#include <future>
#include <functional>
#include "tiny_pool.h"

class TinyPool { // OOP for tiny_thread_pool
    pool_t *pool;
    static void wrap_c_func(void *func) { // wrap std::function as c-style function ptr
        auto func_ptr = static_cast<std::function<void()>*>(func);
        (*func_ptr)();
        delete func_ptr; // free lambda function
    }

public:
    void boot() { tiny_pool_boot(pool); }
    void join() { tiny_pool_join(pool); }
    void kill() { tiny_pool_kill(pool); }
    void detach() { tiny_pool_detach(pool); }
    explicit TinyPool(uint32_t size) { pool = tiny_pool_create(size); }

    template <typename Func, typename ...Args>
    auto submit(Func &&func, Args &&...args) -> std::future<decltype(func(args...))> { // submit new task
        std::function<decltype(func(args...))()> wrap_func = std::bind(
            std::forward<Func>(func), std::forward<Args>(args)... // wrap as a function without params
        );
        auto func_ptr = std::make_shared<
            std::packaged_task<decltype(func(args...))()> // function task as shared ptr
        >(wrap_func);
        tiny_pool_submit(pool, TinyPool::wrap_c_func, (void*)( // submit with thread pool interface
            new std::function<void()> (
                [func_ptr]() { (*func_ptr)(); } // create lambda for running task
            )
        ));
        return func_ptr->get_future(); // return future object
    }
};

/// ------------------------------------ start test ------------------------------------

#include <iostream>
#include <unistd.h>

int test_func(char c) {
    int num = c - '0';
    printf("char -> `%c`\n", c);
    for (int i = 0; i < num; ++i) {
        printf("task %d running...\n", num);
        usleep(500 * 1000);
    }
    return num;
}

int main() {
    auto pool = TinyPool(3);

    auto f0 = pool.submit(test_func, '0');
    auto f1 = pool.submit(test_func, '1');
    auto f2 = pool.submit(test_func, '2');
    auto f3 = pool.submit(test_func, '3');

    pool.boot();

    auto f4 = pool.submit(test_func, '4');
    auto f5 = pool.submit(test_func, '5');

    printf("get future: %d\n", f0.get());
    printf("get future: %d\n", f4.get());
    printf("get future: %d\n", f3.get());

    auto f6 = pool.submit(test_func, '6');
    auto f7 = pool.submit(test_func, '7');
    auto f8 = pool.submit(test_func, '8');
    auto f9 = pool.submit(test_func, '9');

    printf("get future: %d\n", f2.get());
    printf("get future: %d\n", f5.get());
    printf("get future: %d\n", f8.get());

    pool.join();

    printf("get future: %d\n", f6.get());
    printf("get future: %d\n", f1.get());
    printf("get future: %d\n", f9.get());
    printf("get future: %d\n", f7.get());
}