Added way to auto calculate item amount

You can find an explanation here:
- https://www.spigotmc.org/threads/shopchest.87948/page-15#post-1820672
- In the configuration file

src/main/java/de/epiceric/shopchest/config/Config.java

@@ -103,6 +103,9 @@ public class Config {
      */
     public boolean remove_shop_on_error;
 
+    /** Whether the item amount should be calculated to fit the available money or inventory space **/
+    public boolean auto_calculate_item_amount;
+
     /** Amount the hologram should be lifted **/
     public double two_line_hologram_lift;
 
@@ -276,6 +279,7 @@ public class Config {
         database_type = Database.DatabaseType.valueOf(plugin.getConfig().getString("database.type"));
         minimum_prices = (plugin.getConfig().getConfigurationSection("minimum-prices") == null) ? new HashSet<String>() : plugin.getConfig().getConfigurationSection("minimum-prices").getKeys(true);
         allow_broken_items = plugin.getConfig().getBoolean("allow-broken-items");
+        auto_calculate_item_amount = plugin.getConfig().getBoolean("auto-calculate-item-amount");
         shopLimits_group = (plugin.getConfig().getConfigurationSection("shop-limits.group") == null) ? new HashSet<String>() : plugin.getConfig().getConfigurationSection("shop-limits.group").getKeys(true);
         shopLimits_player = (plugin.getConfig().getConfigurationSection("shop-limits.player") == null) ? new HashSet<String>() : plugin.getConfig().getConfigurationSection("shop-limits.player").getKeys(true);
         blacklist = (plugin.getConfig().getStringList("blacklist") == null) ? new ArrayList<String>() : plugin.getConfig().getStringList("blacklist");

src/main/java/de/epiceric/shopchest/event/ShopBuySellEvent.java

@@ -11,12 +11,16 @@ public class ShopBuySellEvent extends ShopEvent implements Cancellable {
     private Player player;
     private Shop shop;
     private Type type;
+    private int newAmount;
+    private double newPrice;
     private boolean cancelled;
 
-    public ShopBuySellEvent(Player player, Shop shop, Type type) {
+    public ShopBuySellEvent(Player player, Shop shop, Type type, int newAmount, double newPrice) {
         this.player = player;
         this.shop = shop;
         this.type = type;
+        this.newAmount = newAmount;
+        this.newPrice = newPrice;
     }
 
     @Override
@@ -31,6 +35,20 @@ public class ShopBuySellEvent extends ShopEvent implements Cancellable {
         return type;
     }
 
+    /**
+     * @return The amount which might be modified because of automatic item amount calculation
+     */
+    public int getNewAmount() {
+        return newAmount;
+    }
+
+    /**
+     * @return The price which might be modified because of automatic item amount calculation
+     */
+    public double getNewPrice() {
+        return newPrice;
+    }
+
     @Override
     public Player getPlayer() {
         return player;

src/main/java/de/epiceric/shopchest/listeners/ShopInteractListener.java

@@ -1,6 +1,7 @@
 package de.epiceric.shopchest.listeners;
 
 import de.epiceric.shopchest.ShopChest;
+import de.epiceric.shopchest.config.Config;
 import de.epiceric.shopchest.config.Regex;
 import de.epiceric.shopchest.event.ShopBuySellEvent;
 import de.epiceric.shopchest.event.ShopCreateEvent;
@@ -48,6 +49,7 @@ public class ShopInteractListener implements Listener {
     private Economy econ;
     private Database database;
     private ShopUtils shopUtils;
+    private Config config;
 
     public ShopInteractListener(ShopChest plugin) {
         this.plugin = plugin;
@@ -55,6 +57,7 @@ public class ShopInteractListener implements Listener {
         this.econ = plugin.getEconomy();
         this.database = plugin.getShopDatabase();
         this.shopUtils = plugin.getShopUtils();
+        this.config = plugin.getShopChestConfig();
     }
 
