/*
 *  Copyright (c) 2013 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_coding/neteq/statistics_calculator.h"

#include <assert.h>
#include <string.h>  // memset

#include "webrtc/base/checks.h"
#include "webrtc/modules/audio_coding/neteq/decision_logic.h"
#include "webrtc/modules/audio_coding/neteq/delay_manager.h"
#include "webrtc/system_wrappers/interface/metrics.h"

namespace webrtc {

StatisticsCalculator::PeriodicUmaLogger::PeriodicUmaLogger(
    const std::string& uma_name,
    int report_interval_ms,
    int max_value)
    : uma_name_(uma_name),
      report_interval_ms_(report_interval_ms),
      max_value_(max_value),
      timer_(0) {
}

StatisticsCalculator::PeriodicUmaLogger::~PeriodicUmaLogger() = default;

void StatisticsCalculator::PeriodicUmaLogger::AdvanceClock(int step_ms) {
  timer_ += step_ms;
  if (timer_ < report_interval_ms_) {
    return;
  }
  LogToUma(Metric());
  Reset();
  timer_ -= report_interval_ms_;
  DCHECK_GE(timer_, 0);
}

void StatisticsCalculator::PeriodicUmaLogger::LogToUma(int value) const {
  RTC_HISTOGRAM_COUNTS(uma_name_, value, 1, max_value_, 50);
}

StatisticsCalculator::PeriodicUmaCount::PeriodicUmaCount(
    const std::string& uma_name,
    int report_interval_ms,
    int max_value)
    : PeriodicUmaLogger(uma_name, report_interval_ms, max_value) {
}

StatisticsCalculator::PeriodicUmaCount::~PeriodicUmaCount() {
  // Log the count for the current (incomplete) interval.
  LogToUma(Metric());
}

void StatisticsCalculator::PeriodicUmaCount::RegisterSample() {
  ++counter_;
}

int StatisticsCalculator::PeriodicUmaCount::Metric() const {
  return counter_;
}

void StatisticsCalculator::PeriodicUmaCount::Reset() {
  counter_ = 0;
}

StatisticsCalculator::PeriodicUmaAverage::PeriodicUmaAverage(
    const std::string& uma_name,
    int report_interval_ms,
    int max_value)
    : PeriodicUmaLogger(uma_name, report_interval_ms, max_value) {
}

StatisticsCalculator::PeriodicUmaAverage::~PeriodicUmaAverage() {
  // Log the average for the current (incomplete) interval.
  LogToUma(Metric());
}

void StatisticsCalculator::PeriodicUmaAverage::RegisterSample(int value) {
  sum_ += value;
  ++counter_;
}

int StatisticsCalculator::PeriodicUmaAverage::Metric() const {
  return static_cast<int>(sum_ / counter_);
}

void StatisticsCalculator::PeriodicUmaAverage::Reset() {
  sum_ = 0.0;
  counter_ = 0;
}

StatisticsCalculator::StatisticsCalculator()
    : preemptive_samples_(0),
      accelerate_samples_(0),
      added_zero_samples_(0),
      expanded_speech_samples_(0),
      expanded_noise_samples_(0),
      discarded_packets_(0),
      lost_timestamps_(0),
      timestamps_since_last_report_(0),
      len_waiting_times_(0),
      next_waiting_time_index_(0),
      secondary_decoded_samples_(0),
      delayed_packet_outage_counter_(
          "WebRTC.Audio.DelayedPacketOutageEventsPerMinute",
          60000,  // 60 seconds report interval.
          100),
      excess_buffer_delay_("WebRTC.Audio.AverageExcessBufferDelayMs",
                           60000,  // 60 seconds report interval.
                           1000) {
  memset(waiting_times_, 0, kLenWaitingTimes * sizeof(waiting_times_[0]));
}

void StatisticsCalculator::Reset() {
  preemptive_samples_ = 0;
  accelerate_samples_ = 0;
  added_zero_samples_ = 0;
  expanded_speech_samples_ = 0;
  expanded_noise_samples_ = 0;
  secondary_decoded_samples_ = 0;
}

void StatisticsCalculator::ResetMcu() {
  discarded_packets_ = 0;
  lost_timestamps_ = 0;
  timestamps_since_last_report_ = 0;
}

void StatisticsCalculator::ResetWaitingTimeStatistics() {
  memset(waiting_times_, 0, kLenWaitingTimes * sizeof(waiting_times_[0]));
  len_waiting_times_ = 0;
  next_waiting_time_index_ = 0;
}

void StatisticsCalculator::ExpandedVoiceSamples(int num_samples) {
  expanded_speech_samples_ += num_samples;
}

void StatisticsCalculator::ExpandedNoiseSamples(int num_samples) {
  expanded_noise_samples_ += num_samples;
}

void StatisticsCalculator::PreemptiveExpandedSamples(int num_samples) {
  preemptive_samples_ += num_samples;
}

