/***

  Olive - Non-Linear Video Editor
  Copyright (C) 2022 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 "previewautocacher.h"

#include <QApplication>
#include <QtConcurrent/QtConcurrent>

#include "codec/conformmanager.h"
#include "node/inputdragger.h"
#include "node/project/project.h"
#include "render/renderprocessor.h"
#include "task/customcache/customcachetask.h"
#include "task/taskmanager.h"
#include "widget/slider/base/numericsliderbase.h"

namespace olive {

PreviewAutoCacher::PreviewAutoCacher(QObject *parent) :
  QObject(parent),
  viewer_node_(nullptr),
  use_custom_range_(false),
  pause_renders_(false),
  single_frame_render_(nullptr)
{
  // Set defaults
  SetPlayhead(0);

  // Wait a certain amount of time before requeuing when we receive an invalidate signal
  delayed_requeue_timer_.setInterval(OLIVE_CONFIG("AutoCacheDelay").toInt());
  delayed_requeue_timer_.setSingleShot(true);
  connect(&delayed_requeue_timer_, &QTimer::timeout, this, &PreviewAutoCacher::TryRender);

  // Catch when a conform is ready
  connect(ConformManager::instance(), &ConformManager::ConformReady, this, &PreviewAutoCacher::ConformFinished);
}

PreviewAutoCacher::~PreviewAutoCacher()
{
  // Ensure everything is cleaned up appropriately
  SetViewerNode(nullptr);
}

RenderTicketPtr PreviewAutoCacher::GetSingleFrame(const rational &t, RenderTicketPriority priority)
{
  // If we have a single frame render queued (but not yet sent to the RenderManager), cancel it now
  CancelQueuedSingleFrameRender();

  // Create a new single frame render ticket
  auto sfr = std::make_shared<RenderTicket>();
  sfr->Start();
  sfr->setProperty("time", QVariant::fromValue(t));
  sfr->setProperty("priority", int(priority));

  // Queue it and try to render
  single_frame_render_ = sfr;
  TryRender();

  return sfr;
}

RenderTicketPtr PreviewAutoCacher::GetRangeOfAudio(TimeRange range, RenderTicketPriority priority)
{
  return RenderAudio(range, false, priority);
}

void PreviewAutoCacher::VideoInvalidatedFromCache(const TimeRange &range)
{
  FrameHashCache *cache = static_cast<FrameHashCache*>(sender());

  VideoInvalidatedFromNode(cache->parent(), range);
}

void PreviewAutoCacher::AudioInvalidatedFromCache(const TimeRange &range)
{
  AudioPlaybackCache *cache = static_cast<AudioPlaybackCache*>(sender());

  AudioInvalidatedFromNode(cache->parent(), range);
}

void PreviewAutoCacher::AudioRendered()
{
  // Receive watcher
  RenderTicketWatcher* watcher = static_cast<RenderTicketWatcher*>(sender());

  // If the task list doesn't contain this watcher, presumably it was cleared as a result of a
  // viewer switch, so we'll completely ignore this watcher
  if (audio_tasks_.contains(watcher)) {
    // Assume that a "result" is a fully completed image and a non-result is a cancelled ticket
    TimeRange range = audio_tasks_.take(watcher);
    Node *node = Node::ValueToPtr<Node>(watcher->property("node"));

    if (watcher->HasResult()) {
      AudioCacheData &d = audio_cache_data_[node];

      JobTime watcher_job_time = watcher->property("job").value<JobTime>();

      TimeRangeList valid_ranges = d.job_tracker.getCurrentSubRanges(range, watcher_job_time);

      AudioVisualWaveform waveform = watcher->GetTicket()->property("waveform").value<AudioVisualWaveform>();

      SampleBuffer buf = watcher->Get().value<SampleBuffer>();
      node->audio_playback_cache()->SetParameters(buf.audio_params());
      /*if (node->audio_playback_cache()->IsEnabled()) {
        // WritePCM is tolerant to its buffer being null, it will just write silence instead
        node->audio_playback_cache()->WritePCM(range,
                                                       valid_ranges,
                                                       watcher->Get().value<SampleBuffer>());
      }*/

