Moved tree detection to the server

src/main/java/com/minelittlepony/unicopia/TreeType.java

@@ -3,7 +3,6 @@ package com.minelittlepony.unicopia;
 import com.minelittlepony.unicopia.util.PosHelper;
 import com.minelittlepony.unicopia.util.Weighted;
 
-import java.util.Collections;
 import java.util.HashSet;
 import java.util.Optional;
 import java.util.Set;
@@ -23,8 +22,8 @@ public final class TreeType {
             new Identifier("unicopia", "none"),
             false,
             new Weighted<Supplier<ItemStack>>(),
-            Collections.emptySet(),
-            Collections.emptySet()
+            Set.of(),
+            Set.of()
     );
     private static final Direction[] WIDE_DIRS = new Direction[] { Direction.UP, Direction.NORTH, Direction.SOUTH, Direction.EAST, Direction.WEST };
 

src/main/java/com/minelittlepony/unicopia/ability/Ability.java

@@ -73,6 +73,15 @@ public interface Ability<T extends Hit> {
         return new TranslatableText("ability." + id.getNamespace() + "." + id.getPath().replace('/', '.'));
     }
 
+    /**
+     * Server-side counterpart to canActivate.
+     *
+     * Called before applying to determine whether to cancel the command or not.
+     */
+    default boolean canApply(Pony player, T data) {
+        return true;
+    }
+
     /**
      * Called to actually apply the ability.
      * Only called on the server side.

src/main/java/com/minelittlepony/unicopia/ability/AbilityDispatcher.java

@@ -39,7 +39,6 @@ public class AbilityDispatcher implements Tickable, NbtSerialisable {
     public void clear(AbilitySlot slot) {
         Stat stat = getStat(slot);
 
-
         if (stat.canSwitchStates()) {
             stat.setActiveAbility(null);
         }

src/main/java/com/minelittlepony/unicopia/ability/EarthPonyKickAbility.java

@@ -1,7 +1,6 @@
 package com.minelittlepony.unicopia.ability;
 
 import java.util.List;
-import java.util.Optional;
 
 import org.jetbrains.annotations.Nullable;
 
@@ -60,20 +59,17 @@ public class EarthPonyKickAbility implements Ability<Pos> {
     @Nullable
     @Override
     public Pos tryActivate(Pony player) {
-        Optional<BlockPos> p = RayTraceHelper.doTrace(player.getMaster(), 6, 1).getBlockPos();
+        return RayTraceHelper.doTrace(player.getMaster(), 6, 1).getBlockPos().map(Pos::new).orElse(null);
+    }
 
-        if (p.isPresent()) {
-            BlockPos pos = p.get();
+    @Override
+    public boolean canApply(Pony player, Pos data) {
+        BlockPos pos = data.pos();
         TreeType tree = TreeType.get(player.getWorld().getBlockState(pos));
 
-            if (tree != TreeType.NONE) {
-                return tree.findBase(player.getWorld(), pos).map(base -> {
-                    return tree.countBlocks(player.getWorld(), pos) > 0 ? new Pos(base) : null;
-                }).orElse(null);
-            }
-        }
-
-        return null;
+        return tree != TreeType.NONE && tree.findBase(player.getWorld(), pos).map(base -> {
+            return tree.countBlocks(player.getWorld(), pos) > 0;
+        }).orElse(false);
     }
 
     @Override
@@ -94,7 +90,6 @@ public class EarthPonyKickAbility implements Ability<Pos> {
 
         BlockPos pos = data.pos();
 
-
         BlockDestructionManager destr = ((BlockDestructionManager.Source)player.world).getDestructionManager();
 
         if (destr.getBlockDestruction(pos) + 4 >= BlockDestructionManager.MAX_DAMAGE) {

src/main/java/com/minelittlepony/unicopia/network/Channel.java

@@ -16,6 +16,7 @@ public interface Channel {
     S2CPacketType<MsgPlayerCapabilities> SERVER_PLAYER_CAPABILITIES = SimpleNetworking.serverToClient(new Identifier("unicopia", "player_capabilities"), MsgPlayerCapabilities::new);
     S2CPacketType<MsgSpawnProjectile> SERVER_SPAWN_PROJECTILE = SimpleNetworking.serverToClient(new Identifier("unicopia", "projectile_entity"), MsgSpawnProjectile::new);
     S2CPacketType<MsgBlockDestruction> SERVER_BLOCK_DESTRUCTION = SimpleNetworking.serverToClient(new Identifier("unicopia", "block_destruction"), MsgBlockDestruction::new);
+    S2CPacketType<MsgCancelPlayerAbility> CANCEL_PLAYER_ABILITY = SimpleNetworking.serverToClient(new Identifier("unicopia", "player_ability_cancel"), MsgCancelPlayerAbility::new);
 
