#include <sys/time.h>
#include <stdio.h>
#include <pthread.h> 
#include <errno.h>
#include <semaphore.h>  // Include for semaphore functions

#define NUMP 5

pthread_mutex_t fork_mutex[NUMP];
sem_t space_avail;  // Semaphore to manage eating slots

void *diner(int *i);

int main()  
{
    int i;
    pthread_t diner_thread[NUMP]; 
    int dn[NUMP];

    // Initialize semaphores and mutexes
    sem_init(&space_avail, 0, NUMP - 1);  // Allows up to NUMP-1 diners to eat
    for (i = 0; i < NUMP; i++)
        pthread_mutex_init(&fork_mutex[i], NULL);

    // Create diner threads
    for (i = 0; i < NUMP; i++) {
        dn[i] = i;
        pthread_create(&diner_thread[i], NULL, (void *)diner, &dn[i]);
    }

    // Wait for diner threads to complete
    for (i = 0; i < NUMP; i++)
        pthread_join(diner_thread[i], NULL);

    // Clean up
    sem_destroy(&space_avail);
    for (i = 0; i < NUMP; i++)
        pthread_mutex_destroy(&fork_mutex[i]);

    return 0;
}

void *diner(int *i)
{
    int v = *i;
    int eating = 0;

    printf("I'm diner %d\n", v);

    while (eating < 25) {
        printf("%d is thinking\n", v);
        sleep(v / 2);
        printf("%d is hungry\n", v);

        // Wait for available eating slot
        sem_wait(&space_avail);

        // Pick up forks
        pthread_mutex_lock(&fork_mutex[v]);
        pthread_mutex_lock(&fork_mutex[(v + 1) % NUMP]);
        printf("%d is eating\n", v);

        eating++;
        sleep(1);

        // Put down forks
        printf("%d is done eating\n", v);
        pthread_mutex_unlock(&fork_mutex[v]);
        pthread_mutex_unlock(&fork_mutex[(v + 1) % NUMP]);

        // Signal an available eating slot
        sem_post(&space_avail);
    }

    pthread_exit(NULL);
}