Filter: implement reset filter

Move initialization to a separate function and connect that to the
reset button.

Two points of note:

1) Reseting the text-fields causes signals. Thus, signals have to
   be ignored during reset. Do this with a new flag.
2) To make reset of the from-date work, the from-date has to be
   initialized to a distinct value. Setting a default-constructed
   QDateTime leaves the widget unchanged.

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

desktop-widgets/filterwidget2.cpp

@@ -5,7 +5,7 @@
 
 #include <QDoubleSpinBox>
 
-FilterWidget2::FilterWidget2(QWidget* parent) : QWidget(parent)
+FilterWidget2::FilterWidget2(QWidget* parent) : QWidget(parent), ignoreSignal(false)
 {
 	ui.setupUi(this);
 
@@ -17,17 +17,6 @@ FilterWidget2::FilterWidget2(QWidget* parent) : QWidget(parent)
 	ui.minWaterTemp->setRange(data.minWaterTemp, data.maxWaterTemp);
 	ui.maxWaterTemp->setRange(data.minWaterTemp, data.maxWaterTemp);
 
-	ui.minRating->setCurrentStars(data.minRating);
-	ui.maxRating->setCurrentStars(data.maxRating);
-	ui.minVisibility->setCurrentStars(data.minVisibility);
-	ui.maxVisibility->setCurrentStars(data.maxVisibility);
-	ui.minAirTemp->setValue(data.minAirTemp);
-	ui.maxAirTemp->setValue(data.maxAirTemp);
-	ui.minWaterTemp->setValue(data.minWaterTemp);
-	ui.maxWaterTemp->setValue(data.maxWaterTemp);
-	ui.planned->setChecked(data.logged);
-	ui.planned->setChecked(data.planned);
-
 	// TODO: unhide this when we discover how to search for equipment.
 	ui.equipment->hide();
 	ui.labelEquipment->hide();
@@ -38,12 +27,13 @@ FilterWidget2::FilterWidget2(QWidget* parent) : QWidget(parent)
 
 	ui.toDate->setDisplayFormat(prefs.date_format);
 	ui.toTime->setDisplayFormat(prefs.time_format);
-	ui.toDate->setDate(data.toDate.date());
-	ui.toTime->setTime(data.toTime);
 
 	// Initialize temperature fields to display correct unit.
 	temperatureChanged();
 
+	connect(ui.clear, &QToolButton::clicked,
+		this, &FilterWidget2::clearFilter);
+
 	connect(ui.maxRating, &StarWidget::valueChanged,
 		this, &FilterWidget2::updateFilter);
 
@@ -100,6 +90,36 @@ FilterWidget2::FilterWidget2(QWidget* parent) : QWidget(parent)
 	// Update counts if dives were added / removed
 	connect(MultiFilterSortModel::instance(), &MultiFilterSortModel::countsChanged,
 		this, &FilterWidget2::countsChanged);
+
+	// Reset all fields.
+	clearFilter();
+}
+
+void FilterWidget2::clearFilter()
+{
+	ignoreSignal = true; // Prevent signals to force filter recalculation
+	filterData = FilterData();
+	ui.minRating->setCurrentStars(filterData.minRating);
+	ui.maxRating->setCurrentStars(filterData.maxRating);
+	ui.minVisibility->setCurrentStars(filterData.minVisibility);
+	ui.maxVisibility->setCurrentStars(filterData.maxVisibility);
+	ui.minAirTemp->setValue(filterData.minAirTemp);
+	ui.maxAirTemp->setValue(filterData.maxAirTemp);
+	ui.minWaterTemp->setValue(filterData.minWaterTemp);
+	ui.maxWaterTemp->setValue(filterData.maxWaterTemp);
+	ui.planned->setChecked(filterData.logged);
+	ui.planned->setChecked(filterData.planned);
+	ui.people->clear();
+	ui.location->clear();
+	ui.equipment->clear();
+	ui.tags->clear();
+	ui.fromDate->setDate(filterData.fromDate.date());
+	ui.fromTime->setTime(filterData.fromTime);
+	ui.toDate->setDate(filterData.toDate.date());
+	ui.toTime->setTime(filterData.toTime);
+	ignoreSignal = false;
+
+	filterDataChanged(filterData);
 }
 
 void FilterWidget2::temperatureChanged()
@@ -113,6 +133,9 @@ void FilterWidget2::temperatureChanged()
 
 void FilterWidget2::updateFilter()
 {
+	if (ignoreSignal)
+		return;
+
 	filterData.validFilter = true;
 	filterData.minVisibility = ui.minVisibility->currentStars();
 	filterData.maxVisibility = ui.maxVisibility->currentStars();

desktop-widgets/filterwidget2.h

@@ -28,10 +28,12 @@ public slots:
 	void updatePlanned(int value);
 	void updateLogged(int value);
 private slots:
+	void clearFilter();
 	void temperatureChanged();
 	void countsChanged();
 
 private:
+	bool ignoreSignal;
 	Ui::FilterWidget2 ui;
 	void filterDataChanged(const FilterData &data);
 	FilterData filterData;

qt-models/filtermodels.h

@@ -27,8 +27,8 @@ struct FilterData {
 	double maxWaterTemp = 200;
 	double minAirTemp = -50;
 	double maxAirTemp = 200;
-	QDateTime fromDate;
+	QDateTime fromDate = QDateTime(QDate(1980,1,1));
-	QTime fromTime;
+	QTime fromTime = QTime(0,0);
 	QDateTime toDate = QDateTime::currentDateTime();
 	QTime toTime = QTime::currentTime();
 	QStringList tags;