/************************************************************
  File:          main.cc
  Description:   A program that simulates a one-lane bridge
                 and some cars trying to get through it.
                                                         
  Author:        Dana Vrajitoru                          
  Organization:  IUSB                                    
  Date:          December 7, 2004
**************************************************************/

#include <stdlib.h>
#include <iostream>
using namespace std;
#include <iomanip>
#include <pthread.h>
#include "bridge.h"

Bridge_monitor bridge;

// Prototypes.
void Create_threads(pthread_t *threads, int nr_threads);
void Synchronise(pthread_t *threads, int nr_threads);
void *Car(void *arg);

int main()
{
  int i, nr_threads;
  bridge.init();
  cout << "enter the total number of cars" << endl;
  cin >> nr_threads;

  pthread_t *threads = new pthread_t[nr_threads];

  Create_threads(threads, nr_threads);
  Synchronise(threads, nr_threads);
}

// Creates the threads calling the producer function, then those
// calling the consumer function, and to each of them it passes the
// pointer to the number of items as the argument.
void Create_threads(pthread_t *threads, int nr_threads)
{
  static int *ids;
  void *arg;
  ids= new int[nr_threads];
  for (int i=0; i<nr_threads; i++) {
    ids[i] = i;
    arg = ids+i;
    if (pthread_create(&threads[i], NULL, Car, arg) != 0)
      printf("Pthread_create fails");    
  }
}

// Joins all of the threads so that the program doesn;t end before
// they have finished the work.
void Synchronise(pthread_t *threads, int nr_threads)
{
  for (int i=0; i<nr_threads; i++)
    if (pthread_join(threads[i], NULL) != 0)
      printf("Pthread_join fails\n");
}

// The thread function that executes the task after waiting for all
// the threads on which it depends to finish their task.
void *Car(void *arg)
{
  int id = *((int *)arg);
  int direction;
  while (true) {
    direction = rand()%2;
    if (direction == 0) {
      cout << setw(50) << " " 
	   << id << endl;
      bridge.request_left();
      cout << setw(20) << " " 
	   << "<-- " << setw(2) << id << " ---" << endl;
      sleep(1);
      //cout << setw(20) << " " 
      //   << " ** " << id << " **" << endl;
      bridge.release_left();
    }
    else {
      // To be completed by the student.
    }
  }
}