#include <stdio.h>
#include <unistd.h>
#include <sys/wait.h>
#include <sys/types.h>
#include <fcntl.h>
#include <stdlib.h>
#include <limits.h>
#include <errno.h>
#include <string.h>
#include <time.h>

typedef int semaphore;

int th[] = {2, 3, 5, 4, 7}, state[5], et[] = {5, 3, 4, 5, 1};
semaphore p[5], mutex = 1;
enum {
    THINKING,
    HUNGRY,
    EATING,
    LEFT = (i - 1) % 5,
    RIGHT = (i + 1) % 5
}

void
think(int i)
{
    printf("PH#%d started thinking\n", i);
    sleep(th[i]);
    printf("PH#%d stopped thinking\n", i);
    return 0;
}

void
eat(int i)
{
    printf("PH#%d started eating\n", i);
    sleep(et[i]);
    printf("PH#%d stopped eating\n", i);
    return 0;
}

void
test(int i)
{
    if (state[i] == HUNGRY && state[LEFT] != EATING && state[RIGHT] != EATING) {
        state[i] = EATING;
        up(&p[i]);
    }
}

void
take_forks(int i)
{
    down(&mutex);
    state[i] = HUNGRY;
    test(i);
    up(&mutex);
    down(p[i]);
}

void
put_forks(int i)
{
    down(&mutex);
    state[i] = THINKING;
    test(LEFT);
    test(RIGHT);
    up(&mutex);
}

void
philosopher(int i, int lim)
{
    for (int j = 0; j < lim; ++j) {
        think(i);
        take_forks(i);
        eat(i);
        put_forks(i);
    }
    printf("PH#%d left the chat\n", i);
}




int
main(int argc, char *argv[])
{
    for (int i = 0; i < 5; ++i) {
        if (!fork()) {
            philosopher(i);
        }
    }

    return 0;
}