#include <iostream>
#include <string>
#include <cstdlib>
#include <pthread.h>
#include "rcmon.h"
#include "rollercoaster.h"
using namespace std;

RCMon::RCMon () {

 pthread_mutex_init (&monlock,nullptr);
 pthread_cond_init (&car,nullptr);
 pthread_cond_init (&board,nullptr);
 pthread_cond_init (&unboard,nullptr);
}

RCMon::~RCMon () {

 pthread_mutex_destroy (&monlock);
 pthread_cond_destroy (&car);
 pthread_cond_destroy (&board);
 pthread_cond_destroy (&unboard);
}

void RCMon::Board (int id) {

 pthread_mutex_lock (&monlock); //mbegin

 if (nr==getC()) {
  nrw++;
  cout << "Rider " << id << " waiting to board!" << endl;
  pthread_cond_wait (&board,&monlock);  //wait on board condition, associating it with monlock

/* This is (essentially)  pthread_mutex_unlock (monlock); pthread_mutex_lock (board); pthread_mutex_lock (monlock); */

  cout << "Rider " << id << " boarding." << endl;
  if (nr==getC()) pthread_cond_signal (&car);
  else if (nrw > 0) {
   nrw--;
   nr++;
   pthread_cond_signal (&board);
  }
 } else {
  nr++;
  cout << "Rider " << id << " boarding." << endl;
  if (nr==getC()) pthread_cond_signal (&car);
 }

 pthread_mutex_unlock (&monlock); //mend
}

void RCMon::Unboard (int id) {

 pthread_mutex_lock (&monlock);

 pthread_cond_wait (&unboard,&monlock);
 cout << "Rider " << id << " unboarding." << endl;
 if (nr > 0) {
  nr--;
  pthread_cond_signal (&unboard);
 } else if (nrw > 0) { //I'm the last guy and someone else is waiting
  nrw--;
  nr++;
  pthread_cond_signal (&board);
 }

 pthread_mutex_unlock (&monlock);
}

void RCMon::BeginRide () {

 pthread_mutex_lock (&monlock);

 pthread_cond_wait (&car,&monlock);
 cout << "Car:  Driving" << endl;

 pthread_mutex_unlock (&monlock);
}

void RCMon::EndRide () {

 pthread_mutex_lock (&monlock);

 cout << "Car:  Ride over" << endl;
 nr--;
 pthread_cond_signal (&unboard);

 pthread_mutex_unlock (&monlock);
}