//------------------------------------------------------------------------------
// emFilePanel.h
//
// Copyright (C) 2004-2008,2010,2016-2017 Oliver Hamann.
//
// Homepage: http://eaglemode.sourceforge.net/
//
// This program is free software: you can redistribute it and/or modify it under
// the terms of the GNU General Public License version 3 as published by the
// Free Software Foundation.
//
// 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 version 3 for
// more details.
//
// You should have received a copy of the GNU General Public License version 3
// along with this program. If not, see <http://www.gnu.org/licenses/>.
//------------------------------------------------------------------------------

#ifndef emFilePanel_h
#define emFilePanel_h

#ifndef emPanel_h
#include <emCore/emPanel.h>
#endif

#ifndef emFileModel_h
#include <emCore/emFileModel.h>
#endif


//==============================================================================
//================================ emFilePanel =================================
//==============================================================================

class emFilePanel : public emPanel {

public:

        // Base class for a panel with which the user can view or edit a file
        // that is interfaced with an emFileModel. Internally, an object of this
        // class manages an emFileModelClient. The memory limit and priority of
        // that client is set and updated from the panel properties. In
        // addition, a virtual file state is provided (a more correct name would
        // be: "virtual file model state"). This is similar to the file state of
        // the model, but with some extensions (see GetVirFileState()). The
        // panel shows information about that virtual file state. A derived
        // class should overload the Paint method for showing the file contents
        // when the virtual file state is good (loaded or unsaved).

        emFilePanel(
                ParentArg parent, const emString & name,
                emFileModel * fileModel=NULL, bool updateFileModel=true
        );
                // Constructor.
                // Arguments:
                //   parent    - Parent for this panel (emPanel or emView).
                //   name      - The name for this panel.
                //   fileModel - See SetFileModel.
                //   updateFileModel - See SetFileModel.

        virtual ~emFilePanel();
                // Destructor.

        emFileModel * GetFileModel() const;
                // Get the file model, NULL if none.

        virtual void SetFileModel(emFileModel * fileModel,
                                  bool updateFileModel=true);
                // Set the file model, NULL for none. If updateFileModel==true,
                // fileModel->Update() is called.

        void SetCustomError(const emString & message);
        void ClearCustomError();
        emString GetCustomError() const;
                // Set, clear or get a custom error message. If set, the message
                // is shown by the default implementation of Paint.

        const emSignal & GetVirFileStateSignal() const;
                // Signaled when the virtual file state has changed.

        enum VirtualFileState {
                VFS_WAITING       = emFileModel::FS_WAITING,
                VFS_LOADING       = emFileModel::FS_LOADING,
                VFS_LOADED        = emFileModel::FS_LOADED,
                VFS_UNSAVED       = emFileModel::FS_UNSAVED,
                VFS_SAVING        = emFileModel::FS_SAVING,
                VFS_TOO_COSTLY    = emFileModel::FS_TOO_COSTLY,
                VFS_LOAD_ERROR    = emFileModel::FS_LOAD_ERROR,
                VFS_SAVE_ERROR    = emFileModel::FS_SAVE_ERROR,
                VFS_NO_FILE_MODEL = emFileModel::FS_MAX_VAL+1,
                VFS_CUSTOM_ERROR  = emFileModel::FS_MAX_VAL+2
        };
        VirtualFileState GetVirFileState() const;
                // Get the virtual file state. This is like the file state of
                // the model (GetFileMode()->GetFileState()), but:
                // - There is the additional state VFS_CUSTOM_ERROR. It is set
                //   when a custom error has been reported through
                //   SetCustomError(...).
                // - There is the additional state VFS_NO_FILE_MODEL. It is set
                //   when GetFileModel()==NULL.
                // - If the memory limit of this panel is smaller than the
                //   memory need of the model, the virtual file state is forced
                //   to VFS_TOO_COSTLY even when the model is in loaded state.
                //   (Otherwise the show state of the panel could depend on the
                //   show state of another panel - too ugly)

        bool IsVFSGood() const;
                // This is a short-cut for:
                //  (GetVirFileState()==VFS_LOADED ||
                //   GetVirFileState()==VFS_UNSAVED)
                // It means that the file model data can safely be shown and
                // modified.

        virtual emString GetIconFileName() const;

        virtual bool IsContentReady(bool * pReadying=NULL) const;

protected:

        virtual bool Cycle();

        virtual void Notice(NoticeFlags flags);

        virtual bool IsOpaque() const;

        virtual void Paint(const emPainter & painter, emColor canvasColor) const;
                // Paints some info about the virtual file state including any
                // error messages. Should be overloaded for showing the file
                // model data when IsVFSGood()==true. InvalidatePainting is
                // called automatically on each change of the virtual file
                // state.

        virtual bool IsHopeForSeeking() const;
                // Returns true if VFS_WAITING, VFS_LOADING or VFS_SAVING.

private:

        emFileModelClient FileModelClient;
        emString * CustomError;
        emSignal VirFileStateSignal;
};

inline emFileModel * emFilePanel::GetFileModel() const
{
        return FileModelClient.GetModel();
}

inline const emSignal & emFilePanel::GetVirFileStateSignal() const
{
        return VirFileStateSignal;
}


#endif