      // Detect if this audio was incomplete because it was waiting on a conform to finish
      if (watcher->GetTicket()->property("incomplete").toBool()) {
        if (last_conform_task_ > watcher_job_time) {
          // Requeue now
          node->audio_playback_cache()->Invalidate(range);
        } else {
          // Wait for conform
          d.needing_conform.insert(range);
        }
      } else {
        qDebug() << "Writing waveforms to" << range << valid_ranges;
        node->audio_playback_cache()->WriteWaveform(range, valid_ranges, &waveform);
      }
    }

    // Continue rendering
    TryRender();
  }

  delete watcher;
}

void PreviewAutoCacher::VideoRendered()
{
  RenderTicketWatcher* watcher = static_cast<RenderTicketWatcher*>(sender());

  // If the task list doesn't contain this watcher, presumably it was cleared as a result of a
  // viewer switch, so we'll completely ignore this watcher
  auto it = video_tasks_.find(watcher);

  if (it != video_tasks_.end()) {
    // Assume that a "result" is a fully completed image and a non-result is a cancelled ticket
    if (watcher->HasResult()) {
      // Download frame in another thread
      if (watcher->GetTicket()->property("cached").toBool()) {
        if (FrameHashCache *cache = Node::ValueToPtr<FrameHashCache>(watcher->property("cache"))) {
          cache->ValidateTime(it.value());
        }
      }
    }

    video_tasks_.erase(it);

    // Continue rendering
    TryRender();
  }

  // Process passthroughs no matter what, if the viewer was switched, the passthrough map would be
  // cleared anyway
  QVector<RenderTicketPtr> tickets = video_immediate_passthroughs_.take(watcher);
  foreach (RenderTicketPtr t, tickets) {
    if (watcher->HasResult()) {
      t->Finish(watcher->Get());
    } else {
      t->Finish();
    }
  }

  delete watcher;
}

void PreviewAutoCacher::ProcessUpdateQueue()
{
  // Iterate everything that happened to the graph and do the same thing on our end
  foreach (const QueuedJob& job, graph_update_queue_) {
    switch (job.type) {
    case QueuedJob::kNodeAdded:
      AddNode(job.node);
      break;
    case QueuedJob::kNodeRemoved:
      RemoveNode(job.node);
      break;
    case QueuedJob::kEdgeAdded:
      AddEdge(job.output, job.input);
      break;
    case QueuedJob::kEdgeRemoved:
      RemoveEdge(job.output, job.input);
      break;
    case QueuedJob::kValueChanged:
      CopyValue(job.input);
      break;
    case QueuedJob::kValueHintChanged:
      CopyValueHint(job.input);
      break;
    }
  }
  graph_update_queue_.clear();

  // Indicate that we have synchronized to this point, which is compared with the graph change
  // time to see if our copied graph is up to date
  UpdateLastSyncedValue();
}

void PreviewAutoCacher::AddNode(Node *node)
{
  if (dynamic_cast<NodeGroup*>(node)) {
    // Group nodes are just dummy nodes, no need to copy them
    return;
  }

  // Copy node
  Node* copy = node->copy();

  // Add to project
  copy->setParent(&copied_project_);

  // Insert into map
  InsertIntoCopyMap(node, copy);

  // Keep track of our nodes
  created_nodes_.append(copy);
}

void PreviewAutoCacher::RemoveNode(Node *node)
{
  // Find our copy and remove it
  Node* copy = copy_map_.take(node);

  // Disconnect from node's caches
  DisconnectFromNodeCache(node);

  // Remove from created list
  created_nodes_.removeOne(copy);

  // Delete it
  delete copy;
}

void PreviewAutoCacher::AddEdge(Node *output, const NodeInput &input)
{
  // Create same connection with our copied graph
  Node* our_output = copy_map_.value(output);
  Node* our_input = copy_map_.value(input.node());

  Node::ConnectEdge(our_output, NodeInput(our_input, input.input(), input.element()));
}

void PreviewAutoCacher::RemoveEdge(Node *output, const NodeInput &input)
{
  // Remove same connection with our copied graph
  Node* our_output = copy_map_.value(output);
  Node* our_input = copy_map_.value(input.node());

