Added Items#toLookupString

eco-api/src/main/java/com/willfp/eco/core/items/Items.java

@@ -115,6 +115,48 @@ public final class Items {
         REGISTRY.remove(key);
     }
 
+    /**
+     * Turn an ItemStack back into a lookup string.
+     *
+     * @param itemStack The ItemStack.
+     * @return The lookup string.
+     */
+    @NotNull
+    public static String toLookupString(@Nullable final ItemStack itemStack) {
+        if (itemStack == null) {
+            return "";
+        }
+
+        StringBuilder builder = new StringBuilder();
+
+        CustomItem customItem = getCustomItem(itemStack);
+
+        if (customItem != null) {
+            builder.append(customItem.getKey());
+        } else {
+            builder.append(itemStack.getType().name().toLowerCase());
+        }
+
+        if (itemStack.getAmount() > 1) {
+            builder.append(" ")
+                    .append(itemStack.getAmount());
+        }
+
+        ItemMeta meta = itemStack.getItemMeta();
+
+        if (meta != null) {
+            for (LookupArgParser parser : ARG_PARSERS) {
+                String parsed = parser.serializeBack(meta);
+                if (parsed != null) {
+                    builder.append(" ")
+                            .append(parsed);
+                }
+            }
+        }
+
+        return builder.toString();
+    }
+
     /**
      * This is the backbone of the entire eco item system.
      * <p>

eco-api/src/main/java/com/willfp/eco/core/items/args/LookupArgParser.java

@@ -22,4 +22,14 @@ public interface LookupArgParser {
      */
     @Nullable Predicate<ItemStack> parseArguments(@NotNull String[] args,
                                                   @NotNull ItemMeta meta);
+
+    /**
+     * Serialize the item back to a string.
+     *
+     * @param meta The ItemMeta.
+     * @return The string, or null if not required.
+     */
+    default @Nullable String serializeBack(@NotNull final ItemMeta meta) {
+        return null;
+    }
 }

eco-api/src/main/kotlin/com/willfp/eco/core/items/Items.kt

@@ -0,0 +1,11 @@
+@file:JvmName("ItemsExtensions")
+
+package com.willfp.eco.core.items
+
+import org.bukkit.inventory.ItemStack
+
+/**
+ * @see Items.toLookupString
+ */
+fun ItemStack?.toLookupString(): String =
+    Items.toLookupString(this)