feat: started plot gui rework

Bukkit/src/main/java/com/plotsquared/bukkit/inject/BukkitModule.java

@@ -28,6 +28,7 @@ package com.plotsquared.bukkit.inject;
 import com.google.inject.AbstractModule;
 import com.google.inject.Provides;
 import com.google.inject.Singleton;
+import com.google.inject.TypeLiteral;
 import com.google.inject.assistedinject.FactoryModuleBuilder;
 import com.plotsquared.bukkit.BukkitPlatform;
 import com.plotsquared.bukkit.listener.SingleWorldListener;
@@ -43,6 +44,8 @@ import com.plotsquared.bukkit.util.BukkitSetupUtils;
 import com.plotsquared.bukkit.util.BukkitUtil;
 import com.plotsquared.bukkit.util.fawe.FaweRegionManager;
 import com.plotsquared.bukkit.util.fawe.FaweSchematicHandler;
+import com.plotsquared.bukkit.util.gui.BukkitPlotInventory;
+import com.plotsquared.bukkit.util.gui.BukkitPlotInventoryProvider;
 import com.plotsquared.core.PlotPlatform;
 import com.plotsquared.core.PlotSquared;
 import com.plotsquared.core.configuration.Settings;
@@ -70,6 +73,7 @@ import com.plotsquared.core.util.RegionManager;
 import com.plotsquared.core.util.SchematicHandler;
 import com.plotsquared.core.util.SetupUtils;
 import com.plotsquared.core.util.WorldUtil;
+import com.plotsquared.core.util.gui.PlotInventoryProvider;
 import com.sk89q.worldedit.bukkit.WorldEditPlugin;
 import com.sk89q.worldedit.extension.platform.Actor;
 import org.apache.logging.log4j.LogManager;
@@ -103,6 +107,7 @@ public class BukkitModule extends AbstractModule {
         bind(InventoryUtil.class).to(BukkitInventoryUtil.class);
         bind(SetupUtils.class).to(BukkitSetupUtils.class);
         bind(WorldUtil.class).to(BukkitUtil.class);
+        bind(new TypeLiteral<PlotInventoryProvider<?, ?>>(){}).to(BukkitPlotInventoryProvider.class);
         install(new FactoryModuleBuilder()
                 .implement(ProgressSubscriber.class, DefaultProgressSubscriber.class)
                 .build(ProgressSubscriberFactory.class));

Bukkit/src/main/java/com/plotsquared/bukkit/player/BukkitPlayer.java

@@ -364,6 +364,11 @@ public class BukkitPlayer extends PlotPlayer<Player> {
         }
     }
 
+    @Override
+    public void closeInventory() {
+        this.player.closeInventory();
+    }
+
     /**
      * Convert from PlotSquared's {@link TeleportCause} to Bukkit's {@link PlayerTeleportEvent.TeleportCause}
      *

