// Copyright 2024 The Cobalt Authors. All Rights Reserved.
//
// 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 <pthread.h>

#if SB_API_VERSION >= 16
#include <sys/time.h>
#else
#include "starboard/time.h"
#endif  // SB_API_VERSION >= 16

#include "starboard/common/time.h"
#include "starboard/nplb/posix_compliance/posix_thread_helpers.h"
#include "starboard/thread.h"
#include "testing/gtest/include/gtest/gtest.h"

namespace starboard {
namespace nplb {
namespace {

void InitCondition(pthread_cond_t* condition, bool use_monotonic) {
#if (SB_API_VERSION >= 16 || !SB_IS(MODULAR)) && \
    !SB_HAS_QUIRK(NO_CONDATTR_SETCLOCK_SUPPORT) && !defined(_WIN32)

  pthread_condattr_t attribute;
  EXPECT_EQ(pthread_condattr_init(&attribute), 0);
  if (use_monotonic) {
    EXPECT_EQ(pthread_condattr_setclock(&attribute, CLOCK_MONOTONIC), 0);
  }
  EXPECT_EQ(pthread_cond_init(condition, &attribute), 0);
  EXPECT_EQ(pthread_condattr_destroy(&attribute), 0);
#else
  EXPECT_EQ(pthread_cond_init(condition, NULL), 0);
#endif
}

int64_t CurrentTime(bool use_monotonic) {
  if (use_monotonic) {
    return starboard::CurrentMonotonicTime();
  } else {
#if SB_API_VERSION >= 16
    struct timeval tv;
    EXPECT_EQ(gettimeofday(&tv, NULL), 0);
    return tv.tv_sec;
#else   // SB_API_VERSION >= 16
    return SbTimeGetNow() / 1'000'000;
#endif  // SB_API_VERSION >= 16
  }
}

struct timespec CalculateDelayTimestampUsec(int64_t delay) {
  int64_t timeout_time_usec = CurrentTime(true /* use_monotonic */);
  timeout_time_usec += delay;
  EXPECT_GT(timeout_time_usec, 0);

  struct timespec delay_timestamp;
  delay_timestamp.tv_sec = timeout_time_usec / 1'000'000;
  delay_timestamp.tv_nsec = (timeout_time_usec % 1'000'000) * 1000;
  return delay_timestamp;
}

struct timespec CalculateDelayTimestampSec(int64_t delay) {
  int64_t timeout_sec = CurrentTime(false /* use_monotonic */) + delay;
  EXPECT_GT(timeout_sec, 0);

  struct timespec delay_timestamp;
  delay_timestamp.tv_sec = timeout_sec;
  delay_timestamp.tv_nsec = 0;
  return delay_timestamp;
}

struct timespec CalculateDelayTimestamp(int64_t delay, bool use_monotonic) {
  if (use_monotonic) {
    return CalculateDelayTimestampUsec(delay);
  } else {
    return CalculateDelayTimestampSec(delay);
  }
}

// The SunnyDay, SunnyDayAutoInit, and SunnyDayNearMaxTime test cases directly
// (performs checks in the test case) or indirectly (invokes DoSunnyDay() which
// performs the checks) rely on timing constraints that are prone to failure,
// such as ensuring an action happens within 10 milliseconds. This requirement
// makes the tests flaky since none of these actions can be guaranteed to always
// run within the specified time.

void DoSunnyDay(posix::TakeThenSignalContext* context,
                bool check_timeout,
                bool use_monotonic) {
  SbThread thread =
      SbThreadCreate(0, kSbThreadNoPriority, kSbThreadNoAffinity, true, NULL,
                     posix::TakeThenSignalEntryPoint, context);

  const int64_t kDelayUs = 10'000;  // 10ms
  // Allow two-millisecond-level precision.
  const int64_t kPrecisionUs = 2'000;  // 2ms

  const int64_t kDelayS = 3;      // 3s
  const int64_t kPrecisionS = 1;  // 1s

  const int64_t kDelay = (use_monotonic) ? kDelayUs : kDelayS;
  const int64_t kPrecision = (use_monotonic) ? kPrecisionUs : kPrecisionS;

  // We know the thread hasn't signaled the condition variable yet, and won't
  // unless we tell it, so it should wait at least the whole delay time.
  if (check_timeout) {
    EXPECT_EQ(pthread_mutex_lock(&context->mutex), 0);
    int64_t start = CurrentTime(use_monotonic);

    struct timespec delay_timestamp =
        CalculateDelayTimestamp(kDelay, use_monotonic);
    EXPECT_EQ(pthread_cond_timedwait(&context->condition, &context->mutex,
                                     &delay_timestamp),
              ETIMEDOUT);
    int64_t end = CurrentTime(use_monotonic);
    int64_t elapsed = end - start;

    EXPECT_LE(kDelay, elapsed + kPrecision);
    EXPECT_GT(kDelay * 2, elapsed - kPrecision);
    EXPECT_EQ(pthread_mutex_unlock(&context->mutex), 0);
  }

  {
    EXPECT_EQ(pthread_mutex_lock(&context->mutex), 0);

