Name Age save folders after player titles

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

@@ -33,6 +33,28 @@ public record AgeDefinition(
         return ResourceLocation.fromNamespaceAndPath(Rivencraft.MOD_ID, "age/" + ageId);
     }
 
+    public static ResourceLocation namedDimensionId(String ageName) {
+        StringBuilder pathName = new StringBuilder();
+        boolean lastWasSeparator = false;
+        for (int index = 0; index < ageName.length(); index++) {
+            char character = Character.toLowerCase(ageName.charAt(index));
+            if (character >= 'a' && character <= 'z' || character >= '0' && character <= '9') {
+                pathName.append(character);
+                lastWasSeparator = false;
+            } else if (!lastWasSeparator && !pathName.isEmpty()) {
+                pathName.append('_');
+                lastWasSeparator = true;
+            }
+        }
+        while (!pathName.isEmpty() && pathName.charAt(pathName.length() - 1) == '_') {
+            pathName.deleteCharAt(pathName.length() - 1);
+        }
+        if (pathName.isEmpty()) {
+            pathName.append("unnamed_age");
+        }
+        return ResourceLocation.fromNamespaceAndPath(Rivencraft.MOD_ID, "age/" + pathName);
+    }
+
     public AgeDefinition withSpawn(BlockPos spawn) {
         return new AgeDefinition(id, name, seed, generationProfile, generationVersion,
                 createdGameTime, dimensionId, spawn.immutable());

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

@@ -71,14 +71,16 @@ public final class AgeRegistrySavedData extends SavedData {
             return existing;
         }
 
+        String name = normalizedName(reference.name());
+        ResourceLocation dimensionId = availableDimensionId(name);
         AgeDefinition created = new AgeDefinition(
                 reference.id(),
-                normalizedName(reference.name()),
-                ageSeed(worldSeed, reference.id()),
+                name,
+                ageSeed(worldSeed, dimensionId),
                 AgeDefinition.RANDOM_VANILLA_PROFILE,
                 AgeDefinition.CURRENT_GENERATION_VERSION,
                 createdGameTime,
-                AgeDefinition.dimensionId(reference.id()),
+                dimensionId,
                 null
         );
         ages.put(created.id(), created);
@@ -150,9 +152,25 @@ public final class AgeRegistrySavedData extends SavedData {
         return normalized.isEmpty() ? "Unnamed Age" : normalized;
     }
 
-    private static long ageSeed(long worldSeed, UUID ageId) {
+    private ResourceLocation availableDimensionId(String ageName) {
+        ResourceLocation base = AgeDefinition.namedDimensionId(ageName);
+        ResourceLocation candidate = base;
+        int suffix = 2;
+        while (dimensionIdInUse(candidate)) {
+            candidate = ResourceLocation.fromNamespaceAndPath(
+                    base.getNamespace(), base.getPath() + "_" + suffix++
+            );
+        }
+        return candidate;
+    }
+
+    private boolean dimensionIdInUse(ResourceLocation candidate) {
+        return ages.values().stream().anyMatch(age -> age.dimensionId().equals(candidate));
+    }
+
+    private static long ageSeed(long worldSeed, ResourceLocation dimensionId) {
         // Dynamic Dimensions AR derives each level seed from the primary world
         // seed and the dimension key. Persist the same value as Age metadata.
-        return worldSeed + AgeDefinition.dimensionId(ageId).hashCode();
+        return worldSeed + dimensionId.hashCode();
     }
 }

src/main/java/net/dnorberg/rivencraft/gametest/LinkingGameTests.java

@@ -82,7 +82,8 @@ public final class LinkingGameTests {
     @GameTest(template = "empty")
     public static void ageDefinitionIsCreatedOnceWithDeterministicData(GameTestHelper helper) {
         UUID ageId = UUID.randomUUID();
-        AgeReference reference = new AgeReference(ageId, "Test Age");
+        String requestedName = "Test Age " + ageId;
+        AgeReference reference = new AgeReference(ageId, requestedName);
 
         AgeDefinition first = AgeRegistrySavedData.resolveOrCreate(helper.getLevel(), reference);
         AgeDefinition second = AgeRegistrySavedData.resolveOrCreate(
@@ -91,10 +92,17 @@ public final class LinkingGameTests {
         AgeDefinition another = AgeRegistrySavedData.resolveOrCreate(
                 helper.getLevel(), new AgeReference(UUID.randomUUID(), "Another Age")
         );
+        AgeDefinition conflicting = AgeRegistrySavedData.resolveOrCreate(
+                helper.getLevel(), new AgeReference(UUID.randomUUID(), requestedName)
+        );
 
         helper.assertValueEqual(second, first,
                 "An existing Age UUID must retain its original immutable generation definition");
-        helper.assertValueEqual(first.name(), "Test Age", "The first book name must become the canonical Age name");
+        helper.assertValueEqual(first.name(), requestedName, "The first book name must become the canonical Age name");
+        helper.assertValueEqual(first.dimensionId(), AgeDefinition.namedDimensionId(requestedName),
+                "A new Age dimension folder must derive from the player-assigned name");
+        helper.assertValueEqual(conflicting.dimensionId().getPath(), first.dimensionId().getPath() + "_2",
+                "A conflicting Age dimension folder must receive an incrementing suffix");
         helper.assertValueEqual(first.generationProfile(), AgeDefinition.RANDOM_VANILLA_PROFILE,
                 "A page-free book must use the random vanilla generation profile");
         helper.assertValueEqual(first.generationVersion(), AgeDefinition.CURRENT_GENERATION_VERSION,