#ifndef CANNY_EDGE_MACHINE_C
#define CANNY_EDGE_MACHINE_C

#include <QtGlobal>
#include <QMainWindow>
#include <QColor>

#include <iostream>

#include <math.h>
#include "lazy_image.cpp"

class CannyEdgeMachine {
  
  private:
    LazyImage* original;
    LazyImage* working_copy;
     
    int width;
    int height;
    int pixels;
    double* gradient_magnitude;
    double* maximum_magnitude;
    int* binary_edge_pixels;
    int* gradient_x;
    int* gradient_y;
    
    // Params
    double t_low;
    double t_high;
    
  public:
    CannyEdgeMachine(LazyImage* original, LazyImage* working_copy){
      this->original = original;
      this->working_copy = working_copy;
      
      this->width = this->original->width();
      this->height = this->original->height();
      this->pixels = this->width * this->height;
      
      this->gradient_magnitude = (double*) malloc(sizeof(double) * this->pixels);
      this->maximum_magnitude = (double*) malloc(sizeof(double) * this->pixels);
      this->binary_edge_pixels = (int*) malloc(sizeof(int) * this->pixels);
      this->gradient_x = (int*) malloc(sizeof(int) * this->pixels);
      this->gradient_y = (int*) malloc(sizeof(int) * this->pixels);
    };
    
    ~CannyEdgeMachine() {
      free(this->gradient_magnitude);
      free(this->maximum_magnitude);
      free(this->binary_edge_pixels);
      free(this->gradient_x);
      free(this->gradient_y);
    };
    
    void setThresholdValues(double t_low, double t_high) {
      this->t_low = t_low;
      this->t_high = t_high;
    };
    
    void reset(void) {
      for(int i=0; i<this->pixels; i++) {
	this->gradient_magnitude = 0;
	this->maximum_magnitude = 0;
	this->binary_edge_pixels = 0;
	this->gradient_x = 0;
	this->gradient_y = 0;
      }
    };
    
    void doGaussBlur(int filter_width=3) {
      // build the gauss filter
      int* filter = (int*) malloc(sizeof(int) * filter_width* filter_width);
      int sum_weights = 0;
      for(int i=0; i<filter_width; i++) {
	for(int j=0; j<filter_width; j++) {
	  filter[i*filter_width + j] = pow(2, i) * pow(2, j);
	  sum_weights += filter[i*filter_width + j];
	}
      }
      // apply gauss filter
      int filter_offset = (filter_width+1)/2;
      for(int x=(0+filter_offset); x<(this->width-filter_offset); x++) {
        for(int y=(0+filter_offset); y<(this->height-filter_offset); y++) {
	  int sum_intensity = 0;
	  int h, s, l;
	  for(int fx=0; fx<filter_width; fx++) {
	    int dx = fx - (filter_width / 2);
	    for(int fy=0; fy<filter_width; fy++) {
	      int dy = fy - (filter_width / 2);
	      QColor color = QColor::fromRgb(this->original->getPixel(x+dx, y+dy, LazyImage::DEFAULT));
	      color.getHsl(&h, &s, &l);
	      sum_intensity += (l * filter[fy*filter_width + fx]);
            }	
          }
          QColor color = QColor::fromRgb(this->original->getPixel(x, y, LazyImage::DEFAULT));
          color.getHsl(&h, &s, &l);
          l = qRound((1.0*sum_intensity) / (1.0*sum_weights));
	  if(l > 255) l = 255;
	  if(l < 0) l = 0;
	  color.setHsl(h, s, l);
	  this->working_copy->getImage()->setPixel(x, y, color.rgb());
        }
      }
      free(filter);
    };
    
    void doGradiants(void) {
      // build the gradiant vector
      int gradiant_size = 3;
      double* gradiant_vector = (double*) malloc(sizeof(double) * gradiant_size);
      gradiant_vector[0] = -0.5;
      gradiant_vector[1] = 0;
      gradiant_vector[2] = 0.5;
      int gradiant_offset = gradiant_size;
      // calculate gradiants
      for(int x=(0+gradiant_offset); x<(this->width-gradiant_offset); x++) {
        for(int y=(0+gradiant_offset); y<(this->height-gradiant_offset); y++) {
	  int h, s, l;
	  // x gradiant
          double sum_intensity = 0;
	  for(int i=0; i<gradiant_size; i++) {
	    int dx = i - gradiant_size/2;
	    QColor color = QColor::fromRgb(this->original->getPixel(x+dx, y, LazyImage::DEFAULT));
	    color.getHsl(&h, &s, &l);
	    sum_intensity += l * gradiant_vector[i];
	  }
	  this->gradient_x[y*width + x] = sum_intensity;
	  // y gradiant
          double sum_intensity = 0;
	  for(int i=0; i<gradiant_size; i++) {
	    int dy = i - gradiant_size/2;
	    QColor color = QColor::fromRgb(this->original->getPixel(x, y+dy, LazyImage::DEFAULT));
	    color.getHsl(&h, &s, &l);
	    sum_intensity += l * gradiant_vector[i];
	  }
	  this->gradient_y[y*width + x] = sum_intensity;
        }
      }
      free(gradiant_vector);
    };
    
    void work() {
      this->reset();
      this->doGaussBlur();
      this->doGradiants();
      
    };
    
};

#endif