#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <pthread.h>
#include <stdatomic.h>
#include <unistd.h>

#define MAXX 100000

#define NTHREADS 30

#ifndef NULL
#define NULL (void *)0
#endif

typedef struct {
    char header[20];
    int count;
    int data[MAXX];
} accumul;

typedef struct {
    int threadNum;
} threadInfo;

accumul primes;

_Atomic long num = ATOMIC_VAR_INIT(19);

pthread_mutex_t mutexUP;


void updatePrimes(long newP) {
    pthread_mutex_lock(&mutexUP);
    primes.data[primes.count++] = newP;
    pthread_mutex_unlock(&mutexUP);
}
void* getPrimes(void * args) {
    threadInfo *tInfo = args;
    while (primes.count < MAXX - 1)
    {
        long np = atomic_fetch_add(&num, 2);
        long sq = sqrt(np);
        int g = 1;
        int mxx = primes.count - 2;
        for (long i = 0; g == 1 && i < mxx && primes.data[i] <= np; i++)
        {
            if (np % primes.data[i] == 0)
                g = 0;
        }
        if (g) {
            updatePrimes(np);
            if (primes.count % 1000 == 0)
        printf("%d %d %ld\n", tInfo->threadNum, primes.count, primes.data[primes.count - 1]);
        }
    }
}
int main(int argc, char const *argv[])
{
    primes.data[0] = 3;
    primes.data[1] = 5;
    primes.data[2] = 7;
    primes.data[3] = 11;
    primes.data[4] = 13;
    primes.data[5] = 17;
    primes.data[6] = 19;
    
    pthread_mutex_init(&mutexUP, NULL);

    pthread_t threads[NTHREADS];
    threadInfo tInfo[NTHREADS];
    for (int i = 0; i < NTHREADS; i++)
    {
        tInfo[i] = (threadInfo){.threadNum = i};
        pthread_create(threads + i, NULL, getPrimes, &tInfo[i]);
        if (i==0) sleep(1); // give the first thread a little time to get the small primes
    }
    for (int i = 0; i < NTHREADS; i++) {
        pthread_join(threads[i], NULL);
        printf("Joined %d\n", i);
    }

    for (int i = (primes.count-10); i < primes.count; i++) {
        printf("%4d  %9d\n", i, primes.data[i]);
    }

    return 0;
}