Bukkit/src/main/java/com/plotsquared/bukkit/util/gui/BukkitPlotInventory.java

@@ -0,0 +1,224 @@
+/*
+ *       _____  _       _    _____                                _
+ *      |  __ \| |     | |  / ____|                              | |
+ *      | |__) | | ___ | |_| (___   __ _ _   _  __ _ _ __ ___  __| |
+ *      |  ___/| |/ _ \| __|\___ \ / _` | | | |/ _` | '__/ _ \/ _` |
+ *      | |    | | (_) | |_ ____) | (_| | |_| | (_| | | |  __/ (_| |
+ *      |_|    |_|\___/ \__|_____/ \__, |\__,_|\__,_|_|  \___|\__,_|
+ *                                    | |
+ *                                    |_|
+ *            PlotSquared plot management system for Minecraft
+ *               Copyright (C) 2014 - 2022 IntellectualSites
+ *
+ *     This program is free software: you can redistribute it and/or modify
+ *     it under the terms of the GNU General Public License as published by
+ *     the Free Software Foundation, either version 3 of the License, or
+ *     (at your option) any later version.
+ *
+ *     This program is distributed in the hope that it will be useful,
+ *     but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *     GNU General Public License for more details.
+ *
+ *     You should have received a copy of the GNU General Public License
+ *     along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package com.plotsquared.bukkit.util.gui;
+
+import com.google.common.base.Preconditions;
+import com.plotsquared.bukkit.BukkitPlatform;
+import com.plotsquared.bukkit.util.BukkitUtil;
+import com.plotsquared.core.PlotSquared;
+import com.plotsquared.core.configuration.caption.Caption;
+import com.plotsquared.core.player.PlotPlayer;
+import com.plotsquared.core.plot.PlotItemStack;
+import com.plotsquared.core.util.gui.PlotInventory;
+import com.plotsquared.core.util.gui.PlotInventoryClickHandler;
+import com.sk89q.worldedit.bukkit.BukkitAdapter;
+import net.kyori.adventure.text.Component;
+import net.kyori.adventure.text.minimessage.MiniMessage;
+import net.kyori.adventure.text.minimessage.tag.resolver.TagResolver;
+import org.bukkit.Bukkit;
+import org.bukkit.Material;
+import org.bukkit.entity.Player;
+import org.bukkit.event.EventHandler;
+import org.bukkit.event.Listener;
+import org.bukkit.event.inventory.InventoryCloseEvent;
+import org.bukkit.inventory.Inventory;
+import org.bukkit.inventory.ItemStack;
+import org.bukkit.inventory.meta.ItemMeta;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+import java.util.Objects;
+import java.util.UUID;
+import java.util.WeakHashMap;
+
+/**
+ * Implementation of the {@link PlotInventory} for the bukkit platform.
+ */
+public class BukkitPlotInventory extends PlotInventory<Player, ItemStack> {
+
+    private static Listener INVENTORY_LISTENER;
+    private final ItemStack[] items;
+    private final PlotInventoryClickHandler<Player>[] clickHandlers;
+    private final Map<UUID, Inventory> viewers = new WeakHashMap<>();
+    private static final Map<UUID, BukkitPlotInventory> INVENTORIES = new WeakHashMap<>();
+
+    /**
+     * {@inheritDoc}
+     */
+    protected BukkitPlotInventory(final int size, final Caption titleCaption, final TagResolver... titleResolvers) {
+        super(size, titleCaption, titleResolvers);
+        this.items = new ItemStack[size];
+        this.clickHandlers = new PlotInventoryClickHandler[size];
+
+        if (INVENTORY_LISTENER != null) {
+            return;
+        }
+        INVENTORY_LISTENER = new Listener() {
+            @EventHandler
+            public void onInventoryClick(final org.bukkit.event.inventory.InventoryClickEvent event) {
+                final PlotPlayer<Player> player = BukkitUtil.adapt((Player) event.getWhoClicked());
+
+                BukkitPlotInventory currentInventory = INVENTORIES.get(player.getUUID());
+                if (currentInventory == null) {
+                    return;
+                }
+                if (!Objects.equals(event.getClickedInventory(), currentInventory.viewers.get(player.getUUID()))) {
+                    return;
+                }
+
+                final int slot = event.getRawSlot();
+                if (slot < 0 || slot >= currentInventory.size()) {
+                    return;
+                }
+                final PlotInventoryClickHandler<Player> clickHandler = currentInventory.clickHandlers[slot];
+                if (clickHandler == null) {
+                    return;
+                }
+                event.setCancelled(true);
+                final ItemStack item = event.getCurrentItem();
+                if (item == null) {
+                    clickHandler.handle(null, player);
+                    return;
+                }
+                clickHandler.handle(new PlotItemStack(
