/*
 * Copyright (C) 2016 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
#include "common/libs/threads/cuttlefish_thread.h"

#include <gtest/gtest.h>

#include <android-base/logging.h>
#include "common/libs/threads/thunkers.h"
#include "common/libs/time/monotonic_time.h"

using cvd::ConditionVariable;
using cvd::Mutex;
using cvd::ScopedThread;
using cvd::time::MonotonicTimePoint;
using cvd::time::Milliseconds;

static const int FINISHED = 100;

static void SleepUntil(const MonotonicTimePoint& in) {
  struct timespec ts;
  in.ToTimespec(&ts);
#ifdef CLOCK_MONOTONIC_RAW
  // WARNING:
  // While we do have CLOCK_MONOTONIC_RAW, we can't depend on it until:
  // - ALL places relying on MonotonicTimePoint are fixed,
  // - pthread supports pthread_timewait_monotonic.
  // - CLOCK_MONOTONIC_RAW is re-enabled in monotonic_time.h.
  //
  // This is currently observable as a LEGITIMATE problem while running
  // this test. DO NOT revert this to CLOCK_MONOTONIC_RAW until this is
  // fixed everywhere AND this test passes.
  clock_nanosleep(CLOCK_MONOTONIC, TIMER_ABSTIME, &ts, NULL);
#else
  clock_nanosleep(CLOCK_MONOTONIC, TIMER_ABSTIME, &ts, NULL);
#endif
}

class MutexTest {
 public:
  MutexTest() : busy_(NULL), stage_(0) {}

  void Run() {
    {
      ScopedThread thread_a(cvd::thunk<void, &MutexTest::FastThread>, this);
      ScopedThread thread_b(cvd::thunk<void, &MutexTest::SlowThread>, this);
    }
    LOG(INFO) << "MutexTest: completed at stage "
              << stage_
              << ", result: "
              << ((stage_ == FINISHED) ? "PASSED" : "FAILED");
  }

protected:
  void* FastThread() {
    mutex_.Lock();
    CHECK(busy_ == NULL);
    busy_ = "FastThread";
    SleepUntil(MonotonicTimePoint::Now() + Milliseconds(100));
    stage_ = 1;
    busy_ = NULL;
    mutex_.Unlock();
    SleepUntil(MonotonicTimePoint::Now() + Milliseconds(10));
    mutex_.Lock();
    CHECK(busy_ == NULL);
    busy_ = "FastThread";
    CHECK(stage_ == 2);
    stage_ = FINISHED;
    busy_ = NULL;
    mutex_.Unlock();
    return NULL;
  }

  void* SlowThread() {
    SleepUntil(MonotonicTimePoint::Now() + Milliseconds(50));
    mutex_.Lock();
    CHECK(busy_== NULL);
    busy_ = "SlowThread";
    CHECK(stage_ == 1);
    SleepUntil(MonotonicTimePoint::Now() + Milliseconds(100));
    stage_ = 2;
    busy_ = NULL;
    mutex_.Unlock();
    return NULL;
  }

  Mutex mutex_;
  const char* busy_;
  int stage_;
};

class NotifyOneTest {
 public:
  NotifyOneTest() : cond_(&mutex_), signalled_(0) {}

  void Run() {
    {
      ScopedThread thread_s(
          cvd::thunk<void, &NotifyOneTest::SignalThread>, this);
      ScopedThread thread_w1(
          cvd::thunk<void, &NotifyOneTest::WaitThread>, this);
      ScopedThread thread_w2(
          cvd::thunk<void, &NotifyOneTest::WaitThread>, this);
    }
    LOG(INFO) << "NotifyOneTest: completed, signalled "
              << signalled_
              << ", result: "
              << ((signalled_ == 2) ? "PASSED" : "FAILED");
  }

protected:
  void* SignalThread() {
    SleepUntil(MonotonicTimePoint::Now() + Milliseconds(100));
    mutex_.Lock();
    cond_.NotifyOne();
    mutex_.Unlock();
    SleepUntil(MonotonicTimePoint::Now() + Milliseconds(100));
    mutex_.Lock();
    CHECK(signalled_== 1);
    cond_.NotifyOne();
    mutex_.Unlock();
    SleepUntil(MonotonicTimePoint::Now() + Milliseconds(100));
    mutex_.Lock();
    CHECK(signalled_ == 2);
    mutex_.Unlock();
    return NULL;
  }

  void* WaitThread() {
    mutex_.Lock();
    cond_.Wait();
    signalled_++;
    mutex_.Unlock();
    return NULL;
  }

