Capped adoptions per template

- Each pack biome now serves as the template for at most five adopted land biomes and three adopted sea, shore, or cave biomes
- A mod biome whose best template is full falls back to the next best template under the cap
- A mod biome that finds every compatible template full is skipped with a reason naming the cap instead of being dropped

core/src/main/java/art/arcane/iris/pack/ingest/BiomeRole.java

@@ -19,17 +19,19 @@
 package art.arcane.iris.pack.ingest;
 
 enum BiomeRole {
-    LAND("landBiomes", "land"),
-    SEA("seaBiomes", "sea"),
-    SHORE("shoreBiomes", "shore"),
-    CAVE("caveBiomes", "cave");
+    LAND("landBiomes", "land", 5),
+    SEA("seaBiomes", "sea", 3),
+    SHORE("shoreBiomes", "shore", 3),
+    CAVE("caveBiomes", "cave", 3);
 
     private final String poolField;
     private final String label;
+    private final int templateCap;
 
-    BiomeRole(String poolField, String label) {
+    BiomeRole(String poolField, String label, int templateCap) {
         this.poolField = poolField;
         this.label = label;
+        this.templateCap = templateCap;
     }
 
     String poolField() {
@@ -39,4 +41,8 @@ enum BiomeRole {
     String label() {
         return label;
     }
+
+    int templateCap() {
+        return templateCap;
+    }
 }

core/src/main/java/art/arcane/iris/pack/ingest/ModBiomeAdopter.java

@@ -77,8 +77,7 @@ final class ModBiomeAdopter {
             boolean ownsVegetation = ownsVegetation(biome, namespace);
             Placement placement = place(role, IngestClimate.of(biome), BiomeCategories.of(biome.tags()), ownsVegetation);
             if (placement == null) {
-                items.add(new ModIngestItem(namespace, biome.key(), "biome", ModIngestTier.SKIPPED, "",
-                        "no region in this dimension accepts a " + role.label() + " biome"));
+                items.add(new ModIngestItem(namespace, biome.key(), "biome", ModIngestTier.SKIPPED, "", unplacedReason(role)));
                 continue;
             }
             IngestPackModel.RegionProfile region = placement.region();
@@ -114,10 +113,14 @@ final class ModBiomeAdopter {
                     + (regionClimate == null ? 0D : REGION_CLIMATE_WEIGHT * climate.distance(regionClimate))
                     + REGION_CATEGORY_WEIGHT * (1D - regionAffinity(region, role, categories));
             for (String template : region.pool(role)) {
+                int uses = templateUses.getOrDefault(template, 0);
+                if (uses >= role.templateCap()) {
+                    continue;
+                }
                 IngestClimate templateClimate = model.biomeClimate(template);
                 double score = climate.distance(templateClimate == null ? region.climate() : templateClimate)
                         + CATEGORY_WEIGHT * BiomeCategories.distance(categories, model.biomeCategories(template))
-                        + REUSE_WEIGHT * templateUses.getOrDefault(template, 0)
+                        + REUSE_WEIGHT * uses
                         + (ownsVegetation ? BARE_SURFACE_PENALTY * (1D - model.plantableShare(template)) : 0D)
                         + regionPenalty;
                 if (best == null || score < bestScore) {
@@ -129,6 +132,15 @@ final class ModBiomeAdopter {
         return best;
     }
 
+    private String unplacedReason(BiomeRole role) {
+        for (IngestPackModel.RegionProfile region : model.regions()) {
+            if (!excludedRegions.contains(region.key()) && !region.pool(role).isEmpty()) {
+                return "every " + role.label() + " template already hosts " + role.templateCap() + " adopted biomes";
+            }
+        }
+        return "no region in this dimension accepts a " + role.label() + " biome";
+    }
+
     private IngestClimate regionClimate(IngestPackModel.RegionProfile region, BiomeRole role, Set<String> categories) {
         if (role != BiomeRole.LAND || categories.isEmpty()) {
             return region.climate();