#include <arpa/inet.h>
#include <array>
#include <codecvt>
#include <csignal>
#include <cstdio>
#include <fcntl.h>
#include <fstream>
#include <iostream>
#include <memory>
#include <netdb.h>
#include <netinet/in.h>
#include <stdexcept>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <string>
#include <sys/socket.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/uio.h>
#include <sys/wait.h>
#include <unistd.h>

#define PORT 54321

std::string exec(std::string cmd) {
  std::array<char, 128> buffer;
  std::string result;
  std::unique_ptr<FILE, void (*)(FILE *)> pipe(popen(cmd.c_str(), "r"),
                                               [](FILE *f) -> void {
                                                 // wrapper to ignore the return
                                                 // value from pclose() is
                                                 // needed with newer versions
                                                 // of gnu g++
                                                 std::ignore = pclose(f);
                                               });
  if (!pipe) {
    throw std::runtime_error("popen() failed!");
  }
  while (fgets(buffer.data(), static_cast<int>(buffer.size()), pipe.get()) !=
         nullptr) {
    result += buffer.data();
  }
  return result;
}

int serverSocket;

void safe_exit(int code) {

  std::clog << "Exiting\n";
  close(serverSocket);
  exit(code);
}

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

  // signal handlers
  signal(SIGTERM, safe_exit);
  signal(SIGINT, safe_exit);
  signal(SIGQUIT, safe_exit);
  signal(SIGHUP, safe_exit);

  // error signal handlers
  signal(SIGSEGV, safe_exit);

  // creating socket
  serverSocket = socket(AF_INET, SOCK_STREAM, 0);

  // specifying the address
  sockaddr_in serverAddress;
  serverAddress.sin_family = AF_INET;
  serverAddress.sin_port = htons(PORT);
  serverAddress.sin_addr.s_addr = INADDR_ANY;

  // binding socket.
  while (bind(serverSocket, (struct sockaddr *)&serverAddress,
              sizeof(serverAddress)) != 0) {
    std::cerr << "error binding socket retring\n";
    sleep(2);
  }

  // listening to the assigned socket
  listen(serverSocket, 5);

  // accepting connection request
  int clientSocket = accept(serverSocket, nullptr, nullptr);

  // recieving data
  char buffer[1024] = {0};
  {
    int RecvRetVal = recv(clientSocket, buffer, sizeof(buffer), 0);
    if (RecvRetVal > sizeof(buffer) || RecvRetVal < 0) {
      std::cerr << "recv() returned an error code\n";
      return RecvRetVal;
    }
  }
  std::cout << "Message from client: " << buffer << std::endl;

  // closing the socket.
  close(serverSocket);

  return 0;
}