I think i'm finally storing/retrieving exp correctly

src/generated/resources/.cache/8202586f691eec5ad0bb88d13a278951d0c130fb

@@ -1,2 +1,2 @@
-// 1.21.1	2024-09-12T11:15:53.905581	Languages: en_us for mod: justdirethings
-80317086157715c924dcacf357e72efab49d8580 assets/justdirethings/lang/en_us.json
+// 1.21.1	2024-09-12T13:18:00.5916321	Languages: en_us for mod: justdirethings
+370a2cb7525636b760559d6e7176176093558760 assets/justdirethings/lang/en_us.json

src/generated/resources/assets/justdirethings/lang/en_us.json

@@ -408,6 +408,7 @@
   "justdirethings.screen.renderarea": "Render Area",
   "justdirethings.screen.renderparadox": "Render Paradox",
   "justdirethings.screen.requireequipped": "Activate if Equipped",
+  "justdirethings.screen.retrieveexp": "Retrieve Exp",
   "justdirethings.screen.rightclicksettings": "Right Click for Settings",
   "justdirethings.screen.save_close": "Save and Close",
   "justdirethings.screen.senditems": "Push Items",
@@ -419,6 +420,7 @@
   "justdirethings.screen.snapshotarea": "Snapshot Area",
   "justdirethings.screen.sneak-click": "Sneak Click",
   "justdirethings.screen.stay_open": "Stay Open",
+  "justdirethings.screen.storeexp": "Store Exp",
   "justdirethings.screen.swapitems": "Swap Items",
   "justdirethings.screen.target-adult": "Target Adult",
   "justdirethings.screen.target-air": "Target Air",

src/main/java/com/direwolf20/justdirethings/client/screens/ExperienceHolderScreen.java

@@ -1,17 +1,44 @@
 package com.direwolf20.justdirethings.client.screens;
 
 import com.direwolf20.justdirethings.client.screens.basescreens.BaseMachineScreen;
+import com.direwolf20.justdirethings.client.screens.standardbuttons.ToggleButtonFactory;
+import com.direwolf20.justdirethings.common.blockentities.ExperienceHolderBE;
 import com.direwolf20.justdirethings.common.containers.ExperienceHolderContainer;
+import com.direwolf20.justdirethings.common.network.data.ExperienceHolderPayload;
+import net.minecraft.client.gui.screens.Screen;
 import net.minecraft.network.chat.Component;
 import net.minecraft.world.entity.player.Inventory;
+import net.neoforged.neoforge.network.PacketDistributor;
 
 public class ExperienceHolderScreen extends BaseMachineScreen<ExperienceHolderContainer> {
+    private ExperienceHolderBE experienceHolderBE;
+    private int exp;
     public ExperienceHolderScreen(ExperienceHolderContainer container, Inventory inv, Component name) {
         super(container, inv, name);
+        if (container.baseMachineBE instanceof ExperienceHolderBE experienceHolderBE) {
+            this.experienceHolderBE = experienceHolderBE;
+            this.exp = experienceHolderBE.exp;
+        }
     }
 
     @Override
     public void init() {
         super.init();
+        addRenderableWidget(ToggleButtonFactory.STOREEXPBUTTON(getGuiLeft() + 62, topSectionTop + 62, true, b -> {
+            int amt = 1;
+            if (Screen.hasControlDown())
+                amt = -1;
+            else if (Screen.hasShiftDown())
+                amt = amt * 10;
+            PacketDistributor.sendToServer(new ExperienceHolderPayload(true, amt));
+        }));
+        addRenderableWidget(ToggleButtonFactory.EXTRACTEXPBUTTON(getGuiLeft() + 102, topSectionTop + 62, true, b -> {
+            int amt = 1;
+            if (Screen.hasControlDown())
+                amt = -1;
+            else if (Screen.hasShiftDown())
+                amt = amt * 10;
+            PacketDistributor.sendToServer(new ExperienceHolderPayload(false, amt));
+        }));
     }
 }

src/main/java/com/direwolf20/justdirethings/client/screens/standardbuttons/ToggleButtonFactory.java

@@ -49,6 +49,20 @@ public static ToggleButton ALLOWLISTBUTTON(int x, int y, boolean startingValue,
         return new ToggleButton(x, y, STANDARD_WIDTH, STANDARD_HEIGHT, ALLOW_LIST_TEXTURES, startingValue, onPress);
     }
 