  Mutex mutex_;
  ConditionVariable cond_;
  int signalled_;
};

class NotifyAllTest {
 public:
  NotifyAllTest() : cond_(&mutex_), signalled_(0) {}

  void Run() {
    {
      ScopedThread thread_s(
          cvd::thunk<void, &NotifyAllTest::SignalThread>, this);
      ScopedThread thread_w1(
          cvd::thunk<void, &NotifyAllTest::WaitThread>, this);
      ScopedThread thread_w2(
          cvd::thunk<void, &NotifyAllTest::WaitThread>, this);
    }
    printf("NotifyAllTest: completed, signalled %d (%s)\n",
           signalled_, (signalled_ == 2) ? "PASSED" : "FAILED");
  }

protected:
  void* SignalThread() {
    SleepUntil(MonotonicTimePoint::Now() + Milliseconds(100));
    mutex_.Lock();
    cond_.NotifyAll();
    mutex_.Unlock();
    SleepUntil(MonotonicTimePoint::Now() + Milliseconds(100));
    mutex_.Lock();
    CHECK(signalled_ == 2);
    mutex_.Unlock();
    return NULL;
  }

  void* WaitThread() {
    mutex_.Lock();
    cond_.Wait();
    signalled_++;
    mutex_.Unlock();
    return NULL;
  }

  Mutex mutex_;
  ConditionVariable cond_;
  int signalled_;
};

class WaitUntilTest {
 public:
  WaitUntilTest() : cond_(&mutex_), stage_(0) {}

  bool Run() {
    start_ = MonotonicTimePoint::Now();
    {
      ScopedThread thread_s(
          cvd::thunk<void, &WaitUntilTest::SignalThread>, this);
      ScopedThread thread_w2(
          cvd::thunk<void, &WaitUntilTest::WaitThread>, this);
    }
    printf("WaitUntilTest: completed, stage %d (%s)\n",
           stage_, (stage_ == FINISHED) ? "PASSED" : "FAILED");
    return stage_ == FINISHED;
  }

protected:
  void* SignalThread() {
    SleepUntil(start_ + Milliseconds(200));
    mutex_.Lock();
    CHECK(stage_ == 2);
    cond_.NotifyOne();
    stage_ = 3;
    mutex_.Unlock();
    return NULL;
  }

  void* WaitThread() {
    mutex_.Lock();
    CHECK(stage_ == 0);
    stage_ = 1;
    cond_.WaitUntil(start_ + Milliseconds(50));
    MonotonicTimePoint current(MonotonicTimePoint::Now());
    CHECK(Milliseconds(current - start_).count() >= 50);
    CHECK(Milliseconds(current - start_).count() <= 100);
    stage_ = 2;
    cond_.WaitUntil(start_ + Milliseconds(1000));
    current = MonotonicTimePoint::Now();
    CHECK(Milliseconds(current - start_).count() <= 500);
    CHECK(stage_ == 3);
    stage_ = FINISHED;
    mutex_.Unlock();
    return NULL;
  }

  Mutex mutex_;
  ConditionVariable cond_;
  int stage_;
  MonotonicTimePoint start_;
};

TEST(ThreadTest, Mutex) {
  MutexTest mt;
  mt.Run();
  NotifyOneTest nt1;
  nt1.Run();
  NotifyAllTest nta;
  nta.Run();
  WaitUntilTest wu;
  bool success = wu.Run();
  EXPECT_TRUE(success);
}