/***

  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 "timelineview.h"

#include <QDebug>
#include <QMimeData>
#include <QMouseEvent>
#include <QScrollBar>
#include <QtMath>
#include <QPen>

#include "common/timecodefunctions.h"
#include "core.h"
#include "node/input/media/media.h"
#include "project/item/footage/footage.h"
#include "tool/tool.h"

TimelineView::TimelineView(QWidget *parent) :
  QGraphicsView(parent),
  pointer_tool_(this),
  import_tool_(this),
  ripple_tool_(this),
  rolling_tool_(this),
  razor_tool_(this),
  slide_tool_(this),
  slip_tool_(this),
  hand_tool_(this),
  zoom_tool_(this),
  timeline_node_(nullptr),
  playhead_(0)
{
  setScene(&scene_);
  setAlignment(Qt::AlignLeft | Qt::AlignTop);
  setDragMode(RubberBandDrag);
  setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOn);
  setBackgroundRole(QPalette::Window);

  connect(&scene_, SIGNAL(changed(const QList<QRectF>&)), this, SLOT(UpdateSceneRect()));

  // Create playhead line
  playhead_line_ = new TimelineViewPlayheadItem();

  scene_.addItem(playhead_line_);

  // Set default scale
  SetScale(1.0);
}

void TimelineView::AddBlock(Block *block, int track)
{
  switch (block->type()) {
  case Block::kClip:
  case Block::kGap:
  {
    TimelineViewBlockItem* item = new TimelineViewBlockItem();

    // Set up clip with view parameters (clip item will automatically size its rect accordingly)
    item->SetBlock(block);
    item->SetY(GetTrackY(track));
    item->SetHeight(GetTrackHeight(track));
    item->SetScale(scale_);
    item->SetTrack(track);

    // Add to list of clip items that can be iterated through
    block_items_.insert(block, item);

    // Add item to graphics scene
    scene_.addItem(item);

    connect(block, SIGNAL(Refreshed()), this, SLOT(BlockChanged()));
    break;
  }
  case Block::kEnd:
    // Do nothing
    break;
  }


}

void TimelineView::RemoveBlock(Block *block)
{
  delete block_items_[block];

  block_items_.remove(block);
}

void TimelineView::AddTrack(TrackOutput *track)
{
  foreach (Block* b, track->Blocks()) {
    AddBlock(b, track->Index());
  }
}

void TimelineView::RemoveTrack(TrackOutput *track)
{
  foreach (Block* b, track->Blocks()) {
    RemoveBlock(b);
  }
}

void TimelineView::SetScale(const double &scale)
{
  scale_ = scale;

  QMapIterator<Block*, TimelineViewRect*> iterator(block_items_);

  while (iterator.hasNext()) {
    iterator.next();

    if (iterator.value() != nullptr) {
      iterator.value()->SetScale(scale_);
    }
  }

  foreach (TimelineViewGhostItem* ghost, ghost_items_) {
    ghost->SetScale(scale_);
  }

  playhead_line_->SetScale(scale_);
}

void TimelineView::SetTimebase(const rational &timebase)
{
  timebase_ = timebase;
  timebase_dbl_ = timebase_.toDouble();

  playhead_line_->SetTimebase(timebase_);
}

void TimelineView::Clear()
{
  QMapIterator<Block*, TimelineViewRect*> iterator(block_items_);

  while (iterator.hasNext()) {
    iterator.next();

