Dive site: create new dive site at location from GPS data

Some dive computers save GPS data. Currently, this is stored
by libdivecomputer in an "extra field". When generating a
new dive site for a dive try to use this data to place the
dive site.

To do so, create a "dive_get_gps_location()" function. This
function can be extended later to use e.g. event. When creating
a dive site, use the result of this function over a potential
pre-existing dive site.

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

core/dive.c

@@ -4500,6 +4500,53 @@ int dive_has_gps_location(const struct dive *dive)
 	return dive_site_has_gps_location(dive->dive_site);
 }
 
+/* Extract GPS location of a dive computer stored in the GPS1
+ * or GPS2 extra data fields */
+static location_t dc_get_gps_location(const struct divecomputer *dc)
+{
+	location_t res = { };
+
+	for (struct extra_data *data = dc->extra_data; data; data = data->next) {
+		if (!strcmp(data->key, "GPS1")) {
+			parse_location(data->value, &res);
+			/* If we found a valid GPS1 field exit early since
+			 * it has priority over GPS2 */
+			if (has_location(&res))
+				break;
+		} else if (!strcmp(data->key, "GPS2")) {
+			/* For GPS2 fields continue searching, as we might
+			 * still find a GPS1 field */
+			parse_location(data->value, &res);
+		}
+	}
+	return res;
+}
+
+/* Get GPS location for a dive. Highest priority is given to the GPS1
+ * extra data written by libdivecomputer, as this comes from a real GPS
+ * device. If that doesn't exits, use the currently set dive site.
+ * This function is potentially slow, therefore only call sparingly
+ * and remember the result.
+ */
+location_t dive_get_gps_location(const struct dive *d)
+{
+	location_t res = { };
+
+	for (const struct divecomputer *dc = &d->dc; dc; dc = dc->next) {
+		res = dc_get_gps_location(dc);
+		if (has_location(&res))
+			return res;
+	}
+
+	/* No libdivecomputer generated GPS data found.
+	 * Let's use the location of the current dive site.
+	 */
+	if (d->dive_site)
+		res = d->dive_site->location;
+
+	return res;
+}
+
 /* When evaluated at the time of a gasswitch, this returns the new gas */
 struct gasmix get_gasmix(const struct dive *dive, const struct divecomputer *dc, int time, const struct event **evp, struct gasmix gasmix)
 {

core/dive.h

@@ -456,6 +456,7 @@ extern struct dive *get_dive_by_uniq_id(int id);
 extern int get_idx_by_uniq_id(int id);
 extern bool dive_site_has_gps_location(const struct dive_site *ds);
 extern int dive_has_gps_location(const struct dive *dive);
+extern location_t dive_get_gps_location(const struct dive *d);
 
 extern int report_error(const char *fmt, ...);
 extern void set_error_cb(void(*cb)(char *));	// Callback takes ownership of passed string

desktop-widgets/command_edit.cpp

@@ -341,6 +341,14 @@ static struct dive_site *createDiveSite(const QString &name)
 		copy_dive_site(old, ds);
 		free(ds->name); // Free name, as we will overwrite it with our own version
 	}
+
+	// If the current dive has a location, use that as location for the new dive site
+	if (current_dive) {
+		location_t loc = dive_get_gps_location(current_dive);
+		if (has_location(&loc))
+			ds->location = loc;
+	}
+
 	ds->name = copy_qstring(name);
 	return ds;
 }