(svn r17147) -Fix [FS#3048]: Keep vehicle news and viewports following vehicles, when autoreplacing/renewing them.

src/autoreplace_cmd.cpp

@@ -4,7 +4,6 @@
 
 #include "stdafx.h"
 #include "company_func.h"
-#include "vehicle_gui.h"
 #include "train.h"
 #include "rail.h"
 #include "command_func.h"
@@ -18,6 +17,10 @@
 
 #include "table/strings.h"
 
+extern void ChangeVehicleViewports(VehicleID from_index, VehicleID to_index);
+extern void ChangeVehicleNews(VehicleID from_index, VehicleID to_index);
+extern void ChangeVehicleViewWindow(VehicleID from_index, VehicleID to_index);
+
 /** Figure out if two engines got at least one type of cargo in common (refitting if needed)
  * @param engine_a one of the EngineIDs
  * @param engine_b the other EngineID
@@ -332,8 +335,10 @@ static CommandCost CopyHeadSpecificThings(Vehicle *old_head, Vehicle *new_head,
 		/* Copy other things which cannot be copied by a command and which shall not stay resetted from the build vehicle command */
 		new_head->CopyVehicleConfigAndStatistics(old_head);
 
-		/* Switch vehicle windows to the new vehicle, so they are not closed when the old vehicle is sold */
+		/* Switch vehicle windows/news to the new vehicle, so they are not closed/deleted when the old vehicle is sold */
+		ChangeVehicleViewports(old_head->index, new_head->index);
 		ChangeVehicleViewWindow(old_head->index, new_head->index);
+		ChangeVehicleNews(old_head->index, new_head->index);
 	}
 
 	return cost;

src/news_func.h

@@ -17,6 +17,15 @@ static inline void AddCompanyNewsItem(StringID string, NewsSubtype subtype, Comp
 	AddNewsItem(string, subtype, NR_NONE, UINT32_MAX, NR_NONE, UINT32_MAX, cni);
 }
 
+/**
+ * Adds a newsitem referencing a vehicle.
+ *
+ * @warning
+ * Be careful!
+ * Vehicles are a special case, as news are kept when vehicles are autoreplaced/renewed.
+ * You have to make sure, #ChangeVehicleNews catches the DParams of your message.
+ * This is NOT ensured by the references.
+ */
 static inline void AddVehicleNewsItem(StringID string, NewsSubtype subtype, VehicleID vehicle, StationID station = INVALID_STATION)
 {
 	AddNewsItem(string, subtype, NR_VEHICLE, vehicle, station == INVALID_STATION ? NR_NONE : NR_STATION, station);

src/news_gui.cpp

@@ -673,6 +673,29 @@ void RemoveOldNewsItems()
 	}
 }
 
+/**
+ * Report a change in vehicle IDs (due to autoreplace) to affected vehicle news.
+ * @note Viewports of currently displayed news is changed via #ChangeVehicleViewports
+ * @param from_index the old vehicle ID
+ * @param to_index the new vehicle ID
+ */
+void ChangeVehicleNews(VehicleID from_index, VehicleID to_index)
+{
+	for (NewsItem *ni = _oldest_news; ni != NULL; ni = ni->next) {
+		if (ni->reftype1 == NR_VEHICLE && ni->ref1 == from_index) ni->ref1 = to_index;
+		if (ni->reftype2 == NR_VEHICLE && ni->ref2 == from_index) ni->ref2 = to_index;
+
+		/* Oh noes :(
+		 * Autoreplace is breaking the whole news-reference concept here, as we want to keep the news,
+		 * but do not know which DParams to change.
+		 *
+		 * Currently only NS_ADVICE news have vehicle IDs in their DParams.
+		 * And all NS_ADVICE news have the ID in param 0.
+		 */
+		if (ni->subtype == NS_ADVICE && ni->params[0] == from_index) ni->params[0] = to_index;
+	}
+}
+
 void NewsLoop()
 {
 	/* no news item yet */

src/news_type.h

@@ -68,6 +68,12 @@ enum NewsMode {
 
 /**
  * References to objects in news.
+ *
+ * @warning
+ * Be careful!
+ * Vehicles are a special case, as news are kept when vehicles are autoreplaced/renewed.
+ * You have to make sure, #ChangeVehicleNews catches the DParams of your message.
+ * This is NOT ensured by the references.
  */
 enum NewsReferenceType {
 	NR_NONE,      ///< Empty reference

src/vehicle_gui.h

@@ -78,10 +78,6 @@ void ShowVehicleListWindow(CompanyID company, VehicleType vehicle_type, StationI
 void ShowVehicleListWindow(CompanyID company, VehicleType vehicle_type, TileIndex depot_tile);
 
 
-/* ChangeVehicleViewWindow() moves all windows for one vehicle to another vehicle.
- * For ease of use it can be called with both Vehicle pointers and VehicleIDs. */
-void ChangeVehicleViewWindow(VehicleID from_index, VehicleID to_index);
-
 static inline uint GetVehicleListHeight(VehicleType type)
 {
 	return (type == VEH_TRAIN || type == VEH_ROAD) ? 14 : 24;

src/window.cpp

@@ -2663,6 +2663,24 @@ void SetHScrollCount(Window *w, int num)
 	if (num < w->hscroll.pos) w->hscroll.pos = num;
 }
 
+
+/**
+ * Switches viewports following vehicles, which get autoreplaced
+ * @param from_index the old vehicle ID
+ * @param to_index the new vehicle ID
+ */
+void ChangeVehicleViewports(VehicleID from_index, VehicleID to_index)
+{
+	Window *w;
+	FOR_ALL_WINDOWS_FROM_BACK(w) {
+		if (w->viewport != NULL && w->viewport->follow_vehicle == from_index) {
+			w->viewport->follow_vehicle = to_index;
+			w->SetDirty();
+		}
+	}
+}
+
+
 /**
  * Relocate all windows to fit the new size of the game application screen
  * @param neww New width of the game application screen