/***

  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 "viewer.h"

#include <QDateTime>
#include <QLabel>
#include <QResizeEvent>
#include <QtMath>
#include <QVBoxLayout>

#include "audio/audiomanager.h"
#include "common/timecodefunctions.h"
#include "config/config.h"
#include "project/item/sequence/sequence.h"
#include "project/project.h"
#include "render/pixelservice.h"
#include "widget/menu/menu.h"

ViewerWidget::ViewerWidget(QWidget *parent) :
  TimeBasedWidget(false, true, parent),
  playback_speed_(0),
  frame_cache_job_time_(0),
  color_menu_enabled_(true),
  divider_(Config::Current()["DefaultViewerDivider"].toInt()),
  override_color_manager_(nullptr),
  time_changed_from_timer_(false)
{
  // Set up main layout
  QVBoxLayout* layout = new QVBoxLayout(this);
  layout->setMargin(0);

  // Create main OpenGL-based view
  sizer_ = new ViewerSizer();
  layout->addWidget(sizer_);

  gl_widget_ = new ViewerGLWidget();
  connect(gl_widget_, &ViewerGLWidget::customContextMenuRequested, this, &ViewerWidget::ShowContextMenu);
  sizer_->SetWidget(gl_widget_);

  // Create time ruler
  layout->addWidget(ruler());

  // Create scrollbar
  layout->addWidget(scrollbar());
  connect(scrollbar(), &QScrollBar::valueChanged, ruler(), &TimeRuler::SetScroll);

  // Create lower controls
  controls_ = new PlaybackControls();
  controls_->SetTimecodeEnabled(true);
  controls_->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Maximum);
  connect(controls_, &PlaybackControls::PlayClicked, this, &ViewerWidget::Play);
  connect(controls_, &PlaybackControls::PauseClicked, this, &ViewerWidget::Pause);
  connect(controls_, &PlaybackControls::PrevFrameClicked, this, &ViewerWidget::PrevFrame);
  connect(controls_, &PlaybackControls::NextFrameClicked, this, &ViewerWidget::NextFrame);
  connect(controls_, &PlaybackControls::BeginClicked, this, &ViewerWidget::GoToStart);
  connect(controls_, &PlaybackControls::EndClicked, this, &ViewerWidget::GoToEnd);
  connect(controls_, &PlaybackControls::TimeChanged, this, &ViewerWidget::SetTimeAndSignal);
  layout->addWidget(controls_);

  // Connect timer
  connect(&playback_timer_, &QTimer::timeout, this, &ViewerWidget::PlaybackTimerUpdate);

  // FIXME: Magic number
  SetScale(48.0);

  // Start background renderers
  video_renderer_ = new OpenGLBackend(this);
  connect(video_renderer_, &VideoRenderBackend::CachedFrameReady, this, &ViewerWidget::RendererCachedFrame);
  connect(video_renderer_, &VideoRenderBackend::CachedTimeReady, this, &ViewerWidget::RendererCachedTime);
  connect(video_renderer_, &VideoRenderBackend::CachedTimeReady, ruler(), &TimeRuler::CacheTimeReady);
  connect(video_renderer_, &VideoRenderBackend::RangeInvalidated, ruler(), &TimeRuler::CacheInvalidatedRange);
  audio_renderer_ = new AudioBackend(this);

  connect(PixelService::instance(), &PixelService::FormatChanged, this, &ViewerWidget::UpdateRendererParameters);

  SetAutoMaxScrollBar(true);
}

void ViewerWidget::TimeChangedEvent(const int64_t &i)
{
  if (!time_changed_from_timer_) {
    Pause();
  }

  controls_->SetTime(i);

  if (GetConnectedNode() && last_time_ != i) {
    rational time_set = Timecode::timestamp_to_time(i, timebase());

    UpdateTextureFromNode(time_set);

    PushScrubbedAudio();
  }

  last_time_ = i;
}

void ViewerWidget::ConnectNodeInternal(ViewerOutput *n)
{
  SetTimebase(n->video_params().time_base());

  connect(n, &ViewerOutput::TimebaseChanged, this, &ViewerWidget::SetTimebase);
  connect(n, &ViewerOutput::SizeChanged, this, &ViewerWidget::SizeChangedSlot);
  connect(n, &ViewerOutput::LengthChanged, this, &ViewerWidget::LengthChangedSlot);
  connect(n, &ViewerOutput::VisibleInvalidated, this, &ViewerWidget::InvalidateVisible);