     @EventHandler(priority = EventPriority.HIGH)
@@ -184,11 +187,15 @@ public class ShopInteractListener implements Listener {
                                                 Chest c = (Chest) b.getState();
                                                 if (Utils.getAmount(c.getInventory(), shop.getProduct()) >= shop.getProduct().getAmount()) {
                                                     buy(p, shop);
+                                                } else {
+                                                    if (config.auto_calculate_item_amount && Utils.getAmount(c.getInventory(), shop.getProduct()) > 0) {
+                                                        buy(p, shop);
                                                     } else {
                                                         p.sendMessage(LanguageUtils.getMessage(LocalizedMessage.Message.OUT_OF_STOCK));
                                                         plugin.debug("Shop is out of stock");
                                                     }
                                                 }
+                                            }
                                         } else {
                                             p.sendMessage(LanguageUtils.getMessage(LocalizedMessage.Message.NO_PERMISSION_BUY));
                                             plugin.debug(p.getName() + " is not permitted to buy");
@@ -221,10 +228,14 @@ public class ShopInteractListener implements Listener {
                                 if (perm.has(p, "shopchest.sell")) {
                                     if (Utils.getAmount(p.getInventory(), shop.getProduct()) >= shop.getProduct().getAmount()) {
                                         sell(p, shop);
+                                    } else {
+                                        if (config.auto_calculate_item_amount && Utils.getAmount(p.getInventory(), shop.getProduct()) > 0) {
+                                            sell(p, shop);
                                         } else {
                                             p.sendMessage(LanguageUtils.getMessage(LocalizedMessage.Message.NOT_ENOUGH_ITEMS));
                                             plugin.debug(p.getName() + " doesn't have enough items");
                                         }
+                                    }
                                 } else {
                                     p.sendMessage(LanguageUtils.getMessage(LocalizedMessage.Message.NO_PERMISSION_SELL));
                                     plugin.debug(p.getName() + " is not permitted to sell");
@@ -262,7 +273,7 @@ public class ShopInteractListener implements Listener {
         plugin.debug(executor.getName() + " is creating new shop...");
 
         int id = database.getNextFreeID();
-        double creationPrice = (shopType == ShopType.NORMAL) ? plugin.getShopChestConfig().shop_creation_price_normal : plugin.getShopChestConfig().shop_creation_price_admin;
+        double creationPrice = (shopType == ShopType.NORMAL) ? config.shop_creation_price_normal : config.shop_creation_price_admin;
 
         ShopCreateEvent event = new ShopCreateEvent(executor, Shop.createImaginaryShop(executor, product, location, buyPrice, sellPrice,shopType), creationPrice);
         Bukkit.getPluginManager().callEvent(event);
@@ -410,78 +421,78 @@ public class ShopInteractListener implements Listener {
      */
     private void buy(Player executor, Shop shop) {
         plugin.debug(executor.getName() + " is buying (#" + shop.getID() + ")");
-        if (econ.getBalance(executor) >= shop.getBuyPrice()) {
+        if (econ.getBalance(executor) >= shop.getBuyPrice() || config.auto_calculate_item_amount) {
-            plugin.debug(executor.getName() + " has enough money (#" + shop.getID() + ")");
+
+            int amountForMoney = (int) (shop.getProduct().getAmount() / shop.getBuyPrice() * econ.getBalance(executor));
+
+            if (amountForMoney == 0 && config.auto_calculate_item_amount) {
+                executor.sendMessage(LanguageUtils.getMessage(LocalizedMessage.Message.NOT_ENOUGH_MONEY));
+                return;
+            }
+
+            plugin.debug(executor.getName() + " has enough money for " + amountForMoney + " item(s) (#" + shop.getID() + ")");
 
             Block b = shop.getLocation().getBlock();
             Chest c = (Chest) b.getState();
 
-            HashMap<Integer, Integer> slotFree = new HashMap<>();
+            int amountForChestSpace = Utils.getAmount(c.getInventory(), shop.getProduct());
+
+            if (amountForChestSpace == 0 && config.auto_calculate_item_amount) {
+                executor.sendMessage(LanguageUtils.getMessage(LocalizedMessage.Message.OUT_OF_STOCK));
+                return;
+            }
+
             ItemStack product = new ItemStack(shop.getProduct());
             Inventory inventory = executor.getInventory();
 
