/*
  timeline-state.hpp  -  Declaration of the timeline state object

  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 widgets/timeline/timeline-state.hpp
 ** This file contains the definition of the timeline state object
 */

#ifndef TIMELINE_STATE_HPP
#define TIMELINE_STATE_HPP

#include "gui/widgets/timeline/timeline-view-window.hpp"
#include "lib/time/mutation.hpp"

#include <boost/shared_ptr.hpp>  /////////////////////////TICKET #796

namespace gui {
  
namespace model {
class Sequence;
}  
  
namespace widgets { 
namespace timeline {
  
using lib::time::Mutation;

/**
 * TimelineState is a container for the state data for TimelineWidget.
 * @remarks TimelineState s can be swapped out so that TimelineWidget
 * can flip between different views.
 */
class TimelineState
{
public:

  /**
   * Constructor
   * @param source_sequence The sequence on which the TimelineWidget
   * will operate when this TimelineState is attached.
   */
  TimelineState(boost::shared_ptr<model::Sequence> source_sequence);
  
public:

  /**
   * Gets the sequence that is attached to this timeline state object.
   * @return Returns a shared_ptr to the sequence object.
   */
  boost::shared_ptr<model::Sequence> get_sequence() const;

  /**
   * Gets a reference to the timeline view window object.
   * @return Returns the timeline view window object.
   */
  timeline::TimelineViewWindow& get_view_window();
  
  
  Time getSelectionStart()      const { return selection_.start();}
  Time getSelectionEnd()        const { return selection_.end();  }
  Time getPlaybackPeriodStart() const { return selection_.start();}
  Time getPlaybackPeriodEnd()   const { return selection_.end();  }
  
  Time getPlaybackPoint()       const { return playbackPoint_; }
  
  /** is there currently any ongoing playback process?
   *  Otherwise the #getPlaybackPoint is meaningless */
  bool isPlaying() const { return isPlayback_; }
  
  
  /**
   * Sets the period of the selection.
   * @param resetPlaybackPeriod Specifies whether to set the
   *        playback period to the same as this new selection.
   */
  void setSelection(Mutation const& change,
                    bool resetPlaybackPeriod = true);
  
  void setPlaybackPeriod(Mutation const& change);
  
  /**
   * Sets the time which is currently being played back.
   * @param point The time index being played.
   * @todo do we ever get the situation that we don't have such a position?
   * @todo very likely to be handled differently, once
   *       the GUI is really connected to the Player
   */
  void setPlaybackPoint(Time newPos);
  
  /**
   * A signal to notify when the selected period has changed.
   */
  sigc::signal<void> selection_changed_signal() const; 
  
  /**
   * A signal to notify when the playback point or playback periods have
   * changed.
   */
  sigc::signal<void> playback_changed_signal() const; 
  
private:

  /**
   * A pointer to the sequence object which this timeline_widget will represent.
   * @remarks This pointer is set by the constructor and is constant, so
   * will not change in value during the lifetime of the class.
   */
  boost::shared_ptr<model::Sequence> sequence;
  
  // View State
  /**
   * The ViewWindow for the TimelineWidget display with.
   */
  timeline::TimelineViewWindow viewWindow;
  
  // Selection State
  
  /** currently selected time period. */
  TimeSpan selection_;
  
  /** current playback period. */
  TimeSpan playbackPeriod_;
  
  /** current playback position.
   * @todo very likely to be handled differently
   *       when actually integrated with the Player
   */
  TimeVar playbackPoint_;
  
  bool isPlayback_;
  
  
  // Signals
  
  /**
   * A signal to notify when the selected period has changed.
   */
  sigc::signal<void> selectionChangedSignal;
  
  /**
   * A signal to notify when the playback point or playback periods have
   * changed.
   */
  sigc::signal<void> playbackChangedSignal;
};

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

#endif // TIMELINE_STATE_HPP