    if (iterator.value() != nullptr) {
      delete iterator.value();
    }
  }

  block_items_.clear();
}

void TimelineView::ConnectTimelineNode(TimelineOutput *node)
{
  if (timeline_node_ != nullptr) {
    disconnect(timeline_node_, SIGNAL(TimebaseChanged(const rational&)), this, SIGNAL(TimebaseChanged(const rational&)));
    disconnect(timeline_node_, SIGNAL(TimebaseChanged(const rational&)), this, SLOT(SetTimebase(const rational&)));
    disconnect(timeline_node_, SIGNAL(TimelineCleared()), this, SLOT(Clear()));
    disconnect(timeline_node_, SIGNAL(BlockAdded(Block*, int)), this, SLOT(AddBlock(Block*, int)));
    disconnect(timeline_node_, SIGNAL(BlockRemoved(Block*)), this, SLOT(RemoveBlock(Block*)));
    disconnect(timeline_node_, SIGNAL(TrackAdded(TrackOutput*)), this, SLOT(AddTrack(TrackOutput*)));
    disconnect(timeline_node_, SIGNAL(TrackRemoved(TrackOutput*)), this, SLOT(RemoveTrack(TrackOutput*)));

    Clear();
  }

  timeline_node_ = node;

  if (timeline_node_ != nullptr) {
    SetTimebase(timeline_node_->Timebase());
    emit TimebaseChanged(timebase_);

    connect(timeline_node_, SIGNAL(TimebaseChanged(const rational&)), this, SIGNAL(TimebaseChanged(const rational&)));
    connect(timeline_node_, SIGNAL(TimebaseChanged(const rational&)), this, SLOT(SetTimebase(const rational&)));
    connect(timeline_node_, SIGNAL(TimelineCleared()), this, SLOT(Clear()));
    connect(timeline_node_, SIGNAL(BlockAdded(Block*, int)), this, SLOT(AddBlock(Block*, int)));
    connect(timeline_node_, SIGNAL(BlockRemoved(Block*)), this, SLOT(RemoveBlock(Block*)));
    connect(timeline_node_, SIGNAL(TrackAdded(TrackOutput*)), this, SLOT(AddTrack(TrackOutput*)));
    connect(timeline_node_, SIGNAL(TrackRemoved(TrackOutput*)), this, SLOT(RemoveTrack(TrackOutput*)));

    foreach (TrackOutput* track, timeline_node_->Tracks()) {
      // Defer to the track to make all the block UI items necessary
      AddTrack(track);
    }
  }
}

void TimelineView::DisconnectTimelineNode()
{
  ConnectTimelineNode(nullptr);
}

void TimelineView::SelectAll()
{
  QList<QGraphicsItem*> all_items = items();

  foreach (QGraphicsItem* i, all_items) {
    i->setSelected(true);
  }
}

void TimelineView::DeselectAll()
{
  QList<QGraphicsItem*> all_items = items();

  foreach (QGraphicsItem* i, all_items) {
    i->setSelected(false);
  }
}

void TimelineView::RippleToIn()
{
  RippleEditTo(olive::timeline::kTrimIn, false);
}

void TimelineView::RippleToOut()
{
  RippleEditTo(olive::timeline::kTrimOut, false);
}

void TimelineView::EditToIn()
{
  RippleEditTo(olive::timeline::kTrimIn, true);
}

void TimelineView::EditToOut()
{
  RippleEditTo(olive::timeline::kTrimOut, true);
}

void TimelineView::GoToPrevCut()
{
  if (timeline_node_ == nullptr) {
    return;
  }

  if (playhead_ == 0) {
    return;
  }

  int64_t closest_cut = 0;

  foreach (TrackOutput* track, timeline_node_->Tracks()) {
    int64_t this_track_closest_cut = 0;

    foreach (Block* block, track->Blocks()) {
      int64_t block_out_ts = olive::time_to_timestamp(block->out(), timebase_);

      if (block_out_ts < playhead_) {
        this_track_closest_cut = block_out_ts;
      } else {
        break;
      }
    }

    closest_cut = qMax(closest_cut, this_track_closest_cut);
  }

  UserSetTime(closest_cut);
}

void TimelineView::GoToNextCut()
{
  if (timeline_node_ == nullptr) {
    return;
  }

  int64_t closest_cut = INT64_MAX;

  foreach (TrackOutput* track, timeline_node_->Tracks()) {
    int64_t this_track_closest_cut = olive::time_to_timestamp(track->in(), timebase_);

