/***

  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 "traverser.h"

#include "node.h"
#include "node/block/clip/clip.h"
#include "render/job/footagejob.h"
#include "render/rendermanager.h"

namespace olive {

NodeValueDatabase NodeTraverser::GenerateDatabase(const Node* node, const TimeRange &range)
{
  NodeValueDatabase database;

  // HACK: Pick up loop mode from clips
  Decoder::LoopMode old_loop_mode = loop_mode_;
  if (const ClipBlock *clip = dynamic_cast<const ClipBlock*>(node)) {
    loop_mode_ = clip->loop_mode();
  }

  // We need to insert tables into the database for each input
  foreach (const QString& input, node->inputs()) {
    if (IsCancelled()) {
      return NodeValueDatabase();
    }

    database.Insert(input, ProcessInput(node, input, range));
  }

  loop_mode_ = old_loop_mode;

  return database;
}

NodeValueRow NodeTraverser::GenerateRow(NodeValueDatabase *database, const Node *node, const TimeRange &range)
{
  // Generate row
  NodeValueRow row;
  for (auto it=database->begin(); it!=database->end(); it++) {
    // Get hint for which value should be pulled
    NodeValue value = GenerateRowValue(node, it.key(), &it.value(), range);
    row.insert(it.key(), value);
  }

  PreProcessRow(range, row);

  return row;
}

NodeValueRow NodeTraverser::GenerateRow(const Node *node, const TimeRange &range)
{
  // Generate database of input values of node
  NodeValueDatabase database = GenerateDatabase(node, range);

  return GenerateRow(&database, node, range);
}

NodeValue NodeTraverser::GenerateRowValue(const Node *node, const QString &input, NodeValueTable *table, const TimeRange &time)
{
  NodeValue value = GenerateRowValueElement(node, input, -1, table, time);

  if (value.array()) {
    // Resolve each element of array
    NodeValueTableArray tables = value.value<NodeValueTableArray>();
    NodeValueArray output;

    for (auto it=tables.begin(); it!=tables.end(); it++) {
      output[it->first] = GenerateRowValueElement(node, input, it->first, &it->second, time);
    }

    value = NodeValue(value.type(), QVariant::fromValue(output), value.source(), value.array(), value.tag());
  }

  return value;
}

NodeValue NodeTraverser::GenerateRowValueElement(const Node *node, const QString &input, int element, NodeValueTable *table, const TimeRange &time)
{
  int value_index = GenerateRowValueElementIndex(node->GetValueHintForInput(input, element), node->GetInputDataType(input), table);

  if (value_index == -1) {
    // If value was -1, try getting the last value
    value_index = table->Count() - 1;
  }

  if (value_index == -1) {
    // If value is still -1, assume the table is empty and return nothing
    return NodeValue();
  }

  NodeValue value = table->TakeAt(value_index);

  if (value.type() == NodeValue::kTexture) {
    QMutexLocker locker(node->video_frame_cache()->mutex());

    node->video_frame_cache()->LoadState();

    QString cache = node->video_frame_cache()->GetValidCacheFilename(time.in());
    if (!cache.isEmpty()) {
      value.set_value(CacheJob(cache, value.data()));
    }
  }

  return value;
}

int NodeTraverser::GenerateRowValueElementIndex(const Node::ValueHint &hint, NodeValue::Type preferred_type, const NodeValueTable *table)
{
  QVector<NodeValue::Type> types = hint.types();

  if (types.isEmpty()) {
    types.append(preferred_type);
  }

  if (hint.index() == -1) {
    // Get most recent value with this type and tag
    return table->GetValueIndex(types, hint.tag());
  } else {
    // Try to find value at this index
    int index = table->Count() - 1 - hint.index();
    int diff = 0;

    while (index + diff < table->Count() && index - diff >= 0) {
      if (index + diff < table->Count() && types.contains(table->at(index + diff).type())) {
        return index + diff;
      }
      if (index - diff >= 0 && types.contains(table->at(index - diff).type())) {
        return index - diff;
      }
      diff++;
    }

    return -1;
  }
}

int NodeTraverser::GenerateRowValueElementIndex(const Node *node, const QString &input, int element, const NodeValueTable *table)
{
  return GenerateRowValueElementIndex(node->GetValueHintForInput(input, element), node->GetInputDataType(input), table);
}

void NodeTraverser::Transform(QTransform *transform, const Node *start, const Node *end, const TimeRange &range)
{
  transform_ = transform;
  transform_start_ = start;
  transform_now_ = nullptr;

  GenerateTable(end, range);

  transform_ = nullptr;
}

NodeGlobals NodeTraverser::GenerateGlobals(const VideoParams &params, const TimeRange &time)
{
  return NodeGlobals(QVector2D(params.width(), params.height()), params.pixel_aspect_ratio(), time);
}

int NodeTraverser::GetChannelCountFromJob(const GenerateJob &job)
{
  return VideoParams::kRGBAChannelCount;
}

