#include <stdio.h>
#include <stdlib.h>

#define WHITE 0
#define RED   1
#define GREEN 2
#define BLUE  3
#define BLACK 4

unsigned char pallete[5][3]={{255,255,255},{255,0,0},{0,255,0},{0,0,255},{0,0,0}};

//convert from pallete number to RGB values
void output_pixel(FILE *fp, unsigned char pixel) 
{
  fprintf(fp,"%d %d %d\n",pallete[pixel][0],pallete[pixel][1],pallete[pixel][2]);
}

void writePPM3(char *filename, unsigned char *buffer, unsigned int xsize, unsigned int ysize)
{
   FILE *fp = fopen(filename, "w");
   if (fp == NULL)
   {
      fprintf(stderr, "Could not open '%s' for writing\n", filename);
      return;
   }
   printf("writing file\n");

   fprintf(fp, "P3\n");
   fprintf(fp, "%d %d\n", xsize, ysize);
   fprintf(fp, "255\n");
                                                                                                           
   for(unsigned int i=0;i<ysize;i++)
   {
      printf(".");
      for(unsigned int e=0;e<xsize;e++)
      {
         unsigned int index=e+i*xsize;
         unsigned char pixel=(unsigned char)buffer[index];
         output_pixel(fp,pixel);
      }
   }
   printf("\ndone!\n");
   fclose(fp);
}

void generate_all_white(char *filename, unsigned int xsize,unsigned int ysize)
{
   printf("generating all white to file: %s\n",filename);

   unsigned char *buffer=(unsigned char *)malloc(xsize*ysize*sizeof(unsigned char));
   if(buffer==NULL)
   {
      printf("no memory!\n");
      return;
   } 

   for(unsigned int y=0;y<ysize;y++)
   {
      for(unsigned int x=0;x<xsize;x++)
      {
         unsigned int index=x+y*xsize;
         buffer[index]=WHITE;
      }
   }

   writePPM3(filename,buffer,xsize,ysize);
   free(buffer);
}

void generate_test(char *filename, unsigned int xsize,unsigned int ysize)
{
   printf("generating all white to file: %s\n",filename);

   unsigned char *buffer=(unsigned char *)malloc(xsize*ysize*sizeof(unsigned char));
   if(buffer==NULL)
   {
      printf("no memory!\n");
      return;
   }
   unsigned int x_center=xsize/2;
   unsigned int y_center=ysize/2;
   printf("center: %d %d\n",x_center,y_center);

   for(unsigned int y=0;y<ysize;y++)
   {
      for(unsigned int x=0;x<xsize;x++)
      {
         unsigned int index=x+y*xsize;
         unsigned char pixel=BLACK;

         if(x==x_center  || y==y_center) pixel=BLACK;
         else if(x%32==0 || y%32==0)     pixel=RED;
         else if(x%8==0  || y%8==0)      pixel=WHITE;
         else if(y%2==0) //internal grid
         {
            if(x%2==0) pixel=BLUE;
            else       pixel=GREEN;
         }
         else
         {
            if(x%2==0) pixel=GREEN;
            else       pixel=BLUE;
         }

         buffer[index]=pixel;
      }
   }

   writePPM3(filename,buffer,xsize,ysize);
   free(buffer);
}

unsigned int x_center;
unsigned int y_center;
unsigned int l_edge;
unsigned int h_edge;
unsigned int y;
unsigned int x;

bool edge_offset(int amount)
{
   if(x==l_edge+amount || y ==l_edge+amount || x==h_edge+amount || y == h_edge+amount) 
      return true;
   else 
      return false;
}

bool center_offset(int amount)
{
   if(x==x_center+amount || y==y_center+amount) 
      return true;
   else 
      return false;
}


bool dashed(int test, int amount)
{
   int half=amount/2;
   int moded=test%amount;

   if(moded>=half) return true;
   else            return false;
}

bool dashed_horiz(int amount) { return dashed(x,amount); }
bool dashed_vert(int amount)  { return dashed(y,amount); }

bool corner_test(int a, int b)
{
   if(x>=a-3 && x<=a+2 && y>=b-3 && y<=b+2)
      return true;
   else
      return false;
}


void generate_subbox(char *filename, unsigned int xsize,unsigned int ysize)
{
   printf("generating subbox to file: %s\n",filename);

   unsigned char *buffer=(unsigned char *)malloc(xsize*ysize*sizeof(unsigned char));
   if(buffer==NULL)
   {
      printf("no memory!\n");
      return;
   }
   
   x_center=xsize/2;
   y_center=ysize/2;
   l_edge=18;
   h_edge=xsize-18-1;

   for(y=0;y<ysize;y++)
   {
      for(x=0;x<xsize;x++)
      {
         unsigned int index=x+y*xsize;
         unsigned char pixel=BLACK;
            
	 if(     center_offset(-3)) pixel=WHITE;
	 else if(center_offset(-2)) pixel=WHITE;
         else if(center_offset( 1)) pixel=WHITE;
         else if(center_offset( 2)) pixel=WHITE;      
         else if(edge_offset  (-3)) pixel=WHITE;
         else if(edge_offset  (-2)) pixel=WHITE;
         else if(edge_offset  ( 1)) pixel=WHITE;
         else if(edge_offset  ( 2)) pixel=WHITE;

         if(corner_test(l_edge,l_edge)) pixel=BLACK;
         if(corner_test(l_edge,h_edge)) pixel=BLACK;
         if(corner_test(h_edge,h_edge)) pixel=BLACK;
         if(corner_test(h_edge,l_edge)) pixel=BLACK;

         if(corner_test(l_edge,y_center))   pixel=BLACK;
         if(corner_test(x_center,l_edge))   pixel=BLACK;
         if(corner_test(x_center,y_center)) pixel=BLACK;
         if(corner_test(x_center,h_edge))   pixel=BLACK;
         if(corner_test(h_edge,y_center))   pixel=BLACK;

         if(x==l_edge || x==l_edge-1) pixel=BLACK;
         if(x==h_edge || x==h_edge-1) pixel=BLACK;
         if(y==l_edge || y==l_edge-1) pixel=BLACK;
         if(y==h_edge || y==h_edge-1) pixel=BLACK;

         if(x==x_center || x==x_center-1) pixel=BLACK;
         if(y==y_center || y==y_center-1) pixel=BLACK;

         buffer[index]=pixel;
      }
   }

   writePPM3(filename,buffer,xsize,ysize);
   free(buffer);
}


int main()
{
   generate_all_white("white.ppm",1056,1056);
   generate_test("test.ppm",1056,1056);
   generate_subbox("subbox.ppm",1056,1056);
   return 0;
}