Prevents WIP books from being lost

This change adds a workaround for writable books used for payment. Only books that don't contain any text can be used for payment, thus preventing any books with important text from being lost.

pom.xml

@@ -88,7 +88,7 @@
             <groupId>org.jetbrains</groupId>
             <artifactId>annotations</artifactId>
             <version>23.0.0</version>
-            <scope>compile</scope>
+            <scope>provided</scope>
         </dependency>
     </dependencies>
 </project>

src/main/java/net/knarcraft/bookswithoutborders/utility/EconomyHelper.java

@@ -8,10 +8,13 @@ import org.bukkit.Server;
 import org.bukkit.entity.Player;
 import org.bukkit.inventory.ItemStack;
 import org.bukkit.inventory.PlayerInventory;
+import org.bukkit.inventory.meta.BookMeta;
 import org.bukkit.plugin.Plugin;
 import org.bukkit.plugin.RegisteredServiceProvider;
 import org.bukkit.plugin.ServicesManager;
 
+import java.util.ArrayList;
+import java.util.List;
 import java.util.Objects;
 
 /**
@@ -73,6 +76,10 @@ public final class EconomyHelper {
 
         if (bookCurrency == Material.AIR) {
             return !EconomyHelper.payForBookPrintingEconomy(player, cost, numCopies);
+        } else {
+            if (bookCurrency == Material.WRITABLE_BOOK) {
+                //Writable books are treated as a special case to prevent WIP books from being used
+                return !takeWritableBookPayment(player, itemCost);
             } else {
                 if (player.getInventory().contains(bookCurrency, itemCost)) {
                     payForBookPrintingItem(player, itemCost);
@@ -84,6 +91,73 @@ public final class EconomyHelper {
                 }
             }
         }
+    }
+
+    /**
+     * Takes a writable book payment, ignoring any books containing text
+     *
+     * @param player   <p>The player to take payment from</p>
+     * @param itemCost <p>The number of writable books to pay</p>
+     * @return <p>True if the payment was successful</p>
+     */
+    private static boolean takeWritableBookPayment(Player player, int itemCost) {
+        List<ItemStack> books = getPlayersEmptyBooks(player);
+        if (countItems(books) < itemCost) {
+            BooksWithoutBorders.sendErrorMessage(player, itemCost + " " + Material.WRITABLE_BOOK +
+                    "(s) are required for this command!");
+            return false;
+        } else {
+            int clearedAmount = 0;
+            for (ItemStack itemStack : books) {
+                if (itemStack.getAmount() > itemCost) {
+                    itemStack.setAmount(itemStack.getAmount() - itemCost);
+                    break;
+                } else {
+                    clearedAmount += itemStack.getAmount();
+                    player.getInventory().remove(itemStack);
+                }
+                if (clearedAmount >= itemCost) {
+                    break;
+                }
+            }
+            return true;
+        }
+    }
+
+    /**
+     * Gets the total number of items contained in the given list of items
+     *
+     * @param items <p>The items to count</p>
+     * @return <p>The total number of items</p>
+     */
+    private static int countItems(List<ItemStack> items) {
+        int totalItems = 0;
+        for (ItemStack itemStack : items) {
+            totalItems += itemStack.getAmount();
+        }
+        return totalItems;
+    }
+
+    /**
+     * Gets all empty books in a player's inventory
+     *
+     * @param player <p>The player to get books for</p>
+     * @return <p>The empty books in the player's inventory</p>
+     */
+    private static List<ItemStack> getPlayersEmptyBooks(Player player) {
+        List<ItemStack> validBooks = new ArrayList<>();
+        for (ItemStack itemStack : player.getInventory().getContents()) {
+            if (itemStack.getType() != Material.WRITABLE_BOOK) {
+                continue;
+            }
+            BookMeta book = (BookMeta) itemStack;
+            //Only accept empty books
+            if (!book.hasPages() || (book.getPageCount() == 1 && book.getPage(1).trim().isEmpty())) {
+                validBooks.add(itemStack);
+            }
+        }
+        return validBooks;
+    }
 
     /**
      * Uses economy to take payment for printing a number of books