/*
* Kevin Bernfeld
* COP3223 Section 2
* November 5, 2007
*
* I think I figured it out. addtopixels adds 103 to the numerical value of each pixel.
* subtract_two_pics actually adds one picture to another, in the form of a watermark... sort of.
* sobelfunc inverts a picture. 
*/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <math.h>

#define  BUFFER_SIZE  70
#define  TRUE          1
#define  FALSE         0

int**  img;
int**  img2;
int**  output;
int    numRows;
int    numCols;
int    maxVal;
int**  temppicx, temppicy;
int**  img,sobelout;
FILE*  fo1;

void  addtopixels(int** imgtemp, int value);
void  writeoutpic(char* fileName, int** imgtemp);
int** readpic(char* fileName);
void  readHeader(FILE* imgFin);
int   isComment(char* line);
void  readImgID(char* line);
void  readImgSize(char* line);
void  readMaxVal(char* line);
int** setImage();
void  readBinaryData(FILE* imgFin, int** imgtemp);
void  subtract_two_pics(int** imgA, int** imgB);
void  sobelfunc(int** pic, int** edges, int** tempx, int** tempy);

int main()
{
        char fileName[BUFFER_SIZE];
        char fileName2[BUFFER_SIZE];
        int i, j, rows, cols;
        char ci;
        int choice;
        int value_choice;
        int test_cont = 0;
        
        while (test_cont == 0) {
                printf("1) Run addtopixels\n");
                printf("2) Run subtract_two_pics\n");
                printf("3) Run sobelfunc\n");
                printf("4) Quit\n");
                printf("Enter your choice: ");
                scanf("%d", &choice);

                if (choice == 1) {
                   printf("Enter image filename: ");
                   scanf("%s", fileName);

                   img = readpic(fileName);

                   printf("Successfully read image file '%s'\n", fileName);
                   printf("Choose a value to add to the picture: ");
                   scanf("%d", &value_choice);

                   addtopixels(img, value_choice);

                   printf("Enter image filename for output: ");
                   scanf("%s", fileName);

                   writeoutpic(fileName,img);

                   free(img);
                   img = NULL;

                   return(EXIT_SUCCESS);
                 }
                 
                 if (choice == 2) {
                     printf("Enter image 1 filename: ");
                     scanf("%s", &fileName);
                     printf("Enter image 2 filename: ");
                     scanf("%s", &fileName2);
                     
                     img = readpic(fileName);
                     img2 = readpic(fileName2);
                     
                     printf("Successfully read image file '%s' and '%s'\n", fileName, fileName2);
                     
                     //output = setImage();  causes program to crash??

                     subtract_two_pics(img, img2);
                     
                     printf("Enter filename for output: ");
                     scanf("%s", &fileName);
                     
                     writeoutpic(fileName, img);
                     free(img);   
                 }
                 if (choice == 3) {
                     printf("Enter image filename: ");
                     scanf("%s", &fileName);
                     
                     img = readpic(fileName);
                     
                     printf("Successfully read image file '%s'.\n", fileName);
                     sobelout = setImage();

                     temppicx = setImage();
                     temppicy = setImage();

                     sobelfunc(img,sobelout,temppicx,temppicy); 

                     printf("Enter image filename for output: ");
                     scanf("%s", fileName);

                     writeoutpic(fileName,sobelout);
                 }
                 if (choice == 4) {
                      printf("Goodbye.\n");
                      break;
                 }
                 
        }
        system("PAUSE");
}

void addtopixels(int** imgtemp, int value)
{  
        int i,j;
        
        for (i = 0; i < numRows; i++) {
            for (j = 0; j < numCols; j++) {
                  imgtemp[i][j] += value;
            }
        }
}

void subtract_two_pics(int** imgA, int** imgB) {
     int i, j;
     for (i = 0; i < numRows; i++) {
         for (j = 0; j < numCols; j++) {
             imgA[i][j] = (imgA[i][j] - imgB[i][j]);
             imgA[i][j] = abs(imgA[i][j]);
         }
     }
}

void writeoutpic(char* fileName, int** imgtemp)
{
        int i,j;
        char ci;
        FILE* fo1;
        
        if((fo1 = fopen(fileName, "wb")) == NULL)
        {
                printf("Unable to open out image file '%s'\n", fileName);
                exit(EXIT_FAILURE);
        }

        fprintf(fo1, "P5\n");
        fprintf(fo1, "%d %d\n", numRows, numCols);
        fprintf(fo1, "255\n");

        for (i = 0; i < numRows; i++) { 
            for (j = 0;j < numCols; j++) {
                  ci   =  (char) (imgtemp[i][j]);
                  fprintf(fo1, "%c", ci);
            }
        }
}




int** readpic(char* fileName)
{
        FILE* imgFin;
        int** imgtemp;

        if((imgFin = fopen(fileName, "rb")) == NULL)
        {
                printf("Unable to open image file '%s'\n", fileName);
                exit(EXIT_FAILURE);
        }

        readHeader(imgFin);

        imgtemp  = setImage();

        readBinaryData(imgFin, imgtemp);

        fclose(imgFin);
        
        return  imgtemp;

