/***

  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 "undo.h"

#include "node/graph.h"
#include "node/block/transition/transition.h"

Block* CreateSplitBlock(Block* block, rational point, QObject* parent = nullptr)
{
  Block* copy = static_cast<Block*>(block->copy());
  copy->set_length_and_media_in(block->length() - (point - block->in()));
  copy->setParent(parent);

  return copy;
}

Node* TakeNodeFromParentGraph(Node* n, QObject* new_parent = nullptr)
{
  static_cast<NodeGraph*>(n->parent())->TakeNode(n, new_parent);

  return n;
}

BlockResizeCommand::BlockResizeCommand(Block *block, rational new_length, QUndoCommand* parent) :
  QUndoCommand(parent),
  block_(block),
  old_length_(block->length()),
  new_length_(new_length)
{
}

void BlockResizeCommand::redo()
{
  block_->set_length(new_length_);
}

void BlockResizeCommand::undo()
{
  block_->set_length(old_length_);
}

BlockResizeWithMediaInCommand::BlockResizeWithMediaInCommand(Block *block, rational new_length, QUndoCommand *parent) :
  QUndoCommand(parent),
  block_(block),
  old_length_(block->length()),
  new_length_(new_length)
{
}

void BlockResizeWithMediaInCommand::redo()
{
  block_->set_length_and_media_in(new_length_);
}

void BlockResizeWithMediaInCommand::undo()
{
  block_->set_length_and_media_in(old_length_);
}

BlockSetMediaInCommand::BlockSetMediaInCommand(Block *block, rational new_media_in, QUndoCommand* parent) :
  QUndoCommand(parent),
  block_(block),
  old_media_in_(block->media_in()),
  new_media_in_(new_media_in)
{
}

void BlockSetMediaInCommand::redo()
{
  block_->set_media_in(new_media_in_);
}

void BlockSetMediaInCommand::undo()
{
  block_->set_media_in(old_media_in_);
}

TrackRippleRemoveBlockCommand::TrackRippleRemoveBlockCommand(TrackOutput *track, Block *block, QUndoCommand *parent) :
  QUndoCommand(parent),
  track_(track),
  block_(block),
  before_(block->previous())
{
}

void TrackRippleRemoveBlockCommand::redo()
{
  track_->RippleRemoveBlock(block_);
}

void TrackRippleRemoveBlockCommand::undo()
{
  if (before_) {
    track_->InsertBlockAfter(block_, before_);
  } else {
    track_->AppendBlock(block_);
  }
}

TrackInsertBlockBetweenBlocksCommand::TrackInsertBlockBetweenBlocksCommand(TrackOutput *track,
                                                                           Block *block,
                                                                           Block *before,
                                                                           Block *after,
                                                                           QUndoCommand *parent) :
  QUndoCommand(parent),
  track_(track),
  block_(block),
  before_(before),
  after_(after)
{
}

void TrackInsertBlockBetweenBlocksCommand::redo()
{
  track_->InsertBlockAfter(block_, before_);
}

void TrackInsertBlockBetweenBlocksCommand::undo()
{
  track_->RippleRemoveBlock(block_);
}

TrackRippleRemoveAreaCommand::TrackRippleRemoveAreaCommand(TrackOutput *track, rational in, rational out, QUndoCommand *parent) :
  QUndoCommand(parent),
  track_(track),
  in_(in),
  out_(out),
  splice_(nullptr),
  trim_out_(nullptr),
  trim_in_(nullptr),
  insert_(nullptr)
{
}

void TrackRippleRemoveAreaCommand::SetInsert(Block *insert)
{
  insert_ = insert;
}

void TrackRippleRemoveAreaCommand::redo()
{
  // Iterate through blocks determining which need trimming/removing/splitting
  foreach (Block* block, track_->Blocks()) {
    if (block->in() < in_ && block->out() > out_) {
      // The area entirely within this Block
      splice_ = block;

      // We don't need to do anything else here
      break;
    } else if (block->in() >= in_ && block->out() <= out_) {
      // This Block's is entirely within the area
      removed_blocks_.append(block);
    } else if (block->in() < in_ && block->out() >= in_) {
      // This Block's out point exceeds `in`
      trim_out_ = block;
    } else if (block->in() <= out_ && block->out() > out_) {
      // This Block's in point exceeds `out`
      trim_in_ = block;
    }
  }

  track_->BlockInvalidateCache();

  // If we picked up a block to splice
  if (splice_ != nullptr) {

    // Split the block here
    Block* copy = CreateSplitBlock(splice_, out_);

    splice_original_length_ = splice_->length();
    splice_->set_length(out_ - splice_->in());

    static_cast<NodeGraph*>(track_->parent())->AddNode(copy);
    Node::CopyInputs(splice_, copy);

    track_->InsertBlockAfter(copy, splice_);