+    private static final ResourceLocation STORE_EXP_BUTTON = ResourceLocation.fromNamespaceAndPath(JustDireThings.MODID, "textures/gui/buttons/add.png");
+    private static final Component STORE_EXP_BUTTON_LOCALIZATION = Component.translatable("justdirethings.screen.storeexp");
+
+    public static GrayscaleButton STOREEXPBUTTON(int x, int y, boolean startingValue, Button.OnPress onPress) {
+        return new GrayscaleButton(x, y, STANDARD_WIDTH, STANDARD_HEIGHT, STORE_EXP_BUTTON, STORE_EXP_BUTTON_LOCALIZATION, startingValue, onPress);
+    }
+
+    private static final ResourceLocation EXTRACT_EXP_BUTTON = ResourceLocation.fromNamespaceAndPath(JustDireThings.MODID, "textures/gui/buttons/remove.png");
+    private static final Component EXTRACT_EXP_BUTTON_LOCALIZATION = Component.translatable("justdirethings.screen.retrieveexp");
+
+    public static GrayscaleButton EXTRACTEXPBUTTON(int x, int y, boolean startingValue, Button.OnPress onPress) {
+        return new GrayscaleButton(x, y, STANDARD_WIDTH, STANDARD_HEIGHT, EXTRACT_EXP_BUTTON, EXTRACT_EXP_BUTTON_LOCALIZATION, startingValue, onPress);
+    }
+
     private static final ResourceLocation FILTER_ONLY = ResourceLocation.fromNamespaceAndPath(JustDireThings.MODID, "textures/gui/buttons/allowlisttrue.png");
     private static final Component FILTER_ONLY_LOCALIZATION = Component.translatable("justdirethings.screen.filteronlytrue");
 

src/main/java/com/direwolf20/justdirethings/common/blockentities/ExperienceHolderBE.java

@@ -5,11 +5,14 @@
 import com.direwolf20.justdirethings.common.blockentities.basebe.BaseMachineBE;
 import com.direwolf20.justdirethings.common.blockentities.basebe.RedstoneControlledBE;
 import com.direwolf20.justdirethings.setup.Registration;
+import com.direwolf20.justdirethings.util.ExperienceUtils;
 import com.direwolf20.justdirethings.util.interfacehelpers.AreaAffectingData;
 import com.direwolf20.justdirethings.util.interfacehelpers.FilterData;
 import com.direwolf20.justdirethings.util.interfacehelpers.RedstoneControlData;
 import net.minecraft.core.BlockPos;
 import net.minecraft.core.Direction;
+import net.minecraft.core.HolderLookup;
+import net.minecraft.nbt.CompoundTag;
 import net.minecraft.server.level.ServerLevel;
 import net.minecraft.world.entity.player.Player;
 import net.minecraft.world.item.ItemStack;
@@ -25,6 +28,7 @@ public class ExperienceHolderBE extends BaseMachineBE implements AreaAffectingBE
     public FilterData filterData = new FilterData();
     public AreaAffectingData areaAffectingData = new AreaAffectingData();
     public RedstoneControlData redstoneControlData = new RedstoneControlData();
+    public int exp;
 
     public ExperienceHolderBE(BlockPos pPos, BlockState pBlockState) {
         super(Registration.ExperienceHolderBE.get(), pPos, pBlockState);
@@ -45,6 +49,70 @@ public AreaAffectingData getAreaAffectingData() {
         return areaAffectingData;
     }
 
