#include "primes.hpp"

bool search_prime_constellation(
	 mpz_t& start_interval,
	 mpz_t& end_interval,
	 unsigned int k,         // size of prime constellation
	 unsigned int offsets[], // k-1 offsets
	 mpz_t& first_prime) {   // found result (if returning true)
   mpz_t p;
   mpz_init_set(p, start_interval);
   mpz_t q; mpz_init(q);
   bool found = false;
   for(;;) {
      // lookout for the next prime in the interval
      mpz_nextprime(p, p);
      if (mpz_cmp(p, end_interval) > 0) break;
      // p is apparently prime, check for an constellation
      found = true;
      for (int i = 0; i < k-1; ++i) {
	 unsigned int offset = offsets[i];
	 mpz_add_ui(q, p, offset);
	 if (mpz_probab_prime_p(q, 10) < 1) {
	    found = false;
	    break; // not a prime
	 }
      }
      if (found) break;
   }
   if (found) {
      mpz_set(first_prime, p);
   }
   mpz_clear(p); mpz_clear(q);
   return found;
}