Change: Use per-company group numbers.

This is used by the default group name, replacing the use of group index.

regression/regression/result.txt

@@ -6093,7 +6093,7 @@ ERROR: IsEnd() is invalid as Begin() is never called
   GetNumEngines():          1
   GetNumEngines():          1
   GetNumEngines():          0
-  GetName():                Group 0
+  GetName():                Group 1
   GetName():                (null : 0x00000000)
   AIVehicle.SellVehicle():  true
   AITile.DemolishTile():    true

src/company_base.h

@@ -144,6 +144,7 @@ struct Company : CompanyProperties, CompanyPool::PoolItem<&_company_pool> {
 	CompanyInfrastructure infrastructure; ///< NOSAVE: Counts of company owned infrastructure.
 
 	FreeUnitIDGenerator freeunits[VEH_COMPANY_END];
+	FreeUnitIDGenerator freegroups;
 
 	Money GetMaxLoan() const;
 

src/economy.cpp

@@ -424,8 +424,12 @@ void ChangeOwnershipOfCompanyItems(Owner old_owner, Owner new_owner)
 	if (new_owner == INVALID_OWNER) {
 		RemoveAllGroupsForCompany(old_owner);
 	} else {
+		Company *c = Company::Get(old_owner);
 		for (Group *g : Group::Iterate()) {
-			if (g->owner == old_owner) g->owner = new_owner;
+			if (g->owner == old_owner) {
+				g->owner = new_owner;
+				g->number = c->freegroups.UseID(c->freegroups.NextID());
+			}
 		}
 	}
 

src/group.h

@@ -81,6 +81,7 @@ struct Group : GroupPool::PoolItem<&_group_pool> {
 	bool folded;                ///< NOSAVE: Is this group folded in the group view?
 
 	GroupID parent;             ///< Parent group
+	uint16_t number; ///< Per-company group number.
 
 	Group(CompanyID owner = INVALID_COMPANY);
 };

src/group_cmd.cpp

@@ -350,8 +350,9 @@ std::tuple<CommandCost, GroupID> CmdCreateGroup(DoCommandFlag flags, VehicleType
 		g->vehicle_type = vt;
 		g->parent = INVALID_GROUP;
 
+		Company *c = Company::Get(g->owner);
+		g->number = c->freegroups.UseID(c->freegroups.NextID());
 		if (pg == nullptr) {
-			const Company *c = Company::Get(_current_company);
 			g->livery.colour1 = c->livery[LS_DEFAULT].colour1;
 			g->livery.colour2 = c->livery[LS_DEFAULT].colour2;
 			if (c->settings.renew_keep_length) SetBit(g->flags, GroupFlags::GF_REPLACE_WAGON_REMOVAL);
@@ -397,14 +398,15 @@ CommandCost CmdDeleteGroup(DoCommandFlag flags, GroupID group_id)
 		/* Update backupped orders if needed */
 		OrderBackup::ClearGroup(g->index);
 
-		/* If we set an autoreplace for the group we delete, remove it. */
-		if (_current_company < MAX_COMPANIES) {
-			Company *c;
+		if (g->owner < MAX_COMPANIES) {
+			Company *c = Company::Get(g->owner);
 
-			c = Company::Get(_current_company);
+			/* If we set an autoreplace for the group we delete, remove it. */
 			for (EngineRenew *er : EngineRenew::Iterate()) {
 				if (er->group_id == g->index) RemoveEngineReplacementForCompany(c, er->from, g->index, flags);
 			}
+
+			c->freegroups.ReleaseID(g->number);
 		}
 
 		VehicleType vt = g->vehicle_type;

src/group_gui.cpp

@@ -180,7 +180,7 @@ void BuildGuiGroupList(GUIGroupList &dst, bool fold, Owner owner, VehicleType ve
 		}
 
 		int r = StrNaturalCompare(last_group[0].second, last_group[1].second); // Sort by name (natural sorting).
-		if (r == 0) return a.group->index < b.group->index;
+		if (r == 0) return a.group->number < b.group->number;
 		return r < 0;
 	});
 

src/saveload/afterload.cpp

@@ -3286,6 +3286,17 @@ bool AfterLoadGame()
 		UpdateCompanyLiveries(c);
 	}
 
+	/* Update free group numbers data for each company, required regardless of savegame version. */
+	for (Group *g : Group::Iterate()) {
+		Company *c = Company::Get(g->owner);
+		if (IsSavegameVersionBefore(SLV_GROUP_NUMBERS)) {
+			/* Use the index as group number when converting old savegames. */
+			g->number = c->freegroups.UseID(g->index);
+		} else {
+			c->freegroups.UseID(g->number);
+		}
+	}
+
 	AfterLoadLabelMaps();
 	AfterLoadCompanyStats();
 	AfterLoadStoryBook();

src/saveload/group_sl.cpp

@@ -26,6 +26,7 @@ static const SaveLoad _group_desc[] = {
 	 SLE_CONDVAR(Group, livery.colour1,     SLE_UINT8,                     SLV_GROUP_LIVERIES, SL_MAX_VERSION),
 	 SLE_CONDVAR(Group, livery.colour2,     SLE_UINT8,                     SLV_GROUP_LIVERIES, SL_MAX_VERSION),
 	 SLE_CONDVAR(Group, parent,             SLE_UINT16,                    SLV_189, SL_MAX_VERSION),
+	 SLE_CONDVAR(Group, number, SLE_UINT16, SLV_GROUP_NUMBERS, SL_MAX_VERSION),
 };
 
 struct GRPSChunkHandler : ChunkHandler {

src/saveload/saveload.h

@@ -379,6 +379,8 @@ enum SaveLoadVersion : uint16_t {
 	SLV_SCRIPT_RANDOMIZER,                  ///< 333  PR#12063 v14.0-RC1 Save script randomizers.
 	SLV_VEHICLE_ECONOMY_AGE,                ///< 334  PR#12141 v14.0 Add vehicle age in economy year, for profit stats minimum age
 
+	SLV_GROUP_NUMBERS,                      ///< 335  PR#12297 Add per-company group numbers.
+
 	SL_MAX_VERSION,                         ///< Highest possible saveload version
 };
 

src/strings.cpp

@@ -1539,7 +1539,7 @@ static void FormatString(StringBuilder &builder, const char *str_arg, StringPara
 						auto tmp_params = MakeParameters(g->name);
 						GetStringWithArgs(builder, STR_JUST_RAW_STRING, tmp_params);
 					} else {
-						auto tmp_params = MakeParameters(g->index);
+						auto tmp_params = MakeParameters(g->number);
 						GetStringWithArgs(builder, STR_FORMAT_GROUP_NAME, tmp_params);
 					}
 					break;