/***************************************************************************
 *                                                                         *
 *   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.                                   *
 *                                                                         *
 *   copyright (C) 2004-2006                                               *
 *   Umbrello UML Modeller Authors <uml-devel@ uml.sf.net>                 *
 ***************************************************************************/

#ifndef TOOLBARSTATEMESSAGES_H
#define TOOLBARSTATEMESSAGES_H

#include "toolbarstatepool.h"
#include <qpoint.h>

class QCanvasLine;
class ObjectWidget;

/**
 * Messages tool to create messages between objects in sequence diagrams.
 * With messages tool, two objects are selected clicking with left button on
 * them and a message of the needed type (depending on the message button
 * selected) is created between the objects. When the first object is selected,
 * a temporal visual message that follows the cursor movement is created until
 * the second object is selected or the message cancelled.
 *
 * A message can be cancelled using right button, which also returns to default
 * tool, or with middle button, which only cancels the message without changing
 * the tool being used.
 *
 * The messages to create can be normal messages or creation messages. Normal
 * messages are created clicking on the line of the two objects. Creation
 * messages are created clicking in the line of the first object, and on the
 * second object itself (not in its line).
 *
 * Associations aren't taken into account, and are treated as empty spaces.
 * Moreover, widgets other than objects aren't neither taken into account.
 *
 * @todo refactor with common code in ToolBarStateAssociation?
 * @todo sequence message lines should be handled by object widgets. Right now,
 * they aren't taken into account in testOnWidget and an explicit check is
 * needed. However, if onWidget in object widgets is changed to also check for
 * the line, a way to make them prioritaries over other widgets in testOnWidget
 * will be needed. For example, when creating a message clicking on an already
 * created message,the message line must be got instead of the message, even if
 * the message is smaller than the line.
 */
class ToolBarStateMessages : public ToolBarStatePool {
    Q_OBJECT
public:

    /**
     * Creates a new ToolBarStateMessages.
     *
     * @param umlView The UMLView to use.
     */
    ToolBarStateMessages(UMLView *umlView);

    /**
     * Destroys this ToolBarStateMessages.
     */
    virtual ~ToolBarStateMessages();

    /**
     * Goes back to the initial state.
     */
    virtual void init();

    /**
     * Called when the current tool is changed to use another tool.
     * Executes base method and cleans the message.
     */
    virtual void cleanBeforeChange();

    /**
     * Called when a mouse event happened.
     * It executes the base method and then updates the position of the
     * message line, if any.
     */
    virtual void mouseMove(QMouseEvent* ome);

public slots:

    /**
     * A widget was removed from the UMLView.
     * If the widget removed was the current widget, the current widget is set
     * to 0.
     * Also, if it was the first object, the message is cleaned.
     */
    virtual void slotWidgetRemoved(UMLWidget* widget);

protected:

    /**
     * Selects only widgets, but no associations.
     * Overrides base class method.
     * If the press event happened on the line of an object, the object is set
     * as current widget. If the press event happened on a widget, the widget is
     * set as current widget.
     */
    virtual void setCurrentElement();

    /**
     * Called when the release event happened on a widget.
     * If the button pressed isn't left button or the widget isn't an object
     * widget, the message is cleaned.
     * If the release event didn't happen on the line of an object and the first
     * object wasn't selected, nothing is done. If the first object was already
     * selected, a creation message is made.
     * If the event happened on the line of an object, the first object or the
     * second are set, depending on whether the first object was already set or
     * not.
     */
    virtual void mouseReleaseWidget();

    /**
     * Called when the release event happened on an empty space.
     * Cleans the message.
     * Empty spaces are not only actual empty spaces, but also associations.
     */
    virtual void mouseReleaseEmpty();

protected:

    /**
     * The type of the message to create.
     */
    enum MessageType {
        NormalMessage,
        CreationMessage
    };

    /**
     * Sets the first object of the message using the specified object.
     * The temporal visual message is created and mouse tracking enabled, so
     * mouse events will be delivered.
     *
     * @param firstObject The first object of the message.
     */
    void setFirstWidget(ObjectWidget* firstObject);

    /**
     * Sets the second object of the message using the specified widget and
     * creates the message.
     * The association is created and added to the view. The dialog to select
     * the operation of the message is shown.
     *
     * @param secondObject The second object of the message.
     * @param messageType The type of the message to create.
     */
    void setSecondWidget(ObjectWidget* secondObject, MessageType messageType);

    /**
     * Returns the message type of this tool.
     *
     * @return The message type of this tool.
     */
    Uml::Sequence_Message_Type getMessageType();

    /**
     * Cleans the first widget and the temporal message line, if any.
     * Both are set to null, and the message line is also deleted.
     */
    void cleanMessage();

    /**
     * The first object in the message.
     */
    ObjectWidget* m_firstObject;

    /**
     * The message line shown while the first widget is selected and the
     * second one wasn't selected yet.
     */
    QCanvasLine* m_messageLine;

    /**
     * If there is a current widget, it is true if the press event happened on
     * the line of an object, or false if it happened on a normal UMLWidget.
     */
    bool m_isObjectWidgetLine;

};

#endif //TOOLBARSTATEMESSAGES_H