    // Perform all further actions as if we were just trimming these clips
    trim_out_ = splice_;
    trim_in_ = copy;
  }

  // If we picked up a block to trim the in point of
  if (trim_in_ != nullptr) {
    trim_in_old_length_ = trim_in_->length();
    trim_in_new_length_ = trim_in_->out() - out_;
  }

  // If we picked up a block to trim the out point of
  if (trim_out_ != nullptr) {
    trim_out_old_length_ = trim_out_->length();
    trim_out_new_length_ = in_ - trim_out_->in();
  }

  // If we picked up a block to trim the in point of
  if (trim_in_old_length_ != trim_in_new_length_) {
    trim_in_->set_length_and_media_in(trim_in_new_length_);
  }

  // Remove all blocks that are flagged for removal
  foreach (Block* remove_block, removed_blocks_) {
    track_->RippleRemoveBlock(remove_block);

    // FIXME: Delete blocks from graph and restore them in undo
  }

  // If we picked up a block to trim the out point of
  if (trim_out_old_length_ != trim_out_new_length_) {
    trim_out_->set_length(trim_out_new_length_);
  }

  // If we were given a block to insert, insert it here
  if (insert_) {
    if (!trim_out_) {
      // This is the start of the Sequence
      track_->PrependBlock(insert_);
    } else if (!trim_in_) {
      // This is the end of the Sequence
      track_->AppendBlock(insert_);
    } else {
      // This is somewhere in the middle of the Sequence
      track_->InsertBlockAfter(insert_, trim_out_);
    }
  }

  track_->UnblockInvalidateCache();

  track_->InvalidateCache(in_, out_);
}

void TrackRippleRemoveAreaCommand::undo()
{
  track_->BlockInvalidateCache();

  // If we were given a block to insert, insert it here
  if (insert_ != nullptr) {
    track_->RippleRemoveBlock(insert_);
  }

  // If we picked up a block to trim the out point of
  if (trim_out_old_length_ != trim_out_new_length_) {
    trim_out_->set_length(trim_out_old_length_);
  }

  // Remove all blocks that are flagged for removal
  foreach (Block* remove_block, removed_blocks_) {
    if (trim_in_ == nullptr) {
      track_->AppendBlock(remove_block);
    } else {
      track_->InsertBlockBefore(remove_block, trim_in_);
    }
  }

  // If we picked up a block to trim the in point of
  if (trim_in_old_length_ != trim_in_new_length_) {
    trim_in_->set_length_and_media_in(trim_in_old_length_);
  }

  // If we're splicing, trim_in_ is a copy
  if (splice_ != nullptr) {
    track_->RippleRemoveBlock(trim_in_);

    // Remove node
    TakeNodeFromParentGraph(trim_in_, &memory_manager_);

    splice_->set_length(splice_original_length_);
  }

  track_->UnblockInvalidateCache();

  track_->InvalidateCache(in_, out_);
}

TrackPlaceBlockCommand::TrackPlaceBlockCommand(TrackList *timeline, int track, Block *block, rational in, QUndoCommand *parent) :
  TrackRippleRemoveAreaCommand(nullptr, in, 0, parent), // Out gets set correctly in redo()
  timeline_(timeline),
  track_index_(track),
  gap_(nullptr)
{
  insert_ = block;
}

void TrackPlaceBlockCommand::redo()
{
  added_track_count_ = 0;

  // Get track (or make it if necessary)
  while (track_index_ >= timeline_->Tracks().size()) {
    timeline_->AddTrack();

    added_track_count_++;
  }

  track_ = timeline_->TrackAt(track_index_);

  append_ = (in_ >= track_->track_length());

  // Check if the placement location is past the end of the timeline
  if (append_) {
    if (in_ > track_->track_length()) {
      // If so, insert a gap here
      gap_ = new GapBlock();
      gap_->set_length(in_ - track_->track_length());
      static_cast<NodeGraph*>(track_->parent())->AddNode(gap_);
      track_->AppendBlock(gap_);
    }

    track_->AppendBlock(insert_);
  } else {
    out_ = in_ + insert_->length();

    // Place the Block at this point
    TrackRippleRemoveAreaCommand::redo();
  }
}

void TrackPlaceBlockCommand::undo()
{
  if (append_) {
    track_->RippleRemoveBlock(insert_);

    if (gap_ != nullptr) {
      track_->RippleRemoveBlock(gap_);
      delete TakeNodeFromParentGraph(gap_);
    }
  } else {
    TrackRippleRemoveAreaCommand::undo();
  }

  for (;added_track_count_>0;added_track_count_--) {
    timeline_->RemoveTrack();
  }
}