    if (this_track_closest_cut <= playhead_) {
      this_track_closest_cut = INT64_MAX;
    }

    foreach (Block* block, track->Blocks()) {
      int64_t block_in_ts = olive::time_to_timestamp(block->in(), timebase_);

      if (block_in_ts > playhead_) {
        this_track_closest_cut = block_in_ts;
        break;
      }
    }

    closest_cut = qMin(closest_cut, this_track_closest_cut);
  }

  if (closest_cut < INT64_MAX) {
    UserSetTime(closest_cut);
  }
}

void TimelineView::SetTime(const int64_t time)
{
  playhead_ = time;

  playhead_line_->SetPlayhead(playhead_);
}

void TimelineView::mousePressEvent(QMouseEvent *event)
{
  active_tool_ = GetActiveTool();

  if (timeline_node_ != nullptr && active_tool_ != nullptr) {
    active_tool_->MousePress(event);
  }
}

void TimelineView::mouseMoveEvent(QMouseEvent *event)
{
  if (timeline_node_ != nullptr && active_tool_ != nullptr) {
    active_tool_->MouseMove(event);
  }
}

void TimelineView::mouseReleaseEvent(QMouseEvent *event)
{
  if (timeline_node_ != nullptr && active_tool_ != nullptr) {
    active_tool_->MouseRelease(event);
  }
}

void TimelineView::dragEnterEvent(QDragEnterEvent *event)
{
  if (timeline_node_ != nullptr) {
    import_tool_.DragEnter(event);
  }
}

void TimelineView::dragMoveEvent(QDragMoveEvent *event)
{
  if (timeline_node_ != nullptr) {
    import_tool_.DragMove(event);
  }
}

void TimelineView::dragLeaveEvent(QDragLeaveEvent *event)
{
  if (timeline_node_ != nullptr) {
    import_tool_.DragLeave(event);
  }
}

void TimelineView::dropEvent(QDropEvent *event)
{
  if (timeline_node_ != nullptr) {
    import_tool_.DragDrop(event);
  }
}

void TimelineView::resizeEvent(QResizeEvent *event)
{
  QGraphicsView::resizeEvent(event);

  UpdateSceneRect();
}

TimelineView::Tool *TimelineView::GetActiveTool()
{
  switch (olive::core.tool()) {
  case olive::tool::kNone:
    return nullptr;
  case olive::tool::kPointer:
    return &pointer_tool_;
  case olive::tool::kEdit:
    return nullptr; // FIXME: Implement
  case olive::tool::kRipple:
    return &ripple_tool_;
  case olive::tool::kRolling:
    return &rolling_tool_;
  case olive::tool::kRazor:
    return &razor_tool_;
  case olive::tool::kSlip:
    return &slip_tool_;
  case olive::tool::kSlide:
    return &slide_tool_;
  case olive::tool::kHand:
    return &hand_tool_;
  case olive::tool::kZoom:
    return &zoom_tool_;
  case olive::tool::kTransition:
    return nullptr; // FIXME: Implement
  case olive::tool::kRecord:
    return nullptr; // FIXME: Implement
  case olive::tool::kAdd:
    return nullptr; // FIXME: Implement
  }

  return nullptr;
}

int TimelineView::GetTrackY(int track_index)
{
  int y = 0;

  for (int i=0;i<track_index;i++) {
    y += GetTrackHeight(i);
  }

  return y;
}

int TimelineView::GetTrackHeight(int track_index)
{
  // FIXME: Make this adjustable
  Q_UNUSED(track_index)

  return fontMetrics().height() * 3;
}

void TimelineView::AddGhost(TimelineViewGhostItem *ghost)
{
  ghost->SetScale(scale_);
  ghost_items_.append(ghost);
  scene_.addItem(ghost);
}

bool TimelineView::HasGhosts()
{
  return !ghost_items_.isEmpty();
}

rational TimelineView::SceneToTime(const double &x)
{
  // Adjust screen point by scale and timebase
  int scaled_x_mvmt = qRound(x / scale_ / timebase_dbl_);