-            for (int i = 0; i < 36; i++) {
+            int freeSpace = Utils.getFreeSpaceForItem(inventory, product);
-                ItemStack item = inventory.getItem(i);
+
-                if (item == null) {
+            int amountForPlayerInvSpace = (freeSpace >= product.getAmount() ? product.getAmount() : freeSpace);
-                    slotFree.put(i, product.getMaxStackSize());
+
-                } else {
+            if (amountForPlayerInvSpace == 0 && config.auto_calculate_item_amount) {
-                    if (item.isSimilar(product)) {
+                executor.sendMessage(LanguageUtils.getMessage(LocalizedMessage.Message.NOT_ENOUGH_INVENTORY_SPACE));
-                        int amountInSlot = item.getAmount();
+                return;
-                        int amountToFullStack = product.getMaxStackSize() - amountInSlot;
-                        slotFree.put(i, amountToFullStack);
-                    }
-                }
             }
 
-            if (Utils.getMajorVersion() >= 9) {
+            int newAmount = Math.min(Math.min(amountForMoney, amountForChestSpace), amountForPlayerInvSpace);
-                ItemStack item = inventory.getItem(40);
+            if (newAmount > shop.getProduct().getAmount()) newAmount = shop.getProduct().getAmount();
-                if (item == null) {
-                    slotFree.put(40, product.getMaxStackSize());
-                } else {
-                    if (item.isSimilar(product)) {
-                        int amountInSlot = item.getAmount();
-                        int amountToFullStack = product.getMaxStackSize() - amountInSlot;
-                        slotFree.put(40, amountToFullStack);
-                    }
-                }
-            }
 
-            int freeAmount = 0;
+            double newPrice = (shop.getBuyPrice() / shop.getProduct().getAmount()) * newAmount;
-            for (int value : slotFree.values()) {
-                freeAmount += value;
-            }
 
-            if (freeAmount >= product.getAmount()) {
+            if (freeSpace >= product.getAmount() || (config.auto_calculate_item_amount && freeSpace >= newAmount)) {
-                plugin.debug(executor.getName() + " has enough inventory space (#" + shop.getID() + ")");
+                plugin.debug(executor.getName() + " has enough inventory space for " + freeSpace + " items (#" + shop.getID() + ")");
 
-                EconomyResponse r = econ.withdrawPlayer(executor, shop.getBuyPrice());
+                ItemStack newProduct = new ItemStack(product);
-                EconomyResponse r2 = (shop.getShopType() != ShopType.ADMIN) ? econ.depositPlayer(shop.getVendor(), shop.getBuyPrice()) : null;
+                newProduct.setAmount(newAmount);
+
+                EconomyResponse r = econ.withdrawPlayer(executor, newPrice);
+                EconomyResponse r2 = (shop.getShopType() != ShopType.ADMIN) ? econ.depositPlayer(shop.getVendor(), newPrice) : null;
 
                 if (r.transactionSuccess()) {
                     if (r2 != null) {
                         if (r2.transactionSuccess()) {
-                            ShopBuySellEvent event = new ShopBuySellEvent(executor, shop, ShopBuySellEvent.Type.BUY);
+                            ShopBuySellEvent event = new ShopBuySellEvent(executor, shop, ShopBuySellEvent.Type.BUY, newAmount, newPrice);
                             Bukkit.getPluginManager().callEvent(event);
 
                             if (event.isCancelled()) {
-                                econ.depositPlayer(executor, shop.getBuyPrice());
+                                econ.depositPlayer(executor, newPrice);
-                                econ.withdrawPlayer(shop.getVendor(), shop.getBuyPrice());
+                                econ.withdrawPlayer(shop.getVendor(), newPrice);
                                 plugin.debug("Buy event cancelled (#" + shop.getID() + ")");
                                 return;
                             }
 
-                            addToInventory(inventory, product);
+                            addToInventory(inventory, newProduct);
-                            removeFromInventory(c.getInventory(), product);
+                            removeFromInventory(c.getInventory(), newProduct);
                             executor.updateInventory();
-                            executor.sendMessage(LanguageUtils.getMessage(LocalizedMessage.Message.BUY_SUCCESS, new LocalizedMessage.ReplacedRegex(Regex.AMOUNT, String.valueOf(product.getAmount())),
+                            executor.sendMessage(LanguageUtils.getMessage(LocalizedMessage.Message.BUY_SUCCESS, new LocalizedMessage.ReplacedRegex(Regex.AMOUNT, String.valueOf(newAmount)),
-                                    new LocalizedMessage.ReplacedRegex(Regex.ITEM_NAME, LanguageUtils.getItemName(product)), new LocalizedMessage.ReplacedRegex(Regex.BUY_PRICE, String.valueOf(shop.getBuyPrice())),
+                                    new LocalizedMessage.ReplacedRegex(Regex.ITEM_NAME, LanguageUtils.getItemName(product)), new LocalizedMessage.ReplacedRegex(Regex.BUY_PRICE, String.valueOf(newPrice)),
                                     new LocalizedMessage.ReplacedRegex(Regex.VENDOR, shop.getVendor().getName())));
 
