// OPT: -lpthread

#include <chrono>
#include <thread>
#include <iostream>
#include <condition_variable>
#include <vector>
#include <fstream>
#include <atomic>


using namespace std;
using namespace std::chrono;

// thread pool to calculate primality of a set of numbers in parallel
class primeprocessor {
public:
	void addproc(int nthread) {
		for(int i=0;i<nthread;i++)
			tpool.emplace_back([this,i]{ this->dowork(i); });
	}

	void dowork(int tnum) {
		int myind;
		long long mynum;
		while(1) {
			{
				unique_lock<mutex> inlock(inmutex);
				while(inputs.empty())
					incond.wait(inlock);
				// incond.wait(inlock, // can add timeout here
				// 			[inputs]{ return !inputs.empty() });

				myind = inputs.size()-1;
				mynum = inputs.back();
				inputs.pop_back();
			}
			bool ans = true;
			// Here's the work:  not a smart algorithm :(
			for(long long i=2;mynum>i*i;i++)
				if (mynum % i == 0) { ans = false; break; }
			{
				lock_guard<mutex> outlock(outmutex);
				outputs[myind] = ans;
			}
			nfinished++;
		}
	}

	vector<bool> areprimes(vector<long long> x) {
		{
			unique_lock<mutex> inlock(inmutex,defer_lock);
			unique_lock<mutex> outlock(outmutex,defer_lock);
			lock(inlock,outlock);
			inputs = x;
			outputs.resize(inputs.size());
			nfinished = 0;
		}
		for(;;) {
			incond.notify_all();  // also notify_one which wakes at least 1
			this_thread::sleep_for(milliseconds(50));
			{
				if (nfinished==x.size()) break;
			}
		}
		return outputs;
	}
		
private:
	vector<thread> tpool;

	vector<long long> inputs;
	vector<bool> outputs;
	atomic<int> nfinished;

	mutex inmutex,outmutex;
	condition_variable incond;
};

int main(int argc, char **argv) {
	primeprocessor pp;
	pp.addproc(4);
	vector<long long> list1 {275604547, 275875889, 4, 3, 99809363, 23, 15485863, 5600056};
	vector<long long> list2;
	ifstream primef("1000primes.txt");
	for(int i=0;i<1000;i++) {
		long long l;
		primef >> l;
		list2.push_back(l);
	}

	vector<long long> list3;
	ifstream primef2("largeprimes.txt");
	for(int i=0;i<64;i++) {
		long long l;
		primef2 >> l;
		list3.push_back(l);
	}
	
	for(bool b : pp.areprimes(list1))
		cout << b << ' ';
	cout << endl;
	cout << endl;
	for(bool b : pp.areprimes(list2))
		cout << b << ' ';
	cout << endl;
	cout << endl;
	for(bool b : pp.areprimes(list3))
		cout << b << ' ';
	cout << endl;
}