/*
 *  Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
 *
 *  Use of this source code is governed by a BSD-style license
 *  that can be found in the LICENSE file in the root of the source
 *  tree. An additional intellectual property rights grant can be found
 *  in the file PATENTS.  All contributing project authors may
 *  be found in the AUTHORS file in the root of the source tree.
 */

#include "webrtc/modules/audio_processing/aec3/echo_path_delay_estimator.h"

#include <algorithm>
#include <sstream>
#include <string>

#include "webrtc/base/random.h"
#include "webrtc/modules/audio_processing/aec3/aec3_constants.h"
#include "webrtc/modules/audio_processing/logging/apm_data_dumper.h"
#include "webrtc/modules/audio_processing/test/echo_canceller_test_tools.h"
#include "webrtc/test/gtest.h"

namespace webrtc {
namespace {

std::string ProduceDebugText(size_t delay) {
  std::ostringstream ss;
  ss << "Delay: " << delay;
  return ss.str();
}

}  // namespace

// Verifies that the basic API calls work.
TEST(EchoPathDelayEstimator, BasicApiCalls) {
  ApmDataDumper data_dumper(0);
  EchoPathDelayEstimator estimator(&data_dumper);
  std::vector<float> render(kBlockSize, 0.f);
  std::vector<float> capture(kBlockSize, 0.f);
  for (size_t k = 0; k < 100; ++k) {
    estimator.EstimateDelay(render, capture);
  }
}

// Verifies that the delay estimator produces correct delay for artificially
// delayed signals.
TEST(EchoPathDelayEstimator, DelayEstimation) {
  Random random_generator(42U);
  std::vector<float> render(kBlockSize, 0.f);
  std::vector<float> capture(kBlockSize, 0.f);
  ApmDataDumper data_dumper(0);
  for (size_t delay_samples : {0, 64, 150, 200, 800, 4000}) {
    SCOPED_TRACE(ProduceDebugText(delay_samples));
    DelayBuffer<float> signal_delay_buffer(delay_samples);
    EchoPathDelayEstimator estimator(&data_dumper);

    rtc::Optional<size_t> estimated_delay_samples;
    for (size_t k = 0; k < (100 + delay_samples / kBlockSize); ++k) {
      RandomizeSampleVector(&random_generator, render);
      signal_delay_buffer.Delay(render, capture);
      estimated_delay_samples = estimator.EstimateDelay(render, capture);
    }
    if (estimated_delay_samples) {
      // Due to the internal down-sampling by 4 done inside the delay estimator
      // the estimated delay cannot be expected to be closer than 4 samples to
      // the true delay.
      EXPECT_NEAR(delay_samples, *estimated_delay_samples, 4);
    } else {
      ADD_FAILURE();
    }
  }
}

// Verifies that the delay estimator does not produce delay estimates too
// quickly.
TEST(EchoPathDelayEstimator, NoInitialDelayestimates) {
  Random random_generator(42U);
  std::vector<float> render(kBlockSize, 0.f);
  std::vector<float> capture(kBlockSize, 0.f);
  ApmDataDumper data_dumper(0);

  EchoPathDelayEstimator estimator(&data_dumper);
  for (size_t k = 0; k < 19; ++k) {
    RandomizeSampleVector(&random_generator, render);
    std::copy(render.begin(), render.end(), capture.begin());
    EXPECT_FALSE(estimator.EstimateDelay(render, capture));
  }
}

// Verifies that the delay estimator does not produce delay estimates for render
// signals of low level.
TEST(EchoPathDelayEstimator, NoDelayEstimatesForLowLevelRenderSignals) {
  Random random_generator(42U);
  std::vector<float> render(kBlockSize, 0.f);
  std::vector<float> capture(kBlockSize, 0.f);
  ApmDataDumper data_dumper(0);
  EchoPathDelayEstimator estimator(&data_dumper);
  for (size_t k = 0; k < 100; ++k) {
    RandomizeSampleVector(&random_generator, render);
    for (auto& render_k : render) {
      render_k *= 100.f / 32767.f;
    }
    std::copy(render.begin(), render.end(), capture.begin());
    EXPECT_FALSE(estimator.EstimateDelay(render, capture));
  }
}

// Verifies that the delay estimator does not produce delay estimates for
// uncorrelated signals.
TEST(EchoPathDelayEstimator, NoDelayEstimatesForUncorrelatedSignals) {
  Random random_generator(42U);
  std::vector<float> render(kBlockSize, 0.f);
  std::vector<float> capture(kBlockSize, 0.f);
  ApmDataDumper data_dumper(0);
  EchoPathDelayEstimator estimator(&data_dumper);
  for (size_t k = 0; k < 100; ++k) {
    RandomizeSampleVector(&random_generator, render);
    RandomizeSampleVector(&random_generator, capture);
    EXPECT_FALSE(estimator.EstimateDelay(render, capture));
  }
}

#if RTC_DCHECK_IS_ON && GTEST_HAS_DEATH_TEST && !defined(WEBRTC_ANDROID)

// Verifies the check for the render blocksize.
// TODO(peah): Re-enable the test once the issue with memory leaks during DEATH
// tests on test bots has been fixed.
TEST(EchoPathDelayEstimator, DISABLED_WrongRenderBlockSize) {
  ApmDataDumper data_dumper(0);
  EchoPathDelayEstimator estimator(&data_dumper);
  std::vector<float> render(std::vector<float>(kBlockSize - 1, 0.f));
  std::vector<float> capture(std::vector<float>(kBlockSize, 0.f));
  EXPECT_DEATH(estimator.EstimateDelay(render, capture), "");
}

// Verifies the check for the capture blocksize.
// TODO(peah): Re-enable the test once the issue with memory leaks during DEATH
// tests on test bots has been fixed.
TEST(EchoPathDelayEstimator, WrongCaptureBlockSize) {
  ApmDataDumper data_dumper(0);
  EchoPathDelayEstimator estimator(&data_dumper);
  std::vector<float> render(std::vector<float>(kBlockSize, 0.f));
  std::vector<float> capture(std::vector<float>(kBlockSize - 1, 0.f));
  EXPECT_DEATH(estimator.EstimateDelay(render, capture), "");
}

// Verifies the check for non-null data dumper.
TEST(EchoPathDelayEstimator, NullDataDumper) {
  EXPECT_DEATH(EchoPathDelayEstimator(nullptr), "");
}

#endif

}  // namespace webrtc