  SizeChangedSlot(n->video_params().width(), n->video_params().height());
  LengthChangedSlot(n->Length());

  if (override_color_manager_) {
    gl_widget_->ConnectColorManager(override_color_manager_);
  } else if (n->parent()) {
    gl_widget_->ConnectColorManager(static_cast<Sequence*>(n->parent())->project()->color_manager());
  } else {
    qWarning() << "Failed to find a suitable color manager for the connected viewer node";
  }

  divider_ = CalculateDivider();

  UpdateRendererParameters();
}

void ViewerWidget::DisconnectNodeInternal(ViewerOutput *n)
{
  SetTimebase(0);

  disconnect(n, &ViewerOutput::TimebaseChanged, this, &ViewerWidget::SetTimebase);
  disconnect(n, &ViewerOutput::SizeChanged, this, &ViewerWidget::SizeChangedSlot);
  disconnect(n, &ViewerOutput::LengthChanged, this, &ViewerWidget::LengthChangedSlot);
  disconnect(n, &ViewerOutput::VisibleInvalidated, this, &ViewerWidget::InvalidateVisible);

  // Effectively disables the viewer and clears the state
  SizeChangedSlot(0, 0);

  gl_widget_->DisconnectColorManager();
}

void ViewerWidget::ConnectedNodeChanged(ViewerOutput *n)
{
  video_renderer_->SetViewerNode(n);
  audio_renderer_->SetViewerNode(n);
}

void ViewerWidget::resizeEvent(QResizeEvent *event)
{
  TimeBasedWidget::resizeEvent(event);

  int new_div = CalculateDivider();
  if (new_div != divider_) {
    divider_ = new_div;

    UpdateRendererParameters();
  }
}

void ViewerWidget::TogglePlayPause()
{
  if (IsPlaying()) {
    Pause();
  } else {
    Play();
  }
}

bool ViewerWidget::IsPlaying() const
{
  return playback_timer_.isActive();
}

void ViewerWidget::ConnectViewerNode(ViewerOutput *node, ColorManager* color_manager)
{
  override_color_manager_ = color_manager;

  TimeBasedWidget::ConnectViewerNode(node);

  // Set texture to new texture (or null if no viewer node is available)
  UpdateTextureFromNode(GetTime());
}

void ViewerWidget::SetColorMenuEnabled(bool enabled)
{
  color_menu_enabled_ = enabled;
}

void ViewerWidget::SetOverrideSize(int width, int height)
{
  SizeChangedSlot(width, height);
}

void ViewerWidget::SetMatrix(const QMatrix4x4 &mat)
{
  gl_widget_->SetMatrix(mat);
}

VideoRenderBackend *ViewerWidget::video_renderer() const
{
  return video_renderer_;
}

void ViewerWidget::SetTexture(OpenGLTexturePtr tex)
{
  gl_widget_->SetTexture(tex);
}

void ViewerWidget::UpdateTextureFromNode(const rational& time)
{
  if (!GetConnectedNode()) {
    SetTexture(nullptr);
  } else {
    SetTexture(video_renderer_->GetCachedFrameAsTexture(time));
  }
}

void ViewerWidget::PlayInternal(int speed)
{
  Q_ASSERT(speed != 0);

  if (timebase().isNull()) {
    qWarning() << "ViewerWidget can't play with an invalid timebase";
    return;
  }

  playback_speed_ = speed;

  QIODevice* audio_src = audio_renderer_->GetAudioPullDevice();
  if (audio_src != nullptr && audio_src->open(QIODevice::ReadOnly)) {
    audio_src->seek(audio_renderer_->params().time_to_bytes(GetTime()));
    AudioManager::instance()->SetOutputParams(audio_renderer_->params());
    AudioManager::instance()->StartOutput(audio_src, playback_speed_);
  }

  start_msec_ = QDateTime::currentMSecsSinceEpoch();
  start_timestamp_ = ruler()->GetTime();

  playback_timer_.start();

  controls_->ShowPauseButton();
}

void ViewerWidget::PushScrubbedAudio()
{
  if (!IsPlaying() && Config::Current()["AudioScrubbing"].toBool()) {
    // Get audio src device from renderer
    QIODevice* audio_src = audio_renderer_->GetAudioPullDevice();

    if (audio_src && audio_src->open(QFile::ReadOnly)) {
      // Try to get one "frame" of audio
      int size_of_sample = audio_renderer_->params().time_to_bytes(timebase());