  Node::DisconnectEdge(our_output, NodeInput(our_input, input.input(), input.element()));
}

void PreviewAutoCacher::CopyValue(const NodeInput &input)
{
  if (dynamic_cast<NodeGroup*>(input.node())) {
    // Group nodes are just dummy nodes, no need to copy them
    return;
  }

  // Copy all values to our graph
  Node* our_input = copy_map_.value(input.node());
  Node::CopyValuesOfElement(input.node(), our_input, input.input(), input.element());
}

void PreviewAutoCacher::CopyValueHint(const NodeInput &input)
{
  if (dynamic_cast<NodeGroup*>(input.node())) {
    // Group nodes are just dummy nodes, no need to copy them
    return;
  }

  // Copy value hint to our graph
  Node* our_input = copy_map_.value(input.node());
  Node::ValueHint hint = input.node()->GetValueHintForInput(input.input(), input.element());
  our_input->SetValueHintForInput(input.input(), hint, input.element());
}

void PreviewAutoCacher::InsertIntoCopyMap(Node *node, Node *copy)
{
  // Insert into map
  copy_map_.insert(node, copy);

  // Copy parameters
  Node::CopyInputs(node, copy, false);

  // Connect to node's cache
  ConnectToNodeCache(node);
}

void PreviewAutoCacher::ConnectToNodeCache(Node *node)
{
  connect(node->video_frame_cache(),
          &PlaybackCache::AutomaticChanged,
          this,
          &PreviewAutoCacher::VideoAutoCacheEnableChanged);

  connect(node->audio_playback_cache(),
          &PlaybackCache::AutomaticChanged,
          this,
          &PreviewAutoCacher::AudioAutoCacheEnableChanged);

  connect(node->video_frame_cache(),
          &PlaybackCache::Request,
          this,
          &PreviewAutoCacher::VideoInvalidatedFromCache);

  connect(node->audio_playback_cache(),
          &PlaybackCache::Request,
          this,
          &PreviewAutoCacher::AudioInvalidatedFromCache);

  // Copy invalidated ranges and start rendering if necessary
  if (node->video_frame_cache()->IsAutomatic()) {
    VideoAutoCacheEnableChangedFromNode(node, true);
  }

  if (node->audio_playback_cache()->IsAutomatic()) {
    AudioAutoCacheEnableChangedFromNode(node, true);
  }
}

void PreviewAutoCacher::DisconnectFromNodeCache(Node *node)
{
  disconnect(node->video_frame_cache(),
             &PlaybackCache::AutomaticChanged,
             this,
             &PreviewAutoCacher::VideoAutoCacheEnableChanged);

  disconnect(node->audio_playback_cache(),
             &PlaybackCache::AutomaticChanged,
             this,
             &PreviewAutoCacher::AudioAutoCacheEnableChanged);

  disconnect(node->video_frame_cache(),
             &PlaybackCache::Request,
             this,
             &PreviewAutoCacher::VideoInvalidatedFromCache);

  disconnect(node->audio_playback_cache(),
             &PlaybackCache::Request,
             this,
             &PreviewAutoCacher::AudioInvalidatedFromCache);

  if (node->video_frame_cache()->IsAutomatic()) {
    VideoAutoCacheEnableChangedFromNode(node, false);
  }

  if (node->audio_playback_cache()->IsAutomatic()) {
    AudioAutoCacheEnableChangedFromNode(node, false);
  }
}

void PreviewAutoCacher::UpdateGraphChangeValue()
{
  graph_changed_time_.Acquire();
}

void PreviewAutoCacher::UpdateLastSyncedValue()
{
  last_update_time_.Acquire();
}

void PreviewAutoCacher::CancelQueuedSingleFrameRender()
{
  if (single_frame_render_) {
    // Signal that this ticket was cancelled with no value
    single_frame_render_->Finish();
    single_frame_render_ = nullptr;
  }
}

void PreviewAutoCacher::VideoInvalidatedList(Node *node, const TimeRangeList &list)
{
  foreach (const TimeRange &range, list) {
    VideoInvalidatedFromNode(node, range);
  }
}

