planner: implement move semantics in DivePlannerPointsModel

When reordering the points, the DivePlannerPointsModel would
not emit the appropriate move signals, but simply a data-changed
signal over all elements. This obviously violates Qt's
model/view API, though it is probably harmless. Let's do
the right thing so that the frontend knows that the selected
item changed place.

Also, emit dataChanged only on the actually changed element,
not all elements.

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

1 files changed, 33 insertions, 4 deletions

diff --git a/qt-models/diveplannermodel.cpp b/qt-models/diveplannermodel.cpp
index 2f9272415..f22dd931e 100644
--- a/qt-models/diveplannermodel.cpp
+++ b/qt-models/diveplannermodel.cpp
@@ -831,20 +831,49 @@ int DivePlannerPointsModel::addStop(int milimeters, int seconds, int cylinderid_
 
 void DivePlannerPointsModel::editStop(int row, divedatapoint newData)
 {
+	if (row < 0 || row >= divepoints.count())
+		return;
+
+	// Refuse to move to 0, since that has special meaning.
+	if (newData.time <= 0)
+		return;
+
 	/*
 	 * When moving divepoints rigorously, we might end up with index
 	 * out of range, thus returning the last one instead.
 	 */
 	int old_first_cylid = divepoints[0].cylinderid;
-	if (row >= divepoints.count())
-		return;
+
+	// Is it ok to change data first and then move the rows?
 	divepoints[row] = newData;
-	std::sort(divepoints.begin(), divepoints.end(), divePointsLessThan);
+
+	// If the time changed, the item might have to be moved. Oh joy.
+	int newRow = row;
+	while (newRow + 1 < divepoints.count() && divepoints[newRow + 1].time < divepoints[row].time)
+		++newRow;
+	if (newRow != row) {
+		++newRow; // Move one past item with smaller time stamp
+	} else {
+		// If we didn't move forward, try moving backwards
+		while (newRow > 0 && divepoints[newRow - 1].time > divepoints[row].time)
+			--newRow;
+	}
+
+	if (newRow != row && newRow != row + 1) {
+		beginMoveRows(QModelIndex(), row, row, QModelIndex(), newRow);
+		moveInVector(divepoints, row, row + 1, newRow);
+		endMoveRows();
+
+		// Account for moving the row backwards in the array.
+		row = newRow > row ? newRow - 1 : newRow;
+	}
+
 	if (updateMaxDepth())
 		cylinders.updateBestMixes();
 	if (divepoints[0].cylinderid != old_first_cylid)
 		cylinders.moveAtFirst(divepoints[0].cylinderid);
-	emitDataChanged();
+
+	emit dataChanged(createIndex(row, 0), createIndex(row, COLUMNS - 1));
 }
 
 int DivePlannerPointsModel::size() const