#include <cstdio>
#include <cstdlib>
#include <omp.h>
#include <queue>

class Task {
        public:
                virtual void execute() = 0;
};

class DoFoo : public Task {
        public:
                DoFoo(int i) : m_i(i) {}
                void execute() { printf("foo %03d\n", m_i); }
        private:
                int m_i;
};

class DoBar : public Task {
        public:
                DoBar(int i) : m_i(i) {}
                void execute() { printf("bar %03d\n", m_i); }
        private:
                int m_i;
};

std::queue<Task *> task_queue;

int main(int argc, char *argv[]) {
        int num_threads;
        if (argc < 2)
                num_threads = 1 + omp_get_max_threads(); // 1 for the master, which will mostly sleep
        else
                num_threads = std::max(atoi(argv[1]), 1);

        bool production = (bool)1;
        #pragma omp parallel num_threads(num_threads) shared(production)
        {
                if (omp_get_thread_num() == 0)
                {
                        printf("%d threads have been created\n", omp_get_num_threads());
                        for (int i = 0; i < 100; ++i) {
                                printf("Pushing task #%d\n", i);
                                task_queue.push(new DoFoo(i));
                        }
                        for (int i = 100; i < 200; ++i) {
                                printf("Pushing additional task #%d\n", i);
                                task_queue.push(new DoBar(i));
                        }
                        #pragma omp atomic
                        production ^= 1;
                } else {
                        while (true) {
                                Task *t;
                                #pragma omp critical
                                {
                                        if (task_queue.size()) {
                                                t = task_queue.front();
                                                task_queue.pop();
                                        } else
                                                t = NULL;
                                }
                                if (t) {
                                        t->execute();
                                        delete t;
                                } else if (!production)
                                        break;
                        }
                }
    }

    printf("Work finished\n");

    return 0;
}