Dive site: sort by distance to current dive

When presenting the list of dive sites on the dive-info tab, sort
the dive sites by distance to the current dive. The idea is that
when the user wants to select a dive site, close dive sites should
be prioritized.

The location of the dive is determined with the dive_get_gps_location()
function introduced in the previous commit. This actual GPS data get
precedence over the currently set dive site for that dive.

On change of dive, the current location is updated in the
DiveLocationFilterProxyModel so that a potentially expensive search
for GPS data is not repeated for every comparison.

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

3 files changed, 26 insertions, 8 deletions

diff --git a/desktop-widgets/locationinformation.cpp b/desktop-widgets/locationinformation.cpp
index 825f440ba..a57c6fb30 100644
--- a/desktop-widgets/locationinformation.cpp
+++ b/desktop-widgets/locationinformation.cpp
@@ -252,7 +252,7 @@ void LocationInformationWidget::reverseGeocode()
 	Command::editDiveSiteTaxonomy(diveSite, taxonomy);
 }
 
-DiveLocationFilterProxyModel::DiveLocationFilterProxyModel(QObject *)
+DiveLocationFilterProxyModel::DiveLocationFilterProxyModel(QObject *) : currentLocation({0, 0})
 {
 }
 
@@ -263,6 +263,12 @@ void DiveLocationFilterProxyModel::setFilter(const QString &filterIn)
 	sort(LocationInformationModel::NAME);
 }
 
+void DiveLocationFilterProxyModel::setCurrentLocation(location_t loc)
+{
+	currentLocation = loc;
+	sort(LocationInformationModel::NAME);
+}
+
 bool DiveLocationFilterProxyModel::filterAcceptsRow(int source_row, const QModelIndex&) const
 {
 	// We don't want to show the first two entries (add dive site with that name)
@@ -282,6 +288,14 @@ bool DiveLocationFilterProxyModel::lessThan(const QModelIndex &source_left, cons
 	// The first two entries are special - we never want to change their order
 	if (source_left.row() <= 1 || source_right.row() <= 1)
 		return source_left.row() < source_right.row();
+
+	// If there is a current location, sort by that - otherwise use the provided column
+	if (has_location(&currentLocation)) {
+		// The dive sites are -2 because of the first two items.
+		struct dive_site *ds1 = get_dive_site(source_left.row() - 2, &dive_site_table);
+		struct dive_site *ds2 = get_dive_site(source_right.row() - 2, &dive_site_table);
+		return get_distance(&ds1->location, &currentLocation) < get_distance(&ds2->location, &currentLocation);
+	}
 	return source_left.data().toString().compare(source_right.data().toString(), Qt::CaseInsensitive) < 0;
 }
 
@@ -543,8 +557,9 @@ void DiveLocationLineEdit::fixPopupPosition()
 	}
 }
 
-void DiveLocationLineEdit::setCurrentDiveSite(struct dive_site *ds)
+void DiveLocationLineEdit::setCurrentDiveSite(struct dive *d)
 {
+	struct dive_site *ds = get_dive_site_for_dive(d);
 	currDs = ds;
 	if (!currDs) {
 		currType = NO_DIVE_SITE;
@@ -552,6 +567,9 @@ void DiveLocationLineEdit::setCurrentDiveSite(struct dive_site *ds)
 	} else {
 		setText(ds->name);
 	}
+
+	location_t currentLocation = d ? dive_get_gps_location(d) : location_t{0, 0};
+	proxy->setCurrentLocation(currentLocation);
 }
 
 void DiveLocationLineEdit::showPopup()
diff --git a/desktop-widgets/locationinformation.h b/desktop-widgets/locationinformation.h
index 434da29ae..f3f9f9eea 100644
--- a/desktop-widgets/locationinformation.h
+++ b/desktop-widgets/locationinformation.h
@@ -51,6 +51,9 @@ public:
 	bool filterAcceptsRow(int source_row, const QModelIndex& source_parent) const override;
 	bool lessThan(const QModelIndex& source_left, const QModelIndex& source_right) const override;
 	void setFilter(const QString &filter);
+	void setCurrentLocation(location_t loc);
+private:
+	location_t currentLocation; // Sort by distance to that location
 };
 
 class DiveLocationModel : public QAbstractTableModel {
@@ -88,7 +91,7 @@ public:
 	DiveSiteType currDiveSiteType() const;
 	struct dive_site *currDiveSite() const;
 	void fixPopupPosition();
-	void setCurrentDiveSite(struct dive_site *ds);
+	void setCurrentDiveSite(struct dive *d);
 
 signals:
 	void diveSiteSelected();
diff --git a/desktop-widgets/tab-widgets/maintab.cpp b/desktop-widgets/tab-widgets/maintab.cpp
index 0638fbded..e70e79ce2 100644
--- a/desktop-widgets/tab-widgets/maintab.cpp
+++ b/desktop-widgets/tab-widgets/maintab.cpp
@@ -391,15 +391,14 @@ void MainTab::updateDateTime(struct dive *d)
 void MainTab::updateDiveSite(struct dive *d)
 {
 	struct dive_site *ds = d->dive_site;
+	ui.location->setCurrentDiveSite(d);
 	if (ds) {
-		ui.location->setCurrentDiveSite(ds);
 		ui.locationTags->setText(constructLocationTags(&ds->taxonomy, true));
 
 		if (ui.locationTags->text().isEmpty() && has_location(&ds->location))
 			ui.locationTags->setText(printGPSCoords(&ds->location));
 		ui.editDiveSiteButton->setEnabled(true);
 	} else {
-		ui.location->clear();
 		ui.locationTags->clear();
 		ui.editDiveSiteButton->setEnabled(false);
 	}
@@ -601,9 +600,7 @@ void MainTab::reload()
 
 void MainTab::refreshDisplayedDiveSite()
 {
-	struct dive_site *ds = get_dive_site_for_dive(current_dive);
-	if (ds)
-		ui.location->setCurrentDiveSite(ds);
+	ui.location->setCurrentDiveSite(current_dive);
 }
 
 void MainTab::acceptChanges()