feat: record the materials each mage weapon was crafted from

src/main/java/net/tfminecraft/magic/gear/GearItemBuilder.java

@@ -147,6 +147,12 @@ private static void copyGearPdc(ItemStack from, ItemStack to) {
             toMeta.getPersistentDataContainer().set(
                     GearKeys.parts(), org.bukkit.persistence.PersistentDataType.STRING, parts);
         }
+        String craftInputs = fromMeta.getPersistentDataContainer().get(
+                GearKeys.craftInputs(), org.bukkit.persistence.PersistentDataType.STRING);
+        if (craftInputs != null) {
+            toMeta.getPersistentDataContainer().set(
+                    GearKeys.craftInputs(), org.bukkit.persistence.PersistentDataType.STRING, craftInputs);
+        }
         toMeta.getPersistentDataContainer().set(
                 GearKeys.archetype(),
                 org.bukkit.persistence.PersistentDataType.STRING,

src/main/java/net/tfminecraft/magic/gear/GearKeys.java

@@ -24,6 +24,11 @@ public static NamespacedKey parts() {
         return new NamespacedKey(Magic.plugin, "gear_parts");
     }
 
+    /** Materials actually charged when the weapon was crafted, as a JSON map of item path to amount. */
+    public static NamespacedKey craftInputs() {
+        return new NamespacedKey(Magic.plugin, "gear_craft_inputs");
+    }
+
     public static NamespacedKey socketsLocked() {
         return new NamespacedKey(Magic.plugin, "gear_sockets_locked");
     }

src/main/java/net/tfminecraft/magic/gear/GearProvenance.java

@@ -1,16 +1,26 @@
 package net.tfminecraft.magic.gear;
 
+import java.lang.reflect.Type;
 import java.util.ArrayList;
 import java.util.Collection;
+import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Locale;
+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;
+
 public final class GearProvenance {
 
+    private static final Gson GSON = new Gson();
+    private static final Type INPUTS_TYPE = new TypeToken<LinkedHashMap<String, Integer>>() {}.getType();
+
     private GearProvenance() {}
 
     public static void stamp(ItemStack stack, GearType type, Collection<PartDef> parts) {
@@ -38,6 +48,33 @@ public static void stamp(ItemStack stack, GearType type, Collection<PartDef> par
         stack.setItemMeta(meta);
     }
 
+    /** Records what the craft actually charged. Empty when staff bypassed the cost. */
+    public static void stampInputs(ItemStack stack, Map<String, Integer> charged) {
+        if (stack == null || !stack.hasItemMeta()) {
+            return;
+        }
+        ItemMeta meta = stack.getItemMeta();
+        meta.getPersistentDataContainer().set(
+                GearKeys.craftInputs(), PersistentDataType.STRING, GSON.toJson(charged == null ? Map.of() : charged));
+        stack.setItemMeta(meta);
+    }
+
+    /** Materials charged at craft time, or null for weapons crafted before this was recorded. */
+    public static Map<String, Integer> readInputs(ItemStack stack) {
+        if (stack == null || !stack.hasItemMeta()) {
+            return null;
+        }
+        String json = stack.getItemMeta().getPersistentDataContainer().get(GearKeys.craftInputs(), PersistentDataType.STRING);
+        if (json == null) {
+            return null;
+        }
+        try {
+            return GSON.fromJson(json, INPUTS_TYPE);
+        } catch (JsonParseException ex) {
+            return null;
+        }
+    }
+
     public static int majorityOf(ItemStack stack) {
         if (stack == null || !stack.hasItemMeta()) {
             return 0;

src/main/java/net/tfminecraft/magic/gear/GearRefresher.java

@@ -140,6 +140,7 @@ private static void copyGearPdc(ItemStack from, ItemStack to) {
         ItemMeta fromMeta = from.getItemMeta();
         ItemMeta toMeta = to.getItemMeta();
         copyString(fromMeta, toMeta, GearKeys.parts());
+        copyString(fromMeta, toMeta, GearKeys.craftInputs());
         copyString(fromMeta, toMeta, GearKeys.archetype());
         copyString(fromMeta, toMeta, GearKeys.orphans());
         Integer archetypeRevision = fromMeta.getPersistentDataContainer().get(

src/main/java/net/tfminecraft/magic/gear/gui/GearInventoryManager.java

@@ -24,6 +24,7 @@
 import net.tfminecraft.magic.gear.GearCosts;
 import net.tfminecraft.magic.gear.GearItemBuilder;
 import net.tfminecraft.magic.gear.GearKeys;
+import net.tfminecraft.magic.gear.GearProvenance;
 import net.tfminecraft.magic.gear.GearStationStore;
 import net.tfminecraft.magic.gear.GearType;
 import net.tfminecraft.magic.gear.PartDef;
@@ -290,6 +291,7 @@ private void tryPrepare(Player player) {
         boolean staffBypass = GearCosts.bypasses(player);
         Map<String, Integer> charged = staffBypass ? Map.of() : GearCosts.total(parts);
         GearCosts.take(player, parts);
+        GearProvenance.stampInputs(prepared, charged);
         GearStationStore.occupy(station, prepared, player.getUniqueId(), charged);
         OpenStationManager.clear(player);
         player.closeInventory();

src/test/java/net/tfminecraft/magic/GearItemCoverageTest.java

@@ -199,6 +199,15 @@ void socketRewriteKeepsIdentityAndLocksFirstAttunement() throws Exception {
         minimal,
         dest);
     assertEquals(GearType.STAFF, GearProvenance.archetypeOf(dest));
+    assertNull(GearProvenance.readInputs(dest));
+    GearProvenance.stampInputs(minimal, Map.of("v.gold", 3));
+    invoke(
+        GearItemBuilder.class,
+        "copyGearPdc",
+        new Class[] {ItemStack.class, ItemStack.class},
+        minimal,
+        dest);
+    assertEquals(Map.of("v.gold", 3), GearProvenance.readInputs(dest));
     for (ItemStack[] pair :
         new ItemStack[][] {
           {null, dest},

src/test/java/net/tfminecraft/magic/GearProvenanceCoverageTest.java

@@ -37,6 +37,22 @@ void unstampedItemsAndMissingMetadataAreSafe() {
     assertTrue(GearProvenance.socketsLocked(item));
   }
 
+  @Test
+  void craftInputsRecordWhatWasChargedAndReadBack() {
+    for (ItemStack item : Arrays.asList(null, new ItemStack(Material.AIR))) {
+      GearProvenance.stampInputs(item, Map.of("v.gold", 1));
+      assertNull(GearProvenance.readInputs(item));
+    }
+    var item = item();
+    assertNull(GearProvenance.readInputs(item), "Weapons crafted before the record have none");
+    GearProvenance.stampInputs(item, null);
+    assertEquals(Map.of(), GearProvenance.readInputs(item));
+    GearProvenance.stampInputs(item, Map.of("m.materials.steel_ingot", 4, "v.gold", 2));
+    assertEquals(Map.of("m.materials.steel_ingot", 4, "v.gold", 2), GearProvenance.readInputs(item));
+    tag(item, GearKeys.craftInputs(), PersistentDataType.STRING, "{not json");
+    assertNull(GearProvenance.readInputs(item));
+  }
+
   @Test
   void stampingTracksPartAndArchetypeRevisions() {
     var item = item();