+    public void storeExp(Player player, int levelChange) {
+        if (levelChange == -1) {
+            // Move all experience from player
+            int totalExp = ExperienceUtils.getPlayerTotalExperience(player);
+            this.exp += totalExp;
+            player.giveExperiencePoints(-totalExp); // Removes all levels
+        } else if (levelChange > 0) {
+            // Handle fractional progress first, if the player is in the middle of a level
+            int expInCurrentLevel = (int) (player.experienceProgress * player.getXpNeededForNextLevel());
+
+            // If the player has partial progress within the current level, remove that first
+            if (expInCurrentLevel > 0) {
+                int expRemoved = ExperienceUtils.removePoints(player, expInCurrentLevel);
+                this.exp += expRemoved;
+                levelChange--;  // We've already removed part of a level
+            }
+
+            if (levelChange > 0) {
+                // Now remove the specified number of full levels
+                int expRemoved = ExperienceUtils.removeLevels(player, levelChange);
+                this.exp += expRemoved;
+            }
+        }
+
+        markDirtyClient();
+    }
+
+    public void extractExp(Player player, int levelChange) {
+        if (exp == 0) return;  // No experience in the block, exit early
+
+        if (levelChange == -1) {
+            // Move all experience from block to player
+            int expToGive = exp;
+            player.giveExperiencePoints(expToGive);
+            this.exp = 0;  // Remove all experience from the block
+        } else if (levelChange > 0) {
+            // Handle fractional progress first, if the player is in the middle of a level
+            if (roundUpToNextLevel(player))
+                levelChange--;
+
+            if (levelChange > 0 && this.exp > 0) {
+                // Give full levels based on the remaining levels requested
+                int expForNextLevels = ExperienceUtils.getTotalExperienceForLevel(player.experienceLevel + levelChange) - ExperienceUtils.getPlayerTotalExperience(player);
+                int expToGive = Math.min(this.exp, expForNextLevels);
+                player.giveExperiencePoints(expToGive);
+                this.exp -= expToGive;
+                roundUpToNextLevel(player); //Thanks Floating point math!!
+            }
+        }
+
+        markDirtyClient();
+    }
+
+    public boolean roundUpToNextLevel(Player player) {
+        int expInCurrentLevel = (int) (player.experienceProgress * player.getXpNeededForNextLevel());
+        if (expInCurrentLevel > 0) {
+            int expToGive = Math.min(exp, ExperienceUtils.getExpNeededForNextLevel(player));
+            player.giveExperiencePoints(expToGive);
+            this.exp -= expToGive;
+            return true;
+        }
+        return false;
+    }
+
     public void tickClient() {
     }
 
@@ -77,4 +145,16 @@ private void handleExperience() {
 
         }
     }
+
+    @Override
+    public void saveAdditional(CompoundTag tag, HolderLookup.Provider provider) {
+        super.saveAdditional(tag, provider);
+        tag.putInt("exp", exp);
+    }
+
+    @Override
+    public void loadAdditional(CompoundTag tag, HolderLookup.Provider provider) {
+        super.loadAdditional(tag, provider);
+        exp = tag.getInt("exp");
+    }
 }

src/main/java/com/direwolf20/justdirethings/common/network/PacketHandler.java

@@ -38,6 +38,7 @@ public static void registerNetworking(final RegisterPayloadHandlersEvent event)
         registrar.playToServer(InventoryHolderSaveSlotPayload.TYPE, InventoryHolderSaveSlotPayload.STREAM_CODEC, InventoryHolderSaveSlotPacket.get()::handle);
         registrar.playToServer(InventoryHolderSettingsPayload.TYPE, InventoryHolderSettingsPayload.STREAM_CODEC, InventoryHolderSettingsPacket.get()::handle);
         registrar.playToServer(InventoryHolderMoveItemsPayload.TYPE, InventoryHolderMoveItemsPayload.STREAM_CODEC, InventoryHolderMoveItemsPacket.get()::handle);
+        registrar.playToServer(ExperienceHolderPayload.TYPE, ExperienceHolderPayload.STREAM_CODEC, ExperienceHolderPacket.get()::handle);
 
         //Going to Client
         registrar.playToClient(ClientSoundPayload.TYPE, ClientSoundPayload.STREAM_CODEC, ClientSoundPacket.get()::handle);

src/main/java/com/direwolf20/justdirethings/common/network/data/ExperienceHolderPayload.java

@@ -0,0 +1,26 @@
+package com.direwolf20.justdirethings.common.network.data;
+
+import com.direwolf20.justdirethings.JustDireThings;
+import net.minecraft.network.FriendlyByteBuf;
+import net.minecraft.network.codec.ByteBufCodecs;
+import net.minecraft.network.codec.StreamCodec;
+import net.minecraft.network.protocol.common.custom.CustomPacketPayload;
+import net.minecraft.resources.ResourceLocation;
+
+public record ExperienceHolderPayload(
+        boolean add,
+        int levels
+) implements CustomPacketPayload {
+    public static final Type<ExperienceHolderPayload> TYPE = new Type<>(ResourceLocation.fromNamespaceAndPath(JustDireThings.MODID, "experience_holder"));
+
+    @Override
+    public Type<ExperienceHolderPayload> type() {
+        return TYPE;
+    }
+
+    public static final StreamCodec<FriendlyByteBuf, ExperienceHolderPayload> STREAM_CODEC = StreamCodec.composite(
+            ByteBufCodecs.BOOL, ExperienceHolderPayload::add,
+            ByteBufCodecs.INT, ExperienceHolderPayload::levels,
+            ExperienceHolderPayload::new
+    );
+}

src/main/java/com/direwolf20/justdirethings/common/network/handler/ExperienceHolderPacket.java

