feat: record the materials each jewelry piece was made from

README.md

@@ -10,7 +10,7 @@ GemInfusion gives gemstones rolled bonuses and turns them into a resource for eq
 - **Rarity and stat rolls** — gems range from common to legendary and provide bonuses such as health, armour, damage, or damage reduction according to their type.
 - **Character influence** — Intelligence affects an infused gem's rolled stat, while Dexterity separately influences the bonus carried into jewellery.
 - **Socketed equipment** — connects gems with MMOItems sockets and preserves rarity information through socketing and removal.
-- **Goldsmithing projects** — craft rings, necklaces, medals, and other pieces from metal materials and an infused gem at a smithing station.
+- **Goldsmithing projects** — craft rings, necklaces, medals, and other pieces from metal materials and an infused gem at a smithing station. Each finished piece records the metal materials actually used, so recycling can return those rather than the listed recipe.
 - **Craftsmanship matters** — recipe accuracy, tool work, project tier, and finishing quality shape how much of the gem's bonus reaches the finished piece.
 
 The same gemstone links discovery and craft: its infusion determines the starting bonus, and the goldsmith's work shapes the jewellery made from it. Legendary infusions can also be announced to other players.

src/main/java/net/tfminecraft/geminfusion/PDCKeys.java

@@ -13,4 +13,8 @@ public static NamespacedKey gemRarity() {
 	public static NamespacedKey socketRarities() {
 		return new NamespacedKey(InfusionMain.plugin, "socket_rarities");
 	}
+
+	public static NamespacedKey goldsmithInputs() {
+		return new NamespacedKey(InfusionMain.plugin, "goldsmith_inputs");
+	}
 }

src/main/java/net/tfminecraft/geminfusion/goldsmith/GoldsmithProvenance.java

@@ -0,0 +1,59 @@
+package net.tfminecraft.geminfusion.goldsmith;
+
+import java.lang.reflect.Type;
+import java.util.LinkedHashMap;
+import java.util.Map;
+
+import org.bukkit.inventory.ItemStack;
+import org.bukkit.inventory.meta.ItemMeta;
+import org.bukkit.persistence.PersistentDataType;
+
+import com.google.gson.Gson;
+import com.google.gson.JsonParseException;
+import com.google.gson.reflect.TypeToken;
+
+import net.tfminecraft.geminfusion.PDCKeys;
+
+/**
+ * Records the materials a finished jewelry piece was actually made from, as item path to amount.
+ * A slot accepts any material of its type, so this can differ from the project recipe.
+ */
+public final class GoldsmithProvenance {
+
+	private static final Gson GSON = new Gson();
+	private static final Type INPUTS_TYPE = new TypeToken<LinkedHashMap<String, Integer>>() {
+	}.getType();
+
+	private GoldsmithProvenance() {
+	}
+
+	public static void stamp(ItemStack item, Map<GoldsmithMaterial, Integer> deposited) {
+		LinkedHashMap<String, Integer> inputs = new LinkedHashMap<>();
+		for (Map.Entry<GoldsmithMaterial, Integer> entry : deposited.entrySet()) {
+			inputs.merge(entry.getKey().getPath(), entry.getValue(), Integer::sum);
+		}
+		ItemMeta meta = item.getItemMeta();
+		meta.getPersistentDataContainer().set(PDCKeys.goldsmithInputs(), PersistentDataType.STRING,
+				GSON.toJson(inputs));
+		item.setItemMeta(meta);
+	}
+
+	/**
+	 * @return deposited material paths and amounts, or null for jewelry made before inputs were recorded
+	 */
+	public static Map<String, Integer> read(ItemStack item) {
+		if (item == null || !item.hasItemMeta()) {
+			return null;
+		}
+		String json = item.getItemMeta().getPersistentDataContainer().get(PDCKeys.goldsmithInputs(),
+				PersistentDataType.STRING);
+		if (json == null) {
+			return null;
+		}
+		try {
+			return GSON.fromJson(json, INPUTS_TYPE);
+		} catch (JsonParseException ex) {
+			return null;
+		}
+	}
+}

src/main/java/net/tfminecraft/geminfusion/goldsmith/JewelryOutput.java

@@ -77,6 +77,7 @@ public static JewelryCraftResult build(GoldsmithStation station, Player player)
 			return null;
 		}
 		out.setAmount(1);
+		GoldsmithProvenance.stamp(out, station.getDepositedByMaterial());
 		return new JewelryCraftResult(out, recipePct, hitPct, finishedTotal, statCarry, quality);
 	}
 

