From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Jake Potrebic <jake.m.potrebic@gmail.com>
Date: Sat, 15 May 2021 10:04:43 -0700
Subject: [PATCH] additions to PlayerGameModeChangeEvent


diff --git a/src/main/java/net/minecraft/server/commands/DefaultGameModeCommands.java b/src/main/java/net/minecraft/server/commands/DefaultGameModeCommands.java
index d446e52aa0951af5f759fa7a91908f4d818bd4a5..3fcdc509649b3d67bfd74404bcdf8d7a65c1babf 100644
--- a/src/main/java/net/minecraft/server/commands/DefaultGameModeCommands.java
+++ b/src/main/java/net/minecraft/server/commands/DefaultGameModeCommands.java
@@ -31,9 +31,13 @@ public class DefaultGameModeCommands {
         GameType gameType = minecraftServer.getForcedGameType();
         if (gameType != null) {
             for(ServerPlayer serverPlayer : minecraftServer.getPlayerList().getPlayers()) {
-                if (serverPlayer.setGameMode(gameType)) {
-                    ++i;
+                // Paper start - extend PlayerGameModeChangeEvent
+                org.bukkit.event.player.PlayerGameModeChangeEvent event = serverPlayer.setGameMode(gameType, org.bukkit.event.player.PlayerGameModeChangeEvent.Cause.DEFAULT_GAMEMODE, net.kyori.adventure.text.Component.empty());
+                if (event != null && event.isCancelled()) {
+                    source.sendSuccess(io.papermc.paper.adventure.PaperAdventure.asVanilla(event.cancelMessage()), false);
                 }
+                // Paper end
+                    ++i;
             }
         }
 
diff --git a/src/main/java/net/minecraft/server/commands/GameModeCommand.java b/src/main/java/net/minecraft/server/commands/GameModeCommand.java
index 65089c0e78c9913a92ae9c66d664f48e2112ad92..7882ee2b7813d437d3b7580f046f38e79fc9e7b6 100644
--- a/src/main/java/net/minecraft/server/commands/GameModeCommand.java
+++ b/src/main/java/net/minecraft/server/commands/GameModeCommand.java
@@ -50,9 +50,14 @@ public class GameModeCommand {
         int i = 0;
 
         for(ServerPlayer serverPlayer : targets) {
-            if (serverPlayer.setGameMode(gameMode)) {
+            // Paper start - extend PlayerGameModeChangeEvent
+            org.bukkit.event.player.PlayerGameModeChangeEvent event = serverPlayer.setGameMode(gameMode, org.bukkit.event.player.PlayerGameModeChangeEvent.Cause.COMMAND, net.kyori.adventure.text.Component.empty());
+            if (event != null && !event.isCancelled()) {
                 logGamemodeChange(context.getSource(), serverPlayer, gameMode);
                 ++i;
+            } else if (event != null && event.cancelMessage() != null) {
+                context.getSource().sendSuccess(io.papermc.paper.adventure.PaperAdventure.asVanilla(event.cancelMessage()), true);
+                // Paper end
             }
         }
 
diff --git a/src/main/java/net/minecraft/server/level/ServerPlayer.java b/src/main/java/net/minecraft/server/level/ServerPlayer.java
index 01ec3d4a3ea2d5edf1d503cdb6a9532774a89480..0f5204733022955df059b3ccff260e1aa375916c 100644
--- a/src/main/java/net/minecraft/server/level/ServerPlayer.java
+++ b/src/main/java/net/minecraft/server/level/ServerPlayer.java
@@ -1810,8 +1810,15 @@ public class ServerPlayer extends Player {
     }
 
     public boolean setGameMode(GameType gameMode) {
-        if (!this.gameMode.changeGameModeForPlayer(gameMode)) {
-            return false;
+        // Paper start - Add cause and nullable message to event
+        org.bukkit.event.player.PlayerGameModeChangeEvent event = this.setGameMode(gameMode, org.bukkit.event.player.PlayerGameModeChangeEvent.Cause.UNKNOWN, null);
+        return event == null ? false : event.isCancelled();
+    }
+    public org.bukkit.event.player.PlayerGameModeChangeEvent setGameMode(GameType gameMode, org.bukkit.event.player.PlayerGameModeChangeEvent.Cause cause, net.kyori.adventure.text.Component message) {
+        org.bukkit.event.player.PlayerGameModeChangeEvent event = this.gameMode.changeGameModeForPlayer(gameMode, cause, message);
+        if (event == null || event.isCancelled()) {
+            // Paper end
+            return null;
         } else {
             this.connection.send(new ClientboundGameEventPacket(ClientboundGameEventPacket.CHANGE_GAME_MODE, (float) gameMode.getId()));
             if (gameMode == GameType.SPECTATOR) {
@@ -1823,7 +1830,7 @@ public class ServerPlayer extends Player {
 
             this.onUpdateAbilities();
             this.updateEffectVisibility();
-            return true;
+            return event; // Paper
         }
     }
 