+                        BukkitAdapter.asItemType(item.getType()),
+                        item.getAmount(),
+                        item.getItemMeta().getDisplayName(),
+                        item.getItemMeta().hasLore() ? item.getItemMeta().getLore().toArray(String[]::new) : new String[0]
+                ), player);
+            }
+
+            @EventHandler
+            public void onInventoryClose(InventoryCloseEvent event) {
+                final PlotPlayer<Player> player = BukkitUtil.adapt((Player) event.getPlayer());
+                BukkitPlotInventory currentInventory = INVENTORIES.get(player.getUUID());
+                if (currentInventory == null) {
+                    return;
+                }
+                currentInventory.viewers.remove(player.getUUID());
+                INVENTORIES.remove(player.getUUID());
+            }
+
+        };
+        BukkitPlatform bukkitPlatform = ((BukkitPlatform) PlotSquared.platform());
+        bukkitPlatform.getServer().getPluginManager().registerEvents(INVENTORY_LISTENER, bukkitPlatform);
+    }
+
+    @Override
+    public void setItem(final int slot, final PlotItemStack item, final PlotInventoryClickHandler<Player> onClick) {
+        Preconditions.checkElementIndex(slot, size(), "Slot must be in range (0, " + size() + ")");
+        this.items[slot] = toPlatformItem(item);
+        this.clickHandlers[slot] = onClick;
+        for (final Inventory value : viewers.values()) {
+            value.setItem(slot, this.items[slot]);
+        }
+    }
+
+    @Override
+    public void addItem(final PlotItemStack item, final PlotInventoryClickHandler<Player> onClick) {
+        // TODO: probably needs more love (who doesn't)
+        int slot = -1;
+        // try to fill stacks
+        for (int i = 0; i < items.length; i++) {
+            if (Objects.equals(items[i], toPlatformItem(item))) {
+                slot = i;
+                break;
+            }
+        }
+        // search for empty slots
+        if (slot == -1) {
+            for (int i = 0; i < items.length; i++) {
+                if (items[i] == null || items[i].getType() == Material.AIR) {
+                    slot = i;
+                    break;
+                }
+            }
+        }
+        Preconditions.checkElementIndex(slot, size());
+        this.items[slot] = toPlatformItem(item);
+        this.clickHandlers[slot] = onClick;
+        for (final Inventory value : viewers.values()) {
+            value.setItem(slot, this.items[slot]);
+        }
+    }
+
+    @Override
+    protected void openPlatformPlayer(final PlotPlayer<Player> player) {
+        Component title = MiniMessage.miniMessage().deserialize(
+                titleCaption().getComponent(player), titleResolvers()
+        );
+        Inventory inventory = Bukkit.createInventory(player.getPlatformPlayer(), size(),
+                BukkitUtil.LEGACY_COMPONENT_SERIALIZER.serialize(title)
+        );
+        for (int i = 0; i < items.length; i++) {
+            inventory.setItem(i, items[i]);
+        }
+        INVENTORIES.put(player.getUUID(), this);
+        viewers.put(player.getUUID(), inventory);
+        player.getPlatformPlayer().openInventory(inventory);
+    }
+
+    @Override
+    protected void closePlatformPlayer(final PlotPlayer<Player> player) {
+        if (player.getPlatformPlayer().getOpenInventory().getTopInventory().equals(INVENTORIES.get(player.getUUID()))) {
+            player.getPlatformPlayer().closeInventory();
+        }
+    }
+
+    @Override
+    public ItemStack toPlatformItem(final PlotItemStack item) {
+        if (item == null) {
+            return null;
+        }
+        Material material = BukkitAdapter.adapt(item.getType());
+        if (material == null) {
+            return null;
+        }
+        ItemStack stack = new ItemStack(material, item.getAmount());
+        ItemMeta meta = null;
+        if (item.getName() != null) {
+            meta = stack.getItemMeta();
+            Component nameComponent = BukkitUtil.MINI_MESSAGE.deserialize(item.getName());
+            meta.setDisplayName(BukkitUtil.LEGACY_COMPONENT_SERIALIZER.serialize(nameComponent));
+        }
+        if (item.getLore() != null) {
+            if (meta == null) {
+                meta = stack.getItemMeta();
+            }
+            List<String> lore = new ArrayList<>();
+            for (String entry : item.getLore()) {
+                lore.add(BukkitUtil.LEGACY_COMPONENT_SERIALIZER.serialize(BukkitUtil.MINI_MESSAGE.deserialize(entry)));
+            }
+            meta.setLore(lore);
+        }
+        if (meta != null) {
+            stack.setItemMeta(meta);
+        }
+        return stack;
+    }
+
+}