      // Push audio
      audio_src->seek(audio_renderer_->params().time_to_bytes(GetTime()));
      QByteArray frame_audio = audio_src->read(size_of_sample);
      AudioManager::instance()->SetOutputParams(audio_renderer_->params());
      AudioManager::instance()->PushToOutput(frame_audio);

      audio_src->close();
    }
  }
}

int ViewerWidget::CalculateDivider()
{
  if (GetConnectedNode() && Config::Current()["AutoSelectDivider"].toBool()) {
    int long_side_of_video = qMax(GetConnectedNode()->video_params().width(), GetConnectedNode()->video_params().height());
    int long_side_of_widget = qMax(gl_widget_->width(), gl_widget_->height());

    return qMax(1, long_side_of_video / long_side_of_widget);
  }

  return divider_;
}

void ViewerWidget::UpdateRendererParameters()
{
  if (!GetConnectedNode()) {
    return;
  }

  RenderMode::Mode render_mode = RenderMode::kOffline;

  video_renderer_->SetParameters(VideoRenderingParams(GetConnectedNode()->video_params(),
                                                      PixelService::instance()->GetConfiguredFormatForMode(render_mode),
                                                      render_mode,
                                                      divider_));
  audio_renderer_->SetParameters(AudioRenderingParams(GetConnectedNode()->audio_params(),
                                                      SampleFormat::GetConfiguredFormatForMode(render_mode)));

  video_renderer_->InvalidateCache(0, GetConnectedNode()->Length());
}

void ViewerWidget::ShowContextMenu(const QPoint &pos)
{
  QMenu menu(this);

  // Color options
  if (gl_widget_->color_manager() && color_menu_enabled_) {
    QStringList displays = gl_widget_->color_manager()->ListAvailableDisplays();
    QMenu* ocio_display_menu = menu.addMenu(tr("Display"));
    connect(ocio_display_menu, &QMenu::triggered, this, &ViewerWidget::ColorDisplayChanged);
    foreach (const QString& d, displays) {
      QAction* action = ocio_display_menu->addAction(d);
      action->setCheckable(true);
      action->setChecked(gl_widget_->ocio_display() == d);
      action->setData(d);
    }

    QStringList views = gl_widget_->color_manager()->ListAvailableViews(gl_widget_->ocio_display());
    QMenu* ocio_view_menu = menu.addMenu(tr("View"));
    connect(ocio_view_menu, &QMenu::triggered, this, &ViewerWidget::ColorViewChanged);
    foreach (const QString& v, views) {
      QAction* action = ocio_view_menu->addAction(v);
      action->setCheckable(true);
      action->setChecked(gl_widget_->ocio_view() == v);
      action->setData(v);
    }

    QStringList looks = gl_widget_->color_manager()->ListAvailableLooks();
    QMenu* ocio_look_menu = menu.addMenu(tr("Look"));
    connect(ocio_look_menu, &QMenu::triggered, this, &ViewerWidget::ColorLookChanged);
    QAction* no_look_action = ocio_look_menu->addAction(tr("(None)"));
    no_look_action->setCheckable(true);
    no_look_action->setChecked(gl_widget_->ocio_look().isEmpty());
    foreach (const QString& l, looks) {
      QAction* action = ocio_look_menu->addAction(l);
      action->setCheckable(true);
      action->setChecked(gl_widget_->ocio_look() == l);
      action->setData(l);
    }

    menu.addSeparator();
  }

  // Playback resolution
  QMenu* playback_resolution_menu = menu.addMenu(tr("Resolution"));
  playback_resolution_menu->addAction(tr("Full"))->setData(1);
  playback_resolution_menu->addAction(tr("1/2"))->setData(2);
  playback_resolution_menu->addAction(tr("1/4"))->setData(4);
  playback_resolution_menu->addAction(tr("1/8"))->setData(8);
  playback_resolution_menu->addAction(tr("1/16"))->setData(16);
  connect(playback_resolution_menu, &QMenu::triggered, this, &ViewerWidget::SetDividerFromMenu);