}

void readHeader(FILE* imgFin)
{
        int  haveReadImgID   = FALSE;
        int  haveReadImgSize = FALSE;
        int  haveReadMaxVal  = FALSE;
        char line[BUFFER_SIZE];

        while(!(haveReadImgID && haveReadImgSize && haveReadMaxVal))
        {
                fgets(line, BUFFER_SIZE, imgFin);

                if((strlen(line) == 0) || (strlen(line) == 1))
                        continue;

                if(isComment(line))
                        continue;

                if(!(haveReadImgID))
                {
                        readImgID(line);
                        haveReadImgID = TRUE;
                }
                else if(!(haveReadImgSize))
                {
                        readImgSize(line);
                        haveReadImgSize = TRUE;
                }
                else if(!(haveReadMaxVal))
                {
                        readMaxVal(line);
                        haveReadMaxVal = TRUE;
                }
        }

}

int isComment(char *line)
{
        if(line[0] == '#')
                return(TRUE);

        return(FALSE);
}

void readImgID(char* line)
{
        if(strcmp(line, "P5\n") != 0)
        {
                printf("Invalid image ID\n");
                exit(EXIT_FAILURE);
        }
}

void readImgSize(char* line)
{
        unsigned i;

        for(i = 0; i < strlen(line); ++i)
        {
                if(!((isdigit((int) line[i])) || (isspace((int) line[i]))))
                {
                        printf("Invalid image size\n");
                        exit(EXIT_FAILURE);
                }
        }

        sscanf(line, "%d %d", &numRows, &numCols);
}

void readMaxVal(char* line)
{
        unsigned i;

        for(i = 0; i < strlen(line); ++i)
        {
                if(!((isdigit((int) line[i])) || (isspace((int) line[i]))))
                {
                        printf("Invalid image max value\n");
                        exit(EXIT_FAILURE);
                }
        }

        maxVal = atoi(line);
}

int** setImage()
{
        int** imgtemp;
        unsigned i;

        imgtemp = (int**) calloc(numRows, sizeof(int*));

        for(i = 0; i < numRows; ++i)
        {
                imgtemp[i] = (int*) calloc(numCols, sizeof(int));
        }
        return imgtemp;
}

void readBinaryData(FILE* imgFin, int** imgtemp)
{
        unsigned  i;
        unsigned  j;
        for(i = 0; i < numRows; ++i)
        {
                for(j = 0; j < numCols; ++j)
                {
                            imgtemp[i][j] = 
                            fgetc(imgFin);
                }
        }
}

void sobelfunc(int** pic, int** edges, int** tempx, int** tempy) {

        int maskx[3][3] = {{-1,0,1},{-2,0,2},{-1,0,1}};
        int masky[3][3] = {{1,2,1},{0,0,0},{-1,-2,-1}};
        int maxival;

        int i,j,p,q,mr,sum1,sum2;
        double threshold;

        mr = 1;

        for (i=mr;i<numRows-mr;i++)
        { for (j=mr;j<numCols-mr;j++)
          {
             sum1 = 0;
             sum2 = 0;
             for (p=-mr;p<=mr;p++)
             {
                for (q=-mr;q<=mr;q++)
                {
                   sum1 += pic[i+p][j+q] * maskx[p+mr][q+mr];
                   sum2 += pic[i+p][j+q] * masky[p+mr][q+mr];
                }
             }
             tempx[i][j] = sum1;
             tempy[i][j] = sum2;
          }
        }

        maxival = 0;
        for (i=mr;i<numRows-mr;i++)
        { for (j=mr;j<numCols-mr;j++)
          {
             edges[i][j]=(int) (sqrt((double)((tempx[i][j]*tempx[i][j]) +
                                      (tempy[i][j]*tempy[i][j]))));
             if (edges[i][j] > maxival)
                maxival = edges[i][j];

           }
        }

        for (i=0;i<numRows;i++)
          { for (j=0;j<numCols;j++)
            {
             edges[i][j] = ((edges[i][j]*1.0) / maxival) * 255;            
             
            }
          }
}