Bukkit/src/main/java/com/plotsquared/bukkit/util/gui/BukkitPlotInventoryProvider.java

@@ -0,0 +1,46 @@
+/*
+ *       _____  _       _    _____                                _
+ *      |  __ \| |     | |  / ____|                              | |
+ *      | |__) | | ___ | |_| (___   __ _ _   _  __ _ _ __ ___  __| |
+ *      |  ___/| |/ _ \| __|\___ \ / _` | | | |/ _` | '__/ _ \/ _` |
+ *      | |    | | (_) | |_ ____) | (_| | |_| | (_| | | |  __/ (_| |
+ *      |_|    |_|\___/ \__|_____/ \__, |\__,_|\__,_|_|  \___|\__,_|
+ *                                    | |
+ *                                    |_|
+ *            PlotSquared plot management system for Minecraft
+ *               Copyright (C) 2014 - 2022 IntellectualSites
+ *
+ *     This program is free software: you can redistribute it and/or modify
+ *     it under the terms of the GNU General Public License as published by
+ *     the Free Software Foundation, either version 3 of the License, or
+ *     (at your option) any later version.
+ *
+ *     This program is distributed in the hope that it will be useful,
+ *     but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *     GNU General Public License for more details.
+ *
+ *     You should have received a copy of the GNU General Public License
+ *     along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package com.plotsquared.bukkit.util.gui;
+
+import com.plotsquared.core.configuration.caption.Caption;
+import com.plotsquared.core.util.gui.PlotInventory;
+import com.plotsquared.core.util.gui.PlotInventoryProvider;
+import net.kyori.adventure.text.minimessage.tag.resolver.TagResolver;
+import org.bukkit.entity.Player;
+import org.bukkit.inventory.ItemStack;
+
+public class BukkitPlotInventoryProvider implements PlotInventoryProvider<Player, ItemStack> {
+
+    @Override
+    public PlotInventory<Player, ItemStack> createInventory(
+            final int size,
+            final Caption titleCaption,
+            final TagResolver... titleResolvers
+    ) {
+        return new BukkitPlotInventory(size, titleCaption, titleResolvers);
+    }
+
+}

Core/src/main/java/com/plotsquared/core/command/Music.java

@@ -34,24 +34,21 @@ import com.plotsquared.core.location.Location;
 import com.plotsquared.core.permissions.Permission;
 import com.plotsquared.core.player.PlotPlayer;
 import com.plotsquared.core.plot.Plot;
-import com.plotsquared.core.plot.PlotInventory;
 import com.plotsquared.core.plot.PlotItemStack;
 import com.plotsquared.core.plot.flag.PlotFlag;
 import com.plotsquared.core.plot.flag.implementations.MusicFlag;
 import com.plotsquared.core.util.EventDispatcher;
-import com.plotsquared.core.util.InventoryUtil;
 import com.plotsquared.core.util.Permissions;
-import com.sk89q.worldedit.world.item.ItemType;
+import com.plotsquared.core.util.gui.PlotInventory;
+import com.plotsquared.core.util.gui.PlotInventoryProvider;
 import com.sk89q.worldedit.world.item.ItemTypes;
 import net.kyori.adventure.text.Component;
 import net.kyori.adventure.text.minimessage.tag.Tag;
 import net.kyori.adventure.text.minimessage.tag.resolver.TagResolver;
 import org.checkerframework.checker.nullness.qual.NonNull;
 
-import javax.annotation.Nullable;
+import java.util.List;
-import java.util.Arrays;
+import java.util.stream.Stream;
-import java.util.Collection;
-import java.util.Locale;
 
 @CommandDeclaration(command = "music",
         permission = "plots.music",
@@ -60,20 +57,33 @@ import java.util.Locale;
         requiredType = RequiredType.PLAYER)
 public class Music extends SubCommand {
 
-    private static final Collection<String> DISCS = Arrays
+    private static final List<String> DISCS = Stream.of(
-            .asList("music_disc_13", "music_disc_cat", "music_disc_blocks", "music_disc_chirp",
+            "music_disc_13",
-                    "music_disc_far", "music_disc_mall", "music_disc_mellohi", "music_disc_stal",
+            "music_disc_cat",
-                    "music_disc_strad", "music_disc_ward", "music_disc_11", "music_disc_wait", "music_disc_otherside",
+            "music_disc_blocks",
-                    "music_disc_pigstep"
+            "music_disc_chirp",
-            );
+            "music_disc_far",
+            "music_disc_mall",
+            "music_disc_mellohi",
+            "music_disc_stal",
+            "music_disc_strad",
+            "music_disc_ward",
+            "music_disc_11",
+            "music_disc_wait",
+            "music_disc_otherside",
+            "music_disc_pigstep"
+    ).filter(s -> ItemTypes.get(s) != null).toList();
 
