/*
 * Copyright 2013-2019 Software Radio Systems Limited
 *
 * This file is part of srsLTE.
 *
 * srsLTE is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of
 * the License, or (at your option) any later version.
 *
 * srsLTE is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * A copy of the GNU Affero General Public License can be found in
 * the LICENSE file in the top-level directory of this distribution
 * and at http://www.gnu.org/licenses/.
 *
 */

#include "srslte/common/timers.h"
#include <iostream>
#include <random>
#include <srslte/common/tti_sync_cv.h>
#include <thread>

#define TESTASSERT(cond)                                                                                               \
  do {                                                                                                                 \
    if (!(cond)) {                                                                                                     \
      std::cout << "[" << __FUNCTION__ << "][Line " << __LINE__ << "]: FAIL at " << (#cond) << std::endl;              \
      return -1;                                                                                                       \
    }                                                                                                                  \
  } while (0)

using namespace srslte;

int timers2_test()
{
  timer_handler timers;
  uint32_t      dur = 5;

  {
    timer_handler::unique_timer t = timers.get_unique_timer();
    TESTASSERT(not t.is_running() and not t.is_expired());
    TESTASSERT(t.id() == 0);
    timer_handler::unique_timer t2 = timers.get_unique_timer();
    TESTASSERT(not t2.is_running() and not t2.is_expired());
    TESTASSERT(t2.id() == 1);
    TESTASSERT(timers.nof_timers() == 2);

    // TEST: Run multiple times with the same duration
    bool callback_called = false;
    t.set(dur, [&callback_called](int) { callback_called = true; });
    TESTASSERT(timers.get_cur_time() == 0);
    for (uint32_t runs = 0; runs < 3; ++runs) {
      callback_called = false;
      TESTASSERT(not t.is_running());
      t.run();
      TESTASSERT(t.is_running() and not t.is_expired());
      for (uint32_t i = 0; i < dur - 1; ++i) {
        timers.step_all();
        TESTASSERT(t.is_running() and not t.is_expired());
      }
      timers.step_all();
      TESTASSERT(not t.is_running() and t.is_expired());
      TESTASSERT(callback_called);
    }
    TESTASSERT(timers.get_cur_time() == 3 * dur);

    // TEST: interrupt a timer. check if callback was called
    callback_called = false;
    t.run();
    timers.step_all();
    TESTASSERT(t.is_running());
    t.stop();
    TESTASSERT(not t.is_running());
    for (uint32_t i = 0; i < dur; ++i) {
      timers.step_all();
      TESTASSERT(not t.is_running());
    }
    TESTASSERT(not callback_called);

    // TEST: call timer::run() when it is already running. Check if duration gets extended.
    callback_called = false;
    t.run();
    timers.step_all();
    TESTASSERT(t.is_running());
    t.run(); // re-run
    for (uint32_t i = 0; i < dur - 1; ++i) {
      timers.step_all();
      TESTASSERT(t.is_running());
    }
    timers.step_all();
    TESTASSERT(not t.is_running());
    TESTASSERT(callback_called);

    // TEST: ordering of timers is respected
    timer_handler::unique_timer t3 = timers.get_unique_timer();
    TESTASSERT(t3.id() == 2);
    int  first_id = -1, last_id = -1;
    auto callback = [&first_id, &last_id](int id) {
      if (first_id < 0) {
        printf("First timer id=%d\n", id);
        first_id = id;
      }
      last_id = id;
    };
    t.set(4, callback);
    t2.set(2, callback);
    t3.set(6, callback);
    t.run();
    t2.run();
    t3.run();
    for (uint32_t i = 0; i < 5; ++i) {
      timers.step_all();
      TESTASSERT(i >= 3 or t.is_running());
      TESTASSERT(i >= 1 or t2.is_running());
      TESTASSERT(t3.is_running());
    }
    timers.step_all();
    TESTASSERT(t.is_expired() and t2.is_expired() and t3.is_expired());
    TESTASSERT(first_id == 1);
    printf("Last timer id=%d\n", last_id);
    TESTASSERT(last_id == 2);
  }
  // TEST: timer dtor is called and removes "timer" from "timers"
  TESTASSERT(timers.nof_timers() == 0);

  return SRSLTE_SUCCESS;
}

int timers2_test2()
{
  /**
   * Description:
   * - calling stop() early, forbids the timer from getting expired
   * - calling stop() after timer has expired should be a noop
   */
  timer_handler timers;
  uint32_t      duration = 2;

  auto utimer  = timers.get_unique_timer();
  auto utimer2 = timers.get_unique_timer();
  utimer.set(duration);
  utimer2.set(duration);

  // TEST 1: call utimer.stop() early and check if timer expires
  utimer.run();
  utimer2.run();
  TESTASSERT(utimer.is_running() and not utimer.is_expired());
  utimer.stop();
  TESTASSERT(not utimer.is_running() and not utimer.is_expired());

  for (uint32_t i = 0; i < 5; ++i) {
    timers.step_all();
  }
  TESTASSERT(not utimer.is_expired());
  TESTASSERT(utimer2.is_expired());

