From 76a10c0cd87818fb7dd6362834c2e14f4f843cb9 Mon Sep 17 00:00:00 2001
From: xXjojaXx <73311246+xXjojaXx@users.noreply.github.com>
Date: Wed, 17 Nov 2021 17:33:52 +0100
Subject: [PATCH] Spectator-Teleport Implementation (#1825)

---
 MinecraftClient/ChatBot.cs                    | 18 ++++++++++
 MinecraftClient/McClient.cs                   | 35 +++++++++++++++++++
 .../Protocol/Handlers/DataTypes.cs            | 10 ++++++
 .../Protocol/Handlers/Protocol16.cs           |  5 +++
 .../Protocol/Handlers/Protocol18.cs           | 14 ++++++++
 MinecraftClient/Protocol/IMinecraftCom.cs     |  6 ++++
 6 files changed, 88 insertions(+)

diff --git a/MinecraftClient/ChatBot.cs b/MinecraftClient/ChatBot.cs
index 1e476a7c..f1505ddb 100644
--- a/MinecraftClient/ChatBot.cs
+++ b/MinecraftClient/ChatBot.cs
@@ -1338,6 +1338,24 @@ namespace MinecraftClient
         {
             return Handler.SelectTrade(selectedSlot);
         }
+
+        /// <summary>
+        /// Teleport to player in spectator mode
+        /// </summary>
+        /// <param name="entity">player to teleport to</param>
+        protected bool SpectatorTeleport(Entity entity)
+        {
+            return Handler.Spectate(entity);
+        }
+
+        /// <summary>
+        /// Teleport to player/entity in spectator mode
+        /// </summary>
+        /// <param name="uuid">uuid of entity to teleport to</param>
+        protected bool SpectatorTeleport(Guid UUID)
+        {
+            return Handler.SpectateByUUID(UUID);
+        }
         
         /// <summary>
         /// Update command block
diff --git a/MinecraftClient/McClient.cs b/MinecraftClient/McClient.cs
index 22ffdf4a..391bfe07 100644
--- a/MinecraftClient/McClient.cs
+++ b/MinecraftClient/McClient.cs
@@ -1695,6 +1695,41 @@ namespace MinecraftClient
         {
             return InvokeOnMainThread(() => handler.UpdateCommandBlock(location, command, mode, flags));
         }
+
+        /// <summary>
+        /// Teleport to player in spectator mode
+        /// </summary>
+        /// <param name="entity">Player to teleport to</param>
+        /// Teleporting to other entityies is NOT implemented yet
+        public bool Spectate(Entity entity)
+        {
+            if(entity.Type == EntityType.Player)
+            {
+                return SpectateByUUID(entity.UUID);
+            }
+            else
+            {
+                return false;
+            }
+        }
+
+        /// <summary>
+        /// Teleport to player/entity in spectator mode
+        /// </summary>
+        /// <param name="UUID">UUID of player/entity to teleport to</param>
+        public bool SpectateByUUID(Guid UUID)
+        {
+            if(GetGamemode() == 3)
+            {
+                if(InvokeRequired)
+                    return InvokeOnMainThread(() => SpectateByUUID(UUID));
+                return handler.SendSpectate(UUID);
+            }
+            else
+            {
+                return false;
+            }
+        }
         #endregion
 
         #region Event handlers: An event occurs on the Server
diff --git a/MinecraftClient/Protocol/Handlers/DataTypes.cs b/MinecraftClient/Protocol/Handlers/DataTypes.cs
index dfe0c194..93c6562e 100644
--- a/MinecraftClient/Protocol/Handlers/DataTypes.cs
+++ b/MinecraftClient/Protocol/Handlers/DataTypes.cs
@@ -1047,6 +1047,16 @@ namespace MinecraftClient.Protocol.Handlers
             }
         }
 
+        /// <summary>
+        /// Get a byte array from the given uuid
+        /// </summary>
+        /// <param name="uuid">UUID of Player/Entity</param>
+        /// <returns>UUID representation</returns>
+        public byte[] GetUUID(Guid UUID)
+        {
+            return UUID.ToBigEndianBytes();
+        }
+
         /// <summary>
         /// Easily append several byte arrays
         /// </summary>
diff --git a/MinecraftClient/Protocol/Handlers/Protocol16.cs b/MinecraftClient/Protocol/Handlers/Protocol16.cs
index aaf5affd..c0b04c33 100644
--- a/MinecraftClient/Protocol/Handlers/Protocol16.cs
+++ b/MinecraftClient/Protocol/Handlers/Protocol16.cs
@@ -860,5 +860,10 @@ namespace MinecraftClient.Protocol.Handlers
         {
             return false; //MC 1.13+
         }
+
+        public bool SendSpectate(Guid UUID)
+        {
+            return false; //Currently not implemented
+        }
     }
 }
diff --git a/MinecraftClient/Protocol/Handlers/Protocol18.cs b/MinecraftClient/Protocol/Handlers/Protocol18.cs
index 3fec7721..ade1d959 100644
--- a/MinecraftClient/Protocol/Handlers/Protocol18.cs
+++ b/MinecraftClient/Protocol/Handlers/Protocol18.cs
@@ -2057,5 +2057,19 @@ namespace MinecraftClient.Protocol.Handlers
             }
             else { return false; }
         }
+
+        public bool SendSpectate(Guid UUID)
+        {
+            try
+            {
+                List<byte> packet = new List<byte>();
+                packet.AddRange(dataTypes.GetUUID(UUID));
+                SendPacket(PacketTypesOut.Spectate, packet);
+                return true;
+            }
+            catch (SocketException) { return false; }
+            catch (System.IO.IOException) { return false; }
+            catch (ObjectDisposedException) { return false; }
+        }
     }
 }
diff --git a/MinecraftClient/Protocol/IMinecraftCom.cs b/MinecraftClient/Protocol/IMinecraftCom.cs
index 42d66fcd..54d19e77 100644
--- a/MinecraftClient/Protocol/IMinecraftCom.cs
+++ b/MinecraftClient/Protocol/IMinecraftCom.cs
@@ -236,6 +236,12 @@ namespace MinecraftClient.Protocol
         /// <param name="selectedSlot">The slot of the trade, starts at 0.</param>
         bool SelectTrade(int selectedSlot);
 
+        /// <summary>
+        /// Spectate a player/entity
+        /// </summary>
+        /// <param name="uuid">The uuid of the player/entity to spectate/teleport to.</param>
+        bool SendSpectate(Guid uuid);
+
         /// <summary>
         /// Get net read thread (main thread) ID
         /// </summary>