Proof of concept server-side CUI handler. Note: This pollutes the world with blocks atm

worldedit-core/src/main/java/com/sk89q/worldedit/LocalSession.java

@@ -25,6 +25,8 @@ import com.sk89q.jchronic.Chronic;
 import com.sk89q.jchronic.Options;
 import com.sk89q.jchronic.utils.Span;
 import com.sk89q.jchronic.utils.Time;
+import com.sk89q.jnbt.IntTag;
+import com.sk89q.jnbt.Tag;
 import com.sk89q.worldedit.command.tool.BlockTool;
 import com.sk89q.worldedit.command.tool.BrushTool;
 import com.sk89q.worldedit.command.tool.InvalidToolBindException;
@@ -37,6 +39,7 @@ import com.sk89q.worldedit.function.mask.Mask;
 import com.sk89q.worldedit.internal.cui.CUIEvent;
 import com.sk89q.worldedit.internal.cui.CUIRegion;
 import com.sk89q.worldedit.internal.cui.SelectionShapeEvent;
+import com.sk89q.worldedit.internal.cui.ServerCUIHandler;
 import com.sk89q.worldedit.regions.Region;
 import com.sk89q.worldedit.regions.RegionSelector;
 import com.sk89q.worldedit.regions.selector.CuboidRegionSelector;
@@ -44,6 +47,8 @@ import com.sk89q.worldedit.regions.selector.RegionSelectorType;
 import com.sk89q.worldedit.session.ClipboardHolder;
 import com.sk89q.worldedit.session.request.Request;
 import com.sk89q.worldedit.world.World;
+import com.sk89q.worldedit.world.block.BaseBlock;
+import com.sk89q.worldedit.world.block.BlockTypes;
 import com.sk89q.worldedit.world.item.ItemType;
 import com.sk89q.worldedit.world.item.ItemTypes;
 import com.sk89q.worldedit.world.snapshot.Snapshot;
@@ -87,10 +92,12 @@ public class LocalSession {
     private transient boolean fastMode = false;
     private transient Mask mask;
     private transient TimeZone timezone = TimeZone.getDefault();
+    private transient Vector cuiTemporaryBlock;
 
     // Saved properties
     private String lastScript;
     private RegionSelectorType defaultSelector;
+    private boolean useServerCUI = true; // Save this to not annoy players.
 
     /**
      * Construct the object.
@@ -612,6 +619,52 @@ public class LocalSession {
     public void tellVersion(Actor player) {
     }
 
+    /**
+     * Update server-side WorldEdit CUI.
+     *
+     * @param actor The player
+     */
+    public void updateServerCUI(Actor actor) {
+        if (!actor.isPlayer()) {
+            return; // This is for players only.
+        }
+
+        if (!useServerCUI || hasCUISupport) {
+            return; // If it's not enabled, ignore this.
+        }
+
+        Player player = (Player) actor;
+
+        // Remove the old block.
+        if (cuiTemporaryBlock != null) {
+            // TODO Tell server to reset fake block.
+            try {
+                createEditSession(player).setBlock(cuiTemporaryBlock, BlockTypes.AIR.getDefaultState());
+            } catch (MaxChangedBlocksException e) {
+                e.printStackTrace();
+            }
+            cuiTemporaryBlock = null;
+        }
+
+        BaseBlock block = ServerCUIHandler.createStructureBlock(player);
+        if (block != null) {
+            // If it's null, we don't need to do anything. The old was already removed.
+            Map<String, Tag> tags = block.getNbtData().getValue();
+            cuiTemporaryBlock = new Vector(
+                    ((IntTag) tags.get("x")).getValue(),
+                    ((IntTag) tags.get("y")).getValue(),
+                    ((IntTag) tags.get("z")).getValue()
+            );
+
+            // TODO Send temporary block at that pos to the player.
+            try {
+                createEditSession(player).setBlock(cuiTemporaryBlock, block);
+            } catch (MaxChangedBlocksException e) {
+                e.printStackTrace();
+            }
+        }
+    }
+
     /**
      * Dispatch a CUI event but only if the actor has CUI support.
      *
@@ -624,6 +677,8 @@ public class LocalSession {
 
         if (hasCUISupport) {
             actor.dispatchCUIEvent(event);
+        } else if (useServerCUI) {
+            updateServerCUI(actor);
         }
     }
 
@@ -647,6 +702,9 @@ public class LocalSession {
         checkNotNull(actor);
 
         if (!hasCUISupport) {
+            if (useServerCUI) {
+                updateServerCUI(actor);
+            }
             return;
         }
 

worldedit-core/src/main/java/com/sk89q/worldedit/internal/cui/ServerCUIHandler.java

