(svn r17113) -Change [FS#265][FS#2094][FS#2589]: apply the subsidy when subsidy's destination is in station's catchment area and cargo packets originate from subsidy's source

-Change [FS#1134]: subsidies aren't bound to stations after awarding anymore, they still apply to town or industry, no matter what station is used for loading and unloading. Awarded subsidies from older savegames are lost
-Change [NoAI]: due to these changes, AISubsidy::GetSource and AISubsidy::GetDestination now return STATION_INVALID for awarded subsidies

1 files changed, 131 insertions, 71 deletions

diff --git a/src/subsidy.cpp b/src/subsidy.cpp
index d09030df4..ad79c37e0 100644
--- a/src/subsidy.cpp
+++ b/src/subsidy.cpp
@@ -22,27 +22,23 @@
 
 /**
  * Marks subsidy as awarded, creates news and AI event
- * @param from source station
- * @param to destination station
  * @param company awarded company
  */
-void Subsidy::AwardTo(StationID from, StationID to, CompanyID company)
+void Subsidy::AwardTo(CompanyID company)
 {
 	assert(!this->IsAwarded());
 
-	this->age = 12;
-	this->src_type = this->dst_type = ST_STATION;
-	this->src = from;
-	this->dst = to;
-
-	/* Add a news item */
-	Pair reftype = SetupSubsidyDecodeParam(this, 0);
-	InjectDParam(1);
+	this->awarded = company;
+	this->remaining = 12;
 
 	char *company_name = MallocT<char>(MAX_LENGTH_COMPANY_NAME_BYTES);
 	SetDParam(0, company);
 	GetString(company_name, STR_COMPANY_NAME, company_name + MAX_LENGTH_COMPANY_NAME_BYTES - 1);
 
+	/* Add a news item */
+	Pair reftype = SetupSubsidyDecodeParam(this, 0);
+	InjectDParam(1);
+
 	SetDParamStr(0, company_name);
 	AddNewsItem(
 		STR_NEWS_SERVICE_SUBSIDY_AWARDED_HALF + _settings_game.difficulty.subsidy_multiplier,
@@ -62,7 +58,10 @@ void Subsidy::AwardTo(StationID from, StationID to, CompanyID company)
 /* static */ Subsidy *Subsidy::AllocateItem()
 {
 	for (Subsidy *s = Subsidy::array; s < endof(Subsidy::array); s++) {
-		if (!s->IsValid()) return s;
+		if (!s->IsValid()) {
+			s->awarded = INVALID_COMPANY;
+			return s;
+		}
 	}
 
 	return NULL;
@@ -105,10 +104,6 @@ Pair SetupSubsidyDecodeParam(const Subsidy *s, bool mode)
 			reftype1 = NR_TOWN;
 			SetDParam(1, STR_TOWN_NAME);
 			break;
-		case ST_STATION:
-			reftype1 = NR_STATION;
-			SetDParam(1, s->src);
-			break;
 		default: NOT_REACHED();
 	}
 	SetDParam(2, s->src);
@@ -122,10 +117,6 @@ Pair SetupSubsidyDecodeParam(const Subsidy *s, bool mode)
 			reftype2 = NR_TOWN;
 			SetDParam(4, STR_TOWN_NAME);
 			break;
-		case ST_STATION:
-			reftype2 = NR_STATION;
-			SetDParam(2, s->dst);
-			break;
 		default: NOT_REACHED();
 	}
 	SetDParam(5, s->dst);
@@ -136,6 +127,42 @@ Pair SetupSubsidyDecodeParam(const Subsidy *s, bool mode)
 	return p;
 }
 
+/**
+ * Sets a flag indicating that given town/industry is part of subsidised route.
+ * @param type is it a town or an industry?
+ * @param index index of town/industry
+ * @param flag flag to set
+ */
+static inline void SetPartOfSubsidyFlag(SourceType type, SourceID index, PartOfSubsidy flag)
+{
+	switch (type) {
+		case ST_INDUSTRY: Industry::Get(index)->part_of_subsidy |= flag; return;
+		case ST_TOWN:         Town::Get(index)->part_of_subsidy |= flag; return;
+		default: NOT_REACHED();
+	}
+}
+
+void RebuildSubsidisedSourceAndDestinationCache()
+{
+	Town *t;
+	FOR_ALL_TOWNS(t) t->part_of_subsidy = POS_NONE;
+
+	Industry *i;
+	FOR_ALL_INDUSTRIES(i) i->part_of_subsidy = POS_NONE;
+
+	const Subsidy *s;
+	FOR_ALL_SUBSIDIES(s) {
+		SetPartOfSubsidyFlag(s->src_type, s->src, POS_SRC);
+		SetPartOfSubsidyFlag(s->dst_type, s->dst, POS_DST);
+	}
+}
+
+void DeleteSubsidy(Subsidy *s)
+{
+	s->cargo_type = CT_INVALID;
+	RebuildSubsidisedSourceAndDestinationCache();
+}
+
 void DeleteSubsidyWith(SourceType type, SourceID index)
 {
 	bool dirty = false;
@@ -252,23 +279,20 @@ void SubsidyMonthlyLoop()
 