                             plugin.debug(executor.getName() + " successfully bought (#" + shop.getID() + ")");
 
                             if (shop.getVendor().isOnline()) {
-                                shop.getVendor().getPlayer().sendMessage(LanguageUtils.getMessage(LocalizedMessage.Message.SOMEONE_BOUGHT, new LocalizedMessage.ReplacedRegex(Regex.AMOUNT, String.valueOf(product.getAmount())),
+                                shop.getVendor().getPlayer().sendMessage(LanguageUtils.getMessage(LocalizedMessage.Message.SOMEONE_BOUGHT, new LocalizedMessage.ReplacedRegex(Regex.AMOUNT, String.valueOf(newAmount)),
-                                        new LocalizedMessage.ReplacedRegex(Regex.ITEM_NAME, LanguageUtils.getItemName(product)), new LocalizedMessage.ReplacedRegex(Regex.BUY_PRICE, String.valueOf(shop.getBuyPrice())),
+                                        new LocalizedMessage.ReplacedRegex(Regex.ITEM_NAME, LanguageUtils.getItemName(product)), new LocalizedMessage.ReplacedRegex(Regex.BUY_PRICE, String.valueOf(newPrice)),
                                         new LocalizedMessage.ReplacedRegex(Regex.PLAYER, executor.getName())));
                             }
 
@@ -490,19 +501,19 @@ public class ShopInteractListener implements Listener {
                             executor.sendMessage(LanguageUtils.getMessage(LocalizedMessage.Message.ERROR_OCCURRED, new LocalizedMessage.ReplacedRegex(Regex.ERROR, r2.errorMessage)));
                         }
                     } else {
-                        ShopBuySellEvent event = new ShopBuySellEvent(executor, shop, ShopBuySellEvent.Type.BUY);
+                        ShopBuySellEvent event = new ShopBuySellEvent(executor, shop, ShopBuySellEvent.Type.BUY, newAmount, newPrice);
                         Bukkit.getPluginManager().callEvent(event);
 
                         if (event.isCancelled()) {
-                            econ.depositPlayer(executor, shop.getBuyPrice());
+                            econ.depositPlayer(executor, newPrice);
                             plugin.debug("Buy event cancelled (#" + shop.getID() + ")");
                             return;
                         }
 
-                        addToInventory(inventory, product);
+                        addToInventory(inventory, newProduct);
                         executor.updateInventory();
-                        executor.sendMessage(LanguageUtils.getMessage(LocalizedMessage.Message.BUY_SUCESS_ADMIN, new LocalizedMessage.ReplacedRegex(Regex.AMOUNT, String.valueOf(product.getAmount())),
+                        executor.sendMessage(LanguageUtils.getMessage(LocalizedMessage.Message.BUY_SUCESS_ADMIN, new LocalizedMessage.ReplacedRegex(Regex.AMOUNT, String.valueOf(newAmount)),
-                                new LocalizedMessage.ReplacedRegex(Regex.ITEM_NAME, LanguageUtils.getItemName(product)), new LocalizedMessage.ReplacedRegex(Regex.BUY_PRICE, String.valueOf(shop.getBuyPrice()))));
+                                new LocalizedMessage.ReplacedRegex(Regex.ITEM_NAME, LanguageUtils.getItemName(product)), new LocalizedMessage.ReplacedRegex(Regex.BUY_PRICE, String.valueOf(newPrice))));
 
                         plugin.debug(executor.getName() + " successfully bought (#" + shop.getID() + ")");
                     }
@@ -526,65 +537,77 @@ public class ShopInteractListener implements Listener {
     private void sell(Player executor, Shop shop) {
         plugin.debug(executor.getName() + " is selling (#" + shop.getID() + ")");
 