-    private final InventoryUtil inventoryUtil;
     private final EventDispatcher eventDispatcher;
+    private final PlotInventoryProvider<?, ?> inventoryProvider;
 
     @Inject
-    public Music(final @Nullable InventoryUtil inventoryUtil, final @NonNull EventDispatcher eventDispatcher) {
+    public Music(
-        this.inventoryUtil = inventoryUtil;
+            final @NonNull EventDispatcher eventDispatcher, final
+    PlotInventoryProvider<?, ?> inventoryProvider
+    ) {
         this.eventDispatcher = eventDispatcher;
+        this.inventoryProvider = inventoryProvider;
     }
 
     @Override
@@ -99,85 +109,67 @@ public class Music extends SubCommand {
             );
             return true;
         }
-        PlotInventory inv = new PlotInventory(
+
-                this.inventoryUtil,
+        final PlotInventory<?, ?> inventory = inventoryProvider.createInventory(
-                player,
+                9 * 2,
-                2,
+                TranslatableCaption.of("plotjukebox.jukebox_header")
-                TranslatableCaption.of("plotjukebox.jukebox_header").getComponent(player)
+        );
-        ) {
-            @Override
-            public boolean onClick(int index) {
-                PlotItemStack item = getItem(index);
-                if (item == null) {
-                    return true;
-                }
-                if (item.getType() == ItemTypes.BEDROCK) {
-                    PlotFlag<?, ?> plotFlag = plot.getFlagContainer().getFlag(MusicFlag.class)
-                            .createFlagInstance(item.getType());
-                    PlotFlagRemoveEvent event = eventDispatcher.callFlagRemove(plotFlag, plot);
-                    if (event.getEventResult() == Result.DENY) {
-                        getPlayer().sendMessage(
-                                TranslatableCaption.of("events.event_denied"),
-                                TagResolver.resolver("value", Tag.inserting(Component.text("Music removal")))
-                        );
-                        return true;
-                    }
-                    plot.removeFlag(event.getFlag());
-                    getPlayer().sendMessage(
-                            TranslatableCaption.of("flag.flag_removed"),
-                            TagResolver.builder()
-                                    .tag("flag", Tag.inserting(Component.text("music")))
-                                    .tag("value", Tag.inserting(Component.text("music_disc")))
-                                    .build()
-                    );
-                } else if (item.getName().toLowerCase(Locale.ENGLISH).contains("disc")) {
-                    PlotFlag<?, ?> plotFlag = plot.getFlagContainer().getFlag(MusicFlag.class)
-                            .createFlagInstance(item.getType());
-                    PlotFlagAddEvent event = eventDispatcher.callFlagAdd(plotFlag, plot);
-                    if (event.getEventResult() == Result.DENY) {
-                        getPlayer().sendMessage(
-                                TranslatableCaption.of("events.event_denied"),
-                                TagResolver.resolver("value", Tag.inserting(Component.text("Music addition")))
-                        );
-                        return true;
-                    }
-                    plot.setFlag(event.getFlag());
-                    getPlayer().sendMessage(
-                            TranslatableCaption.of("flag.flag_added"),
-                            TagResolver.builder()
-                                    .tag("flag", Tag.inserting(Component.text("music")))
-                                    .tag("value", Tag.inserting(Component.text(event.getFlag().getValue().toString())))
-                                    .build()
-                    );
-                } else {
-                    getPlayer().sendMessage(TranslatableCaption.of("flag.flag_not_added"));
-                }
-                return false;
-            }
-        };
-        int index = 0;
 
