#include <dmlc/io.h>
#include <dmlc/memory_io.h>
#include <dmlc/blockingconcurrentqueue.h>
#include <dmlc/thread_group.h>
#include <gtest/gtest.h>

#if (defined _WIN32)

#define NOMINMAX
#include <Windows.h>
static inline void dmlc_usleep(__int64 usec) {
  HANDLE timer;
  LARGE_INTEGER ft;

  ft.QuadPart = -(10*usec); // Convert to 100 nanosecond interval, negative value indicates relative time

  timer = CreateWaitableTimer(NULL, TRUE, NULL);
  SetWaitableTimer(timer, &ft, 0, NULL, NULL, 0);
  WaitForSingleObject(timer, INFINITE);
  CloseHandle(timer);
}

#elif (defined DMLC_NANOSLEEP_PRESENT)

#include <sys/types.h>  // for useconds_t, time_t
#include <time.h>  // for timespec, nanosleep

static inline int dmlc_usleep(useconds_t useconds) {
  timespec ts;
  ts.tv_sec = static_cast<time_t>(useconds / 1000000);
  ts.tv_nsec = static_cast<long>(useconds % 1000000 * 1000ul);
  return nanosleep(&ts, NULL);
}

#else

#include <unistd.h>   // for usleep()

static inline int dmlc_usleep(useconds_t useconds) {
  return usleep(useconds);
}

#endif

static std::atomic<int> thread_count(0);

static int this_is_thread_func(std::string label, const bool with_delay) {
  ++thread_count;
  if(with_delay) {
    dmlc_usleep(1e4);
  }
  --thread_count;
  return 0;
}

/*!
 * \brief Generic Thread launch to standalone function, passing ThreadGroup owner
 */
TEST(ThreadGroup, ThreadLaunchAutoRemove) {
  std::shared_ptr<dmlc::ThreadGroup> thread_group = std::make_shared<dmlc::ThreadGroup>();
  for(int x = 0; x < 200; ++x) {
    dmlc::ThreadGroup::Thread::SharedPtr thread =
      std::make_shared<dmlc::ThreadGroup::Thread>(std::string("test_thread_ar ")
                                                         + std::to_string(x), thread_group.get());
    dmlc::ThreadGroup::Thread::launch(thread, true, this_is_thread_func, "Runner", false);
  }
  thread_group.reset();
  CHECK_EQ(thread_count, 0);
}

/*!
 * \brief Generic Thread launch to standalone function, passing ThreadGroup owner
 */
TEST(ThreadGroup, ThreadLaunchAutoRemoveWithDelay) {
  std::shared_ptr<dmlc::ThreadGroup> thread_group = std::make_shared<dmlc::ThreadGroup>();
  for(int x = 0; x < 200; ++x) {
    dmlc::ThreadGroup::Thread::SharedPtr thread =
      std::make_shared<dmlc::ThreadGroup::Thread>(std::string("test_thread_rwd ")
                                                         + std::to_string(x), thread_group.get());
    dmlc::ThreadGroup::Thread::launch(thread, true, this_is_thread_func, "Runner", true);
  }
  thread_group.reset();
  CHECK_EQ(thread_count, 0);
}

/*!
 * \brief Generic Thread launch to standalone function, passing ThreadGroup owner
 */
TEST(ThreadGroup, ThreadLaunchNoAutoRemove) {
  std::shared_ptr<dmlc::ThreadGroup> thread_group = std::make_shared<dmlc::ThreadGroup>();
  for(int x = 0; x < 200; ++x) {
    dmlc::ThreadGroup::Thread::SharedPtr thread =
      std::make_shared<dmlc::ThreadGroup::Thread>(std::string("test_thread_nao ")
                                                         + std::to_string(x), thread_group.get());
    dmlc::ThreadGroup::Thread::launch(thread, false, this_is_thread_func, "Runner", false);
  }
  thread_group.reset();
  CHECK_EQ(thread_count, 0);
}

/*!
 * \brief Generic Thread launch to standalone function, passing ThreadGroup owner
 */
TEST(ThreadGroup, ThreadLaunchNoAutoRemoveWithDelay) {
  std::shared_ptr<dmlc::ThreadGroup> thread_group = std::make_shared<dmlc::ThreadGroup>();
  for(int x = 0; x < 200; ++x) {
    dmlc::ThreadGroup::Thread::SharedPtr thread =
      std::make_shared<dmlc::ThreadGroup::Thread>(std::string("test_thread_narwd ")
                                                         + std::to_string(x), thread_group.get());
    dmlc::ThreadGroup::Thread::launch(thread, false, this_is_thread_func, "Runner", true);
  }
  thread_group.reset();
  CHECK_EQ(thread_count, 0);
}

/*!
 * \brief Test BlockingQueueThread
 */
TEST(ThreadGroup, ThreadLaunchQueueThread) {
  // Define the queue type for convenience
  using BQ = dmlc::BlockingQueueThread<int, -1>;

  // Create the thread group
  std::shared_ptr<dmlc::ThreadGroup> thread_group = std::make_shared<dmlc::ThreadGroup>();