void PreviewAutoCacher::AudioInvalidatedList(Node *node, const TimeRangeList &list)
{
  foreach (const TimeRange &range, list) {
    AudioInvalidatedFromNode(node, range);
  }
}

void PreviewAutoCacher::StartCachingRange(const TimeRange &range, TimeRangeList *range_list, RenderJobTracker *tracker)
{
  range_list->insert(range);
  tracker->insert(range, graph_changed_time_);
}

void PreviewAutoCacher::StartCachingVideoRange(Node *node, const TimeRange &range)
{
  VideoCacheData &d = video_cache_data_[node];

  StartCachingRange(range, &d.invalidated, &d.job_tracker);
  TryRender();
}

void PreviewAutoCacher::StartCachingAudioRange(Node *node, const TimeRange &range)
{
  AudioCacheData &d = audio_cache_data_[node];

  StartCachingRange(range, &d.invalidated, &d.job_tracker);
  TryRender();
}

void PreviewAutoCacher::VideoInvalidatedFromNode(Node *node, const TimeRange &range)
{
  // Stop any current render tasks because a) they might be out of date now anyway, and b) we
  // want to dedicate all our rendering power to realtime feedback for the user
  CancelVideoTasks(node);

  // If auto-cache is enabled and a slider is not being dragged, queue up to hash these frames
  if (!NodeInputDragger::IsInputBeingDragged()) {
    StartCachingVideoRange(node, range);
  }
}

void PreviewAutoCacher::AudioInvalidatedFromNode(Node *node, const TimeRange &range)
{
  // We don't stop rendering audio because currently there's no system of requeuing audio if it's
  // cancelled, so some areas may end up unrendered forever
  //  ClearAudioQueue();

  // If we're auto-caching audio or require realtime waveforms, we'll have to render this
  StartCachingAudioRange(node, range);
}

void PreviewAutoCacher::VideoAutoCacheEnableChangedFromNode(Node *node, bool e)
{
  if (e) {
    VideoInvalidatedList(node, node->video_frame_cache()->GetInvalidatedRanges(node->GetVideoCacheRange()));
  } else {
    CancelVideoTasks(node);
  }
}

void PreviewAutoCacher::AudioAutoCacheEnableChangedFromNode(Node *node, bool e)
{
  if (e) {
    AudioInvalidatedList(node, node->audio_playback_cache()->GetInvalidatedRanges(node->GetAudioCacheRange()));
  } else {
    CancelAudioTasks(node);
  }
}

void PreviewAutoCacher::SetPlayhead(const rational &playhead)
{
  cache_range_ = TimeRange(playhead - OLIVE_CONFIG("DiskCacheBehind").value<rational>(),
                           playhead + OLIVE_CONFIG("DiskCacheAhead").value<rational>());

  TryRender();
}

template<typename T>
void CancelTasks(const T &task_list, bool and_wait)
{
  for (auto it=task_list.cbegin(); it!=task_list.cend(); it++) {
    // Signal that the ticket should not be finished
    it.key()->Cancel();
  }

  if (and_wait) {
    // Wait for each ticket to finish
    for (auto it=task_list.cbegin(); it!=task_list.cend(); it++) {
      it.key()->WaitForFinished();
    }
  }
}

void PreviewAutoCacher::CancelVideoTasks(bool and_wait_for_them_to_finish)
{
  CancelTasks(video_tasks_, and_wait_for_them_to_finish);
}

void PreviewAutoCacher::CancelAudioTasks(bool and_wait_for_them_to_finish)
{
  CancelTasks(audio_tasks_, and_wait_for_them_to_finish);
}

bool PreviewAutoCacher::IsRenderingCustomRange() const
{
  const VideoCacheData &d = video_cache_data_.value(viewer_node_);
  return d.iterator.IsCustomRange() && d.iterator.HasNext();
}

void PreviewAutoCacher::SetRendersPaused(bool e)
{
  pause_renders_ = e;
  if (!e) {
    TryRender();
  }
}

