Dive list: move dive-selection code from filter to list

After invalidating the filter, the dive-selection was modified to
ensure that at least one dive is selected. This was done in the
filter code, but it seems preferrable to do this in the dive-list
code, which has direct access to the selection-model.

Therefore, move the code from MultiFilterSortModel to DiveListView.
While doing so, split the code in DiveListView into more functions to:
1) Get the index of the first dive (if any).
2) Select the first dive (if any).

This allows a distinct size reduction of conditional compilation
in MultiFilterSortModel (accesses to MainWindow are not possible
in mobile code).

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

3 files changed, 62 insertions, 47 deletions

diff --git a/desktop-widgets/divelistview.cpp b/desktop-widgets/divelistview.cpp
index eb65e9e6e..5a1741a7f 100644
--- a/desktop-widgets/divelistview.cpp
+++ b/desktop-widgets/divelistview.cpp
@@ -47,6 +47,9 @@ DiveListView::DiveListView(QWidget *parent) : QTreeView(parent), mouseClickSelec
 	connect(DiveTripModel::instance(), &DiveTripModel::selectionChanged, this, &DiveListView::diveSelectionChanged);
 	connect(DiveTripModel::instance(), &DiveTripModel::newCurrentDive, this, &DiveListView::currentDiveChanged);
 
+	// Update selection if all selected dives were hidden by filter
+	connect(MultiFilterSortModel::instance(), &MultiFilterSortModel::filterFinished, this, &DiveListView::filterFinished);
+
 	header()->setStretchLastSection(true);
 
 	installEventFilter(this);
@@ -349,17 +352,11 @@ QList<dive_trip_t *> DiveListView::selectedTrips()
 	return ret;
 }
 
-void DiveListView::selectDive(int i, bool scrollto, bool toggle)
+void DiveListView::selectDive(QModelIndex idx, bool scrollto, bool toggle)
 {
-	if (i == -1)
+	if (!idx.isValid())
 		return;
-	QSortFilterProxyModel *m = qobject_cast<QSortFilterProxyModel *>(model());
-	QModelIndexList match = m->match(m->index(0, 0), DiveTripModel::DIVE_IDX, i, 2, Qt::MatchRecursive);
-	QItemSelectionModel::SelectionFlags flags;
-	if (match.isEmpty())
-		return;
-	QModelIndex idx = match.first();
-	flags = toggle ? QItemSelectionModel::Toggle : QItemSelectionModel::Select;
+	QItemSelectionModel::SelectionFlags flags = toggle ? QItemSelectionModel::Toggle : QItemSelectionModel::Select;
 	flags |= QItemSelectionModel::Rows;
 	selectionModel()->setCurrentIndex(idx, flags);
 	if (idx.parent().isValid()) {
@@ -373,6 +370,18 @@ void DiveListView::selectDive(int i, bool scrollto, bool toggle)
 		scrollTo(idx, PositionAtCenter);
 }
 
+void DiveListView::selectDive(int i, bool scrollto, bool toggle)
+{
+	if (i == -1)
+		return;
+	QSortFilterProxyModel *m = qobject_cast<QSortFilterProxyModel *>(model());
+	QModelIndexList match = m->match(m->index(0, 0), DiveTripModel::DIVE_IDX, i, 2, Qt::MatchRecursive);
+	if (match.isEmpty())
+		return;
+	QModelIndex idx = match.first();
+	selectDive(idx, scrollto, toggle);
+}
+
 void DiveListView::selectDives(const QList<int> &newDiveSelection)
 {
 	int firstInList, newSelection;
@@ -416,6 +425,28 @@ void DiveListView::selectDives(const QList<int> &newDiveSelection)
 	return;
 }
 
+// Get index of first dive. This assumes that trips without dives are never shown.
+// May return an invalid index if no dive is found.
+QModelIndex DiveListView::indexOfFirstDive()
+{
+	// Fetch the first top-level item. If this is a trip, it is supposed to have at least
+	// one child. In that case return the child. Otherwise return the top-level item, which
+	// should be a dive.
+	QAbstractItemModel *m = model();
+	QModelIndex firstDiveOrTrip = m->index(0, 0);
+	if (!firstDiveOrTrip.isValid())
+		return QModelIndex();
+	QModelIndex child = m->index(0, 0, firstDiveOrTrip);
+	return child.isValid() ? child : firstDiveOrTrip;
+}
+
+void DiveListView::selectFirstDive()
+{
+	QModelIndex first = indexOfFirstDive();
+	if (first.isValid())
+		setCurrentIndex(first);
+}
+
 bool DiveListView::eventFilter(QObject *, QEvent *event)
 {
 	if (event->type() != QEvent::KeyPress)
@@ -476,19 +507,11 @@ void DiveListView::reload(DiveTripModel::Layout layout, bool forceSort)
 	if (!forceSort)
 		return;
 
