using System;
using System.Diagnostics.CodeAnalysis;
using System.IO;
using Galaxy.Api;
using StardewValley.Network;
using StardewValley.SDKs;

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 SGalaxyNetServer : GalaxyNetServer
    {
        /*********
        ** Fields
        *********/
        /// <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;

        /// <summary>SMAPI's implementation of the game's core multiplayer logic.</summary>
        private readonly SMultiplayer Multiplayer;


        /*********
        ** Public methods
        *********/
        /// <summary>Construct an instance.</summary>
        /// <param name="gameServer">The underlying game server.</param>
        /// <param name="multiplayer">SMAPI's implementation of the game's core multiplayer logic.</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 SGalaxyNetServer(IGameServer gameServer, SMultiplayer multiplayer, Action<IncomingMessage, Action<OutgoingMessage>, Action> onProcessingMessage)
            : base(gameServer)
        {
            this.Multiplayer = multiplayer;
            this.OnProcessingMessage = onProcessingMessage;
        }


        /*********
        ** Protected methods
        *********/
        /// <summary>Read and process a message from the client.</summary>
        /// <param name="peer">The Galaxy peer ID.</param>
        /// <param name="messageStream">The data to process.</param>
        /// <remarks>This reimplements <see cref="GalaxyNetServer.onReceiveMessage"/>, but adds a callback to <see cref="OnProcessingMessage"/>.</remarks>
        [SuppressMessage("ReSharper", "AccessToDisposedClosure", Justification = "The callback is invoked synchronously.")]
        protected override void onReceiveMessage(GalaxyID peer, Stream messageStream)
        {
            using (IncomingMessage message = new IncomingMessage())
            using (BinaryReader reader = new BinaryReader(messageStream))
            {
                message.Read(reader);
                ulong peerID = peer.ToUint64(); // note: GalaxyID instances get reused, so need to store the underlying ID instead
                this.OnProcessingMessage(message, outgoing => this.SendMessageToPeerID(peerID, outgoing), () =>
                {
                    if (this.peers.ContainsLeft(message.FarmerID) && (long)this.peers[message.FarmerID] == (long)peerID)
                        this.gameServer.processIncomingMessage(message);
                    else if (message.MessageType == StardewValley.Multiplayer.playerIntroduction)
                    {
                        NetFarmerRoot farmer = this.Multiplayer.readFarmer(message.Reader);
                        GalaxyID capturedPeer = new GalaxyID(peerID);
                        this.gameServer.checkFarmhandRequest(Convert.ToString(peerID), farmer, msg => this.sendMessage(capturedPeer, msg), () => this.peers[farmer.Value.UniqueMultiplayerID] = capturedPeer.ToUint64());
                    }
                });
            }
        }

        /// <summary>Send a message to a remote peer.</summary>
        /// <param name="peerID">The unique Galaxy ID, derived from <see cref="GalaxyID.ToUint64"/>.</param>
        /// <param name="message">The message to send.</param>
        private void SendMessageToPeerID(ulong peerID, OutgoingMessage message)
        {
            this.sendMessage(new GalaxyID(peerID), message);
        }
    }
}