     Identifier SERVER_SELECT_TRIBE_ID = new Identifier("unicopia", "select_tribe");
     S2CPacketType<MsgTribeSelect> SERVER_SELECT_TRIBE = SimpleNetworking.serverToClient(SERVER_SELECT_TRIBE_ID, MsgTribeSelect::new);

src/main/java/com/minelittlepony/unicopia/network/MsgCancelPlayerAbility.java

@@ -0,0 +1,27 @@
+package com.minelittlepony.unicopia.network;
+
+import com.minelittlepony.unicopia.InteractionManager;
+import com.minelittlepony.unicopia.util.network.Packet;
+import net.minecraft.entity.player.PlayerEntity;
+import net.minecraft.network.PacketByteBuf;
+
+/**
+ * Sent to the client when an ability fails its server-side activation checks.
+ */
+public class MsgCancelPlayerAbility implements Packet<PlayerEntity> {
+
+    MsgCancelPlayerAbility(PacketByteBuf buffer) {
+    }
+
+    public MsgCancelPlayerAbility() {
+    }
+
+    @Override
+    public void toBuffer(PacketByteBuf buffer) {
+    }
+
+    @Override
+    public void handle(PlayerEntity sender) {
+        InteractionManager.instance().getClientNetworkHandler().handleCancelAbility(this);
+    }
+}

src/main/java/com/minelittlepony/unicopia/network/MsgPlayerAbility.java

@@ -43,6 +43,10 @@ public class MsgPlayerAbility<T extends Hit> implements Packet<ServerPlayerEntit
             return;
         }
 
+        if (!power.canApply(player, data)) {
+            Channel.CANCEL_PLAYER_ABILITY.send(sender, new MsgCancelPlayerAbility());
+        } else {
             power.apply(player, data);
         }
+    }
 }

src/main/java/com/minelittlepony/unicopia/network/handler/ClientNetworkHandler.java

@@ -1,6 +1,7 @@
 package com.minelittlepony.unicopia.network.handler;
 
 import com.minelittlepony.unicopia.network.MsgBlockDestruction;
+import com.minelittlepony.unicopia.network.MsgCancelPlayerAbility;
 import com.minelittlepony.unicopia.network.MsgSpawnProjectile;
 import com.minelittlepony.unicopia.network.MsgTribeSelect;
 
@@ -11,4 +12,6 @@ public interface ClientNetworkHandler {
     void handleSpawnProjectile(MsgSpawnProjectile packet);
 
     void handleBlockDestruction(MsgBlockDestruction packet);
+
+    void handleCancelAbility(MsgCancelPlayerAbility packet);
 }

src/main/java/com/minelittlepony/unicopia/network/handler/ClientNetworkHandlerImpl.java

@@ -3,13 +3,16 @@ package com.minelittlepony.unicopia.network.handler;
 import com.minelittlepony.unicopia.Owned;
 import com.minelittlepony.unicopia.client.ClientBlockDestructionManager;
 import com.minelittlepony.unicopia.client.gui.TribeSelectionScreen;
+import com.minelittlepony.unicopia.entity.player.Pony;
 import com.minelittlepony.unicopia.network.MsgBlockDestruction;
+import com.minelittlepony.unicopia.network.MsgCancelPlayerAbility;
 import com.minelittlepony.unicopia.network.MsgSpawnProjectile;
 import com.minelittlepony.unicopia.network.MsgTribeSelect;
 
 import net.minecraft.client.MinecraftClient;
 import net.minecraft.client.world.ClientWorld;
 import net.minecraft.entity.Entity;
+import net.minecraft.sound.SoundEvents;
 
 public class ClientNetworkHandlerImpl implements ClientNetworkHandler {
 
@@ -50,4 +53,10 @@ public class ClientNetworkHandlerImpl implements ClientNetworkHandler {
         });
     }
 
+    @Override
+    public void handleCancelAbility(MsgCancelPlayerAbility packet) {
+        client.player.playSound(SoundEvents.BLOCK_NOTE_BLOCK_DIDGERIDOO, 1, 1);
+        Pony.of(client.player).getAbilities().getStats().forEach(s -> s.setCooldown(0));
+    }
+
 }