Undo: select dives after add, remove, merge, split dive commands

Select the proper dives after the add, remove, split and merge
dives commands on undo *and* redo. Generally, select the added
dives. For undo of add, remember the pre-addition selection.
For redo of remove, select the closest dive to the first removed
dive.

The biggest part of the commit is the signal-interface between
the dive commands and the dive-list model and dive-list view.
This is done in two steps:
1) To the DiveTripModel in batches of trips. The dive trip model
   transforms the dives into indices.
2) To the DiveListView. The DiveListView has to translate the
   DiveTripModel indexes to actual indexes via its QSortFilterProxy-
   model.

For code-reuse, derive all divelist-changing commands from a new base-class,
which has a flag that describes whether the divelist changed. The helper
functions which add and remove dives are made members of the base class and
set the flag is a selected dive is added or removed.

To properly detect when the current dive was deleted it
became necessary to turn the current dive from an index
to a pointer, because indices are not stable.

Unfortunately, in some cases an index was expected and these
places now have to transform the dive into an index. These
should be converted in due course.

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

1 files changed, 59 insertions, 23 deletions

diff --git a/core/divelist.c b/core/divelist.c
index 1c6ad9fc0..72685b40f 100644
--- a/core/divelist.c
+++ b/core/divelist.c
@@ -32,14 +32,18 @@
  * void delete_single_dive(int idx)
  * void add_single_dive(int idx, struct dive *dive)
  * struct dive *merge_two_dives(struct dive *a, struct dive *b)
- * void select_dive(int idx)
- * void deselect_dive(int idx)
+ * void select_dive(struct dive *dive)
+ * void deselect_dive(struct dive *dive)
  * void mark_divelist_changed(int changed)
  * int unsaved_changes()
  * void remove_autogen_trips()
  * void sort_table(struct dive_table *table)
  * bool is_trip_before_after(const struct dive *dive, bool before)
+<<<<<<< HEAD
  * void delete_dive_from_table(struct dive_table *table, int idx)
+=======
+ * int find_next_visible_dive(timestamp_t when);
+>>>>>>> Undo: select dives after add, remove, merge, split dive commands
  */
 #include <unistd.h>
 #include <stdio.h>
@@ -1058,7 +1062,8 @@ void delete_dive_from_table(struct dive_table *table, int idx)
 
 /* this removes a dive from the dive table and trip-list but doesn't
  * free the resources associated with the dive. It returns a pointer
- * to the unregistered dive. */
+ * to the unregistered dive. The returned dive has the selection-
+ * and hidden-flags cleared. */
 struct dive *unregister_dive(int idx)
 {
 	struct dive *dive = get_dive(idx);
@@ -1068,6 +1073,7 @@ struct dive *unregister_dive(int idx)
 	unregister_dive_from_table(&dive_table, idx);
 	if (dive->selected)
 		amount_selected--;
+	dive->selected = false;
 	return dive;
 }
 
@@ -1079,7 +1085,7 @@ void delete_single_dive(int idx)
 	if (!dive)
 		return; /* this should never happen */
 	if (dive->selected)
-		deselect_dive(idx);
+		deselect_dive(dive);
 	dive = unregister_dive(idx);
 	free_dive(dive);
 }
@@ -1104,6 +1110,7 @@ struct dive **grow_dive_table(struct dive_table *table)
  * ordered reverse-chronologically */
 int dive_get_insertion_index(struct dive *dive)
 {
+	/* we might want to use binary search here */
 	for (int i = 0; i < dive_table.nr; i++) {
 		if (dive->when <= dive_table.dives[i]->when)
 			return i;
@@ -1235,42 +1242,42 @@ struct dive *merge_two_dives(struct dive *a, struct dive *b)
 	return res;
 }
 
-void select_dive(int idx)
+void select_dive(struct dive *dive)
 {
-	struct dive *dive = get_dive(idx);
-	if (dive) {
-		/* never select an invalid dive that isn't displayed */
-		if (!dive->selected) {
-			dive->selected = 1;
-			amount_selected++;
-		}
-		selected_dive = idx;
+	if (dive && !dive->selected) {
+		dive->selected = 1;
+		amount_selected++;
+		current_dive = dive;
 	}
 }
 
-void deselect_dive(int idx)
+void deselect_dive(struct dive *dive)
 {
-	struct dive *dive = get_dive(idx);
+	int idx;
 	if (dive && dive->selected) {
 		dive->selected = 0;
 		if (amount_selected)
 			amount_selected--;
-		if (selected_dive == idx && amount_selected > 0) {
+		if (current_dive == dive && amount_selected > 0) {
 			/* pick a different dive as selected */
+			int selected_dive = idx = get_divenr(dive);
 			while (--selected_dive >= 0) {
 				dive = get_dive(selected_dive);
-				if (dive && dive->selected)
+				if (dive && dive->selected) {
+					current_dive = dive;
 					return;
+				}
 			}
 			selected_dive = idx;
 			while (++selected_dive < dive_table.nr) {
 				dive = get_dive(selected_dive);
-				if (dive && dive->selected)
+				if (dive && dive->selected) {
+					current_dive = dive;
 					return;
+				}
 			}
 		}
-		if (amount_selected == 0)
-			selected_dive = -1;
+		current_dive = NULL;
 	}
 }
 
@@ -1280,7 +1287,7 @@ void deselect_dives_in_trip(struct dive_trip *trip)
 	if (!trip)
 		return;
 	for (dive = trip->dives; dive; dive = dive->next)
-		deselect_dive(get_divenr(dive));
+		deselect_dive(dive);
 }
 
 void select_dives_in_trip(struct dive_trip *trip)
@@ -1290,7 +1297,7 @@ void select_dives_in_trip(struct dive_trip *trip)
 		return;
 	for (dive = trip->dives; dive; dive = dive->next)
 		if (!dive->hidden_by_filter)
-			select_dive(get_divenr(dive));
+			select_dive(dive);
 }
 
 void filter_dive(struct dive *d, bool shown)
@@ -1299,7 +1306,7 @@ void filter_dive(struct dive *d, bool shown)
 		return;
 	d->hidden_by_filter = !shown;
 	if (!shown && d->selected)
-		deselect_dive(get_divenr(d));
+		deselect_dive(d);
 }
 
 
@@ -1610,6 +1617,7 @@ int get_dive_nr_at_idx(int idx)
 
 void set_dive_nr_for_current_dive()
 {
+	int selected_dive = get_divenr(current_dive);
 	if (dive_table.nr == 1)
 		current_dive->number = 1;
 	else if (selected_dive == dive_table.nr - 1 && get_dive(dive_table.nr - 2)->number)
@@ -1719,3 +1727,31 @@ timestamp_t get_surface_interval(timestamp_t when)
 		return 0;
 	return when - prev_end;
 }
+
+/* Find visible dive close to given date. First search towards older,
+ * then newer dives. */
+struct dive *find_next_visible_dive(timestamp_t when)
+{
+	int i, j;
+
+	if (!dive_table.nr)
+		return NULL;
+
+	/* we might want to use binary search here */
+	for (i = 0; i < dive_table.nr; i++) {
+		if (when <= get_dive(i)->when)
+			break;
+	}
+
+	for (j = i - 1; j > 0; j--) {
+		if (!get_dive(j)->hidden_by_filter)
+			return get_dive(j);
+	}
+
+	for (j = i; j < dive_table.nr; j++) {
+		if (!get_dive(j)->hidden_by_filter)
+			return get_dive(j);
+	}
+
+	return NULL;
+}