@@ -0,0 +1,30 @@
+package com.direwolf20.justdirethings.common.network.handler;
+
+import com.direwolf20.justdirethings.common.blockentities.ExperienceHolderBE;
+import com.direwolf20.justdirethings.common.containers.ExperienceHolderContainer;
+import com.direwolf20.justdirethings.common.network.data.ExperienceHolderPayload;
+import net.minecraft.world.entity.player.Player;
+import net.minecraft.world.inventory.AbstractContainerMenu;
+import net.neoforged.neoforge.network.handling.IPayloadContext;
+
+public class ExperienceHolderPacket {
+    public static final ExperienceHolderPacket INSTANCE = new ExperienceHolderPacket();
+
+    public static ExperienceHolderPacket get() {
+        return INSTANCE;
+    }
+
+    public void handle(final ExperienceHolderPayload payload, final IPayloadContext context) {
+        context.enqueueWork(() -> {
+            Player sender = context.player();
+            AbstractContainerMenu container = sender.containerMenu;
+
+            if (container instanceof ExperienceHolderContainer experienceHolderContainer && experienceHolderContainer.baseMachineBE instanceof ExperienceHolderBE experienceHolderBE) {
+                if (payload.add())
+                    experienceHolderBE.storeExp(sender, payload.levels());
+                else
+                    experienceHolderBE.extractExp(sender, payload.levels());
+            }
+        });
+    }
+}

src/main/java/com/direwolf20/justdirethings/datagen/JustDireLanguageProvider.java

@@ -521,6 +521,8 @@ protected void addTranslations() {
         add("justdirethings.screen.senditems", "Push Items");
         add("justdirethings.screen.pullitems", "Pull Items");
         add("justdirethings.screen.swapitems", "Swap Items");
+        add("justdirethings.screen.storeexp", "Store Exp");
+        add("justdirethings.screen.retrieveexp", "Retrieve Exp");
 
         //Buttons
         //add("justdirethings.buttons.save", "Save");

src/main/java/com/direwolf20/justdirethings/util/ExperienceUtils.java

@@ -0,0 +1,57 @@
+package com.direwolf20.justdirethings.util;
+
+import net.minecraft.world.entity.player.Player;
+
+public class ExperienceUtils {
+    // Calculate experience required to go from level 0 to target level
+    public static int getTotalExperienceForLevel(int level) {
+        if (level <= 16) {
+            return level * level + 6 * level;
+        } else if (level <= 31) {
+            return (int) (2.5 * level * level - 40.5 * level + 360);
+        } else {
+            return (int) (4.5 * level * level - 162.5 * level + 2220);
+        }
+    }
+
+    // Remove levels from a player, ensuring they don't lose more than available
+    public static int removeLevels(Player player, int levelsToRemove) {
+        int currentTotalExp = getPlayerTotalExperience(player);
+        int targetLevel = Math.max(0, player.experienceLevel - levelsToRemove);
+
+        // Calculate how much exp is required to be at the target level
+        int targetTotalExp = getTotalExperienceForLevel(targetLevel);
+        int expToRemove = currentTotalExp - targetTotalExp;
+
+        player.giveExperienceLevels(-levelsToRemove);
+        return expToRemove;  // Amount of exp removed
+    }
+
+    // Calculate experience required to go from one level to the next
+    public static int getExperienceForNextLevel(int level) {
+        if (level >= 30) {
+            return 112 + (level - 30) * 9;
+        } else {
+            return level >= 15 ? 37 + (level - 15) * 5 : 7 + level * 2;
+        }
+    }
+
+    // Calculate total experience points player currently has (given level and progress)
+    public static int getPlayerTotalExperience(Player player) {
+        int exp = getTotalExperienceForLevel(player.experienceLevel);
+        exp += Math.round(player.experienceProgress * player.getXpNeededForNextLevel());
+        return exp;
+    }
+
+    public static int getExpNeededForNextLevel(Player player) {
+        return player.getXpNeededForNextLevel() - (int) (player.experienceProgress * player.getXpNeededForNextLevel());
+    }
+
+    // Remove points from a player, ensuring they don't lose more than available
+    public static int removePoints(Player player, int pointsToRemove) {
+        int currentTotalExp = getPlayerTotalExperience(player);
+        int expToRemove = Math.min(currentTotalExp, pointsToRemove);
+        player.giveExperiencePoints(-expToRemove);
+        return expToRemove;  // Amount of exp removed
+    }
+}