  foreach (QAction* a, playback_resolution_menu->actions()) {
    a->setCheckable(true);
    if (a->data() == divider_) {
      a->setChecked(true);
    }
  }

  menu.exec(mapToGlobal(pos));
}

void ViewerWidget::Play()
{
  PlayInternal(1);
}

void ViewerWidget::Pause()
{
  if (IsPlaying()) {
    AudioManager::instance()->StopOutput();
    playback_speed_ = 0;
    controls_->ShowPlayButton();
    playback_timer_.stop();
  }
}

void ViewerWidget::ShuttleLeft()
{
  int current_speed = playback_speed_;

  if (current_speed != 0) {
    Pause();
  }

  current_speed--;

  if (current_speed != 0) {
    PlayInternal(current_speed);
  }
}

void ViewerWidget::ShuttleStop()
{
  Pause();
}

void ViewerWidget::ShuttleRight()
{
  int current_speed = playback_speed_;

  if (current_speed != 0) {
    Pause();
  }

  current_speed++;

  if (current_speed != 0) {
    PlayInternal(current_speed);
  }
}

void ViewerWidget::SetOCIOParameters(const QString &display, const QString &view, const QString &look)
{
  gl_widget_->SetOCIOParameters(display, view, look);
}

void ViewerWidget::SetOCIODisplay(const QString &display)
{
  gl_widget_->SetOCIODisplay(display);
}

void ViewerWidget::SetOCIOView(const QString &view)
{
  gl_widget_->SetOCIOView(view);
}

void ViewerWidget::SetOCIOLook(const QString &look)
{
  gl_widget_->SetOCIOLook(look);
}

void ViewerWidget::TimebaseChangedEvent(const rational &timebase)
{
  TimeBasedWidget::TimebaseChangedEvent(timebase);

  controls_->SetTimebase(timebase);

  controls_->SetTime(ruler()->GetTime());
  LengthChangedSlot(GetConnectedNode() ? GetConnectedNode()->Length() : 0);

  playback_timer_.setInterval(qFloor(timebase.toDouble()));
}

void ViewerWidget::PlaybackTimerUpdate()
{
  int64_t real_time = QDateTime::currentMSecsSinceEpoch() - start_msec_;

  int64_t frames_since_start = qRound(static_cast<double>(real_time) / (timebase_dbl() * 1000));

  int64_t current_time = start_timestamp_ + frames_since_start * playback_speed_;

  if (current_time < 0) {
    SetTimeAndSignal(0);
  } else {
    time_changed_from_timer_ = true;
    SetTimeAndSignal(current_time);
    time_changed_from_timer_ = false;
  }
}

void ViewerWidget::RendererCachedFrame(const rational &time, QVariant value, qint64 job_time)
{
  if (GetTime() == time && job_time > frame_cache_job_time_) {
    frame_cache_job_time_ = job_time;

    SetTexture(value.value<OpenGLTexturePtr>());
  }
}

void ViewerWidget::RendererCachedTime(const rational &time, qint64 job_time)
{
  if (GetTime() == time && job_time > frame_cache_job_time_) {
    frame_cache_job_time_ = job_time;

    UpdateTextureFromNode(GetTime());
  }
}

void ViewerWidget::SizeChangedSlot(int width, int height)
{
  sizer_->SetChildSize(width, height);
}

void ViewerWidget::LengthChangedSlot(const rational &length)
{
  controls_->SetEndTime(Timecode::time_to_timestamp(length, timebase()));
  ruler()->SetCacheStatusLength(length);
}

void ViewerWidget::ColorDisplayChanged(QAction* action)
{
  SetOCIODisplay(action->data().toString());
}

void ViewerWidget::ColorViewChanged(QAction *action)
{
  SetOCIOView(action->data().toString());
}

void ViewerWidget::ColorLookChanged(QAction *action)
{
  SetOCIOLook(action->data().toString());
}

void ViewerWidget::SetDividerFromMenu(QAction *action)
{
  int divider = action->data().toInt();

  if (divider <= 0) {
    qWarning() << "Tried to set invalid divider:" << divider;
    return;
  }

  divider_ = divider;

  UpdateRendererParameters();
}

void ViewerWidget::InvalidateVisible()
{
  video_renderer_->InvalidateCache(GetTime(), GetTime());
}