feat: tag alloy scrap with the base metal it consumed

src/main/java/net/tfminecraft/advancedcrafting/objects/alloys/AlloyForger.java

@@ -17,6 +17,7 @@
 import net.tfminecraft.advancedcrafting.managers.AlloyManager;
 import net.tfminecraft.advancedcrafting.objects.crafting.hits.CraftingHit;
 import net.tfminecraft.advancedcrafting.objects.data.AlloyRecipe;
+import net.tfminecraft.advancedcrafting.objects.data.ScrapProvenance;
 import net.tfminecraft.advancedcrafting.objects.data.StatData;
 import net.tfminecraft.advancedcrafting.objects.ingredients.Ingredient;
 import net.tfminecraft.advancedcrafting.objects.stats.StatModifier;
@@ -86,6 +87,7 @@ public NamableAlloy forge(Player p, int i) {
 			String scrapId = Cache.scrap.split("\\.")[1].toUpperCase();
 			ItemManager itemManager = MMOItems.plugin.getItems();
 			ItemStack template = itemManager.getMMOItem(MMOItems.plugin.getTypes().get(scrapType),scrapId).newBuilder().build();
+			if(station.getBaseItem() != null) ScrapProvenance.applyTo(template, station.getBaseItem().getId());
 			loc.getWorld().dropItem(loc, template);
 			return null;
 		}

src/main/java/net/tfminecraft/advancedcrafting/objects/data/ScrapProvenance.java

@@ -0,0 +1,37 @@
+package net.tfminecraft.advancedcrafting.objects.data;
+
+import java.util.Locale;
+
+import org.bukkit.inventory.ItemStack;
+import org.bukkit.inventory.meta.ItemMeta;
+import org.bukkit.persistence.PersistentDataType;
+
+import net.tfminecraft.advancedcrafting.utils.PDCKeys;
+
+/**
+ * Records which base ingredient a failed alloy forge consumed, so scrap can be recycled into it.
+ */
+public final class ScrapProvenance {
+	private ScrapProvenance() {
+	}
+
+	public static void applyTo(ItemStack item, String baseId) {
+		if (item == null || baseId == null || baseId.isBlank()) {
+			return;
+		}
+		ItemMeta meta = item.getItemMeta();
+		if (meta == null) {
+			return;
+		}
+		meta.getPersistentDataContainer().set(PDCKeys.scrapBase(), PersistentDataType.STRING, baseId.toLowerCase(Locale.ROOT));
+		item.setItemMeta(meta);
+	}
+
+	/** Base ingredient id the scrap came from, or null for untagged items (including scrap forged before tagging). */
+	public static String readBaseId(ItemStack item) {
+		if (item == null || !item.hasItemMeta()) {
+			return null;
+		}
+		return item.getItemMeta().getPersistentDataContainer().get(PDCKeys.scrapBase(), PersistentDataType.STRING);
+	}
+}

src/main/java/net/tfminecraft/advancedcrafting/utils/PDCKeys.java

@@ -24,6 +24,10 @@ public static NamespacedKey craftStatTemplateRevision() {
 		return new NamespacedKey(AdvancedCrafting.plugin, "ac_craft_stat_template_revision");
 	}
 
+	public static NamespacedKey scrapBase() {
+		return new NamespacedKey(AdvancedCrafting.plugin, "ac_scrap_base");
+	}
+
 	public static NamespacedKey ingredientId() {
 		return new NamespacedKey(AdvancedCrafting.plugin, "ac_ingredient_id");
 	}