(svn r3535) -Feature: [autoreplace] allow autoreplacing of train wagons

	currently ALL available wagons are displayed in the right menu in the replace window
	however the replacement will only be done if the new wagon can be refitted to carry same cargo as the old one is currently carrying

	Since the standard vehicles do not have any valid wagon replacements, this feature can only be used when using newgrf sets

5 files changed, 35 insertions, 7 deletions

diff --git a/lang/english.txt b/lang/english.txt
index 0db025bf6..86a7b85f3 100644
--- a/lang/english.txt
+++ b/lang/english.txt
@@ -2769,8 +2769,13 @@ STR_REPLACE_HELP_REPLACE_INFO_TAB                               :{BLACK}Displays
 STR_REPLACE_HELP                                                :{BLACK}This allows you to replace one engine type with another type, when trains of the original type enter a depot
 STR_REPLACE_REMOVE_WAGON                                        :{BLACK}Wagon removal: {ORANGE}{SKIP}{STRING}
 STR_REPLACE_REMOVE_WAGON_HELP                                   :{BLACK}Make autoreplace keep the length of a train the same by removing wagons (starting at the front), if replacing the engine would make the train longer.
+STR_REPLACE_ENGINE_WAGON_SELECT                                 :{BLACK}Replacing: {ORANGE}{SKIP}{SKIP}{STRING}
+STR_REPLACE_ENGINE_WAGON_SELECT_HELP                            :{BLACK} EXPERIMENTAL FEATURE {}Switch between engine and wagon replacement windows.{}Wagon replacement will only be done if the new wagon can be refitted into carrying the same type of cargo as the old one. This is checked for each wagon when the actual replacement takes place.
 STR_ENGINE_NOT_BUILDABLE                                        :{WHITE}Engine is not buildable
 
+STR_ENGINES                                                     :Engines
+STR_WAGONS                                                      :Wagons
+
 STR_SHORT_DATE                                                  :{WHITE}{DATE_TINY}
 STR_SIGN_LIST_CAPTION                                           :{WHITE}Sign List - {COMMA} Sign{P "" s}
 
diff --git a/train_cmd.c b/train_cmd.c
index 01e6554f5..ce67e3bb3 100644
--- a/train_cmd.c
+++ b/train_cmd.c
@@ -584,6 +584,9 @@ static int32 CmdBuildRailWagon(EngineID engine, TileIndex tile, uint32 flags)
 			TrainConsistChanged(GetFirstVehicleInChain(v));
 
 			InvalidateWindow(WC_VEHICLE_DEPOT, v->tile);
+			if (IsLocalPlayer()) {
+				InvalidateWindow(WC_REPLACE_VEHICLE, VEH_Train); // updates the replace Train window
+			}
 		}
 	}
 
diff --git a/vehicle.c b/vehicle.c
index ffd513a33..5d67f6200 100644
--- a/vehicle.c
+++ b/vehicle.c
@@ -1742,6 +1742,11 @@ static void MaybeReplaceVehicle(Vehicle *v)
 					continue;
 			}
 
+			if (w->type == VEH_Train && IsTrainWagon(w) && !CanRefitTo(EngineReplacementForPlayer(p, w->engine_type), w->cargo_type)) {
+				// we can't replace this wagon since we can't refit the new one to the right cargo type
+				continue;
+			}
+
 			/* Now replace the vehicle */
 			temp_cost = ReplaceVehicle(&w, flags);
 
diff --git a/vehicle_gui.c b/vehicle_gui.c
index 51d810f34..0b2f77387 100644
--- a/vehicle_gui.c
+++ b/vehicle_gui.c
@@ -464,7 +464,7 @@ static void train_engine_drawing_loop(int *x, int *y, int *pos, int *sel, Engine
 
 		if (!EngineHasReplacementForPlayer(p, i) && _player_num_engines[i] == 0 && show_outdated) continue;
 
-		if (rvi->power == 0 && !show_cars)   // disables display of cars (works since they do not have power)
+		if ((rvi->power == 0 && !show_cars) || (rvi->power != 0 && show_cars))  // show wagons or engines (works since wagons do not have power)
 			continue;
 
 		if (*sel == 0) *selected_id = i;
@@ -520,7 +520,7 @@ static void SetupScrollStuffForReplaceWindow(Window *w)
 				const Engine *e = GetEngine(engine_id);
 				const EngineInfo *info = &_engine_info[engine_id];
 
