#include <map>
#include "math.hpp"
#include <stdexcept>
#include <queue>
#include <opencv2/opencv.hpp>
#include <boost/filesystem.hpp>
#include <iterator>
#include <iostream>
#include <algorithm>

using dataset = std::vector<std::pair<math::csignal, std::string>>;

struct path_leaf_string {
  std::string operator()(const boost::filesystem::directory_entry& entry) const
  {
    return entry.path().leaf().string();
  }
};

void read_directory(const std::string& name, std::vector<std::string>& v) {
  boost::filesystem::path p(name);
  boost::filesystem::directory_iterator start(p);
  boost::filesystem::directory_iterator end;
  std::transform(start, end, std::back_inserter(v), path_leaf_string());
}

double distance(math::csignal& v1, math::csignal& v2, int n){
  if (v1.size() != v2.size()) {
    throw std::runtime_error("les deux vecteurs doivent être de même longueur");
  }
  double d = 0;

  auto v1_it = v1.begin();
  auto v2_it = v2.begin();

  while (v1_it != v1.end()) {
    double dist = std::abs(*(v1_it++) - *(v2_it++));
    d += std::pow(dist, n);
  }
  return std::pow(d, 1/n);
};

int argmax(std::vector<int>& v){
  int arg = 0;
  int max = v[0];
  for(int i = 1; i < v.size() ; ++i){
    if (v[i]>max){
      arg = i;
      max = v[i];
    };
  };
  return arg;
};

struct pair_comp {
  bool operator()(std::pair<double, std::string> a, std::pair<double, std::string> b) {
    if (a.first == b.first) {
      return false;
    }
    if (a.first > b.first) {
      return true;
    }
    return false;
  };
};

math::csignal img2desc(std::string filename, int cmax, int threshold) {
  cv::Mat img = cv::imread(filename, CV_LOAD_IMAGE_COLOR);
  return math::descriptors(img, cmax, threshold);
}

dataset get_data(std::string path, int size, int cmax, int threshold) {
  dataset res;
  std::vector<std::string> dirs;
  read_directory(path, dirs);
  for (auto dir: dirs) {
    std::vector<std::string> files;
    read_directory(path+"/"+dir, files);

    std::string label = dir;
    int count = 0;
    for (int i=0; count<size/4 && i<files.size(); ++i) {
      try {
        math::csignal d = img2desc(path+"/"+dir+"/"+files[i], cmax, threshold);
        res.push_back({d, label});
        count++;
      } catch (std::length_error& e) {
        std::cout << "No contour: image skiped." << std::endl;
      }
    }
    std::cout << res.size() << std::endl;
  }
  return res;
}

int main(int argc, char** argv) {

  int k = 20;
  int size = 100;
  std::string path;
  int cmax = 10;
  int threshold = 20;

  if (argc > 2) {
    path = argv[1];
    threshold = atoi(argv[2]);
  } else {
    std::cout << "Invalid number of arguments" << std::endl;
    return 0;
  }

  dataset references = get_data(path, size, cmax, threshold);
  math::csignal sample = img2desc(path+"/arret/arret0199.jpg", cmax, threshold);
  std::priority_queue<std::pair<double, std::string>, std::vector<std::pair<double, std::string>>, pair_comp> neighbors;
  std::map<std::string, int> labels;

  for (auto desc: references) {
    double d = distance(desc.first, sample, 1);
    neighbors.push({d, desc.second});
  }
  
  for (int i=0; i<k; ++i) {
    std::pair<double, std::string> nearest = neighbors.top();
    neighbors.pop();
    labels[nearest.second] += 1;
  }

  int max = 0;
  std::string label;

  for (auto val: labels) {
    if (val.second > max) {
      max = val.second;
      label = val.first;
    } 
  }

  std::cout << label << std::endl;
};