BlockSplitCommand::BlockSplitCommand(TrackOutput* track, Block *block, rational point, QUndoCommand *parent) :
  QUndoCommand(parent),
  track_(track),
  block_(block),
  new_length_(point - block->in()),
  old_length_(block->length())
{
  Q_ASSERT(point > block_->in() && point < block_->out());

  // Ensures that this block is deleted if this action is undone
  new_block_ = CreateSplitBlock(block_, point, &memory_manager_);

  // Determine if the block outputs to an "out" transition
  foreach (NodeEdgePtr edge, block_->output()->edges()) {
    if (edge->input()->parentNode()->IsBlock()
        && static_cast<Block*>(edge->input()->parentNode())->type() == Block::kTransition
        && edge->input() == static_cast<TransitionBlock*>(edge->input()->parentNode())->out_block_input()) {
      transitions_to_move_.append(edge->input());
    }
  }
}

void BlockSplitCommand::redo()
{
  track_->BlockInvalidateCache();

  block_->set_length(new_length_);

  static_cast<NodeGraph*>(block_->parent())->AddNode(new_block_);
  Node::CopyInputs(block_, new_block_);

  // Will re-parent new_block_ to the track's graph
  track_->InsertBlockAfter(new_block_, block_);

  track_->UnblockInvalidateCache();

  foreach (NodeInput* transition, transitions_to_move_) {
    NodeParam::DisconnectEdge(block_->output(), transition);
    NodeParam::ConnectEdge(new_block_->output(), transition);
  }
}

void BlockSplitCommand::undo()
{
  track_->BlockInvalidateCache();

  block_->set_length(old_length_);
  track_->RippleRemoveBlock(new_block_);

  TakeNodeFromParentGraph(new_block_, &memory_manager_);

  track_->UnblockInvalidateCache();

  foreach (NodeInput* transition, transitions_to_move_) {
    NodeParam::DisconnectEdge(new_block_->output(), transition);
    NodeParam::ConnectEdge(block_->output(), transition);
  }
}

Block *BlockSplitCommand::new_block()
{
  return new_block_;
}

TrackSplitAtTimeCommand::TrackSplitAtTimeCommand(TrackOutput *track, rational point, QUndoCommand *parent) :
  QUndoCommand(parent)
{
  // Find Block that contains this time
  foreach (Block* b, track->Blocks()) {
    if (b->out() == point) {
      // This time is between blocks, no split needs to occur
      return;
    } else if (b->in() < point && b->out() > point) {
      // We found the Block, split it
      new BlockSplitCommand(track, b, point, this);
      return;
    }
  }
}

TrackReplaceBlockCommand::TrackReplaceBlockCommand(TrackOutput* track, Block *old, Block *replace, QUndoCommand *parent) :
  QUndoCommand(parent),
  track_(track),
  old_(old),
  replace_(replace)
{
}

void TrackReplaceBlockCommand::redo()
{
  track_->ReplaceBlock(old_, replace_);
}

void TrackReplaceBlockCommand::undo()
{
  track_->ReplaceBlock(replace_, old_);
}

TrackPrependBlockCommand::TrackPrependBlockCommand(TrackOutput *track, Block *block, QUndoCommand *parent) :
  QUndoCommand(parent),
  track_(track),
  block_(block)
{
}

void TrackPrependBlockCommand::redo()
{
  track_->PrependBlock(block_);
}

void TrackPrependBlockCommand::undo()
{
  track_->RippleRemoveBlock(block_);
}

BlockSplitPreservingLinksCommand::BlockSplitPreservingLinksCommand(const QVector<Block *> &blocks, const QList<rational> &times, QUndoCommand *parent) :
  QUndoCommand(parent),
  blocks_(blocks),
  times_(times)
{
  QVector< QVector<Block*> > split_blocks(times.size());

  for (int i=0;i<times.size();i++) {
    const rational& time = times.at(i);

    QVector<Block*> splits(blocks.size());

    for (int j=0;j<blocks.size();j++) {
      Block* b = blocks.at(j);

      if (b->in() < time && b->out() > time) {
        TrackOutput* track = TrackOutput::TrackFromBlock(b);

        Q_ASSERT(track);

        BlockSplitCommand* split_command = new BlockSplitCommand(track, b, time, this);
        splits.replace(j, split_command->new_block());
      } else {
        splits.replace(j, nullptr);
      }
    }

    split_blocks.replace(i, splits);
  }

  // Now that we've determined all the splits, we can relink everything
  for (int i=0;i<blocks_.size();i++) {
    Block* a = blocks.at(i);

    for (int j=0;j<blocks.size();j++) {
      if (i == j) {
        continue;
      }

      Block* b = blocks.at(j);

      if (Block::AreLinked(a, b)) {
        // These blocks are linked, ensure all the splits are linked too

        foreach (const QVector<Block*>& split_list, split_blocks) {
          Block::Link(split_list.at(i), split_list.at(j));
        }
      }
    }
  }
}