Complete Milestone 6 acceptance and runtime cleanup (#74)

src/main/java/net/dnorberg/rivencraft/book/AgeBlockInstability.java

@@ -289,8 +289,9 @@ public final class AgeBlockInstability {
 
     public static AgeInstabilityPlan effectivePlan(ServerLevel level, AgeDefinition age) {
         int blockScore = score(level, age);
-        if (blockScore == 0 && RivencraftConfig.instabilityDifficulty() == 2) return age.instabilityPlan();
-        int combined = effectiveScore(level, age);
+        int difficulty = RivencraftConfig.instabilityDifficulty();
+        if (blockScore == 0 && difficulty == 2) return age.instabilityPlan();
+        int combined = difficultyScore((long) age.instability().score() + blockScore, difficulty);
         AgeInstability effective = new AgeInstability(AgeInstability.CURRENT_VERSION, combined,
                 java.util.List.of(new AgeInstability.Contribution("effective_block_profile", -1, combined,
                         "Saved writing score plus sampled excess blocks")));

src/main/java/net/dnorberg/rivencraft/book/AgeEnvironmentalProviders.java

@@ -93,8 +93,9 @@ public final class AgeEnvironmentalProviders {
         return METEORS.equals(id) || BURNING.equals(id) || EROSION.equals(id);
     }
 
-    static void tickPlanned(ServerLevel level, AgeDefinition age, long tick) {
-        List<AgeInstabilityPlan.ProviderLevel> cards = AgeBlockInstability.effectivePlan(level, age).providers().stream()
+    static void tickPlanned(ServerLevel level, AgeDefinition age, long tick,
+                            List<AgeInstabilityPlan.ProviderLevel> providers) {
+        List<AgeInstabilityPlan.ProviderLevel> cards = providers.stream()
                 .filter(card -> isEnvironmental(card.id())).toList();
         boolean optInErosion = RivencraftConfig.erosionEnabled()
                 && AgeBlockInstability.effectiveScore(level, age) >= InstabilityProviderCatalog.Deck.DESTRUCTIVE.entryCost();

src/main/java/net/dnorberg/rivencraft/book/AgeGenerationPlan.java

@@ -1,8 +1,12 @@
 package net.dnorberg.rivencraft.book;
 
 import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.HashSet;
 import java.util.List;
+import java.util.Map;
 import java.util.Objects;
+import java.util.Set;
 import net.dnorberg.rivencraft.writing.OrderedWriting;
 import net.dnorberg.rivencraft.writing.SymbolReference;
 import net.dnorberg.rivencraft.writing.SymbolSemantics;
@@ -44,11 +48,14 @@ public record AgeGenerationPlan(int version, long ageSeed, OrderedWriting writin
         if (version >= 3 && !symbols.isEmpty() && activeSymbolIndices.isEmpty()) {
             throw new IllegalArgumentException("Version 3 Age plan has no active symbols");
         }
-        if (activeSymbolIndices.stream().distinct().count() != activeSymbolIndices.size()) {
-            throw new IllegalArgumentException("Age plan repeats an active symbol index");
-        }
+        Set<Integer> resolvedIndices = new HashSet<>();
+        for (ResolvedSymbol symbol : symbols) resolvedIndices.add(symbol.index());
+        Set<Integer> seenActive = new HashSet<>();
         for (int index : activeSymbolIndices) {
-            if (symbols.stream().noneMatch(symbol -> symbol.index() == index)) {
+            if (!seenActive.add(index)) {
+                throw new IllegalArgumentException("Age plan repeats an active symbol index");
+            }
+            if (!resolvedIndices.contains(index)) {
                 throw new IllegalArgumentException("Active symbol is not in the saved writing: " + index);
             }
         }
@@ -107,8 +114,13 @@ public record AgeGenerationPlan(int version, long ageSeed, OrderedWriting writin
     }
 
     public List<ResolvedSymbol> activeSymbols() {
-        return activeSymbolIndices.stream().map(index -> symbols.stream()
-                .filter(symbol -> symbol.index() == index).findFirst().orElseThrow()).toList();
+        Map<Integer, ResolvedSymbol> byIndex = new HashMap<>(symbols.size());
+        for (ResolvedSymbol symbol : symbols) byIndex.putIfAbsent(symbol.index(), symbol);
+        return activeSymbolIndices.stream().map(index -> {
+            ResolvedSymbol symbol = byIndex.get(index);
+            if (symbol == null) throw new IllegalStateException("Missing active symbol " + index);
+            return symbol;
+        }).toList();
     }
 
     public CompoundTag save() {

src/main/java/net/dnorberg/rivencraft/book/AgeHazardProviders.java

@@ -55,9 +55,10 @@ public final class AgeHazardProviders {
     }
 
     /** Roll every selected hazard card each scheduler pass, independently of other providers. */
-    static void tickPlanned(ServerLevel level, AgeDefinition age, long tick) {
+    static void tickPlanned(ServerLevel level, AgeDefinition age, long tick,
+                            List<AgeInstabilityPlan.ProviderLevel> providers) {
         if (!RivencraftConfig.hazardsEnabled()) return;
-        List<AgeInstabilityPlan.ProviderLevel> hazards = AgeBlockInstability.effectivePlan(level, age).providers().stream()
+        List<AgeInstabilityPlan.ProviderLevel> hazards = providers.stream()
                 .filter(provider -> isHazard(provider.id())).toList();
         if (hazards.isEmpty()) return;
         List<ChunkPos> chunks = loadedChunksNearPlayers(level, RivencraftConfig.hazardsMaxChunks());

src/main/java/net/dnorberg/rivencraft/book/AgeInstabilityRuntime.java

@@ -55,16 +55,16 @@ public final class AgeInstabilityRuntime {
         if (!admitted(state.eligible, level.dimension().location(), tick / cooldown,
                 RivencraftConfig.instabilityMaxAges())) return;
         AgeDefinition age = AgeRegistrySavedData.get(level).findByDimension(level.dimension().location()).orElse(null);
-        if (age == null || AgeBlockInstability.effectivePlan(level, age).providers().isEmpty()
-                || !AgeInstabilityControls.get(level).enabled(age.id())) return;
+        if (age == null || !AgeInstabilityControls.get(level).enabled(age.id())) return;
+        List<AgeInstabilityPlan.ProviderLevel> providers = AgeBlockInstability.effectivePlan(level, age).providers();
+        if (providers.isEmpty()) return;
         // Legacy's per-chunk hazards must not wait for the rotating two-provider sample.
-        AgeHazardProviders.tickPlanned(level, age, tick);
-        AgeEnvironmentalProviders.tickPlanned(level, age, tick);
+        AgeHazardProviders.tickPlanned(level, age, tick, providers);
+        AgeEnvironmentalProviders.tickPlanned(level, age, tick, providers);
         List<ChunkPos> chunks = loadedChunksNearPlayers(level, RivencraftConfig.instabilityMaxChunks());
         if (chunks.isEmpty()) return;
         Budget budget = new Budget(RivencraftConfig.instabilityMaxActions());
         Context context = new Context(level, age, chunks, tick, budget);
-        List<AgeInstabilityPlan.ProviderLevel> providers = AgeBlockInstability.effectivePlan(level, age).providers();
         int first = (int) Math.floorMod(tick / cooldown + age.seed(), providers.size());
         int ran = 0;
         for (int offset = 0; offset < providers.size() && ran < RivencraftConfig.instabilityMaxProviders()