core: add shared export functions (copy from desktop-widgets)

desktop-widgets/divelogexportdialog.* contains both the desktop
dialog as well as the "real" export functions.

Create a class to be shared between desktop and mobile

Copy the export functions 1-1 from divelogexportdialog.* of course
changing class names.

saveProfile is highly dependent on the UI, so the implementaion will
be done in each UI directory (desktop-widgets, mobile-widgets).

Remark this commit just add the copied functions, in order to secure
nothing is broken.

Signed-off-by: Jan Iversen <jan@casacondor.com>

core/exportfuncs.h

@@ -0,0 +1,39 @@
+// SPDX-License-Identifier: GPL-2.0
+#ifndef EXPORTFUNCS_H
+#define EXPORTFUNCS_H
+
+#include <QObject>
+#include <QFuture>
+#include "dive.h"
+
+class exportFuncs: public QObject {
+	Q_OBJECT
+
+public:
+	static exportFuncs *instance();
+
+	void exportProfile(QString filename, const bool selected_only);
+	void export_TeX(const char *filename, const bool selected_only, bool plain);
+	void export_depths(const char *filename, const bool selected_only);
+	std::vector<const dive_site *> getDiveSitesToExport(bool selectedOnly);
+	void exportUsingStyleSheet(QString filename, bool doExport, int units,
+		QString stylesheet, bool anonymize);
+	QFuture<int> future;
+
+	// prepareDivesForUploadDiveLog
+	// prepareDivesForUploadDiveShare
+
+private:
+	exportFuncs() {}
+
+	// WARNING
+	// saveProfile uses the UI and are therefore different between
+	// Desktop (UI) and Mobile (QML)
+	// In order to solve this difference, the actual implementations
+	// are done in
+	// desktop-widgets/divelogexportdialog.cpp and
+	// mobile-widgets/qmlmanager.cpp
+	void saveProfile(const struct dive *dive, const QString filename);
+};
+
+#endif // EXPORT_FUNCS_H