#ifndef TIMELINEWIDGET_H
#define TIMELINEWIDGET_H

#include <QScrollBar>
#include <QRubberBand>
#include <QWidget>

#include "timelineandtrackview.h"
#include "widget/slider/timeslider.h"
#include "widget/timelinewidget/timelinescaledobject.h"
#include "widget/timeruler/timeruler.h"

/**
 * @brief Full widget for working with TimelineOutput nodes
 *
 * Encapsulates TimelineViews, TimeRulers, and scrollbars for a complete widget to manipulate Timelines
 */
class TimelineWidget : public QWidget, public TimelineScaledObject
{
  Q_OBJECT
public:
  TimelineWidget(QWidget* parent = nullptr);

  void Clear();

  void SetTime(int64_t timestamp);

  void ConnectTimelineNode(TimelineOutput* node);

  void DisconnectTimelineNode();

  void ZoomIn();

  void ZoomOut();

  void SelectAll();

  void DeselectAll();

  void RippleToIn();

  void RippleToOut();

  void EditToIn();

  void EditToOut();

  void GoToPrevCut();

  void GoToNextCut();

  void SplitAtPlayhead();

  QList<TimelineViewBlockItem*> GetSelectedBlocks();

public slots:
  void SetTimebase(const rational& timebase);

protected:
  virtual void resizeEvent(QResizeEvent *event) override;

signals:
  void TimeChanged(const int64_t& time);

private:
  class Tool
  {
  public:
    Tool(TimelineWidget* parent);
    virtual ~Tool();

    virtual void MousePress(TimelineViewMouseEvent *){}
    virtual void MouseMove(TimelineViewMouseEvent *){}
    virtual void MouseRelease(TimelineViewMouseEvent *){}
    virtual void MouseDoubleClick(TimelineViewMouseEvent *){}

    virtual void DragEnter(TimelineViewMouseEvent *){}
    virtual void DragMove(TimelineViewMouseEvent *){}
    virtual void DragLeave(QDragLeaveEvent *){}
    virtual void DragDrop(TimelineViewMouseEvent *){}

    TimelineWidget* parent();

    static olive::timeline::MovementMode FlipTrimMode(const olive::timeline::MovementMode& trim_mode);

  protected:
    /**
     * @brief Retrieve the QGraphicsItem at a particular scene position
     *
     * Requires a float-based scene position. If you have a screen position, use GetScenePos() first to convert it to a
     * scene position
     */
    TimelineViewBlockItem* GetItemAtScenePos(const TimelineCoordinate &coord);

    /**
     * @brief Validates Ghosts that are moving horizontally (time-based)
     *
     * Validation is the process of ensuring that whatever movements the user is making are "valid" and "legal". This
     * function's validation ensures that no Ghost's in point ends up in a negative timecode.
     */
    rational ValidateFrameMovement(rational movement, const QVector<TimelineViewGhostItem*> ghosts);

    /**
     * @brief Validates Ghosts that are moving vertically (track-based)
     *
     * This function's validation ensures that no Ghost's track ends up in a negative (non-existent) track.
     */
    int ValidateTrackMovement(int movement, const QVector<TimelineViewGhostItem*> ghosts);

    enum SnapPoints {
      kSnapToClips = 0x1,
      kSnapToPlayhead = 0x2,
      kSnapAll = 0xFF
    };

    /**
     * @brief Snaps point `start_point` that is moving by `movement` to currently existing clips
     */
    bool SnapPoint(QList<rational> start_times, rational *movement, int snap_points = kSnapAll);

    QList<rational> snap_points_;

    bool dragging_;

    TimelineCoordinate drag_start_;

  private:
    TimelineWidget* parent_;

  };

  class PointerTool : public Tool
  {
  public:
    PointerTool(TimelineWidget* parent);

    virtual void MousePress(TimelineViewMouseEvent *event) override;
    virtual void MouseMove(TimelineViewMouseEvent *event) override;
    virtual void MouseRelease(TimelineViewMouseEvent *event) override;
  protected:
    void SetMovementAllowed(bool allowed);
    void SetTrackMovementAllowed(bool allowed);
    void SetTrimmingAllowed(bool allowed);
    virtual void MouseReleaseInternal(TimelineViewMouseEvent *event);
    virtual rational FrameValidateInternal(rational time_movement, const QVector<TimelineViewGhostItem *> &ghosts);

    virtual void InitiateGhosts(TimelineViewBlockItem* clicked_item,
                                olive::timeline::MovementMode trim_mode,
                                bool allow_gap_trimming);

