/**********************************************************************

Audacity: A Digital Audio Editor

TrackPanelCell.h

Paul Licameli

**********************************************************************/

#ifndef __AUDACITY_TRACK_PANEL_CELL__
#define __AUDACITY_TRACK_PANEL_CELL__

#include "Audacity.h"

#include "MemoryX.h"
#include "TrackPanelDrawable.h" // to inherit

class AudacityProject;
struct HitTestPreview;
struct TrackPanelDrawingContext;
struct TrackPanelMouseEvent;
struct TrackPanelMouseState;
class ViewInfo;
class wxKeyEvent;
class wxPoint;
class wxRect;
class wxWindow;

class UIHandle;
using UIHandlePtr = std::shared_ptr<UIHandle>;

#include <vector>

/// \brief The TrackPanel is built up of nodes, subtrees of the CellularPanel's area
/// Common base class for TrackPanelCell (leaf) and TrackPanelGroup (nonleaf)
class AUDACITY_DLL_API /* not final */ TrackPanelNode
   : public TrackPanelDrawable
{
public:
   TrackPanelNode();
   virtual ~TrackPanelNode() = 0;
};

// A node of the TrackPanel that contains other nodes.
class AUDACITY_DLL_API TrackPanelGroup /* not final */ : public TrackPanelNode
{
public:
   TrackPanelGroup();
   virtual ~TrackPanelGroup();

   enum class Axis { X, Y };

   // A refinement of a given rectangle partitions it along one of its axes
   // and associates TrackPanelNodes with the partition.
   // The sequence of coordinates should be increasing, giving left or top
   // coordinates of sub-rectangles.
   // Null pointers are permitted to define empty spaces with no cell object.
   // If the first coordinate is right of or below the rectangle boundary,
   // then that also defines an empty space at the edge.
   // Sub-rectangles may be defined partly or wholly out of the bounds of the
   // given rectangle.  Such portions are ignored.
   using Child = std::pair< wxCoord, std::shared_ptr<TrackPanelNode> >;
   using Refinement = std::vector< Child >;
   using Subdivision = std::pair< Axis, Refinement >;

   // Report a subdivision of one of the axes of the given rectangle
   virtual Subdivision Children( const wxRect &rect ) = 0;
};

/// Abstract base class defining TrackPanel's access to specialist classes that
/// implement drawing and user interactions
class AUDACITY_DLL_API TrackPanelCell /* not final */ : public TrackPanelNode
{
public:
   TrackPanelCell() = default;
   TrackPanelCell( const TrackPanelCell & ) PROHIBITED;
   TrackPanelCell &operator=( const TrackPanelCell & ) PROHIBITED;

   virtual ~TrackPanelCell () = 0;

   // May supply default cursor, status message, and tooltip, when there is no
   // handle to hit at the mouse position, or the handle does not supply them.
   virtual HitTestPreview DefaultPreview
      (const TrackPanelMouseState &state, const AudacityProject *pProject);

   // Return pointers to objects that can be queried for a status
   // bar message and cursor appropriate to the point, and that dispatch
   // mouse button events.
   // The button-down state passed to the function is as it will be at click
   // time -- not necessarily as it is now.
   virtual std::vector<UIHandlePtr> HitTest
      (const TrackPanelMouseState &state,
       const AudacityProject *pProject) = 0;

   // Return value is a bitwise OR of RefreshCode values
   // Include Cancelled in the flags to indicate that the event is not handled.
   // Default does only that.
   virtual unsigned HandleWheelRotation
      (const TrackPanelMouseEvent &event,
       AudacityProject *pProject);

   // A cell may delegate context menu handling to another one
   virtual std::shared_ptr<TrackPanelCell> ContextMenuDelegate()
      { return {}; }

   // The pPosition parameter indicates mouse position but may be NULL
   // Return value is a bitwise OR of RefreshCode values
   // Default implementation does nothing
   virtual unsigned DoContextMenu
      (const wxRect &rect,
       wxWindow *pParent, wxPoint *pPosition, AudacityProject *pProject);

   // Return value is a bitwise OR of RefreshCode values
   // Default skips the event and does nothing
   virtual unsigned CaptureKey
      (wxKeyEvent &event, ViewInfo &viewInfo, wxWindow *pParent,
       AudacityProject *project);

   // Return value is a bitwise OR of RefreshCode values
   // Default skips the event and does nothing
   virtual unsigned KeyDown
      (wxKeyEvent & event, ViewInfo &viewInfo, wxWindow *pParent,
       AudacityProject *project);

   // Return value is a bitwise OR of RefreshCode values
   // Default skips the event and does nothing
   virtual unsigned KeyUp
      (wxKeyEvent & event, ViewInfo &viewInfo, wxWindow *pParent,
       AudacityProject *project);

   // Return value is a bitwise OR of RefreshCode values
   // Default skips the event and does nothing
   virtual unsigned Char
      (wxKeyEvent & event, ViewInfo &viewInfo, wxWindow *pParent,
       AudacityProject *project);
};

#endif
