/*
  timeline-ibeam-tool.hpp  -  Declaration of the ArrowTool class
 
  Copyright (C)         Lumiera.org
    2008,               Joel Holdsworth <joel@airwebreathe.org.uk>
 
  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 2 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, write to the Free Software
  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 
*/
/** @file timeline-ibeam-tool.hpp
 ** This file contains the definition of ibeam tool class
 ** tool objects
 */

#ifndef TIMELINE_IBEAM_TOOL_HPP
#define TIMELINE_IBEAM_TOOL_HPP

#include <gtkmm.h>
#include "timeline-tool.hpp"

namespace gui {
namespace widgets {
namespace timeline {

/**
 * A helper class to implement the timeline i-beam tool
 */
class IBeamTool : public Tool
{
public:
  /**
   * Constructor
   * @param timeline_body The owner timeline body object
   */
  IBeamTool(TimelineBody *timeline_body);
  
  /**
   * Gets the type of tool represented by this class
   */
  ToolType get_type() const;
  
protected:

  /**
   * Destructor
   */
  ~IBeamTool();

  /**
   * Gets the cursor to display for this tool at this moment.
   */
  Gdk::Cursor get_cursor() const;
  
protected:
  /**
   * The event handler for button press events.
   */
  void on_button_press_event(GdkEventButton* event);
  
  /**
   * The event handler for button release events.
   */
  void on_button_release_event(GdkEventButton* event);
  
  /**
   * The event handler for mouse move events.
   */
  void on_motion_notify_event(GdkEventMotion *event);
  
private:
  /* ===== Internal Event Handlers ===== */

  /**
   * An internal event handler, which is called when the scroll slide
   * timer calls it.
   */
  bool on_scroll_slide_timer();
  
private:
  /* ===== Internal Methods ===== */

  /**
   * As the user drags, this function is called to update the position
   * of the moving end of the selection.
   */
  void set_leading_x(const int x);
  
  /**
   * Begins, or continues a scroll slide at a given rate
   * @param scroll_slide_rate The distance to slide every timer event
   * in units of 1/256th of the view width.
   */
  void begin_scroll_slide(int scroll_slide_rate);
  
  /**
   * Ends a scroll slide, and disconnects the slide timer
   */
  void end_scroll_slide();
  
  /**
   * Determines if the cursor is hovering over the start of the
   * selection.
   */
  bool is_mouse_in_start_drag_zone() const;

  /**
   * Determines if the cursor is hovering over the end of the
   * selection.
   */
  bool is_mouse_in_end_drag_zone() const;
  
private:
  /* ==== Enums ===== */
  
  /**
   * An enum used to represent the type of drag currently take place.
   */
  enum DragType
    {
      /**
       * No drag is occuring
       */
      None,
      
      /**
       * A selection drag is occuring.
       * @remarks The position of one end of the selection was set at
       * mouse-down of the drag, and the other end is set by
       * drag-release.
       */
      Selection,
      
      /**
       * The start of the selection is being dragged.
       */
      GrabStart,
      
      /**
       * The end of the selection is being dragged.
       */
      GrabEnd
    };

  /* ==== Internals ===== */
  /**
   * Specifies the type of drag currently taking place.
   */
  DragType dragType;
  
  /**
   * During a selection drag, one end of the selection is moving with
   * the mouse, the other is pinned. pinnedDragTime specifies the time
   * of that point.
   */
  gavl_time_t pinnedDragTime;
  
  /**
   * This connection is used to represent the timer which causes scroll
   * sliding to occur.
   * @remarks Scroll sliding is an animated scroll which occurs when
   * the user drags a selection outside the area of the timeline body.
   */
  sigc::connection scrollSlideEvent;
  
  /**
   * Specifies the rate at which scroll sliding is currently taking
   * place.
   */
  int scrollSlideRate;
  
  /* ===== Constants ===== */
  /**
   * DragZoneSize defines the width of the zone near to the end of the
   * selection in which dragging will cause the selection to resize.
   * @remarks The selection marque can be resized by dragging the ends
   * of it. Special cursors are shown when the mouse is in this region.
   */
  static const int DragZoneWidth;
  
  /**
   * The amount to divide the mouse overshoot by to produce the slide
   * scroll rate.
   * @remarks Smaller values cause faster scrolling.
   */
  static const int ScrollSlideRateDivisor;
  
  /**
   * The interval between scroll slide events in ms.
   */
  static const int ScrollSlideEventInterval;
};

}   // namespace timeline
}   // namespace widgets
}   // namespace gui

#endif // TIMELINE_IBEAM_TOOL_HPP