void PreviewAutoCacher::NodeAdded(Node *node)
{
  graph_update_queue_.append({QueuedJob::kNodeAdded, node, NodeInput(), nullptr});
  UpdateGraphChangeValue();
}

void PreviewAutoCacher::NodeRemoved(Node *node)
{
  graph_update_queue_.append({QueuedJob::kNodeRemoved, node, NodeInput(), nullptr});
  UpdateGraphChangeValue();
}

void PreviewAutoCacher::EdgeAdded(Node *output, const NodeInput &input)
{
  graph_update_queue_.append({QueuedJob::kEdgeAdded, nullptr, input, output});
  UpdateGraphChangeValue();
}

void PreviewAutoCacher::EdgeRemoved(Node *output, const NodeInput &input)
{
  graph_update_queue_.append({QueuedJob::kEdgeRemoved, nullptr, input, output});
  UpdateGraphChangeValue();
}

void PreviewAutoCacher::ValueChanged(const NodeInput &input)
{
  graph_update_queue_.append({QueuedJob::kValueChanged, nullptr, input, nullptr});
  UpdateGraphChangeValue();
}

void PreviewAutoCacher::ValueHintChanged(const NodeInput &input)
{
  graph_update_queue_.append({QueuedJob::kValueHintChanged, nullptr, input, nullptr});
  UpdateGraphChangeValue();
}

void PreviewAutoCacher::TryRender()
{
  delayed_requeue_timer_.stop();

  if (pause_renders_) {
    return;
  }

  if (!graph_update_queue_.isEmpty()) {
    // Check if we have jobs running in other threads that shouldn't be interrupted right now
    // NOTE: We don't check for downloads because, while they run in another thread, they don't
    //       require any access to the graph and therefore don't risk race conditions.
    if (!audio_tasks_.isEmpty()
        || !video_tasks_.isEmpty()) {
      return;
    }

    // No jobs are active, we can process the update queue
    ProcessUpdateQueue();
  }

  if (single_frame_render_) {
    // Check if already caching this
    RenderTicketWatcher *watcher = RenderFrame(single_frame_render_->property("time").value<rational>(),
                                               RenderTicketPriority(single_frame_render_->property("priority").toInt()),
                                               nullptr);
    video_immediate_passthroughs_[watcher].append(single_frame_render_);

    single_frame_render_ = nullptr;
  }

  // Ensure we are running tasks if we have any
  const int max_tasks = RenderManager::GetNumberOfIdealConcurrentJobs();

  // Handle video tasks
  for (auto it=video_cache_data_.begin(); it!=video_cache_data_.end(); it++) {
    VideoCacheData &d = it.value();

    // Check for newly invalidated video
    if (!d.invalidated.isEmpty()) {
      if (d.iterator.HasNext()) {
        d.iterator.insert(d.invalidated);
      } else {
        d.iterator = TimeRangeListFrameIterator(d.invalidated, viewer_node_->GetVideoParams().frame_rate_as_time_base());
      }
      d.invalidated.clear();
    }

    // Queue next frames
    rational t;
    while (video_tasks_.size() < max_tasks && d.iterator.GetNext(&t)) {
      RenderTicketWatcher* render_task = video_tasks_.key(t);

      // We want this hash, if we're not already rendering, start render now
      if (!render_task) {
        // Don't render any hash more than once
        RenderFrame(it.key(), t, RenderTicketPriority::kNormal, it.key()->video_frame_cache());
      }

      emit SignalCacheProxyTaskProgress(double(d.iterator.frame_index()) / double(d.iterator.size()));

      if (!d.iterator.HasNext()) {
        emit StopCacheProxyTasks();
      }
    }
  }


  // Handle audio tasks
  for (auto it=audio_cache_data_.begin(); it!=audio_cache_data_.end(); it++) {
    AudioCacheData &d = it.value();

    if (!d.invalidated.isEmpty()) {
      // Add newly invalidated audio to iterator
      d.iterator.insert(d.invalidated);
      d.invalidated.clear();
    }

    while (!d.iterator.isEmpty() && audio_tasks_.size() < max_tasks) {
      // Copy first range in list
      TimeRange r = d.iterator.first();