-	QSortFilterProxyModel *m = qobject_cast<QSortFilterProxyModel *>(model());
 	sortByColumn(sortColumn, currentOrder);
-	if (amount_selected && current_dive != NULL) {
+	if (amount_selected && current_dive != NULL)
 		selectDive(get_divenr(current_dive), true);
-	} else {
-		QModelIndex firstDiveOrTrip = m->index(0, 0);
-		if (firstDiveOrTrip.isValid()) {
-			if (m->index(0, 0, firstDiveOrTrip).isValid())
-				setCurrentIndex(m->index(0, 0, firstDiveOrTrip));
-			else
-				setCurrentIndex(firstDiveOrTrip);
-		}
-	}
+	else
+		selectFirstDive();
 	if (selectedIndexes().count()) {
 		QModelIndex curr = selectedIndexes().first();
 		curr = curr.parent().isValid() ? curr.parent() : curr;
@@ -1029,6 +1052,18 @@ void DiveListView::loadImageFromURL(QUrl url)
 	}
 }
 
+void DiveListView::filterFinished()
+{
+	// first make sure the trips are no longer shown as selected
+	// (but without updating the selection state of the dives... this just cleans
+	// up an oddity in the filter handling)
+	clearTripSelection();
+
+	// If there are no more selected dives, select the first visible dive
+	if (!selectionModel()->hasSelection())
+		selectFirstDive();
+}
+
 QString DiveListView::lastUsedImageDir()
 {
 	QSettings settings;
diff --git a/desktop-widgets/divelistview.h b/desktop-widgets/divelistview.h
index 5c9ac2f25..c53e2aa01 100644
--- a/desktop-widgets/divelistview.h
+++ b/desktop-widgets/divelistview.h
@@ -29,8 +29,11 @@ public:
 	bool eventFilter(QObject *, QEvent *);
 	void unselectDives();
 	void clearTripSelection();
+	void selectDive(QModelIndex index, bool scrollto = false, bool toggle = false);
 	void selectDive(int dive_table_idx, bool scrollto = false, bool toggle = false);
 	void selectDives(const QList<int> &newDiveSelection);
+	void selectFirstDive();
+	QModelIndex indexOfFirstDive();
 	void rememberSelection();
 	void restoreSelection();
 	void contextMenuEvent(QContextMenuEvent *event);
@@ -60,6 +63,7 @@ slots:
 	void loadWebImages();
 	void diveSelectionChanged(const QVector<QModelIndex> &indexes, bool select);
 	void currentDiveChanged(QModelIndex index);
+	void filterFinished();
 private:
 	bool mouseClickSelection;
 	QList<int> expandedRows;
diff --git a/qt-models/filtermodels.cpp b/qt-models/filtermodels.cpp
index fb513f250..58d0277bd 100644
--- a/qt-models/filtermodels.cpp
+++ b/qt-models/filtermodels.cpp
@@ -641,10 +641,8 @@ void MultiFilterSortModel::filterChanged(const QModelIndex &from, const QModelIn
 
 void MultiFilterSortModel::myInvalidate()
 {
-#if !defined(SUBSURFACE_MOBILE)
 	int i;
 	struct dive *d;
-	DiveListView *dlv = MainWindow::instance()->diveList;
 
 	divesDisplayed = 0;
 
@@ -658,33 +656,11 @@ void MultiFilterSortModel::myInvalidate()
 
 	invalidateFilter();
 
-	// first make sure the trips are no longer shown as selected
-	// (but without updating the selection state of the dives... this just cleans
-	//  up an oddity in the filter handling)
-	// TODO: This should go internally to DiveList, to be triggered after a filter is due.
-	dlv->clearTripSelection();
-
-	// if we have no more selected dives, clean up the display - this later triggers us
-	// to pick one of the dives that are shown in the list as selected dive which is the
-	// natural behavior
-	if (amount_selected == 0) {
-		MainWindow::instance()->cleanUpEmpty();
-	} else {
-		// otherwise find the dives that should still be selected (the filter above unselected any
-		// dive that's no longer visible) and select them again
-		QList<int> curSelectedDives;
-		for_each_dive (i, d) {
-			if (d->selected)
-				curSelectedDives.append(get_divenr(d));
-		}
-		dlv->selectDives(curSelectedDives);
-	}
-
 	emit filterFinished();
 
-	if (curr_dive_site) {
-		dlv->expandAll();
-	}
+#if !defined(SUBSURFACE_MOBILE)
+	if (curr_dive_site)
+		MainWindow::instance()->diveList->expandAll();
 #endif
 }