-        if (econ.getBalance(shop.getVendor()) >= shop.getSellPrice() || shop.getShopType() == ShopType.ADMIN) {
+        if (econ.getBalance(shop.getVendor()) >= shop.getSellPrice() || shop.getShopType() == ShopType.ADMIN || config.auto_calculate_item_amount) {
-            plugin.debug("Vendor has enough money (#" + shop.getID() + ")");
+            int amountForMoney = (int) (shop.getProduct().getAmount() / shop.getSellPrice() * econ.getBalance(shop.getVendor()));
+
+            plugin.debug("Vendor has enough money for " + amountForMoney + " item(s) (#" + shop.getID() + ")");
+
+            if (amountForMoney == 0 && config.auto_calculate_item_amount) {
+                executor.sendMessage(LanguageUtils.getMessage(LocalizedMessage.Message.VENDOR_NOT_ENOUGH_MONEY));
+                return;
+            }
 
             Block block = shop.getLocation().getBlock();
             Chest chest = (Chest) block.getState();
 
-            HashMap<Integer, Integer> slotFree = new HashMap<>();
+            int amountForItemCount = Utils.getAmount(executor.getInventory(), shop.getProduct());
+
+            if (amountForItemCount == 0 && config.auto_calculate_item_amount) {
+                executor.sendMessage(LanguageUtils.getMessage(LocalizedMessage.Message.NOT_ENOUGH_ITEMS));
+                return;
+            }
+
             ItemStack product = new ItemStack(shop.getProduct());
             Inventory inventory = chest.getInventory();
 
-            for (int i = 0; i < inventory.getSize(); i++) {
+            int freeSpace = Utils.getFreeSpaceForItem(inventory, product);
-                ItemStack item = inventory.getItem(i);
+
-                if (item == null) {
+            int amountForChestSpace = (freeSpace >= product.getAmount() ? product.getAmount() : freeSpace);
-                    slotFree.put(i, product.getMaxStackSize());
+
-                } else {
+            if (amountForChestSpace == 0 && config.auto_calculate_item_amount) {
-                    if (item.isSimilar(product)) {
+                executor.sendMessage(LanguageUtils.getMessage(LocalizedMessage.Message.CHEST_NOT_ENOUGH_INVENTORY_SPACE));
-                        int amountInSlot = item.getAmount();
+                return;
-                        int amountToFullStack = product.getMaxStackSize() - amountInSlot;
-                        slotFree.put(i, amountToFullStack);
-                    }
-                }
             }
 
-            int freeAmount = 0;
+            int newAmount = Math.min(Math.min(amountForMoney, amountForItemCount), amountForChestSpace);
-            for (int value : slotFree.values()) {
+            if (newAmount > shop.getProduct().getAmount()) newAmount = shop.getProduct().getAmount();
-                freeAmount += value;
-            }
 
-            if (freeAmount >= product.getAmount()) {
+            double newPrice = (shop.getSellPrice() / shop.getProduct().getAmount()) * newAmount;
-                plugin.debug("Chest has enough inventory space (#" + shop.getID() + ")");
 
-                EconomyResponse r = econ.depositPlayer(executor, shop.getSellPrice());
+            if (freeSpace >= product.getAmount() || (config.auto_calculate_item_amount && freeSpace >= newAmount)) {
-                EconomyResponse r2 = (shop.getShopType() != ShopType.ADMIN) ? econ.withdrawPlayer(shop.getVendor(), shop.getSellPrice()) : null;
+                plugin.debug("Chest has enough inventory space for " + freeSpace + " items (#" + shop.getID() + ")");
+
+                ItemStack newProduct = new ItemStack(product);
+                newProduct.setAmount(newAmount);
+
+                EconomyResponse r = econ.depositPlayer(executor, newPrice);
+                EconomyResponse r2 = (shop.getShopType() != ShopType.ADMIN) ? econ.withdrawPlayer(shop.getVendor(), newPrice) : null;
 
                 if (r.transactionSuccess()) {
                     if (r2 != null) {
                         if (r2.transactionSuccess()) {
-                            ShopBuySellEvent event = new ShopBuySellEvent(executor, shop, ShopBuySellEvent.Type.SELL);
+                            ShopBuySellEvent event = new ShopBuySellEvent(executor, shop, ShopBuySellEvent.Type.SELL, newAmount, newPrice);
                             Bukkit.getPluginManager().callEvent(event);
 