      // Limit to the minimum sample rate supported by AudioVisualWaveform - we use this value so that
      // whatever chunk we render can be summed down to the smallest mipmap whole
      r.set_out(qMin(r.out(), r.in() + AudioVisualWaveform::kMinimumSampleRate.flipped()));

      // Start job
      RenderAudio(it.key(), r, true, RenderTicketPriority::kNormal);

      d.iterator.remove(r);
    }
  }
}

RenderTicketWatcher* PreviewAutoCacher::RenderFrame(Node *node, const rational& time, RenderTicketPriority priority, FrameHashCache *cache)
{
  RenderTicketWatcher* watcher = new RenderTicketWatcher();
  watcher->setProperty("job", QVariant::fromValue(last_update_time_));
  watcher->setProperty("cache", Node::PtrToValue(cache));
  if (cache) {
    cache->SetTimebase(viewer_node_->GetVideoParams().frame_rate_as_time_base());
  }
  connect(watcher, &RenderTicketWatcher::Finished, this, &PreviewAutoCacher::VideoRendered);
  video_tasks_.insert(watcher, time);
  watcher->SetTicket(RenderManager::instance()->RenderFrame(node,
                                                            copied_viewer_node_->GetVideoParams(),
                                                            copied_viewer_node_->GetAudioParams(),
                                                            copied_color_manager_,
                                                            time,
                                                            RenderMode::kOffline,
                                                            cache,
                                                            priority,
                                                            RenderManager::kTexture));
  return watcher;
}

RenderTicketPtr PreviewAutoCacher::RenderAudio(Node *node, const TimeRange &r, bool generate_waveforms, RenderTicketPriority priority)
{
  qDebug() << "Rendering" << r << "for" << node;

  RenderTicketWatcher* watcher = new RenderTicketWatcher();
  watcher->setProperty("job", QVariant::fromValue(last_update_time_));
  watcher->setProperty("node", Node::PtrToValue(node));
  connect(watcher, &RenderTicketWatcher::Finished, this, &PreviewAutoCacher::AudioRendered);
  audio_tasks_.insert(watcher, r);

  RenderTicketPtr ticket = RenderManager::instance()->RenderAudio(node, r, copied_viewer_node_->GetAudioParams(), RenderMode::kOffline, generate_waveforms, priority);
  watcher->SetTicket(ticket);
  return ticket;
}

void PreviewAutoCacher::ConformFinished()
{
  // Got an audio conform, requeue all the audio currently needing a conform
  last_conform_task_.Acquire();

  for (auto it=audio_cache_data_.begin(); it!=audio_cache_data_.end(); it++) {
    AudioCacheData &d = it.value();

    if (!d.needing_conform.isEmpty()) {
      // This list should be empty if there was a viewer switch
      foreach (const TimeRange &range, d.needing_conform) {
        it.key()->audio_playback_cache()->Invalidate(range);
      }
      d.needing_conform.clear();
    }
  }
}

void PreviewAutoCacher::VideoAutoCacheEnableChanged(bool e)
{
  FrameHashCache *cache = static_cast<FrameHashCache*>(sender());

  VideoAutoCacheEnableChangedFromNode(cache->parent(), e);
}

void PreviewAutoCacher::AudioAutoCacheEnableChanged(bool e)
{
  AudioPlaybackCache *cache = static_cast<AudioPlaybackCache*>(sender());

  AudioAutoCacheEnableChangedFromNode(cache->parent(), e);
}

void PreviewAutoCacher::CacheProxyTaskCancelled()
{
  for (auto it=video_cache_data_.begin(); it!=video_cache_data_.end(); it++) {
    it->iterator.reset();
  }

  TryRender();
}

void PreviewAutoCacher::ForceCacheRange(const TimeRange &range)
{
  use_custom_range_ = true;
  custom_autocache_range_ = range;

  // Re-hash these frames and start rendering
  StartCachingVideoRange(viewer_node_, range);
}

void PreviewAutoCacher::SetViewerNode(ViewerOutput *viewer_node)
{
  if (viewer_node_ == viewer_node) {
    return;
  }

  if (viewer_node_) {
    // We must wait for any jobs to finish because they'll be using our copied graph and we're
    // about to destroy it