@@ -2225,6 +2232,16 @@ public class ServerPlayer extends Player {
     }
 
     public void loadGameTypes(@Nullable CompoundTag nbt) {
+        // Paper start
+        if (this.server.getForcedGameType() != null && this.server.getForcedGameType() != ServerPlayer.readPlayerMode(nbt, "playerGameType")) {
+            if (new org.bukkit.event.player.PlayerGameModeChangeEvent(this.getBukkitEntity(), org.bukkit.GameMode.getByValue(this.server.getDefaultGameType().getId()), org.bukkit.event.player.PlayerGameModeChangeEvent.Cause.DEFAULT_GAMEMODE, null).callEvent()) {
+                this.gameMode.setGameModeForPlayer(this.server.getForcedGameType(), GameType.DEFAULT_MODE);
+            } else {
+                this.gameMode.setGameModeForPlayer(ServerPlayer.readPlayerMode(nbt,"playerGameType"), ServerPlayer.readPlayerMode(nbt, "previousPlayerGameType"));
+            }
+            return;
+        }
+        // Paper end
         this.gameMode.setGameModeForPlayer(this.calculateGameModeForNewPlayer(ServerPlayer.readPlayerMode(nbt, "playerGameType")), ServerPlayer.readPlayerMode(nbt, "previousPlayerGameType"));
     }
 
diff --git a/src/main/java/net/minecraft/server/level/ServerPlayerGameMode.java b/src/main/java/net/minecraft/server/level/ServerPlayerGameMode.java
index 32746dfbc2fdfc150583676b1bf0762398b76d75..1ad1f958a9b6e1bc21f1c505aa7ea54950de6cad 100644
--- a/src/main/java/net/minecraft/server/level/ServerPlayerGameMode.java
+++ b/src/main/java/net/minecraft/server/level/ServerPlayerGameMode.java
@@ -73,18 +73,24 @@ public class ServerPlayerGameMode {
     }
 
     public boolean changeGameModeForPlayer(GameType gameMode) {
+        // Paper end
+        PlayerGameModeChangeEvent event = this.changeGameModeForPlayer(gameMode, org.bukkit.event.player.PlayerGameModeChangeEvent.Cause.UNKNOWN, null);
+        return event == null ? false : event.isCancelled();
+    }
+    public PlayerGameModeChangeEvent changeGameModeForPlayer(GameType gameMode, org.bukkit.event.player.PlayerGameModeChangeEvent.Cause cause, net.kyori.adventure.text.Component cancelMessage) {
+        // Paper end
         if (gameMode == this.gameModeForPlayer) {
-            return false;
+            return null; // Paper
         } else {
             // CraftBukkit start
-            PlayerGameModeChangeEvent event = new PlayerGameModeChangeEvent(this.player.getBukkitEntity(), GameMode.getByValue(gameMode.getId()));
+            PlayerGameModeChangeEvent event = new PlayerGameModeChangeEvent(this.player.getBukkitEntity(), GameMode.getByValue(gameMode.getId()), cause, cancelMessage); // Paper
             this.level.getCraftServer().getPluginManager().callEvent(event);
             if (event.isCancelled()) {
-                return false;
+                return event; // Paper
             }
             // CraftBukkit end
             this.setGameModeForPlayer(gameMode, this.gameModeForPlayer);
-            return true;
+            return event; // Paper
         }
     }
 
diff --git a/src/main/java/net/minecraft/server/network/ServerGamePacketListenerImpl.java b/src/main/java/net/minecraft/server/network/ServerGamePacketListenerImpl.java
index fe40e0ffdb9f9a1c0ce2accba0dbb46238fc5ced..3737b9c62d8d1820041e49e4ec75a61fcfbcf10b 100644
--- a/src/main/java/net/minecraft/server/network/ServerGamePacketListenerImpl.java
+++ b/src/main/java/net/minecraft/server/network/ServerGamePacketListenerImpl.java
@@ -2895,7 +2895,7 @@ public class ServerGamePacketListenerImpl implements ServerPlayerConnection, Tic
 
                     this.player = this.server.getPlayerList().respawn(this.player, false);
                     if (this.server.isHardcore()) {
-                        this.player.setGameMode(GameType.SPECTATOR);
+                        this.player.setGameMode(GameType.SPECTATOR, org.bukkit.event.player.PlayerGameModeChangeEvent.Cause.HARDCORE_DEATH, null); // Paper
                         ((GameRules.BooleanValue) this.player.getLevel().getGameRules().getRule(GameRules.RULE_SPECTATORSGENERATECHUNKS)).set(false, this.server);
                     }
                 }
diff --git a/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java b/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
index af3990e601a3e3b0ccb96e212bb071e3e240f6ff..7d030d7a8a58f4a031e09d09c9718af3d3c1e707 100644
--- a/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
+++ b/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
@@ -1396,7 +1396,7 @@ public class CraftPlayer extends CraftHumanEntity implements Player {
             throw new IllegalArgumentException("Mode cannot be null");
         }
 
-        this.getHandle().setGameMode(GameType.byId(mode.getValue()));
+        this.getHandle().setGameMode(GameType.byId(mode.getValue()), org.bukkit.event.player.PlayerGameModeChangeEvent.Cause.PLUGIN, null); // Paper
     }
 
     @Override