  // TEST 2: call utimer.stop() after it expires and assert it is still expired
  utimer2.stop();
  TESTASSERT(utimer2.is_expired());

  return SRSLTE_SUCCESS;
}

int timers2_test3()
{
  /**
   * Description:
   * - setting a new duration while the timer is already running should not stop timer, and should extend timeout
   */
  timer_handler timers;
  uint32_t      duration = 5;

  auto utimer = timers.get_unique_timer();
  utimer.set(duration);
  utimer.run();

  for (uint32_t i = 0; i < 2 * duration + 1; ++i) {
    timers.step_all();
    if ((i % 2) == 0) {
      // extends lifetime
      utimer.set(duration);
    }
    TESTASSERT(utimer.is_running());
  }
  for (uint32_t i = 0; i < duration - 1; ++i) {
    timers.step_all();
    TESTASSERT(utimer.is_running());
  }
  timers.step_all();
  TESTASSERT(not utimer.is_running());

  return SRSLTE_SUCCESS;
}

static std::vector<timer_handler::unique_timer> timers2_test4_t;
static srslte::tti_sync_cv                      timers2_test4_tti_sync1;
static srslte::tti_sync_cv                      timers2_test4_tti_sync2;
static uint32_t                                 duration = 1000;

static void timers2_test4_thread()
{
  std::mt19937                          mt19937(4);
  std::uniform_real_distribution<float> real_dist(0.0f, 1.0f);
  for (uint32_t d = 0; d < duration; d++) {
    // make random events
    for (uint32_t i = 1; i < timers2_test4_t.size(); i++) {
      if (0.1f > real_dist(mt19937)) {
        timers2_test4_t[i].run();
      }
      if (0.1f > real_dist(mt19937)) {
        timers2_test4_t[i].stop();
      }
      if (0.1f > real_dist(mt19937)) {
        timers2_test4_t[i].set(static_cast<uint32_t>(duration * real_dist(mt19937)));
        timers2_test4_t[i].run();
      }
    }

    // Send finished to main thread
    timers2_test4_tti_sync1.increase();

    // Wait to main thread to check results
    timers2_test4_tti_sync2.wait();
  }
}

int timers2_test4()
{
  timer_handler                         timers;
  uint32_t                              nof_timers = 32;
  std::mt19937                          mt19937(4);
  std::uniform_real_distribution<float> real_dist(0.0f, 1.0f);

  // Generate all timers and start them
  for (uint32_t i = 0; i < nof_timers; i++) {
    timers2_test4_t.push_back(timers.get_unique_timer());
    timers2_test4_t[i].set(duration);
    timers2_test4_t[i].run();
  }

  // Create side thread
  std::thread thread(timers2_test4_thread);

  for (uint32_t d = 0; d < duration; d++) {
    // make random events
    for (uint32_t i = 1; i < nof_timers; i++) {
      if (0.1f > real_dist(mt19937)) {
        timers2_test4_t[i].run();
      }
      if (0.1f > real_dist(mt19937)) {
        timers2_test4_t[i].stop();
      }
      if (0.1f > real_dist(mt19937)) {
        timers2_test4_t[i].set(static_cast<uint32_t>(duration * real_dist(mt19937)));
        timers2_test4_t[i].run();
      }
    }

    // first times, does not have event, it shall keep running
    TESTASSERT(timers2_test4_t[0].is_running());

    // Increment time
    timers.step_all();

    // wait second thread to finish events
    timers2_test4_tti_sync1.wait();

    // assert no timer got wrong values
    for (uint32_t i = 0; i < nof_timers; i++) {
      if (timers2_test4_t[i].is_running()) {
        TESTASSERT(timers2_test4_t[i].value() <= timers2_test4_t[i].duration());
      }
    }

    // Start new TTI
    timers2_test4_tti_sync2.increase();
  }

  // Finish asynchronous thread
  thread.join();

  // First timer should have expired
  TESTASSERT(timers2_test4_t[0].is_expired());
  TESTASSERT(not timers2_test4_t[0].is_running());

  // Run for the maximum period
  for (uint32_t d = 0; d < duration; d++) {
    timers.step_all();
  }

  // No timer should be running
  for (uint32_t i = 0; i < nof_timers; i++) {
    TESTASSERT(not timers2_test4_t[i].is_running());
  }
  return SRSLTE_SUCCESS;
}

int main()
{
  TESTASSERT(timers2_test() == SRSLTE_SUCCESS);
  TESTASSERT(timers2_test2() == SRSLTE_SUCCESS);
  TESTASSERT(timers2_test3() == SRSLTE_SUCCESS);
  TESTASSERT(timers2_test4() == SRSLTE_SUCCESS);
  printf("Success\n");
  return 0;
}