Dive site: introduce proxy model DiveSiteSortedModel

The LocationInformationModel used to sort its entries and was completely
rebuilt after every change. This makes it rather complex to support
incremental changes.

Instead, keep LocationInformationModel sorted by UUID so that indexes
are consistent with indices in the core dive site table.

Implement sorting by other columns than name and enable sorting in the
dive site view.

Finally, don't cache the list of dive site names for the mobile app,
since that would also need some rather convoluted methods of keeping
the list up to date. Calculate it on the fly.

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

2 files changed, 59 insertions, 16 deletions

diff --git a/qt-models/divelocationmodel.cpp b/qt-models/divelocationmodel.cpp
index 0a0eacaaf..383de43ca 100644
--- a/qt-models/divelocationmodel.cpp
+++ b/qt-models/divelocationmodel.cpp
@@ -11,11 +11,6 @@
 #include <QIcon>
 #include <core/gettextfromc.h>
 
-static bool dive_site_less_than(dive_site *a, dive_site *b)
-{
-	return QString(a->name) < QString(b->name);
-}
-
 LocationInformationModel *LocationInformationModel::instance()
 {
 	static LocationInformationModel *self = new LocationInformationModel();
@@ -133,18 +128,9 @@ QVariant LocationInformationModel::data(const QModelIndex &index, int role) cons
 void LocationInformationModel::update()
 {
 	beginResetModel();
-	std::sort(dive_site_table.dive_sites, dive_site_table.dive_sites + dive_site_table.nr, dive_site_less_than);
-	locationNames.clear();
-	for (int i = 0; i < dive_site_table.nr; i++)
-		locationNames << QString(dive_site_table.dive_sites[i]->name);
 	endResetModel();
 }
 
-QStringList LocationInformationModel::allSiteNames() const
-{
-	return locationNames;
-}
-
 bool LocationInformationModel::removeRows(int row, int, const QModelIndex&)
 {
 	if(row >= rowCount())
@@ -183,6 +169,56 @@ void LocationInformationModel::diveSiteDeleted(struct dive_site *, int idx)
 	endRemoveRows();
 }
 
+bool DiveSiteSortedModel::filterAcceptsRow(int sourceRow, const QModelIndex &source_parent) const
+{
+	// TODO: filtering
+	return true;
+}
+
+bool DiveSiteSortedModel::lessThan(const QModelIndex &i1, const QModelIndex &i2) const
+{
+	// The source indices correspond to indices in the global dive site table.
+	// Let's access them directly without going via the source model.
+	// Kind of dirty, but less effort.
+	struct dive_site *ds1 = get_dive_site(i1.row(), &dive_site_table);
+	struct dive_site *ds2 = get_dive_site(i2.row(), &dive_site_table);
+	if (!ds1 || !ds2) // Invalid dive sites compare as different
+		return false;
+	switch (i1.column()) {
+	case LocationInformationModel::NAME:
+	default:
+		return QString::localeAwareCompare(QString(ds1->name), QString(ds2->name)) < 0; // TODO: avoid copy
+	case LocationInformationModel::DESCRIPTION: {
+		int cmp = QString::localeAwareCompare(QString(ds1->description), QString(ds2->description)); // TODO: avoid copy
+		return cmp != 0 ? cmp < 0 :
+		       QString::localeAwareCompare(QString(ds1->name), QString(ds2->name)) < 0; // TODO: avoid copy
+	}
+	case LocationInformationModel::NUM_DIVES: {
+		int cmp = ds1->dives.nr - ds2->dives.nr;
+		// Since by default nr dives is descending, invert sort direction of names, such that
+		// the names are listed as ascending.
+		return cmp != 0 ? cmp < 0 :
+		       QString::localeAwareCompare(QString(ds1->name), QString(ds2->name)) < 0; // TODO: avoid copy
+	}
+	}
+}
+
+DiveSiteSortedModel::DiveSiteSortedModel()
+{
+	setSourceModel(LocationInformationModel::instance());
+}
+
+QStringList DiveSiteSortedModel::allSiteNames() const
+{
+	QStringList locationNames;
+	int num = rowCount();
+	for (int i = 0; i < num; i++) {
+		int idx = mapToSource(index(i, 0)).row();
+		locationNames << QString(dive_site_table.dive_sites[idx]->name);
+	}
+	return locationNames;
+}
+
 GeoReferencingOptionsModel *GeoReferencingOptionsModel::instance()
 {
 	static GeoReferencingOptionsModel *self = new GeoReferencingOptionsModel();
diff --git a/qt-models/divelocationmodel.h b/qt-models/divelocationmodel.h
index 65fabca96..f2bcc7cf7 100644
--- a/qt-models/divelocationmodel.h
+++ b/qt-models/divelocationmodel.h
@@ -32,12 +32,19 @@ public:
 
 public slots:
 	void update();
-	QStringList allSiteNames() const;
 	void diveSiteDiveCountChanged(struct dive_site *ds);
 	void diveSiteAdded(struct dive_site *ds, int idx);
 	void diveSiteDeleted(struct dive_site *ds, int idx);
+};
+
+class DiveSiteSortedModel : public QSortFilterProxyModel {
+	Q_OBJECT
 private:
-	QStringList locationNames;
+	bool filterAcceptsRow(int sourceRow, const QModelIndex &source_parent) const override;
+	bool lessThan(const QModelIndex &i1, const QModelIndex &i2) const override;
+public:
+	DiveSiteSortedModel();
+	QStringList allSiteNames() const;
 };
 
 // To access only divesites at the given GPS coordinates with the exception of a given dive site