Implement kits placing items in specific slots

Essentials/src/main/java/com/earth2me/essentials/Kit.java

@@ -174,10 +174,11 @@ public boolean expandItems(final User user, final List<String> items) throws Exc
             final boolean allowUnsafe = ess.getSettings().allowUnsafeEnchantments();
             final boolean autoEquip = ess.getSettings().isKitAutoEquip();
             final List<ItemStack> itemList = new ArrayList<>();
+            final List<Integer> slotList = new ArrayList<>();
             final List<String> commandQueue = new ArrayList<>();
             final List<String> moneyQueue = new ArrayList<>();
             final String currencySymbol = ess.getSettings().getCurrencySymbol().isEmpty() ? "$" : ess.getSettings().getCurrencySymbol();
-            for (final String kitItem : output.getLines()) {
+            for (String kitItem : output.getLines()) {
                 if (kitItem.startsWith("$") || kitItem.startsWith(currencySymbol)) {
                     moneyQueue.add(NumberUtil.sanitizeCurrencyString(kitItem, ess));
                     continue;
@@ -191,6 +192,15 @@ public boolean expandItems(final User user, final List<String> items) throws Exc
                     continue;
                 }
 
+                if (kitItem.startsWith("slot:")) {
+                    final String slotStr = kitItem.substring("slot:".length(), kitItem.indexOf(" "));
+                    final int slot = NumberUtil.isInt(slotStr) ? Integer.parseInt(slotStr) : -1;
+                    slotList.add(slot);
+                    kitItem = kitItem.substring(kitItem.indexOf(" ") + 1);
+                } else {
+                    slotList.add(-1);
+                }
+
                 final ItemStack stack;
                 final SerializationProvider serializationProvider = ess.provider(SerializationProvider.class);
 
@@ -234,7 +244,8 @@ public boolean expandItems(final User user, final List<String> items) throws Exc
                 return false;
             }
 
-            final Map<Integer, ItemStack> leftover = Inventories.addItem(user.getBase(), maxStackSize, autoEquip, itemArray);
+            final ItemStack[] unplacedItems = Inventories.addItem(user.getBase(), maxStackSize, itemList, slotList);
+            final Map<Integer, ItemStack> leftover = Inventories.addItem(user.getBase(), maxStackSize, autoEquip, unplacedItems);
             if (!isDropItemsIfFull && !leftover.isEmpty()) {
                 // Inventories#hasSpace should prevent this state from EVER being reached; If it does, something has gone terribly wrong, and we should just give up and hope people report it :(
                 throw new IllegalStateException("Something has gone terribly wrong while adding items to the user's inventory. Please report this to the EssentialsX developers. Items left over: " + leftover + ". Original items: " + Arrays.toString(itemArray));

Essentials/src/main/java/com/earth2me/essentials/commands/Commandcreatekit.java

@@ -51,13 +51,14 @@ public void run(final Server server, final User user, final String commandLabel,
             useSerializationProvider = false;
         }
 
-        for (ItemStack is : items) {
+        for (int i = 0; i < items.length; i++) {
+            final ItemStack is = items[i];
             if (is != null && is.getType() != null && is.getType() != Material.AIR) {
                 final String serialized;
                 if (useSerializationProvider) {
-                    serialized = "@" + Base64Coder.encodeLines(serializationProvider.serializeItem(is));
+                    serialized = "slot:" + i + " @" + Base64Coder.encodeLines(serializationProvider.serializeItem(is));
                 } else {
-                    serialized = ess.getItemDb().serialize(is);
+                    serialized = "slot:" + i + " " + ess.getItemDb().serialize(is);
                 }
                 list.add(serialized);
             }

Essentials/src/main/java/com/earth2me/essentials/craftbukkit/Inventories.java

@@ -142,6 +142,46 @@ public static Map<Integer, ItemStack> addItem(final Player player, final int max
         return addItem(player, maxStack, false, items);
     }
 
+    public static ItemStack[] addItem(final Player player, final int maxStack, List<ItemStack> items, List<Integer> slots) {
+        final List<ItemStack> leftover = new ArrayList<>();
+        for (int i = 0; i < items.size(); i++) {
+            final ItemStack item = items.get(i);
+            final int itemMax = Math.max(maxStack, item.getMaxStackSize());
+            final int slot = slots.get(i);
+            if (slot == -1) {
+                leftover.add(item);
+                continue;
+            }
+
+            ItemStack existing = player.getInventory().getItem(slot);
+            final int existingAmount;
+            if (isEmpty(existing)) {
+                existing = item.clone();
+                existingAmount = 0;
+            } else {
+                existingAmount = existing.getAmount();
+            }
+
+            if (!item.isSimilar(existing)) {
+                leftover.add(item);
+                continue;
+            }
+
+            final int amount = item.getAmount();
+            if (amount + existingAmount <= itemMax) {
+                existing.setAmount(amount + existingAmount);
+                player.getInventory().setItem(slot, existing);
+            } else {
+                existing.setAmount(itemMax);
+                player.getInventory().setItem(slot, existing);
+                item.setAmount(amount + existingAmount - itemMax);
+                leftover.add(item);
+            }
+        }
+
+        return leftover.toArray(new ItemStack[0]);
+    }
+
     public static Map<Integer, ItemStack> addItem(final Player player, final int maxStack, final boolean allowArmor, ItemStack... items) {
         items = normalizeItems(cloneItems(items));
         final Map<Integer, ItemStack> leftover = new HashMap<>();