#include<stdio.h>
#include <pthread.h> 
#include <omp.h>
#include <stdlib.h>
#include <unistd.h>

#define N_THREADS 16
#define N_STEPS 100
#define N_NUMBERS_CALCULATED 10000

pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER;
pthread_spinlock_t alive_threads_lock;
pthread_spinlock_t produced_numbers_lock;

int amicable_numbers[N_NUMBERS_CALCULATED];
long produced = 0;
int threads_alive = 0;

int calculate_amicable_number(int number) {
    for(int i=1; i< number; i++){
        if(number % i == 0){
            number = number + i;
        }
    }
    return number;
}

void *calculate_amicable_number_invterval(void * arg) {
  int start = *((int *)arg);
  int calculated = 0;
  int h = 0;

  for(int i = 0; i < N_STEPS; i++){ 
    calculated = calculate_amicable_number(start + i);
    h++;
    if (start + i < N_NUMBERS_CALCULATED) {
      amicable_numbers[start +i] = calculated;
    } else {
	    pthread_spin_lock(&alive_threads_lock);
      threads_alive--;
	    pthread_spin_unlock(&alive_threads_lock);
      free(arg);
      return NULL;
    }
  }

	pthread_spin_lock(&alive_threads_lock);
  threads_alive--;
	pthread_spin_unlock(&alive_threads_lock);
  free(arg);
  return NULL;
}

int not_all_numbers_calculated() {
  int ret = 0;
  pthread_spin_lock(&produced_numbers_lock);
  if(produced < N_NUMBERS_CALCULATED)
    ret = 1;
  pthread_spin_unlock(&produced_numbers_lock); 
  return ret;
}

int is_there_space_for_new_thread() {
  int ret = 0;
  pthread_spin_lock(&alive_threads_lock);
  if (threads_alive < N_THREADS)
    ret = 1;
  pthread_spin_unlock(&alive_threads_lock);
  return ret;
}

int main() {
	pthread_spin_init(&alive_threads_lock, PTHREAD_PROCESS_PRIVATE);
	pthread_spin_init(&produced_numbers_lock, PTHREAD_PROCESS_PRIVATE);
	pthread_t t[N_THREADS];

	double dt = omp_get_wtime();
  
  while(not_all_numbers_calculated()){

  
    for (int i = 0; i<N_THREADS; i++) {
      int *arg = malloc(sizeof(*arg));
      pthread_spin_lock(&produced_numbers_lock);
      *arg = produced;
      pthread_spin_unlock(&produced_numbers_lock);
      pthread_create(&t[i], NULL, calculate_amicable_number_invterval,(void *) arg);
      pthread_spin_lock(&produced_numbers_lock);
      produced += N_STEPS;
      pthread_spin_unlock(&produced_numbers_lock);
    }

    for (int i = 0; i<N_THREADS; i++)
      pthread_join(t[i], NULL);
  }
	dt = omp_get_wtime() - dt;
  
	printf("\nExecution time: %lf\n",  dt);
  return 0;

  /// 10 000 korakov
  /// 1 THREAD:  14.294979
  /// 2 THREADS: 11.441722
  /// 4 THREADS:  9.474156
  /// 8 THREADS:  7.467914
  /// 16 THREADS: 3.413084

}