void StatisticsCalculator::AcceleratedSamples(int num_samples) {
  accelerate_samples_ += num_samples;
}

void StatisticsCalculator::AddZeros(int num_samples) {
  added_zero_samples_ += num_samples;
}

void StatisticsCalculator::PacketsDiscarded(int num_packets) {
  discarded_packets_ += num_packets;
}

void StatisticsCalculator::LostSamples(int num_samples) {
  lost_timestamps_ += num_samples;
}

void StatisticsCalculator::IncreaseCounter(int num_samples, int fs_hz) {
  const int time_step_ms = rtc::CheckedDivExact(1000 * num_samples, fs_hz);
  delayed_packet_outage_counter_.AdvanceClock(time_step_ms);
  excess_buffer_delay_.AdvanceClock(time_step_ms);
  timestamps_since_last_report_ += static_cast<uint32_t>(num_samples);
  if (timestamps_since_last_report_ >
      static_cast<uint32_t>(fs_hz * kMaxReportPeriod)) {
    lost_timestamps_ = 0;
    timestamps_since_last_report_ = 0;
    discarded_packets_ = 0;
  }
}

void StatisticsCalculator::SecondaryDecodedSamples(int num_samples) {
  secondary_decoded_samples_ += num_samples;
}

void StatisticsCalculator::LogDelayedPacketOutageEvent(int outage_duration_ms) {
  RTC_HISTOGRAM_COUNTS("WebRTC.Audio.DelayedPacketOutageEventMs",
                       outage_duration_ms, 1 /* min */, 2000 /* max */,
                       100 /* bucket count */);
  delayed_packet_outage_counter_.RegisterSample();
}

void StatisticsCalculator::StoreWaitingTime(int waiting_time_ms) {
  excess_buffer_delay_.RegisterSample(waiting_time_ms);
  assert(next_waiting_time_index_ < kLenWaitingTimes);
  waiting_times_[next_waiting_time_index_] = waiting_time_ms;
  next_waiting_time_index_++;
  if (next_waiting_time_index_ >= kLenWaitingTimes) {
    next_waiting_time_index_ = 0;
  }
  if (len_waiting_times_ < kLenWaitingTimes) {
    len_waiting_times_++;
  }
}

void StatisticsCalculator::GetNetworkStatistics(
    int fs_hz,
    int num_samples_in_buffers,
    int samples_per_packet,
    const DelayManager& delay_manager,
    const DecisionLogic& decision_logic,
    NetEqNetworkStatistics *stats) {
  if (fs_hz <= 0 || !stats) {
    assert(false);
    return;
  }

  stats->added_zero_samples = added_zero_samples_;
  stats->current_buffer_size_ms =
      static_cast<uint16_t>(num_samples_in_buffers * 1000 / fs_hz);
  const int ms_per_packet = decision_logic.packet_length_samples() /
      (fs_hz / 1000);
  stats->preferred_buffer_size_ms = (delay_manager.TargetLevel() >> 8) *
      ms_per_packet;
  stats->jitter_peaks_found = delay_manager.PeakFound();
  stats->clockdrift_ppm = delay_manager.AverageIAT();

  stats->packet_loss_rate =
      CalculateQ14Ratio(lost_timestamps_, timestamps_since_last_report_);

  const unsigned discarded_samples = discarded_packets_ * samples_per_packet;
  stats->packet_discard_rate =
      CalculateQ14Ratio(discarded_samples, timestamps_since_last_report_);

  stats->accelerate_rate =
      CalculateQ14Ratio(accelerate_samples_, timestamps_since_last_report_);

  stats->preemptive_rate =
      CalculateQ14Ratio(preemptive_samples_, timestamps_since_last_report_);

  stats->expand_rate =
      CalculateQ14Ratio(expanded_speech_samples_ + expanded_noise_samples_,
                        timestamps_since_last_report_);

  stats->speech_expand_rate =
      CalculateQ14Ratio(expanded_speech_samples_,
                        timestamps_since_last_report_);

  stats->secondary_decoded_rate =
      CalculateQ14Ratio(secondary_decoded_samples_,
                        timestamps_since_last_report_);

  // Reset counters.
  ResetMcu();
  Reset();
}

void StatisticsCalculator::WaitingTimes(std::vector<int>* waiting_times) {
  if (!waiting_times) {
    return;
  }
  waiting_times->assign(waiting_times_, waiting_times_ + len_waiting_times_);
  ResetWaitingTimeStatistics();
}

uint16_t StatisticsCalculator::CalculateQ14Ratio(uint32_t numerator,
                                                 uint32_t denominator) {
  if (numerator == 0) {
    return 0;
  } else if (numerator < denominator) {
    // Ratio must be smaller than 1 in Q14.
    assert((numerator << 14) / denominator < (1 << 14));
    return static_cast<uint16_t>((numerator << 14) / denominator);
  } else {
    // Will not produce a ratio larger than 1, since this is probably an error.
    return 1 << 14;
  }
}

}  // namespace webrtc