                             if (event.isCancelled()) {
-                                econ.withdrawPlayer(executor, shop.getBuyPrice());
+                                econ.withdrawPlayer(executor, newPrice);
-                                econ.depositPlayer(shop.getVendor(), shop.getBuyPrice());
+                                econ.depositPlayer(shop.getVendor(), newPrice);
                                 plugin.debug("Sell event cancelled (#" + shop.getID() + ")");
                                 return;
                             }
 
-                            addToInventory(inventory, product);
+                            addToInventory(inventory, newProduct);
-                            removeFromInventory(executor.getInventory(), product);
+                            removeFromInventory(executor.getInventory(), newProduct);
                             executor.updateInventory();
-                            executor.sendMessage(LanguageUtils.getMessage(LocalizedMessage.Message.SELL_SUCESS, new LocalizedMessage.ReplacedRegex(Regex.AMOUNT, String.valueOf(product.getAmount())),
+                            executor.sendMessage(LanguageUtils.getMessage(LocalizedMessage.Message.SELL_SUCESS, new LocalizedMessage.ReplacedRegex(Regex.AMOUNT, String.valueOf(newAmount)),
-                                    new LocalizedMessage.ReplacedRegex(Regex.ITEM_NAME, LanguageUtils.getItemName(product)), new LocalizedMessage.ReplacedRegex(Regex.SELL_PRICE, String.valueOf(shop.getSellPrice())),
+                                    new LocalizedMessage.ReplacedRegex(Regex.ITEM_NAME, LanguageUtils.getItemName(product)), new LocalizedMessage.ReplacedRegex(Regex.SELL_PRICE, String.valueOf(newPrice)),
                                     new LocalizedMessage.ReplacedRegex(Regex.VENDOR, shop.getVendor().getName())));
 
                             plugin.debug(executor.getName() + " successfully sold (#" + shop.getID() + ")");
 
                             if (shop.getVendor().isOnline()) {
-                                shop.getVendor().getPlayer().sendMessage(LanguageUtils.getMessage(LocalizedMessage.Message.SOMEONE_SOLD, new LocalizedMessage.ReplacedRegex(Regex.AMOUNT, String.valueOf(product.getAmount())),
+                                shop.getVendor().getPlayer().sendMessage(LanguageUtils.getMessage(LocalizedMessage.Message.SOMEONE_SOLD, new LocalizedMessage.ReplacedRegex(Regex.AMOUNT, String.valueOf(newAmount)),
-                                        new LocalizedMessage.ReplacedRegex(Regex.ITEM_NAME, LanguageUtils.getItemName(product)), new LocalizedMessage.ReplacedRegex(Regex.SELL_PRICE, String.valueOf(shop.getSellPrice())),
+                                        new LocalizedMessage.ReplacedRegex(Regex.ITEM_NAME, LanguageUtils.getItemName(product)), new LocalizedMessage.ReplacedRegex(Regex.SELL_PRICE, String.valueOf(newPrice)),
                                         new LocalizedMessage.ReplacedRegex(Regex.PLAYER, executor.getName())));
                             }
 
@@ -594,19 +617,19 @@ public class ShopInteractListener implements Listener {
                         }
 
                     } else {
-                        ShopBuySellEvent event = new ShopBuySellEvent(executor, shop, ShopBuySellEvent.Type.SELL);
+                        ShopBuySellEvent event = new ShopBuySellEvent(executor, shop, ShopBuySellEvent.Type.SELL, newAmount, newPrice);
                         Bukkit.getPluginManager().callEvent(event);
 
                         if (event.isCancelled()) {
-                            econ.withdrawPlayer(executor, shop.getBuyPrice());
+                            econ.withdrawPlayer(executor, newPrice);
                             plugin.debug("Sell event cancelled (#" + shop.getID() + ")");
                             return;
                         }
 
-                        removeFromInventory(executor.getInventory(), product);
+                        removeFromInventory(executor.getInventory(), newProduct);
                         executor.updateInventory();
-                        executor.sendMessage(LanguageUtils.getMessage(LocalizedMessage.Message.SELL_SUCESS_ADMIN, new LocalizedMessage.ReplacedRegex(Regex.AMOUNT, String.valueOf(product.getAmount())),
+                        executor.sendMessage(LanguageUtils.getMessage(LocalizedMessage.Message.SELL_SUCESS_ADMIN, new LocalizedMessage.ReplacedRegex(Regex.AMOUNT, String.valueOf(newAmount)),
-                                new LocalizedMessage.ReplacedRegex(Regex.ITEM_NAME, LanguageUtils.getItemName(product)), new LocalizedMessage.ReplacedRegex(Regex.SELL_PRICE, String.valueOf(shop.getSellPrice()))));
+                                new LocalizedMessage.ReplacedRegex(Regex.ITEM_NAME, LanguageUtils.getItemName(product)), new LocalizedMessage.ReplacedRegex(Regex.SELL_PRICE, String.valueOf(newPrice))));
 