 	Subsidy *s;
 	FOR_ALL_SUBSIDIES(s) {
-		if (s->age == 12 - 1) {
-			Pair reftype = SetupSubsidyDecodeParam(s, 1);
-			AddNewsItem(STR_NEWS_OFFER_OF_SUBSIDY_EXPIRED, NS_SUBSIDIES, (NewsReferenceType)reftype.a, s->src, (NewsReferenceType)reftype.b, s->dst);
-			s->cargo_type = CT_INVALID;
-			modified = true;
-			AI::BroadcastNewEvent(new AIEventSubsidyOfferExpired(s->Index()));
-		} else if (s->age == 2 * 12 - 1) {
-			Station *st = Station::Get(s->dst);
-			if (st->owner == _local_company) {
+		if (--s->remaining == 0) {
+			if (!s->IsAwarded()) {
 				Pair reftype = SetupSubsidyDecodeParam(s, 1);
-				AddNewsItem(STR_NEWS_SUBSIDY_WITHDRAWN_SERVICE, NS_SUBSIDIES, (NewsReferenceType)reftype.a, s->src, (NewsReferenceType)reftype.b, s->dst);
+				AddNewsItem(STR_NEWS_OFFER_OF_SUBSIDY_EXPIRED, NS_SUBSIDIES, (NewsReferenceType)reftype.a, s->src, (NewsReferenceType)reftype.b, s->dst);
+				AI::BroadcastNewEvent(new AIEventSubsidyOfferExpired(s->Index()));
+			} else {
+				if (s->awarded == _local_company) {
+					Pair reftype = SetupSubsidyDecodeParam(s, 1);
+					AddNewsItem(STR_NEWS_SUBSIDY_WITHDRAWN_SERVICE, NS_SUBSIDIES, (NewsReferenceType)reftype.a, s->src, (NewsReferenceType)reftype.b, s->dst);
+				}
+				AI::BroadcastNewEvent(new AIEventSubsidyExpired(s->Index()));
 			}
-			s->cargo_type = CT_INVALID;
+			DeleteSubsidy(s);
 			modified = true;
-			AI::BroadcastNewEvent(new AIEventSubsidyExpired(s->Index()));
-		} else {
-			s->age++;
 		}
 	}
 
@@ -306,9 +330,11 @@ void SubsidyMonthlyLoop()
 				}
 	add_subsidy:
 				if (!CheckSubsidyDuplicate(s)) {
-					s->age = 0;
+					s->remaining = 12;
 					Pair reftype = SetupSubsidyDecodeParam(s, 0);
 					AddNewsItem(STR_NEWS_SERVICE_SUBSIDY_OFFERED, NS_SUBSIDIES, (NewsReferenceType)reftype.a, s->src, (NewsReferenceType)reftype.b, s->dst);
+					SetPartOfSubsidyFlag(s->src_type, s->src, POS_SRC);
+					SetPartOfSubsidyFlag(s->dst_type, s->dst, POS_DST);
 					AI::BroadcastNewEvent(new AIEventSubsidyOffer(s->Index()));
 					modified = true;
 					break;
@@ -321,51 +347,85 @@ no_add:;
 		InvalidateWindow(WC_SUBSIDIES_LIST, 0);
 }
 