    // Tell the thread to signal the condvar, which will cause it to attempt to
    // acquire the mutex we are holding.
    context->do_signal.Put();

    int64_t start = CurrentTime(use_monotonic);

    // We release the mutex when we wait, allowing the thread to actually do the
    // signaling, and ensuring we are waiting before it signals.

    struct timespec delay_timestamp =
        CalculateDelayTimestamp(kDelay, use_monotonic);
    EXPECT_EQ(pthread_cond_timedwait(&context->condition, &context->mutex,
                                     &delay_timestamp),
              0);

    // We should have waited only a very small amount of time.
    EXPECT_GT(kDelay, CurrentTime(use_monotonic) - start);

    EXPECT_EQ(pthread_mutex_unlock(&context->mutex), 0);
  }

  // Now we wait for the thread to exit.
  EXPECT_TRUE(SbThreadJoin(thread, NULL));
  EXPECT_EQ(pthread_cond_destroy(&context->condition), 0);
  EXPECT_EQ(pthread_mutex_destroy(&context->mutex), 0);
}

// Test marked as flaky because it calls DoSunnyDay().
TEST(PosixConditionVariableWaitTimedTest, FLAKY_SunnyDay) {
  posix::TakeThenSignalContext context;
  context.delay_after_signal = 0;

  EXPECT_EQ(pthread_mutex_init(&context.mutex, NULL), 0);

#if !SB_HAS_QUIRK(NO_CONDATTR_SETCLOCK_SUPPORT)
  InitCondition(&context.condition, true);
  DoSunnyDay(&context, true, true /* use_monotonic */);
#else
  InitCondition(&context.condition, false);
  DoSunnyDay(&context, true, false /* use_monotinic */);
#endif  // !SB_HAS_QUIRK(NO_CONDATTR_SETCLOCK_SUPPORT)
}

// For Starboard < 16 only monotonic time is used for
// conditional waits.
#if SB_API_VERSION >= 16 && !defined(_WIN32)
// Test marked as flaky because it calls DoSunnyDay().
TEST(PosixConditionVariableWaitTimedTest, FLAKY_SunnyDayAutoInit) {
  {
    posix::TakeThenSignalContext context = {posix::TestSemaphore(0),
                                            PTHREAD_MUTEX_INITIALIZER,
                                            PTHREAD_COND_INITIALIZER, 0};

    DoSunnyDay(&context, true, false);
  }

  // Without the initial timeout test, the two threads will be racing to
  // auto-init the mutex and condition variable. So we run several trials in
  // this mode, hoping to have the auto-initting contend in various ways.
  const int kTrials = 64;
  for (int i = 0; i < kTrials; ++i) {
    posix::TakeThenSignalContext context = {posix::TestSemaphore(0),
                                            PTHREAD_MUTEX_INITIALIZER,
                                            PTHREAD_COND_INITIALIZER, 0};
    DoSunnyDay(&context, false, false);
  }
}

// Test marked as flaky because it relies on timing sensitive execution similar
// to DoSunnyDay().
TEST(PosixConditionVariableWaitTimedTest, FLAKY_SunnyDayNearMaxTime) {
  const int64_t kOtherDelaySec = 3'000'000;  // 3s
  posix::TakeThenSignalContext context = {
      posix::TestSemaphore(0), PTHREAD_MUTEX_INITIALIZER,
      PTHREAD_COND_INITIALIZER, kOtherDelaySec};
  EXPECT_EQ(pthread_mutex_init(&context.mutex, NULL), 0);

  InitCondition(&context.condition, false /* use_monotonic */);
  SbThread thread =
      SbThreadCreate(0, kSbThreadNoPriority, kSbThreadNoAffinity, true, NULL,
                     posix::TakeThenSignalEntryPoint, &context);

  EXPECT_EQ(pthread_mutex_lock(&context.mutex), 0);

  // Tell the thread to signal the condvar, which will cause it to attempt to
  // acquire the mutex we are holding, after it waits for delay_after_signal.
  context.do_signal.Put();

  int64_t start = CurrentTime(false /* use_monotonic */);

  // Try to wait until the end of time.
  struct timespec delay_timestamp = {0};
  delay_timestamp.tv_sec = INT_MAX;

  // We release the mutex when we wait, allowing the thread to actually do the
  EXPECT_EQ(pthread_cond_timedwait(&context.condition, &context.mutex,
                                   &delay_timestamp),
            0);

  // We should have waited at least the delay_after_signal amount, but not the
  // full delay.
  int64_t delay_after_singal_sec = context.delay_after_signal / 1'000'000;
  EXPECT_LE(delay_after_singal_sec,
            CurrentTime(false /* use_monotonic */) - start);
  EXPECT_GT(INT_MAX, CurrentTime(false /* use_monotonic */) - start);

  EXPECT_EQ(pthread_mutex_unlock(&context.mutex), 0);

  // Now we wait for the thread to exit.
  EXPECT_TRUE(SbThreadJoin(thread, NULL));
  EXPECT_EQ(pthread_cond_destroy(&context.condition), 0);
  EXPECT_EQ(pthread_mutex_destroy(&context.mutex), 0);
}

#endif  // SB_API_VERSION >= 16
}  // namespace
}  // namespace nplb
}  // namespace starboard