@@ -0,0 +1,151 @@
+/*
+ * WorldEdit, a Minecraft world manipulation toolkit
+ * Copyright (C) sk89q <http://www.sk89q.com>
+ * Copyright (C) WorldEdit team and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser 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 Lesser General Public License
+ * for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package com.sk89q.worldedit.internal.cui;
+
+import com.sk89q.jnbt.ByteTag;
+import com.sk89q.jnbt.CompoundTag;
+import com.sk89q.jnbt.IntTag;
+import com.sk89q.jnbt.StringTag;
+import com.sk89q.jnbt.Tag;
+import com.sk89q.worldedit.IncompleteRegionException;
+import com.sk89q.worldedit.LocalSession;
+import com.sk89q.worldedit.Vector;
+import com.sk89q.worldedit.WorldEdit;
+import com.sk89q.worldedit.entity.Player;
+import com.sk89q.worldedit.regions.CuboidRegion;
+import com.sk89q.worldedit.regions.RegionSelector;
+import com.sk89q.worldedit.regions.selector.CuboidRegionSelector;
+import com.sk89q.worldedit.world.block.BaseBlock;
+import com.sk89q.worldedit.world.block.BlockTypes;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import javax.annotation.Nullable;
+
+/**
+ * Handles creation of server-side CUI systems.
+ */
+public class ServerCUIHandler {
+
+    private ServerCUIHandler() {
+    }
+
+    /**
+     * Creates a structure block that shows the region.
+     *
+     * <p>
+     *     Null symbolises removal of the CUI.
+     * </p>
+     *
+     * @param player The player to create the structure block for.
+     * @return The structure block, or null
+     */
+    @Nullable
+    public static BaseBlock createStructureBlock(Player player) {
+        LocalSession session = WorldEdit.getInstance().getSessionManager().get(player);
+        RegionSelector regionSelector = session.getRegionSelector(player.getWorld());
+
+        int posX, posY, posZ;
+        int width, height, length;
+
+        if (regionSelector instanceof CuboidRegionSelector) {
+            if (regionSelector.isDefined()) {
+                try {
+                    CuboidRegion region = ((CuboidRegionSelector) regionSelector).getRegion();
+
+                    posX = region.getMinimumPoint().getBlockX();
+                    posY = region.getMinimumPoint().getBlockY();
+                    posZ = region.getMinimumPoint().getBlockZ();
+
+                    width = region.getWidth();
+                    height = region.getHeight();
+                    length = region.getLength();
+                } catch (IncompleteRegionException e) {
+                    // This will never happen.
+                    e.printStackTrace();
+                    return null;
+                }
+            } else {
+                CuboidRegion region = ((CuboidRegionSelector) regionSelector).getIncompleteRegion();
+                Vector point;
+                if (region.getPos1() != null) {
+                    point = region.getPos1();
+                } else if (region.getPos2() != null) {
+                    point = region.getPos2();
+                } else {
+                    // No more selection
+                    return null;
+                }
+
+                // Just select the point.
+                posX = point.getBlockX();
+                posY = point.getBlockY();
+                posZ = point.getBlockZ();
+                width = 1;
+                height = 1;
+                length = 1;
+            }
+        } else {
+            // We only support cuboid regions right now.
+            return null;
+        }
+
+        if (width > 32 || length > 32 || height > 32) {
+            // Structure blocks have a limit of 32x32x32
+            return null;
+        }
+
+        // Borrowed this math from FAWE
+        double rotX = player.getLocation().getYaw();
+        double rotY = player.getLocation().getPitch();
+        double xz = Math.cos(Math.toRadians(rotY));
+        int x = (int) (player.getLocation().getX() - (-xz * Math.sin(Math.toRadians(rotX))) * 12);
+        int z = (int) (player.getLocation().getZ() - (xz * Math.cos(Math.toRadians(rotX))) * 12);
+        int y = Math.max(0, Math.min(Math.min(255, posY + 32), posY + 3));
+
+        Map<String, Tag> structureTag = new HashMap<>();
+
+        posX -= x;
+        posY -= y;
+        posZ -= z;
+
+        structureTag.put("name", new StringTag(player.getUniqueId().toString()));
+        structureTag.put("author", new StringTag(player.getName()));
+        structureTag.put("metadata", new StringTag(""));
+        structureTag.put("x", new IntTag(x));
+        structureTag.put("y", new IntTag(y));
+        structureTag.put("z", new IntTag(z));
+        structureTag.put("posX", new IntTag(posX));
+        structureTag.put("posY", new IntTag(posY));
+        structureTag.put("posZ", new IntTag(posZ));
+        structureTag.put("sizeX", new IntTag(width));
+        structureTag.put("sizeY", new IntTag(height));
+        structureTag.put("sizeZ", new IntTag(length));
+        structureTag.put("rotation", new StringTag("NONE"));
+        structureTag.put("mirror", new StringTag("NONE"));
+        structureTag.put("mode", new StringTag("SAVE"));
+        structureTag.put("ignoreEntities", new ByteTag((byte) 1));
+        structureTag.put("showboundingbox", new ByteTag((byte) 1));
+        structureTag.put("id", new StringTag(BlockTypes.STRUCTURE_BLOCK.getId()));
+
+        return BlockTypes.STRUCTURE_BLOCK.getDefaultState().toBaseBlock(new CompoundTag(structureTag));
+    }
+}