// Copyright (c) 2013 The Chromium Authors. All rights reserved.

//

// Redistribution and use in source and binary forms, with or without

// modification, are permitted provided that the following conditions are

// met:

//

//    * Redistributions of source code must retain the above copyright

// notice, this list of conditions and the following disclaimer.

//    * Redistributions in binary form must reproduce the above

// copyright notice, this list of conditions and the following disclaimer

// in the documentation and/or other materials provided with the

// distribution.

//    * Neither the name of Google Inc. nor the names of its

// contributors may be used to endorse or promote products derived from

// this software without specific prior written permission.

//

// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT

// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR

// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT

// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT

// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

#include "endpointer.h"

#include "AudioSegment.h"

namespace {

const int kFrameRate = 200;  // 1 frame = 5ms of audio.

}

namespace mozilla {

Endpointer::Endpointer(int sample_rate)

    : speech_input_possibly_complete_silence_length_us_(-1),

      speech_input_complete_silence_length_us_(-1),

      audio_frame_time_us_(0),

      sample_rate_(sample_rate),

      frame_size_(0) {

  Reset();

  frame_size_ = static_cast<int>(sample_rate / static_cast<float>(kFrameRate));

  speech_input_minimum_length_us_ =

      static_cast<int64_t>(1.7 * 1000000);

  speech_input_complete_silence_length_us_ =

      static_cast<int64_t>(0.5 * 1000000);

  long_speech_input_complete_silence_length_us_ = -1;

  long_speech_length_us_ = -1;

  speech_input_possibly_complete_silence_length_us_ =

      1 * 1000000;

  // Set the default configuration for Push To Talk mode.

  EnergyEndpointerParams ep_config;

  ep_config.set_frame_period(1.0f / static_cast<float>(kFrameRate));

  ep_config.set_frame_duration(1.0f / static_cast<float>(kFrameRate));

  ep_config.set_endpoint_margin(0.2f);

  ep_config.set_onset_window(0.15f);

  ep_config.set_speech_on_window(0.4f);

  ep_config.set_offset_window(0.15f);

  ep_config.set_onset_detect_dur(0.09f);

  ep_config.set_onset_confirm_dur(0.075f);

  ep_config.set_on_maintain_dur(0.10f);

  ep_config.set_offset_confirm_dur(0.12f);

  ep_config.set_decision_threshold(1000.0f);

  ep_config.set_min_decision_threshold(50.0f);

  ep_config.set_fast_update_dur(0.2f);

  ep_config.set_sample_rate(static_cast<float>(sample_rate));

  ep_config.set_min_fundamental_frequency(57.143f);

  ep_config.set_max_fundamental_frequency(400.0f);

  ep_config.set_contamination_rejection_period(0.25f);

  energy_endpointer_.Init(ep_config);

}

void Endpointer::Reset() {

  old_ep_status_ = EP_PRE_SPEECH;

  waiting_for_speech_possibly_complete_timeout_ = false;

  waiting_for_speech_complete_timeout_ = false;

  speech_previously_detected_ = false;

  speech_input_complete_ = false;

  audio_frame_time_us_ = 0; // Reset time for packets sent to endpointer.

  speech_end_time_us_ = -1;

  speech_start_time_us_ = -1;

}

void Endpointer::StartSession() {

  Reset();

  energy_endpointer_.StartSession();

}

void Endpointer::EndSession() {

  energy_endpointer_.EndSession();

}

void Endpointer::SetEnvironmentEstimationMode() {

  Reset();

  energy_endpointer_.SetEnvironmentEstimationMode();

}

void Endpointer::SetUserInputMode() {

  energy_endpointer_.SetUserInputMode();

}

EpStatus Endpointer::Status(int64_t *time) {

  return energy_endpointer_.Status(time);

}

EpStatus Endpointer::ProcessAudio(const AudioChunk& raw_audio, float* rms_out) {

  MOZ_ASSERT(raw_audio.mBufferFormat == AUDIO_FORMAT_S16, "Audio is not in 16 bit format");

  const int16_t* audio_data = static_cast<const int16_t*>(raw_audio.mChannelData[0]);

  const int num_samples = raw_audio.mDuration;

  EpStatus ep_status = EP_PRE_SPEECH;

  // Process the input data in blocks of frame_size_, dropping any incomplete

  // frames at the end (which is ok since typically the caller will be recording

  // audio in multiples of our frame size).

  int sample_index = 0;

  while (sample_index + frame_size_ <= num_samples) {

    // Have the endpointer process the frame.

    energy_endpointer_.ProcessAudioFrame(audio_frame_time_us_,

                                         audio_data + sample_index,

                                         frame_size_,

                                         rms_out);

    sample_index += frame_size_;

    audio_frame_time_us_ += (frame_size_ * 1000000) /

                         sample_rate_;

    // Get the status of the endpointer.

    int64_t ep_time;

    ep_status = energy_endpointer_.Status(&ep_time);

    if (old_ep_status_ != ep_status)

        fprintf(stderr, "Status changed old= %d, new= %d\n", old_ep_status_, ep_status);

    // Handle state changes.

    if ((EP_SPEECH_PRESENT == ep_status) &&

        (EP_POSSIBLE_ONSET == old_ep_status_)) {

      speech_end_time_us_ = -1;

      waiting_for_speech_possibly_complete_timeout_ = false;

      waiting_for_speech_complete_timeout_ = false;

      // Trigger SpeechInputDidStart event on first detection.

      if (false == speech_previously_detected_) {

        speech_previously_detected_ = true;

        speech_start_time_us_ = ep_time;

      }

    }

    if ((EP_PRE_SPEECH == ep_status) &&

        (EP_POSSIBLE_OFFSET == old_ep_status_)) {

      speech_end_time_us_ = ep_time;

      waiting_for_speech_possibly_complete_timeout_ = true;

      waiting_for_speech_complete_timeout_ = true;

    }

    if (ep_time > speech_input_minimum_length_us_) {

      // Speech possibly complete timeout.

      if ((waiting_for_speech_possibly_complete_timeout_) &&

          (ep_time - speech_end_time_us_ >

              speech_input_possibly_complete_silence_length_us_)) {

        waiting_for_speech_possibly_complete_timeout_ = false;

      }

      if (waiting_for_speech_complete_timeout_) {

        // The length of the silence timeout period can be held constant, or it

        // can be changed after a fixed amount of time from the beginning of

        // speech.

        bool has_stepped_silence =

            (long_speech_length_us_ > 0) &&

            (long_speech_input_complete_silence_length_us_ > 0);

        int64_t requested_silence_length;

        if (has_stepped_silence &&

            (ep_time - speech_start_time_us_) > long_speech_length_us_) {

          requested_silence_length =

              long_speech_input_complete_silence_length_us_;

        } else {

          requested_silence_length =

              speech_input_complete_silence_length_us_;

        }

        // Speech complete timeout.

        if ((ep_time - speech_end_time_us_) > requested_silence_length) {

          waiting_for_speech_complete_timeout_ = false;

          speech_input_complete_ = true;

        }

      }

    }

    old_ep_status_ = ep_status;

  }

  return ep_status;

}

}  // namespace mozilla