// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Author:
 *   Gustav Broberg <broberg@kth.se>
 *   Jon A. Cruz <jon@joncruz.org>
 *
 * Copyright (c) 2014 Authors
 *
 * Released under GNU GPL v2+, read the file 'COPYING' for more information.
 */

#ifndef INKSCAPE_EVENT_LOG_H
#define INKSCAPE_EVENT_LOG_H

#include <gtkmm/treestore.h>
#include <glibmm/refptr.h>
#include <gtkmm/treeselection.h>
#include <gtkmm/treeview.h>
#include <sigc++/trackable.h>

#include "undo-stack-observer.h"
#include "event.h"

class SPDocument;

namespace Inkscape {

class EventLogPrivate;

/**
 * A simple log for maintaining a history of committed, undone and redone events along with their
 * type. It implements the UndoStackObserver and should be registered with a
 * CompositeUndoStackObserver for each document. The event log is then notified on all commit, undo
 * and redo events and will store a representation of them in an internal Gtk::TreeStore.
 *
 * Consecutive events of the same type are grouped with the first event as a parent and following
 * as its children.
 *
 * If a Gtk::TreeView is connected to the event log, the TreeView's selection and its nodes
 * expanded/collapsed state will be updated as events are committed, undone and redone. Whenever
 * this happens, the event log will block the TreeView's callbacks to prevent circular updates.
 */
class EventLog : public UndoStackObserver, public sigc::trackable
{
        
public:
    typedef Gtk::TreeModel::iterator iterator;
    typedef Gtk::TreeModel::const_iterator const_iterator;

    EventLog(SPDocument* document);
    ~EventLog() override;

    /**
     * Event datatype
     */
    struct EventModelColumns : public Gtk::TreeModelColumnRecord
    {
        Gtk::TreeModelColumn<Event *> event;
        Gtk::TreeModelColumn<Glib::ustring> icon_name;
        Gtk::TreeModelColumn<Glib::ustring> description;
        Gtk::TreeModelColumn<int> child_count;

        EventModelColumns()
        { 
            add(event); add(icon_name); add(description); add(child_count);
        }
    };

    // Implementation of Inkscape::UndoStackObserver methods

    /**
     * Modifies the log's entries and the view's selection when triggered.
     */
    void notifyUndoEvent(Event *log) override;
    void notifyRedoEvent(Event *log) override;
    void notifyUndoCommitEvent(Event *log) override;
    void notifyClearUndoEvent() override;
    void notifyClearRedoEvent() override;

    // Accessor functions

    Glib::RefPtr<Gtk::TreeModel> getEventListStore() const { return _event_list_store; }
    static const EventModelColumns& getColumns();
    iterator getCurrEvent() const                          { return _curr_event; }
    iterator getCurrEventParent() const                    { return _curr_event_parent; }

    void setCurrEvent(iterator event)          { _curr_event = event; }
    void setCurrEventParent(iterator event)    { _curr_event_parent = event; }
    void blockNotifications(bool status=true)  { _notifications_blocked = status; }
    void rememberFileSave()                    { _last_saved = _curr_event; }

    // Callback types for TreeView changes.

    enum CallbackTypes { 
        CALLB_SELECTION_CHANGE, 
        CALLB_EXPAND, 
        CALLB_COLLAPSE, 
        CALLB_LAST 
    };

    typedef std::map<const CallbackTypes, sigc::connection> CallbackMap;

    /**
     * Connect with a TreeView.
     */
    void addDialogConnection(Gtk::TreeView *event_list_view, CallbackMap *callback_connections);

    /**
     * Disconnect from a TreeView.
     */
    void removeDialogConnection(Gtk::TreeView *event_list_view, CallbackMap *callback_connections);

    /*
     * Updates the sensitivity of undo and redo actions.
     */
    void updateUndoVerbs();

private:
    EventLogPrivate *_priv;

    SPDocument *_document;       //< document that is logged

    Glib::RefPtr<Gtk::TreeStore> _event_list_store; 

    iterator _curr_event;        //< current event in _event_list_store
    iterator _last_event;        //< end position in _event_list_store
    iterator _curr_event_parent; //< parent to current event, if any

    iterator _last_saved;        //< position where last document save occurred

    bool _notifications_blocked; //< if notifications should be handled

    // Helper functions

    const_iterator _getUndoEvent() const; //< returns the current undoable event or NULL if none
    const_iterator _getRedoEvent() const; //< returns the current redoable event or NULL if none

    void _clearUndo();  //< erase all previously committed events
    void _clearRedo();  //< erase all previously undone events

    void checkForVirginity(); //< marks the document as untouched if undo/redo reaches a previously saved state

    // noncopyable, nonassignable
    EventLog(EventLog const &other) = delete;
    EventLog& operator=(EventLog const &other) = delete;
};

} // namespace Inkscape

#endif // INKSCAPE_EVENT_LOG_H

/*
  Local Variables:
  mode:c++
  c-file-style:"stroustrup"
  c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
  indent-tabs-mode:nil
  fill-column:99
  End:
*/
// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:fileencoding=utf-8:textwidth=99 :