#include <stdio.h>
#include <stdlib.h>
#include <semaphore.h>
#include <pthread.h>
#include <iostream>
#include <queue>
#include <pthread.h>
#include <time.h>
#include <fstream>

using namespace std;

struct car {
  int CarID;
  char direction;
  string arrival_time;
  string start_time;
  string end_time;
};

//returns a string with Hours:minute:seconds
string getTime()
{
  time_t rawtime;
  struct tm *info;
  char buffer[80];

  time( &rawtime );

  info = localtime( &rawtime );

  strftime(buffer,80,"%I:%M:%S", info);
  string output(buffer);
  return output;
}

int pthread_sleep(int seconds)
{
  pthread_mutex_t mutex;
  pthread_cond_t conditionvar;
  struct timespec timetoexpire;
  if (pthread_mutex_init(&mutex, NULL))
    {
      return -1;
    }
  if (pthread_cond_init(&conditionvar, NULL))
    {
      return -1;
    }
  timetoexpire.tv_sec = (unsigned int)time(NULL) + seconds + 1;
  timetoexpire.tv_nsec = 0;
  return pthread_cond_timedwait(&conditionvar, &mutex, &timetoexpire);
}

int carCounter = 0;
queue<car> northCars, southCars;
sem_t countSouth, countNorth;
pthread_mutex_t road;
bool flagPerson = false;
ofstream carFile;
ofstream flagFile;


void printToCar(car& c)
{
  carFile << c.CarID << "\t" << c.direction << "\t\t" << c.arrival_time << "\t" << c.start_time << "\t" << c.end_time << endl;
}

void printToFlag(string status)
{
  flagFile << getTime() << "\t" << status << endl;
}

void* southGenerator(void* args) {
  while(true)
    {

      do {
        car c;
        c.CarID = carCounter++;
        c.direction = 'S';
        c.arrival_time = getTime();
        c.start_time = "";
        c.end_time = "";

        southCars.push(c);
        sem_post(&countSouth);
      } while (rand() % 100 + 1 <= 80);
      pthread_sleep(20);
    }
  return 0;
}

void* northGenerator(void* args) {
  while(true)
    {
      do {
        car c;
        c.CarID = carCounter++;
        c.direction = 'N';
        c.arrival_time = getTime();
        c.start_time = "";
        c.end_time = "";

        northCars.push(c);
        sem_post(&countNorth);
      } while (rand() % 100 + 1 <= 80);
      pthread_sleep(20);
    }
  return 0;
}

void* southHandler(void* args) {
  bool locked = true;
  while(true) {
    //wait for a car going south and the mutex lock
    sem_wait(&countSouth);
    if(locked)
      pthread_mutex_lock(&road);
    locked = false;
    if (!flagPerson) {
      flagPerson = true;
      printToFlag("woken-up");
    }
    car c = southCars.front();
    c.start_time = getTime();
    pthread_sleep(1);
    southCars.pop();
    c.end_time = getTime();
    printToCar(c);
    if (northCars.size() >= 10 || southCars.empty()) {
      pthread_mutex_unlock(&road);
      locked = true;
      if (southCars.empty() && northCars.empty()) {
        flagPerson = false;
        printToFlag("sleep");
      }
    }
  }
  return 0;
}

void* northHandler(void* args) {
  bool locked = true;
  while(true) {
    //wait for a car going north and the mutex lock
    sem_wait(&countNorth);
    if(locked)
      pthread_mutex_lock(&road);
    locked = false;
    if (!flagPerson) {
      flagPerson = true;
      printToFlag("woken-up");
    }
    car c = northCars.front();
    c.start_time = getTime();
    pthread_sleep(1);
    northCars.pop();
    c.end_time = getTime();
    printToCar(c);
    if (northCars.size() >= 10 || northCars.empty()) {
      pthread_mutex_unlock(&road);
      locked = true;
      if (southCars.empty() && northCars.empty()) {
        flagPerson = false;
        printToFlag("sleep");
      }
    }
  }
  return 0;
}

int main() {
  srand (time(NULL));
  sem_init(&countSouth, 0, 0);
  sem_init(&countNorth, 0, 0);
  pthread_t south, north, sHandler, nHandler;
  carFile.open("car.log");
  flagFile.open("flagperson.log");
  carFile << "carID\tdirection\tarrival-time\tstart-time\tend-time" << endl;
  flagFile << "time\t\tstate" << endl;

  if ( -1 == pthread_create(&south, NULL, southGenerator, NULL) ) {
    perror("pthread_create");
    return -1;
  }

  if ( -1 == pthread_create(&north, NULL, northGenerator, NULL) ) {
    perror("pthread_create");
    return -1;
  }

  if ( -1 == pthread_create(&sHandler, NULL, southHandler, NULL) ) {
    perror("pthread_create");
    return -1;
  }

  if ( -1 == pthread_create(&nHandler, NULL, northHandler, NULL) ) {
    perror("pthread_create");
    return -1;
  }

  cout << "Press enter to stop the simulation.";
  cin.ignore();
  carFile.close();
  flagFile.close();
  sem_destroy(&countSouth);
  sem_destroy(&countNorth);
  pthread_mutex_destroy(&road);
  return 0;
}