sync SMAPI context between players in multiplayer (#480)

6 files changed, 291 insertions, 0 deletions

diff --git a/src/SMAPI/Framework/Networking/MultiplayerPeer.cs b/src/SMAPI/Framework/Networking/MultiplayerPeer.cs
new file mode 100644
index 00000000..e97e36bc
--- /dev/null
+++ b/src/SMAPI/Framework/Networking/MultiplayerPeer.cs
@@ -0,0 +1,128 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using Lidgren.Network;
+using StardewValley;
+using StardewValley.Network;
+
+namespace StardewModdingAPI.Framework.Networking
+{
+    /// <summary>Metadata about a connected player.</summary>
+    internal class MultiplayerPeer : IMultiplayerPeer
+    {
+        /*********
+        ** Properties
+        *********/
+        /// <summary>The server through which to send messages, if this is an incoming farmhand.</summary>
+        private readonly SLidgrenServer Server;
+
+        /// <summary>The client through which to send messages, if this is the host player.</summary>
+        private readonly SLidgrenClient Client;
+
+        /// <summary>The network connection to the player.</summary>
+        private readonly NetConnection ServerConnection;
+
+
+        /*********
+        ** Accessors
+        *********/
+        /// <summary>The player's unique ID.</summary>
+        public long PlayerID { get; }
+
+        /// <summary>Whether this is a connection to the host player.</summary>
+        public bool IsHostPlayer => this.PlayerID == Game1.MasterPlayer.UniqueMultiplayerID;
+
+        /// <summary>Whether the player has SMAPI installed.</summary>
+        public bool HasSmapi => this.ApiVersion != null;
+
+        /// <summary>The player's OS platform, if <see cref="HasSmapi"/> is true.</summary>
+        public GamePlatform? Platform { get; }
+
+        /// <summary>The installed version of Stardew Valley, if <see cref="HasSmapi"/> is true.</summary>
+        public ISemanticVersion GameVersion { get; }
+
+        /// <summary>The installed version of SMAPI, if <see cref="HasSmapi"/> is true.</summary>
+        public ISemanticVersion ApiVersion { get; }
+
+        /// <summary>The installed mods, if <see cref="HasSmapi"/> is true.</summary>
+        public IEnumerable<IMultiplayerPeerMod> Mods { get; }
+
+
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Construct an instance.</summary>
+        /// <param name="playerID">The player's unique ID.</param>
+        /// <param name="model">The metadata to copy.</param>
+        /// <param name="server">The server through which to send messages.</param>
+        /// <param name="serverConnection">The server connection through which to send messages.</param>
+        /// <param name="client">The client through which to send messages.</param>
+        public MultiplayerPeer(long playerID, RemoteContextModel model, SLidgrenServer server, NetConnection serverConnection, SLidgrenClient client)
+        {
+            this.PlayerID = playerID;
+            if (model != null)
+            {
+                this.Platform = model.Platform;
+                this.GameVersion = model.GameVersion;
+                this.ApiVersion = model.ApiVersion;
+                this.Mods = model.Mods.Select(mod => new MultiplayerPeerMod(mod)).ToArray();
+            }
+            this.Server = server;
+            this.ServerConnection = serverConnection;
+            this.Client = client;
+        }
+
+        /// <summary>Construct an instance for a connection to an incoming farmhand.</summary>
+        /// <param name="playerID">The player's unique ID.</param>
+        /// <param name="model">The metadata to copy, if available.</param>
+        /// <param name="server">The server through which to send messages.</param>
+        /// <param name="serverConnection">The server connection through which to send messages.</param>
+        public static MultiplayerPeer ForConnectionToFarmhand(long playerID, RemoteContextModel model, SLidgrenServer server, NetConnection serverConnection)
+        {
+            return new MultiplayerPeer(
+                playerID: playerID,
+                model: model,
+                server: server,
+                serverConnection: serverConnection,
+                client: null
+            );
+        }
+
+        /// <summary>Construct an instance for a connection to the host player.</summary>
+        /// <param name="playerID">The player's unique ID.</param>
+        /// <param name="model">The metadata to copy.</param>
+        /// <param name="client">The client through which to send messages.</param>