         for (final String disc : DISCS) {
-            final String name = String.format("<gold>%s</gold>", disc);
+            PlotItemStack itemStack = new PlotItemStack(
-            final String[] lore = {TranslatableCaption.of("plotjukebox.click_to_play").getComponent(player)};
+                    disc, 1, String.format("<gold>%s</gold>", disc),
-            ItemType type = ItemTypes.get(disc);
+                    TranslatableCaption.of("plotjukebox.click_to_play").getComponent(player)
-            if (type == null) {
+            );
-                continue;
+            inventory.addItem(itemStack, (item, clicker) -> {
-            }
+                clicker.closeInventory();
-            final PlotItemStack item = new PlotItemStack(type, 1, name, lore);
+                PlotFlag<?, ?> plotFlag = plot.getFlagContainer().getFlag(MusicFlag.class)
-            if (inv.setItemChecked(index, item)) {
+                        .createFlagInstance(item.getType());
-                index++;
+                PlotFlagAddEvent event = eventDispatcher.callFlagAdd(plotFlag, plot);
-            }
+                if (event.getEventResult() == Result.DENY) {
+                    clicker.sendMessage(
+                            TranslatableCaption.of("events.event_denied"),
+                            TagResolver.resolver("value", Tag.inserting(Component.text("Music addition")))
+                    );
+                    return;
+                }
+                plot.setFlag(event.getFlag());
+                clicker.sendMessage(
+                        TranslatableCaption.of("flag.flag_added"),
+                        TagResolver.builder()
+                                .tag("flag", Tag.inserting(Component.text("music")))
+                                .tag("value", Tag.inserting(Component.text(event.getFlag().getValue().toString())))
+                                .build()
+                );
+            });
         }
 
-        // Always add the cancel button
+        PlotItemStack cancelItem = new PlotItemStack(
-        // if (player.getMeta("music") != null) {
+                ItemTypes.BEDROCK, 1,
-        String name = TranslatableCaption.of("plotjukebox.cancel_music").getComponent(player);
+                TranslatableCaption.of("plotjukebox.cancel_music").getComponent(player),
-        String[] lore = {TranslatableCaption.of("plotjukebox.reset_music").getComponent(player)};
+                TranslatableCaption.of("plotjukebox.reset_music").getComponent(player)
-        inv.setItem(index, new PlotItemStack("bedrock", 1, name, lore));
+        );
-        // }
+        inventory.setItem(inventory.size() - 1, cancelItem, (item, clicker) -> {
-
+            clicker.closeInventory();
-        inv.openInventory();
+            PlotFlag<?, ?> plotFlag = plot.getFlagContainer().getFlag(MusicFlag.class)
+                    .createFlagInstance(item.getType());
+            PlotFlagRemoveEvent event = eventDispatcher.callFlagRemove(plotFlag, plot);
+            if (event.getEventResult() == Result.DENY) {
+                clicker.sendMessage(
+                        TranslatableCaption.of("events.event_denied"),
+                        TagResolver.resolver("value", Tag.inserting(Component.text("Music removal")))
+                );
+                return;
+            }
+            plot.removeFlag(event.getFlag());
+            clicker.sendMessage(
+                    TranslatableCaption.of("flag.flag_removed"),
+                    TagResolver.builder()
+                            .tag("flag", Tag.inserting(Component.text("music")))
+                            .tag("value", Tag.inserting(Component.text("music_disc")))
+                            .build()
+            );
+        });
+        inventory.open(player);
         return true;
     }
 

Core/src/main/java/com/plotsquared/core/player/ConsolePlayer.java

@@ -258,4 +258,8 @@ public class ConsolePlayer extends PlotPlayer<Actor> {
         return true;
     }
 
+    @Override
+    public void closeInventory() {
+    }
+
 }

Core/src/main/java/com/plotsquared/core/player/PlotPlayer.java

@@ -1015,6 +1015,12 @@ public abstract class PlotPlayer<P> implements CommandCaller, OfflinePlotPlayer,
     public @NonNull
     abstract Audience getAudience();
 
+    /**
+     * Closes the current open inventory, if present
+     * @since TODO
+     */
+    public abstract void closeInventory();
+
     /**
      * Get this player's {@link LockRepository}
      *

