From 278c31f86729eea8e34ad152dca0d03168b1d8a8 Mon Sep 17 00:00:00 2001
From: sorokya <richard@richardleek.com>
Date: Sun, 27 Mar 2022 14:45:21 +0200
Subject: [PATCH] Request map info for new characters/npcs in the walk reply

---
 EOLib/PacketHandlers/MainPlayerWalkHandler.cs | 63 ++++++++++++++++++-
 EOLib/PacketHandlers/MapInfoHandler.cs        |  7 ++-
 2 files changed, 65 insertions(+), 5 deletions(-)

diff --git a/EOLib/PacketHandlers/MainPlayerWalkHandler.cs b/EOLib/PacketHandlers/MainPlayerWalkHandler.cs
index 2783ae533..99dd1e6ae 100644
--- a/EOLib/PacketHandlers/MainPlayerWalkHandler.cs
+++ b/EOLib/PacketHandlers/MainPlayerWalkHandler.cs
@@ -2,7 +2,10 @@
 using EOLib.Domain.Login;
 using EOLib.Domain.Map;
 using EOLib.Net;
+using EOLib.Net.Communication;
 using EOLib.Net.Handlers;
+using System.Collections.Generic;
+using System.Linq;
 
 namespace EOLib.PacketHandlers
 {
@@ -10,21 +13,35 @@ namespace EOLib.PacketHandlers
     public class MainPlayerWalkHandler : InGameOnlyPacketHandler
     {
         private readonly ICurrentMapStateRepository _currentMapStateRepository;
+        private readonly IPacketSendService _packetSendService;
 
         public override PacketFamily Family => PacketFamily.Walk;
         public override PacketAction Action => PacketAction.Reply;
 
         public MainPlayerWalkHandler(IPlayerInfoProvider playerInfoProvider,
-                                     ICurrentMapStateRepository currentMapStateRepository)
+                                     ICurrentMapStateRepository currentMapStateRepository,
+                                     IPacketSendService packetSendService)
             : base(playerInfoProvider)
         {
             _currentMapStateRepository = currentMapStateRepository;
+            _packetSendService = packetSendService;
         }
 
         public override bool HandlePacket(IPacket packet)
         {
-            if (packet.ReadByte() != 255 || packet.ReadByte() != 255)
-                return false;
+            var playerIDs = new List<short>();
+            while (packet.PeekByte() != 0xFF)
+            {
+                playerIDs.Add(packet.ReadShort());
+            }
+            packet.ReadByte();
+
+            var npcIndexes = new List<byte>();
+            while (packet.PeekByte() != 0xFF)
+            {
+                npcIndexes.Add(packet.ReadChar());
+            }
+            packet.ReadByte();
 
             var numberOfMapItems = packet.PeekEndString().Length / 9;
             for (int i = 0; i < numberOfMapItems; ++i)
@@ -39,6 +56,46 @@ public override bool HandlePacket(IPacket packet)
                 _currentMapStateRepository.MapItems.Add(newItem);
             }
 
+            var newPlayerIDs = playerIDs
+                .Where(id => !_currentMapStateRepository.Characters.ContainsKey(id))
+                .ToList();
+
+            var newNPCIndxes = npcIndexes
+                .Where(index => !_currentMapStateRepository.NPCs.Any((npc) => npc.Index == index))
+                .ToList();
+
+            if (newPlayerIDs.Count > 0 || newNPCIndxes.Count > 0)
+            {
+                IPacketBuilder builder = new PacketBuilder(PacketFamily.MapInfo, PacketAction.Request);
+
+                if (newPlayerIDs.Count > 0)
+                {
+                    foreach (var playerId in newPlayerIDs)
+                    {
+                        builder = builder.AddShort(playerId);
+                    }
+                }
+
+                if (newNPCIndxes.Count > 0)
+                {
+                    builder.AddByte(0xFF);
+                    foreach (var npcIndex in newNPCIndxes)
+                    {
+                        builder = builder.AddChar(npcIndex);
+                    }
+                }
+
+                try
+                {
+                    var request = builder.Build();
+                    _packetSendService.SendPacket(request);
+                }
+                catch (NoDataSentException)
+                {
+                    return false;
+                }
+            }
+
             return true;
         }
     }
diff --git a/EOLib/PacketHandlers/MapInfoHandler.cs b/EOLib/PacketHandlers/MapInfoHandler.cs
index 0dcd5ff59..ebf0ab556 100644
--- a/EOLib/PacketHandlers/MapInfoHandler.cs
+++ b/EOLib/PacketHandlers/MapInfoHandler.cs
@@ -25,13 +25,15 @@ public class MapInfoHandler : InGameOnlyPacketHandler
         public MapInfoHandler(IPlayerInfoProvider playerInfoProvider,
                               ICurrentMapStateRepository currentMapStateRepository,
                               ICharacterFromPacketFactory characterFromPacketFactory,
-                              INPCFromPacketFactory npcFromPacketFactory
+                              INPCFromPacketFactory npcFromPacketFactory,
+                              IEIFFileProvider eifFileProvider
                               )
             : base(playerInfoProvider)
         {
             _currentMapStateRepository = currentMapStateRepository;
             _characterFromPacketFactory = characterFromPacketFactory;
             _npcFromPacketFactory = npcFromPacketFactory;
+            _eifFileProvider = eifFileProvider;
         }
 
         public override bool HandlePacket(IPacket packet)
@@ -40,6 +42,7 @@ public override bool HandlePacket(IPacket packet)
 
             if (packet.PeekByte() == 0xFF)
             {
+                packet.ReadByte();
                 for (var i = 0; i < num_entities; i++)
                 {
                     var character = _characterFromPacketFactory.CreateCharacter(packet);
@@ -53,7 +56,7 @@ public override bool HandlePacket(IPacket packet)
                 }
             }
 
-            while (packet.ReadPosition < packet.Length)
+            while (num_entities > 0 && packet.ReadPosition < packet.Length)
             {
                 var npc = _npcFromPacketFactory.CreateNPC(packet);
                 _currentMapStateRepository.NPCs.RemoveWhere(n => n.Index == npc.Index);