using Lidgren.Network;
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Barotrauma.Networking
{
    abstract class NetEntityEventManager
    {
        public const int MaxEventBufferLength = 1024;
        public const int MaxEventsPerWrite = 64;

        //public UInt32 LastReceivedEntityEventID
        //{
        //    get { return lastReceivedEntityEventID; }
        //}

        /// <summary>
        /// Write the events to the outgoing message. The recipient parameter is only needed for ServerEntityEventManager
        /// </summary>
        protected void Write(NetOutgoingMessage msg, List<NetEntityEvent> eventsToSync, Client recipient = null)
        {
            msg.Write(eventsToSync[0].ID);
            msg.Write((byte)eventsToSync.Count);

            foreach (NetEntityEvent e in eventsToSync)
            {
                //write into a temporary buffer so we can write the length before the actual data
                NetBuffer tempBuffer = new NetBuffer();
                WriteEvent(tempBuffer, e, recipient);

                Debug.Assert(
                    tempBuffer.LengthBytes < 256, 
                    "Maximum EntityEvent size exceeded when serializing \""+e.Entity+"\"!");

                msg.Write((UInt16)e.Entity.ID);
                msg.Write((byte)tempBuffer.LengthBytes);
                msg.Write(tempBuffer);
                msg.WritePadBits();
            }
        }

        /// <summary>
        /// Read the events from the message, ignoring ones we've already received
        /// </summary>
        protected void Read(NetIncomingMessage msg, float sendingTime, ref UInt32 lastReceivedID, Client sender = null)
        {
            UInt32 firstEventID = msg.ReadUInt32();
            int eventCount      = msg.ReadByte();

            for (int i = 0; i < eventCount; i++)
            {
                UInt32 thisEventID  = firstEventID + (UInt32)i;
                UInt16 entityID     = msg.ReadUInt16();
                byte msgLength      = msg.ReadByte();

                INetSerializable entity = Entity.FindEntityByID(entityID) as INetSerializable;

                //skip the event if we've already received it or if the entity isn't found
                if (thisEventID != lastReceivedID + 1 || entity == null)
                {
                    if (thisEventID != lastReceivedID + 1)
                    {
                        DebugConsole.NewMessage("received msg "+thisEventID, Microsoft.Xna.Framework.Color.Red);
                    }
                    else if (entity == null)
                    {
                        DebugConsole.NewMessage("received msg " + thisEventID+", entity "+entityID+" not found", Microsoft.Xna.Framework.Color.Red);
                    }
                    msg.Position += msgLength * 8; 
                }
                else
                {
                    long msgPosition = msg.Position;

                    DebugConsole.NewMessage("received msg "+thisEventID+ " ("+entity.ToString()+")", Microsoft.Xna.Framework.Color.Green);
                    lastReceivedID++;
                    try
                    {
                        ReadEvent(msg, entity, sendingTime, sender);
                    }

                    catch (Exception e)
                    {
#if DEBUG
                        DebugConsole.ThrowError("Failed to read event for entity \""+entity.ToString()+"\"!", e);
#endif
                        msg.Position = msgPosition + msgLength * 8;
                    }
                }
                msg.ReadPadBits();
            }            
        }
        
        protected virtual void WriteEvent(NetBuffer buffer, NetEntityEvent entityEvent, Client recipient = null)
        {
            throw new NotImplementedException();
        }

        protected virtual void ReadEvent(NetIncomingMessage buffer, INetSerializable entity, float sendingTime, Client sender = null)
        {
            throw new NotImplementedException();
        }
    }    
}