Core/src/main/java/com/plotsquared/core/util/gui/PlotInventory.java

@@ -0,0 +1,145 @@
+/*
+ *       _____  _       _    _____                                _
+ *      |  __ \| |     | |  / ____|                              | |
+ *      | |__) | | ___ | |_| (___   __ _ _   _  __ _ _ __ ___  __| |
+ *      |  ___/| |/ _ \| __|\___ \ / _` | | | |/ _` | '__/ _ \/ _` |
+ *      | |    | | (_) | |_ ____) | (_| | |_| | (_| | | |  __/ (_| |
+ *      |_|    |_|\___/ \__|_____/ \__, |\__,_|\__,_|_|  \___|\__,_|
+ *                                    | |
+ *                                    |_|
+ *            PlotSquared plot management system for Minecraft
+ *               Copyright (C) 2014 - 2022 IntellectualSites
+ *
+ *     This program is free software: you can redistribute it and/or modify
+ *     it under the terms of the GNU General Public License as published by
+ *     the Free Software Foundation, either version 3 of the License, or
+ *     (at your option) any later version.
+ *
+ *     This program is distributed in the hope that it will be useful,
+ *     but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *     GNU General Public License for more details.
+ *
+ *     You should have received a copy of the GNU General Public License
+ *     along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package com.plotsquared.core.util.gui;
+
+import com.plotsquared.core.configuration.caption.Caption;
+import com.plotsquared.core.player.PlotPlayer;
+import com.plotsquared.core.plot.PlotItemStack;
+import net.kyori.adventure.text.minimessage.tag.resolver.TagResolver;
+
+/**
+ * @param <P> The platform player
+ * @param <I> The platform item object
+ * @since TODO
+ */
+public abstract class PlotInventory<P, I> {
+
+    private final PlotInventoryClickHandler<P> NOOP_CLICK_HANDLER = (x, y) -> {
+    };
+
+    private final int size;
+    private final Caption titleCaption;
+    private final TagResolver[] titleResolvers;
+
+    /**
+     * Instantiates a new Plot inventory.
+     *
+     * @param size           The size of the inventory - must be a multiple of 9
+     * @param titleCaption   The caption to use for the title
+     * @param titleResolvers The tag resolvers to use for the title
+     * @since 7.0.0
+     */
+    protected PlotInventory(int size, Caption titleCaption, TagResolver... titleResolvers) {
+        this.size = size;
+        this.titleCaption = titleCaption;
+        this.titleResolvers = titleResolvers;
+    }
+
+    /**
+     * Set an item in this inventory at a specific slot / index.
+     * Overrides existing items and click handler.
+     *
+     * @param slot    The slot / index where to place the item
+     * @param item    The item to add to this inventory
+     * @param onClick The handler to call when clicking this item
+     * @since TODO
+     */
+    public abstract void setItem(int slot, PlotItemStack item, PlotInventoryClickHandler<P> onClick);
+
+    /**
+     * Set an item in this inventory at a specific slot / index.
+     * Overrides existing items and click handler.
+     *
+     * @param slot The slot / index where to place the item
+     * @param item The item to add to this inventory
+     * @since TODO
+     */
+    public void setItem(int slot, PlotItemStack item) {
+        setItem(slot, item, NOOP_CLICK_HANDLER);
+    }
+
+    /**
+     * Add an item to this inventory, at the first slot possible (first empty slot, or first slot with the exact same item)
+     *
+     * @param item    The item to add to this inventory
+     * @param onClick The handler to call when clicking this item
+     * @since TODO
+     */
+    public abstract void addItem(PlotItemStack item, PlotInventoryClickHandler<P> onClick);
+
+    /**
+     * Add an item to this inventory, at the first slot possible (first empty slot, or first slot with the exact same item)
+     *
+     * @param item The item to add to this inventory
+     * @since TODO
+     */
+    public void addItem(PlotItemStack item) {
+        addItem(item, NOOP_CLICK_HANDLER);
+    }
+
+    /**
+     * Opens this inventory for a specific {@link PlotPlayer}
+     *
+     * @param player The player to open this inventory for
+     * @since TODO
+     */
+    public void open(PlotPlayer<?> player) {
+        this.openPlatformPlayer((PlotPlayer<P>) player);
+    }
+
+    protected abstract void openPlatformPlayer(PlotPlayer<P> player);
+
+    /**
+     * Close this inventory for a specific {@link PlotPlayer}
+     *
+     * @param player The player to close this inventory for
+     * @since TODO
+     */
+    public void close(PlotPlayer<?> player) {
+        this.closePlatformPlayer((PlotPlayer<P>) player);
+    }
+
+    protected abstract void closePlatformPlayer(PlotPlayer<P> player);
+
+    public abstract I toPlatformItem(PlotItemStack item);
+
+    /**
+     * @return the size of this inventory (must be a multiple of 9)
+     * @since TODO
+     */
+    public int size() {
+        return size;
+    }
+
+    protected Caption titleCaption() {
+        return titleCaption;
+    }
+
+    protected TagResolver[] titleResolvers() {
+        return titleResolvers;
+    }
+
+}