    TimelineViewGhostItem* AddGhostFromBlock(Block *block, const TrackReference& track, olive::timeline::MovementMode mode);

    TimelineViewGhostItem* AddGhostFromNull(const rational& in, const rational& out, const TrackReference& track, olive::timeline::MovementMode mode);

    /**
     * @brief Validates Ghosts that are getting their in points trimmed
     *
     * Assumes ghost->data() is a Block. Ensures no Ghost's in point becomes a negative timecode. Also ensures no
     * Ghost's length becomes 0 or negative.
     */
    rational ValidateInTrimming(rational movement, const QVector<TimelineViewGhostItem*> ghosts, bool prevent_overwriting);

    /**
     * @brief Validates Ghosts that are getting their out points trimmed
     *
     * Assumes ghost->data() is a Block. Ensures no Ghost's in point becomes a negative timecode. Also ensures no
     * Ghost's length becomes 0 or negative.
     */
    rational ValidateOutTrimming(rational movement, const QVector<TimelineViewGhostItem*> ghosts, bool prevent_overwriting);

    virtual void ProcessDrag(const TimelineCoordinate &mouse_pos);

  private:
    void InitiateDrag(const TimelineCoordinate &mouse_pos);

    void AddGhostInternal(TimelineViewGhostItem* ghost, olive::timeline::MovementMode mode);

    bool IsClipTrimmable(TimelineViewBlockItem* clip,
                         const QList<TimelineViewBlockItem*>& items,
                         const olive::timeline::MovementMode& mode);

    TrackReference track_start_;
    bool movement_allowed_;
    bool trimming_allowed_;
    bool track_movement_allowed_;
    bool rubberband_selecting_;

    TrackType drag_track_type_;
  };

  class ImportTool : public Tool
  {
  public:
    ImportTool(TimelineWidget* parent);

    virtual void DragEnter(TimelineViewMouseEvent *event) override;
    virtual void DragMove(TimelineViewMouseEvent *event) override;
    virtual void DragLeave(QDragLeaveEvent *event) override;
    virtual void DragDrop(TimelineViewMouseEvent *event) override;
  private:
    int import_pre_buffer_;
  };

  class RazorTool : public Tool
  {
  public:
    RazorTool(TimelineWidget* parent);

    virtual void MousePress(TimelineViewMouseEvent *event) override;
    virtual void MouseMove(TimelineViewMouseEvent *event) override;
    virtual void MouseRelease(TimelineViewMouseEvent *event) override;

  private:
    QVector<TrackReference> split_tracks_;
  };

  class RippleTool : public PointerTool
  {
  public:
    RippleTool(TimelineWidget* parent);
  protected:
    virtual void MouseReleaseInternal(TimelineViewMouseEvent *event) override;
    virtual rational FrameValidateInternal(rational time_movement, const QVector<TimelineViewGhostItem*>& ghosts) override;

    virtual void InitiateGhosts(TimelineViewBlockItem* clicked_item,
                                olive::timeline::MovementMode trim_mode,
                                bool allow_gap_trimming) override;
  };

  class RollingTool : public PointerTool
  {
  public:
    RollingTool(TimelineWidget* parent);

  protected:
    virtual void MouseReleaseInternal(TimelineViewMouseEvent *event) override;
    virtual rational FrameValidateInternal(rational time_movement, const QVector<TimelineViewGhostItem*>& ghosts) override;

    virtual void InitiateGhosts(TimelineViewBlockItem* clicked_item,
                                olive::timeline::MovementMode trim_mode,
                                bool allow_gap_trimming) override;
  };

  class SlideTool : public PointerTool
  {
  public:
    SlideTool(TimelineWidget* parent);

  protected:
    virtual void MouseReleaseInternal(TimelineViewMouseEvent *event) override;
    virtual rational FrameValidateInternal(rational time_movement, const QVector<TimelineViewGhostItem*>& ghosts) override;
    virtual void InitiateGhosts(TimelineViewBlockItem* clicked_item,
                                olive::timeline::MovementMode trim_mode,
                                bool allow_gap_trimming) override;
  };

  class SlipTool : public PointerTool
  {
  public:
    SlipTool(TimelineWidget* parent);

  protected:
    virtual void ProcessDrag(const TimelineCoordinate &mouse_pos) override;
    virtual void MouseReleaseInternal(TimelineViewMouseEvent *event) override;
  };

  class HandTool : public Tool
  {
  public:
    HandTool(TimelineWidget* parent);

