#include <iostream>
#include <sstream>
#include <random>
#include <vector>

#define STB_IMAGE_IMPLEMENTATION
#include <stb_image.h>
#define STB_IMAGE_WRITE_IMPLEMENTATION
#include <stb_image_write.h>

#include "utils.hpp"

bool nearly_equal(float a, float b) {
  return std::nextafter(a, std::numeric_limits<float>::lowest()) <= b &&
    std::nextafter(a, std::numeric_limits<float>::max()) >= b;
}

bool does_seam_remove_mask(std::vector<std::pair<int, float>> energy, int width, int height, int nbChannels,
  std::vector<int> opt_seam, bool vertical)
  {
  int dim_large = vertical ? width : height;
  int dim_long = vertical ? height : width;

  for (int i=0; i < dim_long; i++) {
    if (energy[im_index(i, opt_seam[i])].first == 0) return true;
  }
  return false;
}

std::vector<std::pair<int, float>> mask_energy(std::vector<float> energy,
  int width, int height, unsigned char* mask) {
  std::vector<std::pair<int, float>> output(width*height);

  for (auto i=0; i < width*height; i++) {
    output[i] = {mask[i], energy[i]};
  }

  return output;
}

std::pair<int, float> operator+(std::pair<int, float>& p1, std::pair<int, float>& p2) {
  return {
    // If one of the two pixels is "protected" (ie 2), we want to prevent this line removing
    // Else, we want to keep the information of "is there a pixel to remove in this seam" (ie 0)
    (p1.first==2) || (p2.first==2) ? 2 : std::min(p1.first, p2.first),
    p1.second+p2.second
  };
}

void operator+=(std::pair<int, float>& p1, std::pair<int, float>& p2) {
  p1 = p1+p2;
}
bool operator==(std::pair<int, float>& p1, std::pair<int, float>& p2) {
  return (p1.first==p2.first && p1.second == p2.second);
}

std::string str_of_e(std::pair<int, float> energy) {
  std::stringstream ss;
  ss << "(" << energy.first << ", " << energy.second << ")";
  return ss.str();
}
std::string str_of_e(float energy) {
  std::stringstream ss;
  ss << "(" << energy << ")";
  return ss.str();
}