  // Return a time in the timebase
  return rational(scaled_x_mvmt * timebase_.numerator(), timebase_.denominator());
}

int TimelineView::SceneToTrack(const double &y)
{
  int track = -1;
  int heights = 0;

  do {
    track++;
    heights += GetTrackHeight(track);
  } while (y > heights);

  return track;
}

void TimelineView::ClearGhosts()
{
  if (!ghost_items_.isEmpty()) {
    foreach (TimelineViewGhostItem* ghost, ghost_items_) {
      delete ghost;
    }

    ghost_items_.clear();
  }
}

void TimelineView::RippleEditTo(olive::timeline::MovementMode mode, bool insert_gaps)
{
  rational playhead_time = olive::timestamp_to_time(playhead_, timebase_);

  rational closest_point_to_playhead;
  if (mode == olive::timeline::kTrimIn) {
    closest_point_to_playhead = 0;
  } else {
    closest_point_to_playhead = RATIONAL_MAX;
  }

  foreach (TrackOutput* track, timeline_node_->Tracks()) {
    Block* b = track->NearestBlockBefore(playhead_time);

    if (b != nullptr) {
      if (mode == olive::timeline::kTrimIn) {
        closest_point_to_playhead = qMax(b->in(), closest_point_to_playhead);
      } else {
        closest_point_to_playhead = qMin(b->out(), closest_point_to_playhead);
      }
    }
  }

  QUndoCommand* command = new QUndoCommand();

  if (closest_point_to_playhead == playhead_time) {
    // Remove one frame only
    if (mode == olive::timeline::kTrimIn) {
      playhead_time += timebase_;
    } else {
      playhead_time -= timebase_;
    }
  }

  rational in_ripple = qMin(closest_point_to_playhead, playhead_time);
  rational out_ripple = qMax(closest_point_to_playhead, playhead_time);
  rational ripple_length = out_ripple - in_ripple;

  foreach (TrackOutput* track, timeline_node_->Tracks()) {
    TrackRippleRemoveAreaCommand* ripple_command = new TrackRippleRemoveAreaCommand(track,
                                                                                    in_ripple,
                                                                                    out_ripple,
                                                                                    command);

    if (insert_gaps) {
      GapBlock* gap = new GapBlock();
      gap->set_length(ripple_length);
      ripple_command->SetInsert(gap);
    }
  }

  olive::undo_stack.pushIfHasChildren(command);

  if (mode == olive::timeline::kTrimIn && !insert_gaps) {
    int64_t new_time = olive::time_to_timestamp(closest_point_to_playhead, timebase_);
    UserSetTime(new_time);
  }
}

void TimelineView::UserSetTime(const int64_t &time)
{
  SetTime(time);
  emit TimeChanged(time);
}

void TimelineView::BlockChanged()
{
  TimelineViewRect* rect = block_items_[static_cast<Block*>(sender())];

  if (rect != nullptr) {
    rect->UpdateRect();
  }
}

void TimelineView::UpdateSceneRect()
{
  QRectF bounding_rect = scene_.itemsBoundingRect();

  // Ensure the scene left and top are always 0
  bounding_rect.setTopLeft(QPointF(0, 0));

  // Ensure the scene height is always AT LEAST the height of the view
  // The scrollbar appears to have a 1px margin on the top and bottom, hence the -2
  int minimum_height = height() - horizontalScrollBar()->height() - 2;
  if (bounding_rect.height() < minimum_height) {
    bounding_rect.setHeight(minimum_height);
  }

  // Ensure playhead is the correct height
  playhead_line_->UpdateRect();

  // If the scene is already this rect, do nothing
  if (scene_.sceneRect() == bounding_rect) {
    return;
  }

  scene_.setSceneRect(bounding_rect);
}