/***

  Olive - Non-Linear Video Editor
  Copyright (C) 2019 Olive Team

  This program is free software: you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation, either version 3 of the License, or
  (at your option) any later version.

  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program.  If not, see <http://www.gnu.org/licenses/>.

***/

#include "outputdeviceproxy.h"

#include "audiomanager.h"
#include "bufferaverage.h"

OLIVE_NAMESPACE_ENTER

AudioOutputDeviceProxy::AudioOutputDeviceProxy() :
  device_(nullptr),
  send_averages_(false)
{
}

void AudioOutputDeviceProxy::SetParameters(const AudioRenderingParams &params)
{
  params_ = params;
}

void AudioOutputDeviceProxy::SetDevice(QIODevice *device, int playback_speed)
{
  device_ = device;

  if (!device_->isOpen()) {
    device_->open(QIODevice::ReadOnly);
  }

  playback_speed_ = playback_speed;

  if (qAbs(playback_speed_) != 1) {
    tempo_processor_.Open(params_, qAbs(playback_speed_));
  }
}

void AudioOutputDeviceProxy::SetSendAverages(bool send)
{
  send_averages_ = send;
}

void AudioOutputDeviceProxy::close()
{
  QIODevice::close();

  device_->close();

  if (tempo_processor_.IsOpen()) {
    tempo_processor_.Close();
  }
}

qint64 AudioOutputDeviceProxy::readData(char *data, qint64 maxlen)
{
  if (device_) {

    qint64 read_count;



    if (tempo_processor_.IsOpen()) {

      while ((read_count = tempo_processor_.Pull(data, static_cast<int>(maxlen))) == 0) {
        int dev_read = static_cast<int>(ReverseAwareRead(data, maxlen));

        if (!dev_read) {
          break;
        }

        tempo_processor_.Push(data, dev_read);
      }

    } else {
      // If we aren't doing any tempo processing, simply passthrough the read signal
      read_count = ReverseAwareRead(data, maxlen);
    }

    // If we read any
    if (read_count > 0 && send_averages_) {
      emit ProcessedAverages(AudioBufferAverage::ProcessAverages(data, static_cast<int>(read_count), params_.channel_count()));
    }

    return read_count;
  }

  return 0;
}

qint64 AudioOutputDeviceProxy::writeData(const char *data, qint64 maxSize)
{
  Q_UNUSED(data)
  Q_UNUSED(maxSize)

  return -1;
}

qint64 AudioOutputDeviceProxy::ReverseAwareRead(char *data, qint64 maxlen)
{
  qint64 new_pos = -1;

  if (playback_speed_ < 0) {
    // If we're reversing, we'll seek back by maxlen bytes before we read
    new_pos = device_->pos() - maxlen;

    if (new_pos < 0) {
      maxlen = device_->pos();

      new_pos = 0;
    }

    device_->seek(new_pos);
  }

  qint64 read_count = device_->read(data, maxlen);

  if (playback_speed_ < 0) {
    device_->seek(new_pos);

    // Reverse the samples here
    AudioManager::ReverseBuffer(data, static_cast<int>(read_count), params_.samples_to_bytes(1));
  }

  return read_count;
}

OLIVE_NAMESPACE_EXIT