#include <future>
#include <string>
#include <vector>

#include "pgxx/pgxx.hpp"
#include "thread/pool.hpp"

const int MAX_QUERY_IN_DB = 10'000;
const float MAX_OVERLAP = 12.f;

struct bit
{
  std::string m_id;
  std::string m_url;
  std::string m_artist;
  std::string m_song;
  std::vector<int> m_key;
  std::vector<int> m_duration;
};

bit target;

std::vector<int> parse_array(const std::string& arr_str) 
{
  std::vector<int> result;
  std::stringstream ss(arr_str);
  std::string item;

  while (std::getline(ss, item, ',')) 
  {
    try 
    {
      result.push_back(std::stoi(item));
    } 
    catch (const std::invalid_argument&) 
    {
      std::cerr << "Ошибка преобразования: " << item << std::endl;
    }
  }
  return result;
}

namespace calc
{
  inline int calculation(int db_offset)
  {
    std::vector<bit> vb;
    vb.reserve(MAX_QUERY_IN_DB);

    std::string query = "SELECT * FROM t_media LIMIT " + std::to_string(MAX_QUERY_IN_DB) + " OFFSET " + std::to_string(db_offset);
    auto r = PGXX().execute("con_1", query);

    for (auto el : r)
    {
      bit b;

      b.m_id = el["m_id"].as<std::string>();
      b.m_url = el["m_url"].as<std::string>();
      b.m_artist = el["m_artist"].as<std::string>();
      b.m_song = el["m_song"].as<std::string>();
      
      std::string str =  el["m_key"].as<std::string>();
      b.m_key = parse_array(str);

      str =  el["m_duration"].as<std::string>();
      b.m_duration = parse_array(str);
      vb.push_back(b);
    }

    return vb.size();
  }
}

namespace executor
{
  inline void get_recomended()
  {
    try
    {
      int count = 0;
      std::string query = "SELECT count(*) FROM t_media WHERE m_cleared = 0;";
      auto r = PGXX().execute("con_1", query);
      for (auto eld : r) count = eld["count"].as<int>();

      thread::pool pool;

      auto start = std::chrono::high_resolution_clock::now();
      int i = 0;
      int def = count / MAX_QUERY_IN_DB + 1;
      int db_offset = 0;

      std::vector<std::future<int>> futures;
      futures.reserve(def);

      while (def > 0)
      {
        futures.push_back(pool.enqueue(calc::calculation, db_offset));
        db_offset += MAX_QUERY_IN_DB;
        --def;
      }

      for (auto &f : futures)
      {
        int r = f.get();
        i += r;
      }

      std::chrono::duration<double> elapsed = std::chrono::high_resolution_clock::now() - start;
      hack::log()(i, elapsed.count());
    }
    catch(const std::exception& e)
    {
      hack::log()(e.what());
      throw; 
    }
    catch(hack::exception& ex)
    {
      ex.log();
      throw;
    }
    catch(...)
    {
      hack::log()("ooops!");
      throw; 
    }
  }
}

void convert_db()
{
  bool is_work = true;
  int count = 0;
  while (is_work)
  {
    try
    {
      std::string query = "SELECT * FROM t_media WHERE m_cleared = 0 LIMIT " + std::to_string(1) + ";";
      auto r = PGXX().execute("con_1", query);
      hack::log("")("size = ", r.size(), ", count = ", count);

      for (auto el : r)
      {
        target.m_id = el["m_id"].as<std::string>();
        target.m_url = el["m_url"].as<std::string>();
        target.m_artist = el["m_artist"].as<std::string>();
        target.m_song = el["m_song"].as<std::string>();

        std::string key = el["m_key"].as<std::string>();
        std::string duration = el["m_duration"].as<std::string>();

        query = "UPDATE t_media SET m_cleared = 1 WHERE m_id = '" + target.m_id + "';";
        PGXX().execute("con_1", query);

        executor::get_recomended();
      }

      query = "SELECT count(*) FROM t_media WHERE m_cleared = 0;";
      r = PGXX().execute("con_1", query);

      for (auto eld : r)
      {
        auto c = eld["count"].as<int>();
        if (count - c > 1) hack::log()("DOUBLE");
        count = c;
      }

      if (count == 0) is_work = false;
    }
    catch(hack::exception& e)
    {
      e.log();
    }
  }
}

auto main(int argc, char* args[]) -> int
{
  const std::string con = "postgres://chatlanin:password_for_connection_to_test_db@localhost:5423/test.db?sslmode=disable";

  try
  {
    PGXX().init("con_1", 300, con);
  }
  catch(hack::exception& ex)
  {
    ex.log();
    throw;
  }

  if (!PGXX().ready())
    hack::log()("error connection");

  convert_db();
}