;
    int count=0;
    int comment;
    char *seps = " ,\n";   //"token" separators in a string
    int i;
    char *pch;     // pointer to a character
    int numCols, numRows, maxPixel, pixel;
    int row, col;
    RowType *picture, oneRow;
   
    
    if ((fp = fopen("widget.pgm", "r")) == NULL)
    {
       printf("Error opening file to read\n");
       exit (0);
    }
    if ((fp2 = fopen("newWidget.pgm", "w")) == NULL)     
    {
       printf("Error opening file to write\n");
       exit (0);
    }
 
    fgets(str, 80, fp);  //read initial "P2" header line
    printf("%s", str);   //echo print for debugging
    fgets(str, 80, fp);  // check if this is a comment line
    printf("%s", str);   //echo print for debugging
    if (str[0] == '#')
       comment = 1;
    else comment = 0;
    
    while (comment)
    {
        fgets(str, 80, fp); 
        printf("%s", str);   //echo print for debugging
        if (str[0] == '#')
           comment = 1;
        else comment = 0;	
    }

  // strtok: breaks a string into "tokens"
   i = 0;
   pch = strtok( str, seps ) ;     /* Find first token        */
   while( pch != NULL )
   {
      if (i == 0)
         numCols = atoi(pch);
      if (i == 1)
         numRows = atoi(pch);
	  
	  printf( "Token %d: %s\n", ++i, pch );
	  pch = strtok( NULL, seps );   /* Find next token         */
   }

// Check what has become of 'str'?
   printf( "str is now '%s', numCols = % d, numRows = %d\n", 
            str, numCols, numRows  );
   

 /*
  THIS CODE READS A FILE LINE BY LINE UNTIL EOF, EACH LINE IS A STRING "STR":  
 
    while (fgets(str, 80, fp) && count<5)  //fgets() reads the end-of-line character \n
    {
        printf("%s", str);
	count++;
    }
*/
  

/*
 THIS CODE READS NUMBERS FROM A FILE OF UNKNOWN LENGTH UNTIL EOF:
 
    while (fscanf(fp, "%d", &pixel) != EOF)
    {
        printf("%5d", pixel);
	count++;
	if (count % 15 == 0)
	   printf("\n");
    }
         
    printf("\n");
*/


     fscanf(fp, "%d", &maxPixel);
     printf("Max Pixel value: %d\n", maxPixel);

     picture = (int **)malloc(sizeof(int*)*numRows);  
     for (i=0; i< numRows; i++)
        picture[i] = (int *)malloc(sizeof(int)*numCols);

     
     for (row=0; row < numRows; row++)
     {
          for (col=0; col < numCols; col++)
	  {
	      fscanf(fp, "%d", &pixel);
	      picture[row][col] = pixel;
	  }   
     }
   
   //echo print the picture matrix:

     printPicture(picture, numRows, numCols);
 
     printToFile(fp2, picture, numRows, numCols, maxPixel);
   
     return 0;
}

void printPicture(RowType picture[], int numRows, int numCols )
{
   int row, col;
   
   for (row=0; row < numRows; row++)
   {
        for (col=0; col < numCols; col++)
	{
	    printf("%4d", picture[row][col]);
	    if (col % 15 == 14)
	       printf("\n");
	}   
	printf("\n");
   }   
}

void printToFile(FILE *fp, RowType picture[], 
                 int numRows, int numCols, int maxPixel )
{
   int row, col;
   
   fprintf(fp, "P2\n");
   fprintf(fp, "#New PGM file with image shifted\n");
   fprintf(fp, "%d %d\n%d\n", numCols, numRows, maxPixel);
   
   for (row=0; row < numRows; row++)
   {
        for (col=0; col < numCols; col++)
	{
	    fprintf(fp, "%4d", picture[row][col]);
	    if (col % 15 == 14)
	       fprintf(fp, "\n");
	}   
	fprintf(fp, "\n");
   }
   fclose(fp);   
}