  // Create the queue thread object
  std::shared_ptr<BQ> queue_thread = std::make_shared<BQ>("BlockingQueueThread",
                                                          thread_group.get());

  // Queue some stuff before the thread starts
  queue_thread->enqueue(1);
  queue_thread->enqueue(2);
  queue_thread->enqueue(3);
  queue_thread->enqueue(4);
  CHECK_EQ(queue_thread->size_approx(), 4U);
  // Launch the queue thread, passing queue item handler as lambda
  BQ::launch_run(queue_thread,
                 // Queue item handler
                 [queue_thread](int item) -> int {
                   std::cout << "ITEM: " << item
                             << std::endl << std::flush;
                   if(item >= 2 && item <= 3) {
                     // Queue some more while thread is running
                     queue_thread->enqueue(100 + item);
                   }
                   return 0;  // return 0 means continue
                 });
  // Trigger the queues to exit
  thread_group->request_shutdown_all(false);
  // Wait for all of the queue threads to exit
  thread_group->join_all();
  // Check that the queue is empty
  CHECK_EQ(queue_thread->size_approx(), 0);
}

using Tick = std::chrono::high_resolution_clock::time_point;
static inline Tick Now() { return std::chrono::high_resolution_clock::now(); }
static inline uint64_t GetDurationInNanoseconds(const Tick &t1, const Tick &t2) {
  return static_cast<uint64_t>(
    std::chrono::duration_cast<std::chrono::nanoseconds>(t2 - t1).count());
}
static inline uint64_t GetDurationInNanoseconds(const Tick &since) {
  return GetDurationInNanoseconds(since, Now());
}

constexpr size_t SLEEP_DURATION = 500;
constexpr size_t TIMER_PERIOD = 10;  // Ideal is 50 periods occur
constexpr size_t MIN_COUNT_WHILE_SLEEPING = 10;
constexpr size_t MAX_COUNT_WHILE_SLEEPING = 150;

inline size_t GetDurationInMilliseconds(const Tick& start_time) {
  return static_cast<size_t>(GetDurationInNanoseconds(start_time)/1000/1000);
}

/*!
 * \brief Test TimerThread
 */
TEST(ThreadGroup, TimerThread) {
  // Create the thread group
  std::shared_ptr<dmlc::ThreadGroup> thread_group = std::make_shared<dmlc::ThreadGroup>();

  using Duration = std::chrono::milliseconds;
  // Create the queue thread object
  std::shared_ptr<dmlc::TimerThread<Duration>> timer_thread =
    std::make_shared<dmlc::TimerThread<Duration>>("TimerThread", thread_group.get());
  Tick start_time = Now();
  size_t count = 0;
  // Launch the queue thread, passing queue item handler as lambda
  dmlc::TimerThread<Duration>::start(
    timer_thread, Duration(TIMER_PERIOD), [timer_thread, start_time, &count]() -> int {
      if ((count + 1) % 5 == 0) {
        // output slows it down a bit, so print fewer times
        std::cout << "[" << (count + 1) << "] TIME: "
                  << GetDurationInMilliseconds(start_time)
                  << std::endl << std::flush;
      }
      ++count;
      return 0;  // return 0 means continue
    });
  std::this_thread::sleep_for(Duration(SLEEP_DURATION));
  // Trigger the queues to exit
  thread_group->request_shutdown_all(true);
  // Wait for all of the queue threads to exit
  thread_group->join_all();
  GTEST_ASSERT_GE(count, MIN_COUNT_WHILE_SLEEPING);  // Should have at least done three
  GTEST_ASSERT_LE(count, MAX_COUNT_WHILE_SLEEPING); // Should not have had time to do 20 of them
}

/*!
 * \brief Test TimerThread Simple
 */
TEST(ThreadGroup, TimerThreadSimple) {
  // Create the thread group
  std::shared_ptr<dmlc::ThreadGroup> thread_group = std::make_shared<dmlc::ThreadGroup>();

  using Duration = std::chrono::milliseconds;
  Tick start_time = Now();
  size_t count = 0;
  // Launch the queue thread, passing queue item handler as lambda
  dmlc::CreateTimer("TimerThreadSimple",
                    Duration(TIMER_PERIOD),
                    thread_group.get(),
                    [start_time, &count]() -> int {
                      if ((count + 1) % 5 == 0) {
                        // output slows it down a bit, so print fewer times
                        std::cout << "[" << (count + 1) << "] TIME: "
                                  << GetDurationInMilliseconds(start_time)
                                  << std::endl << std::flush;
                      }
                      ++count;
                      return 0;  // return 0 means continue
                    });
  std::this_thread::sleep_for(Duration(SLEEP_DURATION));
  // Trigger the queues to exit
  thread_group->request_shutdown_all();
  // Wait for all of the queue threads to exit
  thread_group->join_all();
  GTEST_ASSERT_GE(count, MIN_COUNT_WHILE_SLEEPING);  // Should have at least done three
  GTEST_ASSERT_LE(count, MAX_COUNT_WHILE_SLEEPING); // Should not have had time to do 20 of them
}