#pragma once

#include <string>
#include <fstream>
#include <thread>
#include <future>
#include <iostream>

class MT2Q4
{
public:
  using FPtr = bool(*)(const std::string&, const std::string&);

  static bool findText(const std::string& text, const std::string& filePath);
  static std::future<bool>  findTextAsync(FPtr pFinder, const std::string& text, const std::string& filePath);
};

bool MT2Q4::findText(const std::string& text, const std::string& filePath)
{
  std::ifstream in(filePath);
  if (!in.good())
  {
    std::cout << "\n  can't open \"" << filePath << "\"";
    return false;
  }
  std::string fileText;
  while (in.good())
  {
    char ch;
    in >> ch;
    fileText += ch;
  }
  size_t pos = fileText.find(text);
  return pos < fileText.size();
}

std::future<bool> MT2Q4::findTextAsync(FPtr pFinder, const std::string& text, const std::string& filePath)
{
  std::future<bool> f;
  std::thread t(
    [&]() {
      std::promise<bool> p;
      std::future<bool> f_thread(p.get_future());
      f = std::move(f_thread);
      bool result = (*pFinder)(text, filePath);
      p.set_value(result);
  }
  );
  t.detach();
  return f;
}