/*
 *  Copyright (c) 2011 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 "common_audio/resampler/include/resampler.h"

#include <array>
#include <cstddef>
#include <cstdint>
#include <cstring>

#include "rtc_base/strings/string_builder.h"
#include "test/gtest.h"

// TODO(andrew): this is a work-in-progress. Many more tests are needed.

namespace webrtc {
namespace {

// Rates we must support.
constexpr int kMaxRate = 96000;
constexpr int kRates[] = {8000, 16000, 32000, 44000, 48000, kMaxRate};
constexpr size_t kRatesSize = sizeof(kRates) / sizeof(*kRates);
constexpr int kMaxChannels = 2;
constexpr size_t kDataSize = static_cast<size_t>(kMaxChannels * kMaxRate / 100);

// TODO(andrew): should we be supporting these combinations?
bool ValidRates(int in_rate, int out_rate) {
  // Not the most compact notation, for clarity.
  if ((in_rate == 44000 && (out_rate == 48000 || out_rate == 96000)) ||
      (out_rate == 44000 && (in_rate == 48000 || in_rate == 96000))) {
    return false;
  }

  return true;
}

class ResamplerTest : public ::testing::Test {
 protected:
  ResamplerTest();
  void SetUp() override;
  void TearDown() override;

  void ResetIfNeededAndPush(int in_rate, int out_rate, int num_channels);

  Resampler rs_;
  int16_t data_in_[kDataSize];
  int16_t data_out_[kDataSize];
};

ResamplerTest::ResamplerTest() {}

void ResamplerTest::SetUp() {
  // Initialize input data with anything. The tests are content independent.
  memset(data_in_, 1, sizeof(data_in_));
}

void ResamplerTest::TearDown() {}

void ResamplerTest::ResetIfNeededAndPush(int in_rate,
                                         int out_rate,
                                         int num_channels) {
  StringBuilder ss;
  ss << "Input rate: " << in_rate << ", output rate: " << out_rate
     << ", channel count: " << num_channels;
  SCOPED_TRACE(ss.str());

  if (ValidRates(in_rate, out_rate)) {
    size_t in_length = static_cast<size_t>(in_rate / 100);
    size_t out_length = 0;
    EXPECT_EQ(0, rs_.ResetIfNeeded(in_rate, out_rate, num_channels));
    EXPECT_EQ(0,
              rs_.Push(data_in_, in_length, data_out_, kDataSize, out_length));
    EXPECT_EQ(static_cast<size_t>(out_rate / 100), out_length);
  } else {
    EXPECT_EQ(-1, rs_.ResetIfNeeded(in_rate, out_rate, num_channels));
  }
}

TEST_F(ResamplerTest, Reset) {
  const int kNumChannels[] = {1, 2};
  const size_t kNumChannelsSize = std::size(kNumChannels);

  // The only failure mode for the constructor is if Reset() fails. For the
  // time being then (until an Init function is added), we rely on Reset()
  // to test the constructor.

  // Check that all required combinations are supported.
  for (size_t i = 0; i < kRatesSize; ++i) {
    for (size_t j = 0; j < kRatesSize; ++j) {
      for (size_t k = 0; k < kNumChannelsSize; ++k) {
        StringBuilder ss;
        ss << "Input rate: " << kRates[i] << ", output rate: " << kRates[j]
           << ", channels: " << kNumChannels[k];
        SCOPED_TRACE(ss.str());
        if (ValidRates(kRates[i], kRates[j]))
          EXPECT_EQ(0, rs_.Reset(kRates[i], kRates[j], kNumChannels[k]));
        else
          EXPECT_EQ(-1, rs_.Reset(kRates[i], kRates[j], kNumChannels[k]));
      }
    }
  }
}

// TODO(tlegrand): Replace code inside the two tests below with a function
// with number of channels and ResamplerType as input.
TEST_F(ResamplerTest, Mono) {
  const int kChannels = 1;
  for (size_t i = 0; i < kRatesSize; ++i) {
    for (size_t j = 0; j < kRatesSize; ++j) {
      StringBuilder ss;
      ss << "Input rate: " << kRates[i] << ", output rate: " << kRates[j];
      SCOPED_TRACE(ss.str());

      if (ValidRates(kRates[i], kRates[j])) {
        size_t in_length = static_cast<size_t>(kRates[i] / 100);
        size_t out_length = 0;
        EXPECT_EQ(0, rs_.Reset(kRates[i], kRates[j], kChannels));
        EXPECT_EQ(
            0, rs_.Push(data_in_, in_length, data_out_, kDataSize, out_length));
        EXPECT_EQ(static_cast<size_t>(kRates[j] / 100), out_length);
      } else {
        EXPECT_EQ(-1, rs_.Reset(kRates[i], kRates[j], kChannels));
      }
    }
  }
}

TEST_F(ResamplerTest, Stereo) {
  const int kChannels = 2;
  for (size_t i = 0; i < kRatesSize; ++i) {
    for (size_t j = 0; j < kRatesSize; ++j) {
      StringBuilder ss;
      ss << "Input rate: " << kRates[i] << ", output rate: " << kRates[j];
      SCOPED_TRACE(ss.str());

      if (ValidRates(kRates[i], kRates[j])) {
        size_t in_length = static_cast<size_t>(kChannels * kRates[i] / 100);
        size_t out_length = 0;
        EXPECT_EQ(0, rs_.Reset(kRates[i], kRates[j], kChannels));
        EXPECT_EQ(
            0, rs_.Push(data_in_, in_length, data_out_, kDataSize, out_length));
        EXPECT_EQ(static_cast<size_t>(kChannels * kRates[j] / 100), out_length);
      } else {
        EXPECT_EQ(-1, rs_.Reset(kRates[i], kRates[j], kChannels));
      }
    }
  }
}

// Try multiple resets between a few supported and unsupported rates.
TEST_F(ResamplerTest, MultipleResets) {
  constexpr size_t kNumChanges = 5;
  constexpr std::array<int, kNumChanges> kInRates = {
      {8000, 44000, 44000, 32000, 32000}};
  constexpr std::array<int, kNumChanges> kOutRates = {
      {16000, 48000, 48000, 16000, 16000}};
  constexpr std::array<int, kNumChanges> kNumChannels = {{2, 2, 2, 2, 1}};
  for (size_t i = 0; i < kNumChanges; ++i) {
    ResetIfNeededAndPush(kInRates[i], kOutRates[i], kNumChannels[i]);
  }
}

}  // namespace
}  // namespace webrtc