using System;
using System.Diagnostics.CodeAnalysis;
using System.IO;
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
    {
        /*********
        ** Fields
        *********/
        /// <summary>SMAPI's implementation of the game's core multiplayer logic.</summary>
        private readonly SMultiplayer Multiplayer;

        /// <summary>A callback to raise when receiving a message. This receives the incoming message, a method to send a message, and a callback to run the default logic.</summary>
        private readonly Action<IncomingMessage, Action<OutgoingMessage>, Action> OnProcessingMessage;


        /*********
        ** Public methods
        *********/
        /// <summary>Construct an instance.</summary>
        /// <param name="multiplayer">SMAPI's implementation of the game's core multiplayer logic.</param>
        /// <param name="gameServer">The underlying game server.</param>
        /// <param name="onProcessingMessage">A callback to raise when receiving a message. This receives the incoming message, a method to send a message, and a callback to run the default logic.</param>
        public SLidgrenServer(IGameServer gameServer, SMultiplayer multiplayer, Action<IncomingMessage, Action<OutgoingMessage>, Action> onProcessingMessage)
            : base(gameServer)
        {
            this.Multiplayer = multiplayer;
            this.OnProcessingMessage = onProcessingMessage;
        }

        /// <summary>Parse a data message from a client.</summary>
        /// <param name="rawMessage">The raw network message to parse.</param>
        [SuppressMessage("ReSharper", "AccessToDisposedClosure", Justification = "The callback is invoked synchronously.")]
        protected override void parseDataMessageFromClient(NetIncomingMessage rawMessage)
        {
            // add hook to call multiplayer core
            NetConnection peer = rawMessage.SenderConnection;
            using (IncomingMessage message = new IncomingMessage())
            using (Stream readStream = new NetBufferReadStream(rawMessage))
            using (BinaryReader reader = new BinaryReader(readStream))
            {
                while (rawMessage.LengthBits - rawMessage.Position >= 8)
                {
                    message.Read(reader);
                    NetConnection connection = rawMessage.SenderConnection; // don't pass rawMessage into context because it gets reused
                    this.OnProcessingMessage(message, outgoing => this.sendMessage(connection, outgoing), () =>
                    {
                        if (this.peers.ContainsLeft(message.FarmerID) && this.peers[message.FarmerID] == peer)
                            this.gameServer.processIncomingMessage(message);
                        else if (message.MessageType == StardewValley.Multiplayer.playerIntroduction)
                        {
                            NetFarmerRoot farmer = this.Multiplayer.readFarmer(message.Reader);
                            this.gameServer.checkFarmhandRequest("", farmer, msg => this.sendMessage(peer, msg), () => this.peers[farmer.Value.UniqueMultiplayerID] = peer);
                        }
                    });
                }
            }
        }
    }
}