When deleting a cylinder, adapt gas changes

When we delete a cylinder the gas changes in that dive may have to be
adjusted. We didn't do this at all in the past. With this commit we should
be doing this right for a single dive that is being edited.

This does NOT handle multiple dives being edited at the same time (or more
specifically - if you have multiple dives selected and delete a cylinder,
the dives that had the same set of cylinders (other than the displayed
dive) will get that particular cylinder deleted, but won't have their gas
change events (and sensor data in the samples) adapted.

Possibly we should simply prohibit deleting cylinders when more than one
dive are selected.

See #834

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

4 files changed, 29 insertions, 2 deletions

diff --git a/dive.c b/dive.c
index bdb6937d4..2b98c2a77 100644
--- a/dive.c
+++ b/dive.c
@@ -1758,7 +1758,7 @@ static void add_initial_gaschange(struct dive *dive, struct divecomputer *dc)
 	add_gas_switch_event(dive, dc, 0, 0);
 }
 
-static void dc_cylinder_renumber(struct dive *dive, struct divecomputer *dc, int mapping[])
+void dc_cylinder_renumber(struct dive *dive, struct divecomputer *dc, int mapping[])
 {
 	int i;
 	struct event *ev;
@@ -2259,7 +2259,7 @@ struct dive *try_to_merge(struct dive *a, struct dive *b, bool prefer_downloaded
 	return NULL;
 }
 
-static void free_events(struct event *ev)
+void free_events(struct event *ev)
 {
 	while (ev) {
 		struct event *next = ev->next;
diff --git a/dive.h b/dive.h
index af4eb0d38..c50fb1a91 100644
--- a/dive.h
+++ b/dive.h
@@ -349,6 +349,7 @@ struct dive {
 };
 
 extern int get_cylinder_idx_by_use(struct dive *dive, enum cylinderuse cylinder_use_type);
+extern void dc_cylinder_renumber(struct dive *dive, struct divecomputer *dc, int mapping[]);
 
 /* when selectively copying dive information, which parts should be copied? */
 struct dive_components {
@@ -721,6 +722,7 @@ extern struct dive *merge_dives(struct dive *a, struct dive *b, int offset, bool
 extern struct dive *try_to_merge(struct dive *a, struct dive *b, bool prefer_downloaded);
 extern void renumber_dives(int start_nr, bool selected_only);
 extern void copy_events(struct divecomputer *s, struct divecomputer *d);
+extern void free_events(struct event *ev);
 extern void copy_cylinders(struct dive *s, struct dive *d, bool used_only);
 extern void copy_samples(struct divecomputer *s, struct divecomputer *d);
 extern bool is_cylinder_used(struct dive *dive, int idx);
diff --git a/qt-ui/maintab.cpp b/qt-ui/maintab.cpp
index a75b80722..314626c5d 100644
--- a/qt-ui/maintab.cpp
+++ b/qt-ui/maintab.cpp
@@ -813,6 +813,16 @@ void MainTab::acceptChanges()
 				cd->cylinder[i] = displayed_dive.cylinder[i];
 				cd->cylinder[i].type.description = copy_string(displayed_dive.cylinder[i].type.description);
 			}
+			/* if cylinders changed we may have changed gas change events
+			 * - so far this is ONLY supported for a single selected dive */
+			struct divecomputer *tdc = &current_dive->dc;
+			struct divecomputer *sdc = &displayed_dive.dc;
+			while(tdc && sdc) {
+				free_events(tdc->events);
+				copy_events(sdc, tdc);
+				tdc = tdc->next;
+				sdc = sdc->next;
+			}
 			do_replot = true;
 		}
 
diff --git a/qt-ui/models.cpp b/qt-ui/models.cpp
index 6376bb82a..d6b425b52 100644
--- a/qt-ui/models.cpp
+++ b/qt-ui/models.cpp
@@ -388,6 +388,7 @@ Qt::ItemFlags CylindersModel::flags(const QModelIndex &index) const
 
 void CylindersModel::remove(const QModelIndex &index)
 {
+	int mapping[MAX_CYLINDERS];
 	if (index.column() != REMOVE) {
 		return;
 	}
@@ -395,6 +396,7 @@ void CylindersModel::remove(const QModelIndex &index)
 	cylinder_t *cyl = &displayed_dive.cylinder[index.row()];
 	struct gasmix *mygas = &cyl->gasmix;
 	for (int i = 0; i < MAX_CYLINDERS; i++) {
+		mapping[i] = i;
 		if (i == index.row() || cylinder_none(&displayed_dive.cylinder[i]))
 			continue;
 		struct gasmix *gas2 = &displayed_dive.cylinder[i].gasmix;
@@ -419,11 +421,24 @@ void CylindersModel::remove(const QModelIndex &index)
 		// as first gas
 		memmove(cyl, &displayed_dive.cylinder[same_gas], sizeof(*cyl));
 		remove_cylinder(&displayed_dive, same_gas);
+		mapping[same_gas] = 0;
+		for (int i = same_gas + 1; i < MAX_CYLINDERS; i++)
+			mapping[i] = i - 1;
 	} else {
 		remove_cylinder(&displayed_dive, index.row());
+		if (same_gas > index.row())
+			same_gas--;
+		mapping[index.row()] = same_gas;
+		for (int i = index.row() + 1; i < MAX_CYLINDERS; i++)
+			mapping[i] = i - 1;
 	}
 	changed = true;
 	endRemoveRows();
+	struct divecomputer *dc = &displayed_dive.dc;
+	while (dc) {
+		dc_cylinder_renumber(&displayed_dive, dc, mapping);
+		dc = dc->next;
+	}
 }
 
 WeightModel::WeightModel(QObject *parent) : CleanerTableModel(parent),