-bool CheckSubsidised(const Station *from, const Station *to, CargoID cargo_type, CompanyID company)
+/**
+ * Tests whether given delivery is subsidised and possibly awards the subsidy to delivering company
+ * @param cargo_type type of cargo
+ * @param company company delivering the cargo
+ * @param src_type type of #src
+ * @param src index of source
+ * @param st station where the cargo is delivered to
+ * @return is the delivery subsidised?
+ */
+bool CheckSubsidised(CargoID cargo_type, CompanyID company, SourceType src_type, SourceID src, const Station *st)
 {
-	Subsidy *s;
-	TileIndex xy;
+	/* If the source isn't subsidised, don't continue */
+	if (src == INVALID_SOURCE) return false;
+	switch (src_type) {
+		case ST_INDUSTRY:
+			if (!(Industry::Get(src)->part_of_subsidy & POS_SRC)) return false;
+			break;
+		case ST_TOWN:
+			if (!(    Town::Get(src)->part_of_subsidy & POS_SRC)) return false;
+			break;
+		default: return false;
+	}
 
-	/* check if there is an already existing subsidy that applies to us */
-	FOR_ALL_SUBSIDIES(s) {
-		if (s->cargo_type == cargo_type &&
-				s->IsAwarded() &&
-				s->src == from->index &&
-				s->dst == to->index) {
-			return true;
+	/* Remember all towns near this station (at least one house in its catchment radius)
+	 * which are destination of subsidised path. Do that only if needed */
+	SmallVector<const Town *, 2> towns_near;
+	if (!st->rect.IsEmpty()) {
+		Subsidy *s;
+		FOR_ALL_SUBSIDIES(s) {
+			/* Don't create the cache if there is no applicable subsidy with town as destination */
+			if (s->dst_type != ST_TOWN) continue;
+			if (s->cargo_type != cargo_type || s->src_type != src_type || s->src != src) continue;
+			if (s->IsAwarded() && s->awarded != company) continue;
+
+			Rect rect = st->GetCatchmentRect();
+
+			for (int y = rect.top; y <= rect.bottom; y++) {
+				for (int x = rect.left; x <= rect.right; x++) {
+					TileIndex tile = TileXY(x, y);
+					if (!IsTileType(tile, MP_HOUSE)) continue;
+					const Town *t = Town::GetByTile(tile);
+					if (t->part_of_subsidy & POS_DST) towns_near.Include(t);
+				}
+			}
+			break;
 		}
 	}
 
-	/* check if there's a new subsidy that applies.. */
+	bool subsidised = false;
+
+	/* Check if there's a (new) subsidy that applies. There can be more subsidies triggered by this delivery!
+	 * Think about the case that subsidies are A->B and A->C and station has both B and C in its catchment area */
+	Subsidy *s;
 	FOR_ALL_SUBSIDIES(s) {
-		if (s->cargo_type == cargo_type && !s->IsAwarded()) {
-			/* Check distance from source */
-			const CargoSpec *cs = CargoSpec::Get(cargo_type);
-			if (cs->town_effect == TE_PASSENGERS || cs->town_effect == TE_MAIL) {
-				xy = Town::Get(s->src)->xy;
-			} else {
-				xy = Industry::Get(s->src)->xy;
-			}
-			if (DistanceMax(xy, from->xy) > 9) continue;
-
-			/* Check distance from dest */
-			switch (cs->town_effect) {
-				case TE_PASSENGERS:
-				case TE_MAIL:
-				case TE_GOODS:
-				case TE_FOOD:
-					xy = Town::Get(s->dst)->xy;
+		if (s->cargo_type == cargo_type && s->src_type == src_type && s->src == src && (!s->IsAwarded() || s->awarded == company)) {
+			switch (s->dst_type) {
+				case ST_INDUSTRY:
+					for (const Industry * const *ip = st->industries_near.Begin(); ip != st->industries_near.End(); ip++) {
+						if (s->dst == (*ip)->index) {
+							assert((*ip)->part_of_subsidy & POS_DST);
+							subsidised = true;
+							if (!s->IsAwarded()) s->AwardTo(company);
+						}
+					}
 					break;
-
-				default:
-					xy = Industry::Get(s->dst)->xy;
+				case ST_TOWN:
+					for (const Town * const *tp = towns_near.Begin(); tp != towns_near.End(); tp++) {
+						if (s->dst == (*tp)->index) {
+							assert((*tp)->part_of_subsidy & POS_DST);
+							subsidised = true;
+							if (!s->IsAwarded()) s->AwardTo(company);
+						}
+					}
 					break;
+				default:
+					NOT_REACHED();
 			}
-			if (DistanceMax(xy, to->xy) > 9) continue;
-
-			s->AwardTo(from->index, to->index, company);
-			return true;
 		}
 	}
-	return false;
+
+	return subsidised;
 }