Location service: add member to apply the gps locations to dives

This is a direct conversion of the existing code in subsurfacewebservices
to the different data structures in use here. I did not try to abstract
this out to have both share a common helper because I assume that the
Subsurface web service will pretty quickly become obsolete (together with
the companion app).

Right now this is not hooked up anywhere.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

qt-mobile/gpslocation.cpp

@@ -2,6 +2,7 @@
 #include "qt-mobile/qmlmanager.h"
 #include "pref.h"
 #include "dive.h"
+#include "helpers.h"
 #include <time.h>
 #include <QDebug>
 #include <QVariant>
@@ -72,3 +73,131 @@ void GpsLocation::status(QString msg)
 	qDebug() << msg;
 	qmlUiShowMessage(qPrintable(msg));
 }
+
+struct gpsTracker {
+	degrees_t latitude;
+	degrees_t longitude;
+	time_t when;
+};
+
+static void copy_gps_location(struct gpsTracker *gps, struct dive *d)
+{
+	struct dive_site *ds = get_dive_site_by_uuid(d->dive_site_uuid);
+	ds->latitude = gps->latitude;
+	ds->longitude = gps->longitude;
+}
+
+#define SAME_GROUP 6 * 3600 /* six hours */
+bool GpsLocation::applyLocations()
+{
+	int i;
+	bool changed = false;
+	int last = 0;
+	int cnt = geoSettings.value("count", 0).toInt();
+	if (cnt == 0)
+		return false;
+
+	// create a table with the GPS information
+	struct gpsTracker *gpsTable = (struct gpsTracker *)calloc(cnt, sizeof(struct gpsTracker));
+	for (int i = 0; i < cnt; i++) {
+		gpsTable[i].latitude.udeg = geoSettings.value(QString("gpsFix%1_lat").arg(i)).toInt();
+		gpsTable[i].longitude.udeg = geoSettings.value(QString("gpsFix%1_lon").arg(i)).toInt();
+		gpsTable[i].when = geoSettings.value(QString("gpsFix%1_time").arg(i)).toULongLong();
+	}
+
+	// now walk the dive table and see if we can fill in missing gps data
+	struct dive *d;
+	for_each_dive(i, d) {
+		if (dive_has_gps_location(d))
+			continue;
+		for (int j = last; j < cnt; j++) {
+			if (time_during_dive_with_offset(d, gpsTable[j].when, SAME_GROUP)) {
+				if (verbose)
+					qDebug() << "processing gpsfix @" << get_dive_date_string(gpsTable[j].when) <<
+						    "which is withing six hours of dive from" <<
+						    get_dive_date_string(d->when) << "until" <<
+						    get_dive_date_string(d->when + d->duration.seconds);
+				/*
+				 * If position is fixed during dive. This is the good one.
+				 * Asign and mark position, and end gps_location loop
+				 */
+				if (time_during_dive_with_offset(d, gpsTable[j].when, 0)) {
+					if (verbose)
+						qDebug() << "gpsfix is during the dive, pick that one";
+					copy_gps_location(gpsTable + j, d);
+					changed = true;
+					last = j;
+					break;
+				} else {
+					/*
+					 * If it is not, check if there are more position fixes in SAME_GROUP range
+					 */
+					if (j + 1 < cnt && time_during_dive_with_offset(d, gpsTable[j+1].when, SAME_GROUP)) {
+						if (verbose)
+							qDebug() << "look at the next gps fix @" << get_dive_date_string(gpsTable[j+1].when);
+						/* first let's test if this one is during the dive */
+						if (time_during_dive_with_offset(d, gpsTable[j+1].when, 0)) {
+							if (verbose)
+								qDebug() << "which is during the dive, pick that one";
+							copy_gps_location(gpsTable + j + 1, d);
+							changed = true;
+							last = j + 1;
+							break;
+						}
+						/* we know the gps fixes are sorted; if they are both before the dive, ignore the first,
+						 * if theay are both after the dive, take the first,
+						 * if the first is before and the second is after, take the closer one */
+						if (gpsTable[j+1].when < d->when) {
+							if (verbose)
+								qDebug() << "which is closer to the start of the dive, do continue with that";
+							continue;
+						} else if (gpsTable[j].when > d->when + d->duration.seconds) {
+							if (verbose)
+								qDebug() << "which is even later after the end of the dive, so pick the previous one";
+							copy_gps_location(gpsTable + j, d);
+							changed = true;
+							last = j;
+							break;
+						} else {
+							/* ok, gpsfix is before, nextgpsfix is after */
+							if (d->when - gpsTable[j].when <= gpsTable[j+1].when - (d->when + d->duration.seconds)) {
+								if (verbose)
+									qDebug() << "pick the one before as it's closer to the start";
+								copy_gps_location(gpsTable + j, d);
+								changed = true;
+								last = j;
+								break;
+							} else {
+								if (verbose)
+									qDebug() << "pick the one after as it's closer to the start";
+								copy_gps_location(gpsTable + j + 1, d);
+								changed = true;
+								last = j + 1;
+								break;
+							}
+						}
+					/*
+					 * If no more positions in range, the actual is the one. Asign, mark and end loop.
+					 */
+					} else {
+						if (verbose)
+							qDebug() << "which seems to be the best one for this dive, so pick it";
+						copy_gps_location(gpsTable + j, d);
+						changed = true;
+						last = j;
+						break;
+					}
+				}
+			} else {
+				/* If position is out of SAME_GROUP range and in the future, mark position for
+				 * next dive iteration and end the gps_location loop
+				 */
+				if (gpsTable[j].when >= d->when + d->duration.seconds + SAME_GROUP) {
+					last = j;
+					break;
+				}
+			}
+
+		}
+	}
+}

qt-mobile/gpslocation.h

@@ -13,6 +13,7 @@ class GpsLocation : QObject
 	Q_OBJECT
 public:
 	GpsLocation(QObject *parent);
+	bool applyLocations();
 
 private:
 	QGeoPositionInfo lastPos;