interact backpack with chest on sneak right click

src/main/java/de/jottyfan/minecraft/quickiefabric/container/BackpackInventory.java

@@ -25,6 +25,14 @@ public class BackpackInventory extends SimpleInventory {
 
 	public static final BackpackInventory getInventory(BackpackScreenHandler handler, PlayerEntity player,
 			ItemStack stack) {
+		return new BackpackInventory(init(stack).getTag().getCompound("backpack"), handler);
+	}
+	
+	public BackpackInventory(ItemStack stack) {
+		this(init(stack).getTag().getCompound("backpack"), null);
+	}
+	
+	private final static ItemStack init(ItemStack stack) {
 		if (stack != null) {
 			if (!stack.hasTag()) {
 				stack.setTag(new CompoundTag());
@@ -33,7 +41,7 @@ public class BackpackInventory extends SimpleInventory {
 				stack.getTag().put("backpack", new CompoundTag());
 			}
 		}
-		return new BackpackInventory(stack.getTag().getCompound("backpack"), handler);
+		return stack;
 	}
 
 	@Override

src/main/java/de/jottyfan/minecraft/quickiefabric/items/ItemBackpack.java

@@ -1,5 +1,6 @@
 package de.jottyfan.minecraft.quickiefabric.items;
 
+import de.jottyfan.minecraft.quickiefabric.container.BackpackInventory;
 import de.jottyfan.minecraft.quickiefabric.container.BackpackScreenHandler;
 import de.jottyfan.minecraft.quickiefabric.init.RegistryManager;
 import io.netty.buffer.Unpooled;
@@ -9,6 +10,7 @@ import net.minecraft.block.BlockState;
 import net.minecraft.block.Blocks;
 import net.minecraft.block.entity.BlockEntity;
 import net.minecraft.block.entity.BlockEntityType;
+import net.minecraft.block.entity.ChestBlockEntity;
 import net.minecraft.entity.player.PlayerEntity;
 import net.minecraft.entity.player.PlayerInventory;
 import net.minecraft.item.Item;
@@ -19,6 +21,7 @@ import net.minecraft.screen.ScreenHandler;
 import net.minecraft.server.network.ServerPlayerEntity;
 import net.minecraft.text.LiteralText;
 import net.minecraft.text.Text;
+import net.minecraft.text.TranslatableText;
 import net.minecraft.util.ActionResult;
 import net.minecraft.util.Hand;
 import net.minecraft.util.TypedActionResult;
@@ -36,7 +39,7 @@ public class ItemBackpack extends Item {
 	public ItemBackpack() {
 		super(new Item.Settings().group(RegistryManager.QUICKIEFABRIC_GROUP).maxCount(1));
 	}
-	
+
 	@Override
 	public TypedActionResult<ItemStack> use(World world, PlayerEntity player, Hand hand) {
 		ItemStack itemStack = player.getStackInHand(hand);
@@ -64,19 +67,52 @@ public class ItemBackpack extends Item {
 		}
 		return new TypedActionResult<ItemStack>(ActionResult.SUCCESS, itemStack);
 	}
-	
+
 	@Override
 	public ActionResult useOnBlock(ItemUsageContext context) {
 		BlockPos pos = context.getBlockPos();
 		World world = context.getWorld();
+		PlayerEntity player = context.getPlayer();
 		BlockState blockState = world.getBlockState(pos);
 		Block block = blockState.getBlock();
 		if (Blocks.CHEST.equals(block)) {
 			BlockEntity entity = world.getBlockEntity(pos);
 			BlockEntityType<?> type = entity.getType();
 			if (BlockEntityType.CHEST.equals(type)) {
-				// TODO: create a new dialog for transferring items from backpack to chest and back
+				ChestBlockEntity cbe = (ChestBlockEntity) entity;
-				//       with the help of some buttons (such as all or so)
+				BackpackInventory bi = new BackpackInventory(context.getStack());
+				bi.setHand(context.getHand());
+				if (cbe.isEmpty()) {
+					for (int slot = 0; slot < ItemBackpack.SLOTSIZE; slot++) {
+						if (slot < cbe.size()) {
+							cbe.setStack(slot, bi.getStack(slot));
+							bi.removeStack(slot);
+						}
+					}
+					bi.onClose(player);
+					if (!world.isClient) {
+						player.sendMessage(new TranslatableText("msg.backpack.transfer.cleared"), false);
+					}
+				} else if (bi.isEmpty()) {
+					for (int slot = 0; slot < ItemBackpack.SLOTSIZE; slot++) {
+						if (slot < cbe.size()) {
+							bi.setStack(slot, cbe.getStack(slot));
+							cbe.setStack(slot, ItemStack.EMPTY);
+						}
+					}
+					bi.onClose(player);
+					if (!world.isClient) {
+						player.sendMessage(new TranslatableText("msg.backpack.transfer.filled"), false);
+					}
+				} else {
+					if (!world.isClient) {
+						player.sendMessage(new TranslatableText("msg.backpack.transfer.cancel"), false);
+					}
+				}
+				// alternative:
+				// TODO: create a new dialog for transferring items from backpack to chest and
+				// back
+				// with the help of some buttons (such as all or so)
 			}
 		}
 		return super.useOnBlock(context);

src/main/resources/assets/quickiefabric/lang/de_de.json

@@ -66,5 +66,8 @@
 	"msg.buildingplan.failonplayer": "Der Bau wurde abgelehnt, um Spieler %s nicht zu gefährden.",
 	"msg.itemhoarder.summary": "Der Itemsauger enthält: %s",
 	"msg.notyetimplemented": "leider noch nicht verfügbar",
+	"msg.backpack.transfer.filled": "Der Rucksack wurde aus der Kiste befüllt.",
+	"msg.backpack.transfer.cleared": "Der Rucksackinhalt wurde in die Kiste geschüttet.",
+	"msg.backpack.transfer.cancel": "Entweder der Rucksack oder die Kiste sind nicht komplett leer.",
 	"error.unleveling.inventory.full": "Es ist kein Platz mehr frei, um die Aufwertungen abzulegen."
 }

src/main/resources/assets/quickiefabric/lang/en_us.json

@@ -66,5 +66,8 @@
 	"msg.buildingplan.failonplayer": "The building execution was rejected because of %s who could be injured.",
 	"msg.itemhoarder.summary": "The item hoarder contains: %s",
 	"msg.notyetimplemented": "not yet implemented",
+	"msg.backpack.transfer.filled": "Filled the backpack from the chest.",
+	"msg.backpack.transfer.cleared": "Filled the chest from the backpack.",
+	"msg.backpack.transfer.cancel": "Eigther backpack or chest are not completely empty.",
 	"error.unleveling.inventory.full": "There is no free stack in your inventory for the level ups."
 }