#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <pthread.h>
#include <time.h>
#include <limits.h>
#include <semaphore.h>

#include <sys/types.h>
#include <sys/wait.h>

#define THREADS 8

int aantal_tickets = 500;
int totaal_aantal_verkocht = 0;

void sell_tickets(pthread_mutex_t *mtx);

struct thread_info {
    pthread_t thread_id;
    pthread_mutex_t *mtx;
};

static void * thread_start(void *arg) {
    struct thread_info* tinfo = arg;
    sell_tickets(tinfo->mtx);
}

int main (int argc, char ** argv) {
    srand(time(NULL));
    struct thread_info *tinfo;
    tinfo = calloc(THREADS, sizeof(struct thread_info));

    pthread_mutex_t mtx = PTHREAD_MUTEX_INITIALIZER;

    for(int tnum = 0; tnum < THREADS; tnum++) {
        tinfo[tnum].mtx = &mtx;
        pthread_create(&tinfo[tnum].thread_id, NULL, &thread_start, &tinfo[tnum]);
    }

    for(int tnum = 0; tnum < THREADS; tnum++) {
        pthread_join(tinfo[tnum].thread_id, NULL);
    }

    printf("totaal tickets verkocht: %d\n", totaal_aantal_verkocht);
}

void sell_tickets(pthread_mutex_t *mtx) {
    int aantal_verkocht = 0;
    while(aantal_tickets > 0) {
        // pthread_mutex_lock(mtx);
        if(aantal_tickets > 0) {
            aantal_tickets--;
            aantal_verkocht++;
        }
        // pthread_mutex_unlock(mtx);
        sleep(rand()%3);
    }
    totaal_aantal_verkocht+= aantal_verkocht;
    printf("aantal verkocht: %d\n", aantal_verkocht);
}