undo: add event removal undo command

This was a trivial copy & past of the event-adding undo command
with a switch of the undo() and redo() actions.

Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>

commands/command.cpp

@@ -349,4 +349,9 @@ void renameEvent(struct dive *d, int dcNr, struct event *ev, const char *name)
 	execute(new RenameEvent(d, dcNr, ev, name));
 }
 
+void removeEvent(struct dive *d, int dcNr, struct event *ev)
+{
+	execute(new RemoveEvent(d, dcNr, ev));
+}
+
 } // namespace Command

commands/command.h

@@ -110,6 +110,7 @@ void addEventBookmark(struct dive *d, int dcNr, int seconds);
 void addEventDivemodeSwitch(struct dive *d, int dcNr, int seconds, int divemode);
 void addEventSetpointChange(struct dive *d, int dcNr, int seconds, pressure_t pO2);
 void renameEvent(struct dive *d, int dcNr, struct event *ev, const char *name);
+void removeEvent(struct dive *d, int dcNr, struct event *ev);
 
 } // namespace Command
 

commands/command_event.cpp

@@ -97,4 +97,30 @@ void RenameEvent::undoit()
 	redoit();
 }
 
+RemoveEvent::RemoveEvent(struct dive *d, int dcNr, struct event *ev) : EventBase(d, dcNr),
+	eventToRemove(ev)
+{
+	setText(tr("Remove %1 event").arg(ev->name));
+}
+
+bool RemoveEvent::workToBeDone()
+{
+	return true;
+}
+
+void RemoveEvent::redoit()
+{
+	struct divecomputer *dc = get_dive_dc(d, dcNr);
+	remove_event_from_dc(dc, eventToRemove);
+	eventToAdd.reset(eventToRemove); // take ownership of event
+	eventToRemove = nullptr;
+}
+
+void RemoveEvent::undoit()
+{
+	struct divecomputer *dc = get_dive_dc(d, dcNr);
+	eventToRemove = eventToAdd.get();
+	add_event_to_dc(dc, eventToAdd.release()); // return ownership to backend
+}
+
 } // namespace Command

commands/command_event.h

@@ -70,6 +70,18 @@ private:
 	event *eventToRemove;		// for undo and redo
 };
 
+class RemoveEvent : public EventBase {
+public:
+	RemoveEvent(struct dive *d, int dcNr, struct event *ev);
+private:
+	bool workToBeDone() override;
+	void undoit() override;
+	void redoit() override;
+
+	OwningEventPtr eventToAdd;	// for undo
+	event *eventToRemove;		// for redo
+};
+
 } // namespace Command
 
 #endif // COMMAND_EVENT_H

profile-widget/profilewidget2.cpp

@@ -1602,17 +1602,15 @@ static event *find_event(const struct event *ev)
 
 void ProfileWidget2::removeEvent(DiveEventItem *item)
 {
-	struct event *event = item->getEvent();
+	struct event *event = find_event(item->getEvent());
+	if (!event)
+		return;
 
 	if (QMessageBox::question(this, TITLE_OR_TEXT(
 					  tr("Remove the selected event?"),
 					  tr("%1 @ %2:%3").arg(event->name).arg(event->time.seconds / 60).arg(event->time.seconds % 60, 2, 10, QChar('0'))),
-				  QMessageBox::Ok | QMessageBox::Cancel) == QMessageBox::Ok) {
-		remove_event(event);
-		invalidate_dive_cache(current_dive);
-		mark_divelist_changed(true);
-		replot();
-	}
+				  QMessageBox::Ok | QMessageBox::Cancel) == QMessageBox::Ok)
+		Command::removeEvent(current_dive, dc_number, event);
 }
 
 void ProfileWidget2::addBookmark(int seconds)