TexturePtr NodeTraverser::GetMainTextureFromJob(const GenerateJob &job)
{
  // FIXME: Should probably take Node::GetEffectInput into account here
  for (auto it=job.GetValues().cbegin(); it!=job.GetValues().cend(); it++) {
    if (it.value().type() == NodeValue::kTexture) {
      if (TexturePtr t = it.value().toTexture()) {
        return t;
      }
    }
  }

  return nullptr;
}

NodeValueTable NodeTraverser::ProcessInput(const Node* node, const QString& input, const TimeRange& range)
{
  if (!node->IsInputActiveAtTime(input, -1, range)) {
    return NodeValueTable();
  }

  // If input is connected, retrieve value directly
  if (node->IsInputConnected(input)) {

    TimeRange adjusted_range = node->InputTimeAdjustment(input, -1, range);

    // Value will equal something from the connected node, follow it
    Node *output = node->GetConnectedOutput(input);
    NodeValueTable table = GenerateTable(output, adjusted_range, node);
    return table;

  } else {

    // Store node
    QVariant return_val;
    bool is_array = node->InputIsArray(input);

    if (is_array) {

      // Value is an array, we will return a list of NodeValueTables
      NodeValueTableArray array_tbl;

      int sz = node->InputArraySize(input);
      for (int i=0; i<sz; i++) {
        if (node->IsInputActiveAtTime(input, i, range)) {
          NodeValueTable& sub_tbl = array_tbl[i];
          TimeRange adjusted_range = node->InputTimeAdjustment(input, i, range);

          if (node->IsInputConnected(input, i)) {
            Node *output = node->GetConnectedOutput(input, i);
            sub_tbl = GenerateTable(output, adjusted_range, node);
          } else {
            QVariant input_value = node->GetValueAtTime(input, adjusted_range.in(), i);
            sub_tbl.Push(node->GetInputDataType(input), input_value, node);
          }
        }
      }

      return_val = QVariant::fromValue(array_tbl);

    } else {

      // Not connected or an array, just pull the immediate
      TimeRange adjusted_range = node->InputTimeAdjustment(input, -1, range);

      return_val = node->GetValueAtTime(input, adjusted_range.in());

    }

    NodeValueTable return_table;
    return_table.Push(node->GetInputDataType(input), return_val, node, is_array);
    return return_table;

  }
}

NodeTraverser::NodeTraverser() :
  cancel_(nullptr),
  transform_(nullptr),
  loop_mode_(Decoder::kLoopModeOff)
{
}

class GTTTime
{
public:
  GTTTime(const Node *n) { t = QDateTime::currentMSecsSinceEpoch(); node = n; }

  ~GTTTime() { qDebug() << "GT for" << node << "took" << (QDateTime::currentMSecsSinceEpoch() - t); }

  qint64 t;
  const Node *node;

};

NodeValueTable NodeTraverser::GenerateTable(const Node *n, const TimeRange& range, const Node *next_node)
{
  // NOTE: Times how long a node takes to process, useful for profiling.
  //GTTTime gtt(n);Q_UNUSED(gtt);

  const Track* track = dynamic_cast<const Track*>(n);
  if (track) {
    // If the range is not wholly contained in this Block, we'll need to do some extra processing
    return GenerateBlockTable(track, range);
  }

  // FIXME: Cache certain values here if we've already processed them before

  // Generate row for node
  NodeValueDatabase database = GenerateDatabase(n, range);

  // Check for bypass
  bool is_enabled;
  if (!database[Node::kEnabledInput].Has(NodeValue::kBoolean)) {
    // Fallback if we couldn't find a bool value
    is_enabled = true;
  } else {
    is_enabled = database[Node::kEnabledInput].Get(NodeValue::kBoolean).toBool();
  }

  if (is_enabled) {
    NodeValueRow row = GenerateRow(&database, n, range);

    // Generate output table
    NodeValueTable table = database.Merge();

    // By this point, the node should have all the inputs it needs to render correctly
    NodeGlobals globals = GenerateGlobals(video_params_, range);
    n->Value(row, globals, &table);

    // `transform_now_` is the next node in the path that needs to be traversed. It only ever goes
    // "down" the graph so that any traversing going back up doesn't unnecessarily transform
    // from unrelated nodes or the same node twice
    if (transform_) {
      if (transform_now_ == n || transform_start_ == n) {
        if (transform_now_ == n) {
          QTransform t = n->GizmoTransformation(row, globals);
          if (!t.isIdentity()) {
            (*transform_) *= t;
          }
        }

        transform_now_ = next_node;
      }
    }

    return table;
  } else {
    // If this node has an effect input, ensure that is pushed last
    NodeValueTable primary;
    if (!n->GetEffectInputID().isEmpty()) {
      primary = database.Take(n->GetEffectInputID());
    }

    NodeValueTable m = database.Merge();
    m.Push(primary);
    return m;
  }
}

NodeValueTable NodeTraverser::GenerateBlockTable(const Track *track, const TimeRange &range)
{
  // By default, just follow the in point
  Block* active_block = track->BlockAtTime(range.in());

