1 files changed, 132 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..e703dbb1
--- /dev/null
+++ b/src/SMAPI/Framework/Networking/MultiplayerPeer.cs
@@ -0,0 +1,132 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using Lidgren.Network;
+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 IsHost { get; }
+
+        /// <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>
+        /// <param name="isHost">Whether this is a connection to the host player.</param>
+        public MultiplayerPeer(long playerID, RemoteContextModel model, SLidgrenServer server, NetConnection serverConnection, SLidgrenClient client, bool isHost)
+        {
+            this.PlayerID = playerID;
+            this.IsHost = isHost;
+            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,
+                isHost: false
+            );
+        }
+
+        /// <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>
+        /// <param name="isHost">Whether this connection is for the host player.</param>
+        public static MultiplayerPeer ForConnectionToHost(long playerID, RemoteContextModel model, SLidgrenClient client, bool isHost)
+        {
+            return new MultiplayerPeer(
+                playerID: playerID,
+                model: model,
+                server: null,
+                serverConnection: null,
+                client: client,
+                isHost: isHost
+            );
+        }
+
+        /// <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.IsHost)
+                this.Client.sendMessage(message);
+            else
+                this.Server.SendMessage(this.ServerConnection, message);
+        }
+    }
+}