    virtual void MousePress(TimelineViewMouseEvent *event) override;
    virtual void MouseMove(TimelineViewMouseEvent *event) override;
    virtual void MouseRelease(TimelineViewMouseEvent *event) override;
  private:
    QPoint screen_drag_start_;
    QPoint scrollbar_start_;
  };

  class ZoomTool : public Tool
  {
  public:
    ZoomTool(TimelineWidget* parent);

    virtual void MousePress(TimelineViewMouseEvent *event) override;
    virtual void MouseMove(TimelineViewMouseEvent *event) override;
    virtual void MouseRelease(TimelineViewMouseEvent *event) override;
  };

  class AddTool : public Tool
  {
  public:
    AddTool(TimelineWidget* parent);

    virtual void MousePress(TimelineViewMouseEvent *event) override;
    virtual void MouseMove(TimelineViewMouseEvent *event) override;
    virtual void MouseRelease(TimelineViewMouseEvent *event) override;

  protected:
    void MouseMoveInternal(const rational& cursor_frame, bool outwards);

    TimelineViewGhostItem* ghost_;

    rational drag_start_point_;
  };

  class TransitionTool : public AddTool
  {
  public:
    TransitionTool(TimelineWidget* parent);

    virtual void MousePress(TimelineViewMouseEvent *event) override;
    virtual void MouseMove(TimelineViewMouseEvent *event) override;
    virtual void MouseRelease(TimelineViewMouseEvent *event) override;
  protected:
  private:
    bool dual_transition_;
  };

  void SetBlockLinksSelected(Block *block, bool selected);

  QPoint drag_origin_;

  void StartRubberBandSelect(bool select_links);
  void MoveRubberBandSelect(bool select_links);
  void EndRubberBandSelect(bool select_links);
  QRubberBand rubberband_;
  QList<QGraphicsItem*> rubberband_now_selected_;

  void StartHandDrag();
  void MoveHandDrag();
  void EndHandDrag();
  TimelineView* hand_drag_view_;
  QPoint hand_drag_view_origin_;

  Tool* GetActiveTool();

  QVector< std::shared_ptr<Tool> > tools_;

  std::shared_ptr<ImportTool> import_tool_;

  Tool* active_tool_;

  void ClearGhosts();

  bool HasGhosts();

  QVector<TimelineViewGhostItem*> ghost_items_;

  QMap<Block*, TimelineViewBlockItem*> block_items_;

  void RippleEditTo(olive::timeline::MovementMode mode, bool insert_gaps);

  void SetTimeAndSignal(const int64_t& t);

  TrackOutput* GetTrackFromReference(const TrackReference& ref);

  QList<TimelineAndTrackView*> views_;

  TimeRuler* ruler_;

  TimelineOutput* timeline_node_;

  int64_t playhead_;

  QScrollBar* horizontal_scroll_;

  TimeSlider* timecode_label_;

  int GetTrackY(const TrackReference& ref);
  int GetTrackHeight(const TrackReference& ref);

  void CenterOn(qreal scene_pos);

  void AddGhost(TimelineViewGhostItem* ghost);

private slots:
  void SetScale(double scale);

  void UpdateInternalTime(const int64_t& timestamp);

  void UpdateTimelineLength(const rational& length);

  void ViewMousePressed(TimelineViewMouseEvent* event);
  void ViewMouseMoved(TimelineViewMouseEvent* event);
  void ViewMouseReleased(TimelineViewMouseEvent* event);
  void ViewMouseDoubleClicked(TimelineViewMouseEvent* event);

  void ViewDragEntered(TimelineViewMouseEvent* event);
  void ViewDragMoved(TimelineViewMouseEvent* event);
  void ViewDragLeft(QDragLeaveEvent* event);
  void ViewDragDropped(TimelineViewMouseEvent* event);

  void AddBlock(Block* block, TrackReference track);
  void RemoveBlock(Block* block);

  void AddTrack(TrackOutput* track, TrackType type);
  void RemoveTrack(TrackOutput* track);

  /**
   * @brief Slot for when a Block node changes its parameters and the graphics need to update
   *
   * This slot does a static_cast on sender() to Block*, meaning all objects triggering this slot must be Blocks or
   * derivatives.
   */
  void BlockChanged();

  void UpdateHorizontalSplitters();

  void UpdateTimecodeWidthFromSplitters(QSplitter *s);

  void TrackHeightChanged(TrackType type, int index, int height);

};

#endif // TIMELINEWIDGET_H