+        public static MultiplayerPeer ForConnectionToHost(long playerID, RemoteContextModel model, SLidgrenClient client)
+        {
+            return new MultiplayerPeer(
+                playerID: playerID,
+                model: model,
+                server: null,
+                serverConnection: null,
+                client: client
+            );
+        }
+
+        /// <summary>Get metadata for a mod installed by the player.</summary>
+        /// <param name="id">The unique mod ID.</param>
+        /// <returns>Returns the mod info, or <c>null</c> if the player doesn't have that mod.</returns>
+        public IMultiplayerPeerMod GetMod(string id)
+        {
+            if (string.IsNullOrWhiteSpace(id))
+                return null;
+
+            id = id.Trim();
+            return this.Mods.FirstOrDefault(mod => mod.ID != null && mod.ID.Equals(id, StringComparison.InvariantCultureIgnoreCase));
+        }
+
+        /// <summary>Send a message to the given peer, bypassing the game's normal validation to allow messages before the connection is approved.</summary>
+        /// <param name="message">The message to send.</param>
+        public void SendMessage(OutgoingMessage message)
+        {
+            if (this.IsHostPlayer)
+                this.Client.sendMessage(message);
+            else
+                this.Server.SendMessage(this.ServerConnection, message);
+        }
+    }
+}
diff --git a/src/SMAPI/Framework/Networking/MultiplayerPeerMod.cs b/src/SMAPI/Framework/Networking/MultiplayerPeerMod.cs
new file mode 100644
index 00000000..1b324bcd
--- /dev/null
+++ b/src/SMAPI/Framework/Networking/MultiplayerPeerMod.cs
@@ -0,0 +1,30 @@
+namespace StardewModdingAPI.Framework.Networking
+{
+    internal class MultiplayerPeerMod : IMultiplayerPeerMod
+    {
+        /*********
+        ** Accessors
+        *********/
+        /// <summary>The mod's display name.</summary>
+        public string Name { get; }
+
+        /// <summary>The unique mod ID.</summary>
+        public string ID { get; }
+
+        /// <summary>The mod version.</summary>
+        public ISemanticVersion Version { get; }
+
+
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Construct an instance.</summary>
+        /// <param name="mod">The mod metadata.</param>
+        public MultiplayerPeerMod(RemoteContextModModel mod)
+        {
+            this.Name = mod.Name;
+            this.ID = mod.ID?.Trim();
+            this.Version = mod.Version;
+        }
+    }
+}
diff --git a/src/SMAPI/Framework/Networking/RemoteContextModModel.cs b/src/SMAPI/Framework/Networking/RemoteContextModModel.cs
new file mode 100644
index 00000000..9795d971
--- /dev/null
+++ b/src/SMAPI/Framework/Networking/RemoteContextModModel.cs
@@ -0,0 +1,15 @@
+namespace StardewModdingAPI.Framework.Networking
+{
+    /// <summary>Metadata about an installed mod exchanged with connected computers.</summary>
+    public class RemoteContextModModel
+    {
+        /// <summary>The mod's display name.</summary>
+        public string Name { get; set; }
+
+        /// <summary>The unique mod ID.</summary>
+        public string ID { get; set; }
+
+        /// <summary>The mod version.</summary>
+        public ISemanticVersion Version { get; set; }
+    }
+}
diff --git a/src/SMAPI/Framework/Networking/RemoteContextModel.cs b/src/SMAPI/Framework/Networking/RemoteContextModel.cs
new file mode 100644
index 00000000..7befb151
--- /dev/null
+++ b/src/SMAPI/Framework/Networking/RemoteContextModel.cs
@@ -0,0 +1,24 @@
+namespace StardewModdingAPI.Framework.Networking
+{
+    /// <summary>Metadata about the game, SMAPI, and installed mods exchanged with connected computers.</summary>
+    internal class RemoteContextModel
+    {
+        /*********
+        ** Accessors
+        *********/
+        /// <summary>Whether this player is the host player.</summary>
+        public bool IsHost { get; set; }
+
+        /// <summary>The game's platform version.</summary>
+        public GamePlatform Platform { get; set; }
+
+        /// <summary>The installed version of Stardew Valley.</summary>
+        public ISemanticVersion GameVersion { get; set; }
+
+        /// <summary>The installed version of SMAPI.</summary>
+        public ISemanticVersion ApiVersion { get; set; }
+
+        /// <summary>The installed mods.</summary>
+        public RemoteContextModModel[] Mods { get; set; }
+    }
+}
diff --git a/src/SMAPI/Framework/Networking/SLidgrenClient.cs b/src/SMAPI/Framework/Networking/SLidgrenClient.cs
