cmd-context.hpp

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/*
  CMD-CONTEXT.hpp  -  interface to access command context binding services within the UI

  Copyright (C)         Lumiera.org
    2017,               Hermann Vosseler <Ichthyostega@web.de>

  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.

*/


#ifndef STAGE_INTERACT_CMD_CONTEXT_H
#define STAGE_INTERACT_CMD_CONTEXT_H


#include "lib/error.hpp"
#include "lib/nocopy.hpp"
//#include "stage/ctrl/bus-term.hpp"
//#include "lib/idi/entry-id.hpp"
#include "lib/hash-indexed.hpp"
#include "lib/opaque-holder.hpp"
#include "lib/symbol.hpp"
#include "lib/nocopy.hpp"
//#include "lib/util.hpp"

//#include <string>
#include <utility>

namespace Gtk {
  class Widget;
}
namespace stage {
namespace interact {
  
//  using lib::HashVal;
  using lib::hash::LuidH;
  using lib::Symbol;
//  using util::isnil;
//  using std::string;
  
  class InteractionState;
  
  
  
  class GestureObserver
    : public util::MoveAssign
    {
      Symbol cmdID_;
      
    public:
      virtual ~GestureObserver();  
      
      GestureObserver (Symbol cmdID) : cmdID_(cmdID)         { }
      
      GestureObserver (GestureObserver&&)             = default;
      GestureObserver& operator= (GestureObserver&&)  = default;
      
      
      Symbol getCmdID()  const { return cmdID_; }
      
      virtual void updateOffset (double deltaX, double deltaY) =0;
      virtual void markGestureCompleted()                      =0;
    };
  
  
  class InactiveObserver
    : public GestureObserver
    {
      void updateOffset (double, double)  override { /*NOOP*/ }
      void markGestureCompleted()         override { /*NOOP*/ }
    public:
      InactiveObserver() : GestureObserver(Symbol::BOTTOM) { }
    };
  
  
  
  class Subject
    : util::NonCopyable
    {
    protected:
        virtual ~Subject();  
        
    public:
        using Buffer = lib::PlantingHandle<GestureObserver, InactiveObserver>;
        virtual void buildGestureObserver (Symbol cmdID, Buffer)                =0;  
        virtual Gtk::Widget& exposeWidget()                                     =0;  
    };
  
  
  
  class CmdContext
    : util::MoveOnly
    {
      InteractionState& iState_;
      Symbol cmdID_;
      
      /* ===== Builder State ===== */
      Subject* subject_{nullptr};
      
      CmdContext (InteractionState& iState, Symbol cmdID)
        : iState_{iState}
        , cmdID_{cmdID}
        { }
    public:
      // using the default move-ctor
        
      /* === access front-end === */
      static CmdContext of (Symbol cmdID, Symbol ctxID);
      
      struct Resolver;
      
      CmdContext&& linkSubject (Subject& subj) { this->subject_ = &subj; return std::move (*this); }
      
      void setupRelocateDrag();
      
    protected:
    private:
    };
  
  
  struct CmdContext::Resolver
    {
      
      operator LuidH ();
      
      
      enum Spec {
        HERE,
        RECENT
      };
      
      
      friend Resolver
      scope (Spec scopeSpec)
      {
        return Resolver{scopeSpec};
      }
      
      
      friend Resolver
      element (Spec elementSpec)
      {
        return Resolver{elementSpec};
      }
      
    private:
      const Spec spec = HERE;
      
      Resolver(Spec s)
        : spec(s)
        { }
    };
  
  
}} // namespace stage::interact
#endif /*STAGE_INTERACT_CMD_CONTEXT_H*/