-				if (ENGINE_AVAILABLE && RailVehInfo(engine_id)->power && e->railtype == railtype) {
+				if (ENGINE_AVAILABLE && ((RailVehInfo(engine_id)->power && WP(w, replaceveh_d).wagon_btnstate) || (!RailVehInfo(engine_id)->power && !WP(w, replaceveh_d).wagon_btnstate)) && e->railtype == railtype) {
 					if (_player_num_engines[engine_id] > 0 || EngineHasReplacementForPlayer(p, engine_id)) {
 						if (sel[0] == 0) selected_id[0] = engine_id;
 						count++;
@@ -667,9 +667,14 @@ static void DrawEngineArrayInReplaceWindow(Window *w, int x, int y, int x2, int
 			* XXX - DO NOT EVER DO THIS EVER AGAIN! GRRR hacking in wagons as
 			* engines to get more types.. Stays here until we have our own format
 			* then it is exit!!! */
-			train_engine_drawing_loop(&x, &y, &pos, &sel[0], &selected_id[0], railtype, w->vscroll.cap, true, false, true); // True engines
-			train_engine_drawing_loop(&x2, &y2, &pos2, &sel[1], &selected_id[1], railtype, w->vscroll.cap, true, false, false); // True engines
-			train_engine_drawing_loop(&x2, &y2, &pos2, &sel[1], &selected_id[1], railtype, w->vscroll.cap, false, false, false); // Feeble wagons
+			if (WP(w,replaceveh_d).wagon_btnstate) {
+				train_engine_drawing_loop(&x, &y, &pos, &sel[0], &selected_id[0], railtype, w->vscroll.cap, true, false, true); // True engines
+				train_engine_drawing_loop(&x2, &y2, &pos2, &sel[1], &selected_id[1], railtype, w->vscroll.cap, true, false, false); // True engines
+				train_engine_drawing_loop(&x2, &y2, &pos2, &sel[1], &selected_id[1], railtype, w->vscroll.cap, false, false, false); // Feeble wagons
+			} else {
+				train_engine_drawing_loop(&x, &y, &pos, &sel[0], &selected_id[0], railtype, w->vscroll.cap, false, true, true);
+				train_engine_drawing_loop(&x2, &y2, &pos2, &sel[1], &selected_id[1], railtype, w->vscroll.cap, false, true, false);
+			}
 			break;
 		}
 
@@ -888,6 +893,9 @@ static void ReplaceVehicleWndProc(Window *w, WindowEvent *e)
 				if (WP(w, replaceveh_d).vehicletype == VEH_Train) {
 					// set on/off for renew_keep_length
 					SetDParam(1, p->renew_keep_length ? STR_CONFIG_PATCHES_ON : STR_CONFIG_PATCHES_OFF);
+
+					// set wagon/engine button
+					SetDParam(2, WP(w, replaceveh_d).wagon_btnstate ? STR_ENGINES : STR_WAGONS);
 				}
 
 				DrawWindowWidgets(w);
@@ -919,7 +927,7 @@ static void ReplaceVehicleWndProc(Window *w, WindowEvent *e)
 						for (i = 0 ; i < 2 ; i++) {
 							if (i > 0) offset = 228;
 							if (selected_id[i] != INVALID_ENGINE) {
-								if (!(RailVehInfo(selected_id[i])->flags & RVI_WAGON)) {
+								if (WP(w, replaceveh_d).wagon_btnstate) {
 									/* it's an engine */
 									DrawTrainEnginePurchaseInfo(2 + offset, 15 + (14 * w->vscroll.cap), selected_id[i]);
 								} else {
@@ -970,6 +978,11 @@ static void ReplaceVehicleWndProc(Window *w, WindowEvent *e)
 			byte click_side = 1;
 
 			switch (e->click.widget) {
+				case 12: {
+						WP(w, replaceveh_d).wagon_btnstate = !(WP(w, replaceveh_d).wagon_btnstate);
+						SetWindowDirty(w);
+						break;
+					}
 				case 14: case 15: { /* Select sorting criteria dropdown menu */
 					ShowDropDownMenu(w, _rail_types_list, _railtype_selected_in_replace_gui, 15, 0, ~GetPlayer(_local_player)->avail_railtypes);
 					break;
@@ -1036,7 +1049,7 @@ static const Widget _replace_rail_vehicle_widgets[] = {
 { WWT_SCROLL2BAR, RESIZE_BOTTOM,    14,   444,   455,    14,   125, STR_NULL,       STR_0190_SCROLL_BAR_SCROLLS_LIST},
 {      WWT_PANEL,     RESIZE_TB,    14,   228,   455,   126,   197, STR_NULL,       STR_NULL},
 // train specific stuff
-{      WWT_PANEL,     RESIZE_TB,    14,     0,   138,   198,   209, STR_NULL,       STR_NULL},
+{ WWT_PUSHTXTBTN,     RESIZE_TB,    14,     0,   138,   198,   209, STR_REPLACE_ENGINE_WAGON_SELECT,       STR_REPLACE_ENGINE_WAGON_SELECT_HELP},  // widget 12
 {      WWT_PANEL,     RESIZE_TB,    14,   139,   153,   210,   221, STR_NULL,       STR_NULL},
 {      WWT_PANEL,     RESIZE_TB,    14,   154,   277,   210,   221, STR_NULL,       STR_REPLACE_HELP_RAILTYPE},
 {    WWT_TEXTBTN,     RESIZE_TB,    14,   278,   289,   210,   221, STR_0225,       STR_REPLACE_HELP_RAILTYPE},
@@ -1117,6 +1130,7 @@ void ShowReplaceVehicleWindow(byte vehicletype)
 			w = AllocateWindowDescFront(&_replace_rail_vehicle_desc, vehicletype);
 			w->vscroll.cap  = 8;
 			w->resize.step_height = 14;
+			WP(w, replaceveh_d).wagon_btnstate = true;
 			break;
 		case VEH_Road:
 			w = AllocateWindowDescFront(&_replace_road_vehicle_desc, vehicletype);
diff --git a/window.h b/window.h
index 2caef2abe..54df4c76e 100644
--- a/window.h
+++ b/window.h
@@ -353,6 +353,7 @@ typedef struct {
 	byte sel_index[2];
 	EngineID sel_engine[2];
 	uint16 count[2];
+	bool wagon_btnstate;	// true means engine is selected
 } replaceveh_d;
 assert_compile(WINDOW_CUSTOM_SIZE >= sizeof(replaceveh_d));