new file mode 100644
index 00000000..9dfdba15
--- /dev/null
+++ b/src/SMAPI/Framework/Networking/SLidgrenClient.cs
@@ -0,0 +1,58 @@
+using System;
+using StardewValley;
+using StardewValley.Network;
+
+namespace StardewModdingAPI.Framework.Networking
+{
+    /// <summary>A multiplayer client used to connect to a hosted server. This is an implementation of <see cref="LidgrenClient"/> that adds support for SMAPI's metadata context exchange.</summary>
+    internal class SLidgrenClient : LidgrenClient
+    {
+        /*********
+        ** Properties
+        *********/
+        /// <summary>Get the metadata to include in a metadata message sent to other players.</summary>
+        private readonly Func<object[]> GetMetadataMessageFields;
+
+        /// <summary>The method to call when receiving a custom SMAPI message from the server, which returns whether the message was processed.</summary>
+        private readonly Func<SLidgrenClient, IncomingMessage, bool> TryProcessMessage;
+
+
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Construct an instance.</summary>
+        /// <param name="address">The remote address being connected.</param>
+        /// <param name="getMetadataMessageFields">Get the metadata to include in a metadata message sent to other players.</param>
+        /// <param name="tryProcessMessage">The method to call when receiving a custom SMAPI message from the server, which returns whether the message was processed..</param>
+        public SLidgrenClient(string address, Func<object[]> getMetadataMessageFields, Func<SLidgrenClient, IncomingMessage, bool> tryProcessMessage)
+            : base(address)
+        {
+            this.GetMetadataMessageFields = getMetadataMessageFields;
+            this.TryProcessMessage = tryProcessMessage;
+        }
+
+        /// <summary>Send the metadata needed to connect with a remote server.</summary>
+        public override void sendPlayerIntroduction()
+        {
+            // send custom intro
+            if (this.getUserID() != "")
+                Game1.player.userID.Value = this.getUserID();
+            this.sendMessage(SMultiplayer.ContextSyncMessageID, this.GetMetadataMessageFields());
+            base.sendPlayerIntroduction();
+        }
+
+
+        /*********
+        ** Protected methods
+        *********/
+        /// <summary>Process an incoming network message.</summary>
+        /// <param name="message">The message to process.</param>
+        protected override void processIncomingMessage(IncomingMessage message)
+        {
+            if (this.TryProcessMessage(this, message))
+                return;
+
+            base.processIncomingMessage(message);
+        }
+    }
+}
diff --git a/src/SMAPI/Framework/Networking/SLidgrenServer.cs b/src/SMAPI/Framework/Networking/SLidgrenServer.cs
new file mode 100644
index 00000000..971eb66d
--- /dev/null
+++ b/src/SMAPI/Framework/Networking/SLidgrenServer.cs
@@ -0,0 +1,36 @@
+using System.Reflection;
+using Lidgren.Network;
+using StardewValley.Network;
+
+namespace StardewModdingAPI.Framework.Networking
+{
+    /// <summary>A multiplayer server used to connect to an incoming player. This is an implementation of <see cref="LidgrenServer"/> that adds support for SMAPI's metadata context exchange.</summary>
+    internal class SLidgrenServer : LidgrenServer
+    {
+        /*********
+        ** Properties
+        *********/
+        /// <summary>A method which sends a message through a specific connection.</summary>
+        private readonly MethodInfo SendMessageToConnectionMethod;
+
+
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Construct an instance.</summary>
+        /// <param name="gameServer">The underlying game server.</param>
+        public SLidgrenServer(IGameServer gameServer)
+            : base(gameServer)
+        {
+            this.SendMessageToConnectionMethod = typeof(LidgrenServer).GetMethod(nameof(LidgrenServer.sendMessage), BindingFlags.NonPublic | BindingFlags.Instance, null, new[] { typeof(NetConnection), typeof(OutgoingMessage) }, null);
+        }
+
+        /// <summary>Send a message to a remote server.</summary>
+        /// <param name="connection">The network connection.</param>
+        /// <param name="message">The message to send.</param>
+        public void SendMessage(NetConnection connection, OutgoingMessage message)
+        {
+            this.SendMessageToConnectionMethod.Invoke(this, new object[] { connection, message });
+        }
+    }
+}