#include <iostream>
#include <string>
#include <map>
#include <vector>
using namespace std;

enum class State
{
  OffHook,
  Connecting,
  Connected,
  OnHold,
  OnHook
};

inline ostream& operator<<(ostream& os, const State& s)
{
  switch (s)
  {
  case State::OffHook:
    os << "off the hook";
    break;
  case State::Connecting:
    os << "connecting";
    break;
  case State::Connected: 
    os << "connected";
    break;
  case State::OnHold:
    os << "on hold";
    break;
  case State::OnHook:
    os << "on the hook";
    break;
  }
  return os;
}

enum class Trigger
{
  CallDialed,
  HungUp,
  CallConnected,
  PlacedOnHold,
  TakenOffHold,
  LeftMessage,
  StopUsingPhone
};

inline ostream& operator<<(ostream& os, const Trigger& t)
{
  switch (t)
  {
  case Trigger::CallDialed:
    os << "call dialed";
    break;
  case Trigger::HungUp:
    os << "hung up";
    break;
  case Trigger::CallConnected:
    os << "call connected";
    break;
  case Trigger::PlacedOnHold:
    os << "placed on hold";
    break;
  case Trigger::TakenOffHold:
    os << "taken off hold";
    break;
  case Trigger::LeftMessage: 
    os << "left message";
    break;
  case Trigger::StopUsingPhone:
    os << "putting phone on hook";
    break;
  default: break;
  }
  return os;
}

int main_f(char* argv[])
{
  map<State, vector<pair<Trigger, State>>> rules;

  rules[State::OffHook] = {
    {Trigger::CallDialed, State::Connecting},
    {Trigger::StopUsingPhone, State::OnHook}
  };

  rules[State::Connecting] = {
    {Trigger::HungUp, State::OffHook},
    {Trigger::CallConnected, State::Connected}
  };

  rules[State::Connected] = {
    {Trigger::LeftMessage, State::OffHook},
    {Trigger::HungUp, State::OffHook},
    {Trigger::PlacedOnHold, State::OnHold}
  };

  rules[State::OnHold] = {
    {Trigger::TakenOffHold, State::Connected},
    {Trigger::HungUp, State::OffHook}
  };

  State currentState{ State::OffHook },
        exitState{ State::OnHook };

  while (true)
  {
    cout << "The phone is currently " << currentState << endl;
  select_trigger:
    cout << "Select a trigger:" << "\n";

    int i = 0;
    for (auto item : rules[currentState])
    {
      cout << i++ << ". " << item.first << "\n";
    }

    int input;
    cin >> input;
    if (input < 0 || (input+1) > rules[currentState].size())
    {
      cout << "Incorrect option. Please try again." << "\n";
      goto select_trigger;
    }

    currentState = rules[currentState][input].second;
    if (currentState == exitState) break;
  }

  cout << "We are done using the phone" << "\n";

  getchar();
  getchar();
  return 0;
}