#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <pthread.h>
#include <sys/types.h>
#include <sys/sem.h>
#define N 5
#define RIGHT_FORK ( left_fork_id + 1 ) % N

int phil_id,sem_id;
pid_t pid;

void grab_forks(int left_fork_id)
{
	int right_fork_id = RIGHT_FORK;
	struct sembuf semaphore[2] =
	{
	        {right_fork_id, -1, 0},
	        {left_fork_id, -1, 0}
	};

	if (semop(sem_id, semaphore, 2) == -1)
	{
		printf("Semop Error \n");
	}

	printf("[%d]: I am taking: %d and: %d.\n", phil_id,left_fork_id,right_fork_id);
}
void put_away_forks(int left_fork_id)
{
	int right_fork_id = RIGHT_FORK;
	struct sembuf semaphore[2] =
	{
	        {right_fork_id, 1, 0},
	        {left_fork_id, 1, 0}
	};

	if (semop(sem_id, semaphore, 2) == -1)
	{
		printf("Semop Error \n");
	}

	printf("[%d]: I am putting away: %d and: %d.\n", phil_id,left_fork_id,right_fork_id);
}

void eat()
{
	printf("[%d], I am eating\n",phil_id);
	sleep(1);
}
void think()
{
	printf("[%d], I am thinking\n",phil_id);
	sleep(2);
}


void philosopher(int i)
{
//	while (1)
 //       {
		think();
		sleep(1);
		grab_forks(i);
		sleep(0);
		eat();
		put_away_forks(i);
 //       }
}



int main()
{
	//getting semaphore set ID
	if ((sem_id = semget(777, 5, IPC_CREAT | 0666)) == -1)
	{
		perror("Cannot get semaphore set id\n");
		exit(1);
	}
	//
	for (int i = 0; i < N; i++)
		semctl(sem_id, i, SETVAL, 1);

	for (int i = 0; i < N; i++)
	{
		if ((pid == fork())== 0)
		{
			phil_id = i;
			philosopher(phil_id);
			printf("[%d], I have finished eating\n", phil_id);
			exit(0);
		}
		else if (pid < 0)
		{
			printf("Something went wrong");
			exit(1);
		}

	}

	return 0;
}