src/test/java/net/tfminecraft/geminfusion/GemOutputTest.java

@@ -263,9 +263,13 @@ void jewelryCarriesScaledStatIntoFreshHistoryAndQualityLore() throws Exception {
       valid.when(() -> InfusedGemValidator.isInfused(gemItem)).thenReturn(true);
       qualityApi.when(() -> QualityLoader.getByAmount(80)).thenReturn(quality);
       qualityApi.when(() -> QualityLoader.resolveStatFactor(80)).thenReturn(50.0);
+      GoldsmithMaterial material = mock(GoldsmithMaterial.class);
+      when(material.getPath()).thenReturn("m.materials.shiny_gold");
+      when(station.getDepositedByMaterial()).thenReturn(Map.of(material, 3));
       JewelryCraftResult result = JewelryOutput.build(station, player);
       assertNotNull(result);
       assertSame(out, result.getItem());
+      assertEquals(Map.of("m.materials.shiny_gold", 3), GoldsmithProvenance.read(out));
       assertEquals(80, result.getFinishedTotal());
       assertEquals(90, result.getRecipePercent());
       assertEquals(80, result.getHitPercent());

src/test/java/net/tfminecraft/geminfusion/goldsmith/GoldsmithProvenanceTest.java

@@ -0,0 +1,74 @@
+package net.tfminecraft.geminfusion.goldsmith;
+
+import static org.junit.jupiter.api.Assertions.*;
+import static org.mockito.Mockito.*;
+
+import java.util.*;
+import net.tfminecraft.geminfusion.InfusionMain;
+import net.tfminecraft.geminfusion.PDCKeys;
+import org.bukkit.Material;
+import org.bukkit.inventory.ItemStack;
+import org.bukkit.inventory.meta.ItemMeta;
+import org.bukkit.persistence.PersistentDataType;
+import org.junit.jupiter.api.*;
+import org.mockbukkit.mockbukkit.MockBukkit;
+
+class GoldsmithProvenanceTest {
+  InfusionMain previous;
+
+  @BeforeEach
+  void setup() {
+    MockBukkit.mock();
+    previous = InfusionMain.plugin;
+    InfusionMain.plugin = mock(InfusionMain.class);
+    when(InfusionMain.plugin.namespace()).thenReturn("geminfusion");
+  }
+
+  @AfterEach
+  void cleanup() {
+    InfusionMain.plugin = previous;
+    MockBukkit.unmock();
+  }
+
+  private static GoldsmithMaterial material(String path) {
+    GoldsmithMaterial material = mock(GoldsmithMaterial.class);
+    when(material.getPath()).thenReturn(path);
+    return material;
+  }
+
+  @Test
+  void stampsTheDepositedMaterialsNotTheRecipe() {
+    ItemStack ring = new ItemStack(Material.GOLD_INGOT);
+    LinkedHashMap<GoldsmithMaterial, Integer> deposited = new LinkedHashMap<>();
+    deposited.put(material("m.materials.shiny_gold"), 3);
+    deposited.put(material("m.materials.rough_gold"), 1);
+    deposited.put(material("m.materials.shiny_gold"), 2);
+
+    GoldsmithProvenance.stamp(ring, deposited);
+
+    assertEquals(
+        Map.of("m.materials.shiny_gold", 5, "m.materials.rough_gold", 1),
+        GoldsmithProvenance.read(ring));
+  }
+
+  @Test
+  void stampsAnEmptyListWhenNothingWasDeposited() {
+    ItemStack ring = new ItemStack(Material.GOLD_INGOT);
+    GoldsmithProvenance.stamp(ring, Map.of());
+    assertEquals(Map.of(), GoldsmithProvenance.read(ring));
+  }
+
+  @Test
+  void readsNothingFromUnstampedOrUnreadableItems() {
+    assertNull(GoldsmithProvenance.read(null));
+    assertNull(GoldsmithProvenance.read(new ItemStack(Material.AIR)));
+    assertNull(GoldsmithProvenance.read(new ItemStack(Material.GOLD_INGOT)));
+
+    ItemStack broken = new ItemStack(Material.GOLD_INGOT);
+    ItemMeta meta = broken.getItemMeta();
+    meta.getPersistentDataContainer()
+        .set(PDCKeys.goldsmithInputs(), PersistentDataType.STRING, "{not json");
+    broken.setItemMeta(meta);
+    assertNull(GoldsmithProvenance.read(broken));
+  }
+}