  NodeValueTable table;

  if (active_block) {
    block_stack_.push_back(active_block);
    table = GenerateTable(active_block, Track::TransformRangeForBlock(active_block, range), track);
    block_stack_.pop_back();
  }

  return table;
}

TexturePtr NodeTraverser::ProcessVideoCacheJob(const CacheJob &val)
{
  return nullptr;
}

QVector2D NodeTraverser::GenerateResolution() const
{
  return QVector2D(video_params_.square_pixel_width(), video_params_.height());
}

void NodeTraverser::ResolveJobs(NodeValue &val, const TimeRange &range)
{
  if (val.type() == NodeValue::kTexture || val.type() == NodeValue::kSamples) {
    if (val.canConvert<CacheJob>()) {
      CacheJob job = val.value<CacheJob>();
      TexturePtr tex = ProcessVideoCacheJob(job);
      if (tex) {
        val.set_value(tex);
      } else {
        val.set_value(job.GetFallback());
      }
    }

    if (val.canConvert<ShaderJob>()) {

      ShaderJob job = val.value<ShaderJob>();

      PreProcessRow(range, job.GetValues());

      VideoParams tex_params = GetCacheVideoParams();
      tex_params.set_channel_count(GetChannelCountFromJob(job));

      if (!job.GetWillChangeImageSize()) {
        if (TexturePtr texture = GetMainTextureFromJob(job)) {
          tex_params.set_width(texture->params().width());
          tex_params.set_height(texture->params().height());
          tex_params.set_divider(texture->params().divider());
        }
      }

      TexturePtr tex = CreateTexture(tex_params);

      ProcessShader(tex, val.source(), range, job);

      val.set_value(tex);

    } else if (val.canConvert<GenerateJob>()) {

      GenerateJob job = val.value<GenerateJob>();

      VideoParams tex_params = GetCacheVideoParams();
      tex_params.set_channel_count(GetChannelCountFromJob(job));

      VideoParams upload_params = tex_params;
      if (job.GetRequestedFormat() != VideoParams::kFormatInvalid) {
        upload_params.set_format(job.GetRequestedFormat());
      }

      TexturePtr tex = CreateTexture(upload_params);

      PreProcessRow(range, job.GetValues());
      ProcessFrameGeneration(tex, val.source(), job);

      if (!job.GetColorspace().isEmpty()) {
        // Convert to reference space
        TexturePtr dest = CreateTexture(tex_params);

        ConvertToReferenceSpace(dest, tex, job.GetColorspace());

        tex = dest;
      }

      val.set_value(tex);

    } else if (val.canConvert<ColorTransformJob>()) {

      ColorTransformJob job = val.value<ColorTransformJob>();

      VideoParams src_params = job.GetInputTexture()->params();
      src_params.set_channel_count(GetChannelCountFromJob(job));

      TexturePtr dest = CreateTexture(src_params);

      ProcessColorTransform(dest, val.source(), job);

      val.set_value(dest);

    } else if (val.canConvert<FootageJob>()) {

      FootageJob job = val.value<FootageJob>();

      if (job.type() == Track::kVideo) {

        rational footage_time = Footage::AdjustTimeByLoopMode(range.in(), loop_mode_, job.length(), job.video_params().video_type(), job.video_params().frame_rate_as_time_base());

        TexturePtr tex;

        // Adjust footage job's divider
        VideoParams render_params = GetCacheVideoParams();
        VideoParams job_params = job.video_params();

        if (render_params.divider() > 1) {
          // Use a divider appropriate for this target resolution
          job_params.set_divider(VideoParams::GetDividerForTargetResolution(job_params.width(), job_params.height(), render_params.effective_width(), render_params.effective_height()));
        } else {
          // Render everything at full res
          job_params.set_divider(1);
        }

        job.set_video_params(job_params);

        if (footage_time.isNaN()) {
          // Push dummy texture
          tex = CreateDummyTexture(job.video_params());
        } else {
          VideoParams managed_params = job.video_params();
          managed_params.set_format(GetCacheVideoParams().format());

          tex = CreateTexture(managed_params);
          ProcessVideoFootage(tex, job, footage_time);
        }

        val.set_value(tex);

      } else if (job.type() == Track::kAudio) {

        SampleBuffer buffer = CreateSampleBuffer(GetCacheAudioParams(), range.length());
        ProcessAudioFootage(buffer, job, range);
        val.set_value(buffer);

      }

    } else if (val.canConvert<SampleJob>()) {

      SampleJob job = val.value<SampleJob>();
      SampleBuffer output_buffer = CreateSampleBuffer(job.samples().audio_params(), job.samples().sample_count());
      ProcessSamples(output_buffer, val.source(), range, job);
      val.set_value(QVariant::fromValue(output_buffer));

    }

  }
}

void NodeTraverser::PreProcessRow(const TimeRange &range, NodeValueRow &row)
{
  QByteArray cached_node_hash;

  // Resolve any jobs
  for (auto it=row.begin(); it!=row.end(); it++) {
    // Jobs will almost always be submitted with one of these types
    NodeValue &val = it.value();

    ResolveJobs(val, range);
  }
}

TexturePtr NodeTraverser::CreateDummyTexture(const VideoParams &p)
{
  return std::make_shared<Texture>(p);
}

}