Core/src/main/java/com/plotsquared/core/util/gui/PlotInventoryClickHandler.java

@@ -0,0 +1,35 @@
+/*
+ *       _____  _       _    _____                                _
+ *      |  __ \| |     | |  / ____|                              | |
+ *      | |__) | | ___ | |_| (___   __ _ _   _  __ _ _ __ ___  __| |
+ *      |  ___/| |/ _ \| __|\___ \ / _` | | | |/ _` | '__/ _ \/ _` |
+ *      | |    | | (_) | |_ ____) | (_| | |_| | (_| | | |  __/ (_| |
+ *      |_|    |_|\___/ \__|_____/ \__, |\__,_|\__,_|_|  \___|\__,_|
+ *                                    | |
+ *                                    |_|
+ *            PlotSquared plot management system for Minecraft
+ *               Copyright (C) 2014 - 2022 IntellectualSites
+ *
+ *     This program is free software: you can redistribute it and/or modify
+ *     it under the terms of the GNU General Public License as published by
+ *     the Free Software Foundation, either version 3 of the License, or
+ *     (at your option) any later version.
+ *
+ *     This program is distributed in the hope that it will be useful,
+ *     but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *     GNU General Public License for more details.
+ *
+ *     You should have received a copy of the GNU General Public License
+ *     along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package com.plotsquared.core.util.gui;
+
+import com.plotsquared.core.player.PlotPlayer;
+import com.plotsquared.core.plot.PlotItemStack;
+
+public interface PlotInventoryClickHandler<P> {
+
+    void handle(PlotItemStack itemStack, PlotPlayer<P> plotPlayer);
+
+}

Core/src/main/java/com/plotsquared/core/util/gui/PlotInventoryProvider.java

@@ -0,0 +1,49 @@
+/*
+ *       _____  _       _    _____                                _
+ *      |  __ \| |     | |  / ____|                              | |
+ *      | |__) | | ___ | |_| (___   __ _ _   _  __ _ _ __ ___  __| |
+ *      |  ___/| |/ _ \| __|\___ \ / _` | | | |/ _` | '__/ _ \/ _` |
+ *      | |    | | (_) | |_ ____) | (_| | |_| | (_| | | |  __/ (_| |
+ *      |_|    |_|\___/ \__|_____/ \__, |\__,_|\__,_|_|  \___|\__,_|
+ *                                    | |
+ *                                    |_|
+ *            PlotSquared plot management system for Minecraft
+ *               Copyright (C) 2014 - 2022 IntellectualSites
+ *
+ *     This program is free software: you can redistribute it and/or modify
+ *     it under the terms of the GNU General Public License as published by
+ *     the Free Software Foundation, either version 3 of the License, or
+ *     (at your option) any later version.
+ *
+ *     This program is distributed in the hope that it will be useful,
+ *     but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *     GNU General Public License for more details.
+ *
+ *     You should have received a copy of the GNU General Public License
+ *     along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package com.plotsquared.core.util.gui;
+
+import com.plotsquared.core.configuration.caption.Caption;
+import net.kyori.adventure.text.minimessage.tag.resolver.TagResolver;
+
+/**
+ * Provider for creating a {@link PlotInventory}
+ *
+ * @param <P> The platform player
+ * @param <I> The platform item
+ */
+public interface PlotInventoryProvider<P, I> {
+
+    /**
+     * Creates a new {@link PlotInventory} based on the passed data for the current platform.
+     *
+     * @param size           The size of the inventory (must be a multiple of 9)
+     * @param titleCaption   The title for the inventory
+     * @param titleResolvers The (optional) placeholder resolvers for the inventory
+     * @return The platform inventory
+     */
+    PlotInventory<P, I> createInventory(int size, Caption titleCaption, TagResolver... titleResolvers);
+
+}