    // Stop requeue timer if it's running
    delayed_requeue_timer_.stop();

    // Handle video rendering tasks
    if (!video_tasks_.isEmpty()) {
      // Cancel any video tasks and wait for them to finish
      CancelVideoTasks(true);
    }

    // Handle audio rendering tasks
    if (!audio_tasks_.isEmpty()) {
      // Cancel any audio tasks and wait for them to finish
      CancelAudioTasks(true);
    }

    // Clear any single frame render that might be queued
    CancelQueuedSingleFrameRender();

    // Not interested in video passthroughs anymore
    video_immediate_passthroughs_.clear();

    // Disconnect from all node cache's
    for (auto it=copy_map_.cbegin(); it!=copy_map_.cend(); it++) {
      DisconnectFromNodeCache(it.key());
    }

    // Delete all of our copied nodes
    qDeleteAll(created_nodes_);
    created_nodes_.clear();
    copy_map_.clear();
    copied_viewer_node_ = nullptr;
    graph_update_queue_.clear();

    // Ensure all cache data is cleared
    video_cache_data_.clear();
    audio_cache_data_.clear();

    // Disconnect signals for future node additions/deletions
    NodeGraph* graph = viewer_node_->parent();

    disconnect(graph, &NodeGraph::NodeAdded, this, &PreviewAutoCacher::NodeAdded);
    disconnect(graph, &NodeGraph::NodeRemoved, this, &PreviewAutoCacher::NodeRemoved);
    disconnect(graph, &NodeGraph::InputConnected, this, &PreviewAutoCacher::EdgeAdded);
    disconnect(graph, &NodeGraph::InputDisconnected, this, &PreviewAutoCacher::EdgeRemoved);
    disconnect(graph, &NodeGraph::ValueChanged, this, &PreviewAutoCacher::ValueChanged);
    disconnect(graph, &NodeGraph::InputValueHintChanged, this, &PreviewAutoCacher::ValueHintChanged);
  }

  viewer_node_ = viewer_node;

  if (viewer_node_) {
    // Copy graph
    NodeGraph* graph = viewer_node_->parent();

    SetRendersPaused(true);

    // Add all nodes
    for (int i=0; i<copied_project_.nodes().size(); i++) {
      InsertIntoCopyMap(graph->nodes().at(i), copied_project_.nodes().at(i));
    }
    for (int i=copied_project_.nodes().size(); i<graph->nodes().size(); i++) {
      AddNode(graph->nodes().at(i));
    }

    // Find copied viewer node
    copied_viewer_node_ = static_cast<ViewerOutput*>(copy_map_.value(viewer_node_));
    copied_color_manager_ = static_cast<ColorManager*>(copy_map_.value(viewer_node_->project()->color_manager()));

    // Add all connections
    foreach (Node* node, graph->nodes()) {
      for (auto it=node->input_connections().cbegin(); it!=node->input_connections().cend(); it++) {
        AddEdge(it->second, it->first);
      }
    }

    // Ensure graph change value is just before the sync value
    UpdateGraphChangeValue();
    UpdateLastSyncedValue();

    // Connect signals for future node additions/deletions
    connect(graph, &NodeGraph::NodeAdded, this, &PreviewAutoCacher::NodeAdded, Qt::DirectConnection);
    connect(graph, &NodeGraph::NodeRemoved, this, &PreviewAutoCacher::NodeRemoved, Qt::DirectConnection);
    connect(graph, &NodeGraph::InputConnected, this, &PreviewAutoCacher::EdgeAdded, Qt::DirectConnection);
    connect(graph, &NodeGraph::InputDisconnected, this, &PreviewAutoCacher::EdgeRemoved, Qt::DirectConnection);
    connect(graph, &NodeGraph::ValueChanged, this, &PreviewAutoCacher::ValueChanged, Qt::DirectConnection);
    connect(graph, &NodeGraph::InputValueHintChanged, this, &PreviewAutoCacher::ValueHintChanged, Qt::DirectConnection);

    SetRendersPaused(false);
  }
}

}