                         plugin.debug(executor.getName() + " successfully sold (#" + shop.getID() + ")");
                     }

src/main/java/de/epiceric/shopchest/utils/Utils.java

@@ -14,6 +14,7 @@ import javax.xml.bind.DatatypeConverter;
 import java.lang.reflect.InvocationTargetException;
 import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
+import java.util.HashMap;
 
 public class Utils {
 
@@ -55,6 +56,65 @@ public class Utils {
         return amount;
     }
 
+    /**
+     * Get the amount of the given item, that fits in the given inventory
+     *
+     * @param inventory Inventory, where to search for free space
+     * @param itemStack Item, of which the amount that fits in the inventory should be returned
+     * @return Amount of the given item, that fits in the given inventory
+     */
+    public static int getFreeSpaceForItem(Inventory inventory, ItemStack itemStack) {
+        HashMap<Integer, Integer> slotFree = new HashMap<>();
+
+        if (inventory instanceof PlayerInventory) {
+            for (int i = 0; i < 36; i++) {
+                ItemStack item = inventory.getItem(i);
+                if (item == null) {
+                    slotFree.put(i, itemStack.getMaxStackSize());
+                } else {
+                    if (item.isSimilar(itemStack)) {
+                        int amountInSlot = item.getAmount();
+                        int amountToFullStack = itemStack.getMaxStackSize() - amountInSlot;
+                        slotFree.put(i, amountToFullStack);
+                    }
+                }
+            }
+
+            if (getMajorVersion() >= 9) {
+                ItemStack item = inventory.getItem(40);
+                if (item == null) {
+                    slotFree.put(40, itemStack.getMaxStackSize());
+                } else {
+                    if (item.isSimilar(itemStack)) {
+                        int amountInSlot = item.getAmount();
+                        int amountToFullStack = itemStack.getMaxStackSize() - amountInSlot;
+                        slotFree.put(40, amountToFullStack);
+                    }
+                }
+            }
+        } else {
+            for (int i = 0; i < inventory.getSize(); i++) {
+                ItemStack item = inventory.getItem(i);
+                if (item == null) {
+                    slotFree.put(i, itemStack.getMaxStackSize());
+                } else {
+                    if (item.isSimilar(itemStack)) {
+                        int amountInSlot = item.getAmount();
+                        int amountToFullStack = itemStack.getMaxStackSize() - amountInSlot;
+                        slotFree.put(i, amountToFullStack);
+                    }
+                }
+            }
+        }
+
+        int freeAmount = 0;
+        for (int value : slotFree.values()) {
+            freeAmount += value;
+        }
+
+        return freeAmount;
+    }
+
     /**
      * @param p Player whose item in his main hand should be returned
      * @return {@link ItemStack} in his main hand, or {@code null} if he doesn't hold one

src/main/resources/config.yml

@@ -31,6 +31,16 @@ two-line-prices: false
 # A value of '1' equals to one block, and a value of '0.25' is equal to the height of one line.
 two-line-hologram-lift: 0.25
 
+# Set whether players should be allowed to sell their items, even if the amount they have, is
+# lower than the amount, the shop owner has set for the given price, or if the inventory of the chest
+# doesn't have enough space for all the items, but only for a few, or if the player only has enough money for
+# a few items, but not for the amount, the shop owner has set. When set to true, players may also
+# buy items from a shop, even if the amount of items in the chest is lower than the amount, the shop owner has
+# set for the given price, or if they don't have enough space in the inventory for all of the items, but
+# only for a few, or if the shop owner doesn't have enough money to buy all of the items, the player wants to sell.
+# The price will be calculated correspondingly. (If it's not clear enough, please let me know)
+auto-calculate-item-amount: false
+
 # Set whether players should be allowed to sell/buy broken items
 allow-broken-items: false